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The raw costs of mitomycin C (MMC) and oxaliplatin for hyperthermic intraperitoneal chemotherapy (HIPEC) differ substantially. We sought to compare the morbidity and toxicity profiles associated with the use of oxaliplatin and MMC in patients undergoing cytoreductive surgery (CRS) and HIPEC for peritoneal carcinomatosis (PC) of colorectal or appendiceal origin, to evaluate whether the costeffectiveness of these 2 agents should dictate drug choice.We conducted a retrospective multi-institutional study of all patients with PC of colorectal or appendiceal origin treated with CRS-HIPEC using MMC or oxaliplatin from 2010 to 2015. Demographic, perioperative, morbidity, toxicity and cost data were compared between the 2 treatment groups and between cancer-origin subgroups.Forty-two patients treated with MMC and 76 treated with oxaliplatin were included in the study. Baseline demographic and tumour characteristics were comparable in the 2 groups, except that the patients treated with MMC had higher Charlson Comorbidity Index scores. The MMC group had a higher rate of cancer of colorectal origin (76.2% v. 57.9%, p = 0.047) and longer operative times (553 v. 320 min, p0.001). In the subgroup of patients whose cancer was of colorectal origin, patients treated with MMC had a higher transfusion rate (50.0% v. 28.6%, p = 0.023) and lower postoperative baseline hemoglobin level (100 v. 119 g/L, p = 0.002) than those treated with oxaliplatin. There was no difference in hematologic toxicity scores after controlling for postoperative anemia. There was no difference in the rates of major complications and 90-day mortality. However, MMC was less costly than oxaliplatin ($724 v. $8928).MMC and oxaliplatin are both suitable agents for HIPEC and are associated with comparable morbidity and toxicity profiles, regardless of cancer origin. Thus, we propose that cost-effectiveness should ultimately dictate drug selection.Les coûts bruts de la mitomycine C (MMC) et de l’oxaliplatine pour la chimiothérapie hyperthermique intrapéritonéale (CHIP) sont très différents. Nous avons voulu comparer la morbidité et la toxicité associées à l’oxaliplatine et à la MMC chez les patients subissant une chirurgie de réduction tumorale (CRT) et une CHIP pour une carcinomatose péritonéale (CP) d’origine colorectale ou appendiculaire afin d’évaluer si le choix des professionnels de la santé devrait reposer sur le rapport coût–efficacité de ces médicaments.Nous avons mené une étude multicentrique rétrospective sur tous les patients qui, entre 2010 et 2015, présentaient une CP d’origine colorectale ou appendiculaire et ont subi une CRT ainsi qu’une CHIP à la MMC ou à l’oxaliplatine. Les données relatives aux caractéristiques démographiques, aux résultats périopératoires, à la morbidité, à la toxicité et aux coûts ont été comparées entre les 2 groupes de traitement et entre les sous-groupes formés en fonction de l’origine du cancer.Au total, 42 patients traités à la MMC et 76 patients traités à l’oxaliplatine ont été inclus dans l’étude. Les caractéristiques démographiques et tumorales des 2 groupes avant le traitement étaient semblables, à l’exception de l’indice de comorbidité de Charlson, qui était plus élevé dans le groupe MMC. Le groupe MMC présentait un taux plus important de cancer d’origine colorectale (76,2 % c. 57,9 %; p = 0,047), de même qu’un temps opératoire plus long (553 min c. 320 min; p0,001). En ce qui concerne le sous-groupe de patients atteints d’un cancer d’origine colorectale, les personnes traitées à la MMC affichaient un taux de transfusion plus élevé (50,0 % c. 28,6 %; p = 0,023) et un taux d’hémoglobine postopératoire de référence plus bas (100 g/L c. 119 g/L; p = 0,002) que celles traitées à l’oxaliplatine. Une fois l’anémie postopératoire prise en compte, aucune différence n’a été observée quant à la toxicité hématologique. Les taux de complications majeures et de mortalité à 90 jours étaient aussi comparables. La MMC coûtait toutefois moins cher que l’oxaliplatine (724 $ c. 8928 $).La MMC et l’oxaliplatine conviennent à la CHIP, et la morbidité et la toxicité qui y sont associées sont comparables, quelle que soit l’origine du cancer. Nous proposons donc que le choix du médicament à utiliser repose sur le rapport coût–efficacité.

Background: Locoregional lymph node involvement has historically been used as the most important deciding factor for the administration of chemotherapy in the adjuvant setting of breast cancer patients. The 21-gene Breast Recurrence Score® assay (the assay) is emerging as an important tool to assist with chemotherapy decisions amongst hormone receptor (HR)-positive, node-positive breast cancer (BC) patients. Previous studies have suggested that node-positive patients with low Recurrence Score (RS) results do not benefit from chemotherapy. We wanted to better understand the impact of the assay upon physician treatment decisions and treatment cost in this patient cohort. Methods: We conducted a multicenter prospective observational trial for ER/PR-positive HER2-negative BC patients that have undergone surgical treatment for T1-T3 disease and 1-3 positive lymph nodes. Physicians were required to complete a questionnaire indicating treatment choice prior to and post availability of Recurrence Score results. Patients were enrolled in the study from the time of consent to 6 months after the start of adjuvant therapy. The primary endpoint was change in the physician’s recommendation for chemotherapy prior to and post assay results. Secondary endpoints include the change in recommendation for additional growth factor (GF) supportive therapy, change in physician’s expressed level of confidence, and changes in estimated cost of recommended treatments prior to and post assay results. Results: 70 patients were enrolled between March 2018 and September 2019 at five hospital centers, as part of the McPeak Sirois Group of Quebec. The median age of the cohort was 61 years (range, 38 to 82 years). 18.5% (n=13) of the cohort consisted of patients < 50 years, and 81.4% (n=57) were > or = to 50 years. 64.3% (n=45) of the patients had one positive lymph node and 35.7% (n=25) of the patients had 2 or 3 positive lymph nodes. 25.7% (n=18) of the patients had a RS < 11 and 68.6% (n=48) had a RS result between 11-25. For the entire cohort, we found that the proportion of patients for whom chemo-hormonal therapy was recommended was reduced by an absolute 67.1% by knowledge of the RS result (OR (odds of having chemo-hormonal therapy post-RS recommendation versus pre-RS recommendation) = 0.03 [95% CI: 0.01-0.08]; P or = to 50 years. Changes in treatment recommendation were identified for patients with one positive node, 73.3% (OR=0.02 [95% CI: 0.01-0.07]; P Conclusions: Overall, we found that the 21-gene Breast Recurrence Score® assay changed physician treatment decisions in about two-thirds of all patients with hormone receptor-positive, node-positive BC, regardless of the number of positive nodes (up to 3). The assay increased physician confidence and was associated with an important decrease in treatment cost. Taken together, the assay is a cost-effective approach that can decrease the use of chemotherapy amongst HR-positive, node-positive BC patients in Quebec. Citation Format: Saima Hassan, Rami Younan, Erica Patocskai, Louise Provencher, Brigitte Poirier, Lucas Sideris, Pierre Dubé, Jean-Francois Boileau, Catalin Mihalcioiu, André Robidoux. A prospective multicenter study evaluating the impact of the 21-Gene Breast Recurrence Score® upon physician treatment decision and cost in lymph node-positive breast cancer patients in Quebec [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-27.

Background Endometrial cancer presenting with peritoneal metastases carries a poor prognosis. The addition of hyperthermic intraperitoneal chemotherapy (HIPEC) to the surgical management of these patients has been studied in recent years, but only with cisplatin. Cases This is a series of 3 patients presenting with endometrial cancer and synchronous peritoneal metastases who underwent cytoreductive surgery and carboplatin HIPEC as primary treatment. Complete cytoreductive surgery was achieved for each patient. No grade 3–5 complications were observed. Two patients died at 12 and 18 months, respectively, and 1 patient was alive with disease at 29 months. Conclusion This case series suggests that the addition of carboplatin HIPEC to the surgical management of peritoneal metastases from endometrial cancer is safe as primary treatment. However, long-term survival remains poor.

BackgroundComplete cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is the only curative treatment for pseudomyxoma peritonei (PMP) arising from the appendix. High peritoneal carcinomatosis index (PCI) is associated with an increased risk of surgical complications. The objective of this study was to present the results of a planned two-step surgical strategy to decrease postoperative morbidity and improve resectability of patients with very high PCI.MethodsAll consecutive patients who underwent a planned two-step surgical approach for PMP between January 2012 and March 2020 were retrospectively included. This approach was offered for patients with low-grade PMP with PCI > 28 for which feasibility of a complete CRS in one operation was uncertain. The first surgery included a complete CRS of the inframesocolic compartment and omentectomy. HIPEC was delivered at the second surgery, after complete CRS of the supramesocolic compartment. Postoperative morbidity was assessed using the Clavien-Dindo classification and survival results were also collected.ResultsEight patients underwent the two-step approach. The median PCI was 33 (29–39) and the median time between the two procedures was 111 days (90–212 days). One patient was deemed unresectable at the second surgery. The rate of major morbidity was 0% for the first step and 25% for the second step, with no mortality. Median follow-up was 53.8 months (3–73 months).ConclusionA two-step surgical management for low-grade PMP patients with very high PCI is safe and feasible, with acceptable postoperative morbidity and no compromise on oncological outcomes.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with poor prognosis, particularly for patients with metastatic disease. Treatment for oligometastatic presentation has been reported in recent literature, but the role of intraperitoneal chemotherapy for patients with peritoneal metastases (PM) remains unclear. We performed a systematic literature search of the PubMed, Cochrane and Embase databases in order to identify clinical trials and case-series reporting on the safety and efficacy of intraperitoneal chemotherapy in patients with PDAC-derived PM. Eight publications reporting on 85 patients were identified, using three different therapeutic strategies. First, 37 patients received cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) for PDAC with PM. Grade 3 and 4 complications occurred in 37.8% of patients, without perioperative mortality. Median disease-free survival and overall survival (OS) rates varied from 4 to 36 months and 4 to 62 months, respectively. Secondly, 40 patients with resectable PDAC without PM received prophylactic HIPEC following pancreatic resection, with postoperative morbidity and mortality rates of 30% and 5%, and 5-year OS rates of 23-24%. Finally, eight patients with PDAC-derived peritoneal disease were converted to resectable disease after receiving neoadjuvant intraperitoneal chemotherapy and operated on with curative intent, achieving a median OS of 27.8 months. In conclusion, CRS with HIPEC for PDAC-derived PM appears to be safe, conferring the same postoperative morbidity and mortality as reported on non-pancreatic malignancies. In highly selected patients, it could be considered for short-term disease control. However, long-term survival remains poor. The addition of prophylactic HIPEC for resectable PDAC cannot be recommended.

Peritoneal mesothelioma (PM) is a rare and aggressive primary peritoneal malignancy characterized by widespread multiple metastatic tumour nodules originating from the peritoneum. The conventional classification distinguishes diffuse malignant peritoneal mesothelioma (DMPM) and border-line forms: multicystic peritoneal mesothelioma (MCPM) and well-differentiated papillary peritoneal mesothelioma (WDPPM). Despite the novel achievements in the management of PM, there is difficulty in conducting randomized trials due to its rarity and aggressive biology in many cases. As there is, a necessity to standardize diagnosis and management of PM, the Peritoneal Surface Oncology Group International (PSOGI) commissioned a steering committee to elaborate clinical guidelines.

Background Peritoneal dissemination of ovarian immature teratoma in children is a rare entity and is associated with a poor prognosis. There are no guidelines on the optimal management of these patients with regard to surgery and systemic treatments. Case This is the case of a 16-year-old patient who experienced an early recurrence of immature teratoma with peritoneal dissemination after surgery and systemic chemotherapy failure, and was treated with an aggressive salvage cytoreductive surgery. She was still disease-free 6 months after her second surgery. Summary and Conclusion Upfront aggressive surgical management with complete cytoreductive surgery is recommended when patients present with disease recurrence and peritoneal dissemination of ovarian immature teratoma. Such cases should be managed in centers with local expertise in the treatment of peritoneal surface malignancies.

Standard treatment for early-stage invasive breast cancer (bca) consists of breast-conserving surgery and several weeks of adjuvant radiotherapy (rt). Neoadjuvant single-fraction rt is a novel approach for early-stage bca. We sought to investigate the effect of delaying surgery after neoadjuvant rt with respect to the rate of pathologic response (pr). Women 65 years of age or older with a new diagnosis of stage i luminal A bca were eligible for inclusion. A single 20 Gy dose to the primary breast tumour was given, followed by breast-conserving surgery 3 months later. The primary endpoint was the pr rate assessed by microscopic evaluation using the Miller&ndash, Payne system. To date, 10 patients have been successfully treated. Median age of the patients was 72 years (range: 65&ndash, 84 years). In 8 patients, neoadjuvant rt resulted in a tumour pr with median residual cellularity of 3%. No immediate rt complications other than mild dermatitis were noted. This study demonstrates a method for delivering single-fraction rt that can lead to a high level of pr in most patients. Continued accrual to this study and subsequent trials are needed to determine the feasibility, safety, and role of this novel technique in the management of early-stage bca.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of desmoplastic small round cell tumor, breast, and gastrointestinal stromal tumor specifically related to peritoneal surface malignancy. These guidelines are developed with input from leading experts including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for palliative care specifically related to peritoneal surface malignancies. These guidelines are developed with input from leading experts including surgical oncologists, medical oncologists, gynecologic oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of neuroendocrine tumors specifically related to the management of peritoneal surface malignancy. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

Background: Although the role of the 21-gene Breast Recurrence Score® assay is well established to predict response to adjuvant chemotherapy in the setting of node-negative hormone receptor (HR)-positive, HER2-negative breast cancers (BC), fewer studies have evaluated the assay in the neoadjuvant setting. Due to the correlation between a high Recurrence Score® (RS) result and pathological complete response (pCR), the Breast Recurrence Score assay has been used to aid in selecting between chemotherapy (CT) or endocrine therapy. We wanted to further understand the impact of the assay upon physician treatment recommendations and the use of chemotherapy in this patient cohort. Methods: We conducted a multicenter, prospective, observational study in patients with clinically node-negative HR-positive, HER2-negative BC with T2-T3 disease being considered for neoadjuvant therapy. Physicians were required to complete two questionnaires indicating treatment choice, including CT, endocrine therapy, or surgery, prior to and post availability of RS result. Patients were followed up for 6 months after commencement of neoadjuvant therapy. The primary objective was to evaluate the change in the physician’s recommendation for neoadjuvant CT prior to and post assay results. As a secondary objective, we also evaluated the impact of the RS result on physician’s expressed level of confidence. Results: A total of 70 patients were enrolled between April 2018 and November 2021 at five hospital centers, as part of the McPeak Sirois Group of Quebec. The median age of the cohort was 60 years (range, 30 to 79 years). 24.3 % (n=17) of the cohort consisted of patients aged < 50 years, and 75.7% (n=53) were ≥ to 50 years. 29.0% (n=20) of the patients had a RS < 16, 39.1% (n=27) had a RS between 16-25, and 31.9% (n=22) had a RS > 25. For the entire cohort, the RS result led to a net reduction in chemotherapy recommendation by 33.3% (OR (odds of having CT post-RS recommendation versus pre-RS recommendation) = 0.23 [95% CI: 0.12-0.44]; P< 0.0001), and 39.2% net reduction in the use of chemotherapy at 6-month follow-up (OR = 0.18 [95% CI: 0.09-0.35]; P< 0.0001). Furthermore, the RS result led to a 35.3% net reduction in physician recommendation of CT for patients < 50 years (OR = 0.19 [95% CI: 0.04-0.83]; P=0.027) and a 32.7% net reduction for patients ≥ 50 years (OR = 0.24 [95% CI: 0.11-0.50]; P=0.0001). For patients with a RS < 16, there was a reduction in CT recommendation by 75.0%, and by 44.4% for patients with a RS between 16 - 25 (OR = 0.15 [95% CI: 0.06-0.38]; P< 0.0001). Moreover, RS results led to an increase in confidence in physician treatment decisions for 59.4% of patients (OR = 12.53 [95% CI: 5.46-28.78]; P< 0.0001). Conclusion: We determined that the 21-gene Breast Recurrence Score assay altered neoadjuvant treatment decisions, leading to a reduction in the use of chemotherapy by about one-third, regardless of age. Additionally, the assay increased physician confidence in their treatment recommendation for about 60% of patients. This demonstrates the potential clinical utility of the assay to decrease the use of CT in the neoadjuvant setting amongst HR-positive, node-negative BC patients in Quebec. Citation Format: Mariya Yordanova, Lucas Sideris, Pierre Dubé, Jean-Francois Boileau, Julie Lemieux, Catalin Mihalcioiu, Sylvie Levesque, Marie-Claude Guertin, Erica Patocskai, Rami Younan, André Robidoux, Saima Hassan. The impact of the 21-gene Recurrence Score® assay upon physician treatment recommendations in the neoadjuvant setting in lymph node-negative breast cancer patients in a multicenter prospective study in Quebec [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-39.

Introduction: Estrogen receptor (ER)-positive/HER2-negative breast cancers are known to be less immunogenic than triple negative and HER2-positive breast cancers. As increasing levels of tumor-infiltrating lymphocytes (TILs) have been associated with increased rates of pathological complete response (pCR) and improved prognosis, there is interest in exploring ways to render ER-positive/HER2-negative breast cancers more immunogenic. Few studies have analysed the histological response to neoadjuvant radiation therapy (RT) as the only pre-operative treatment modality; in most case series, chemotherapy was concomitantly given, as these studies focused on the treatment of advanced breast cancer. Aims: The objectives of this study are to assess pathological and immunological responses induced by a single dose of pre-operative RT in early breast cancer. Material and methods: women aged 60 years or older diagnosed with invasive breast carcinoma were prospectively identified. Only cT1N0 unifocal tumors that were low to intermediate grade and ER-positive/HER2 negative were eligible. Patients received a single pre-operative radiation dose of 20Gy in a single fraction. Surgery was performed either 24-72 hours after RT (SPORT group) or 11-13 weeks after RT (SPORT -DS [delayed surgery] group). Assessment of pathological response was performed using the Miller-Payne system and Residual Cancer Burden was calculated. Immunohistochemistry for Ki67 was performed on the biopsy and excision specimens. CD8 immunostain was used to evaluate the immune infiltrate. Both groups (SPORT and SPORT-DS) were compared using the independent t-test and Fisher exact test. Results: a total of thirteen patients were included, with an average age of 73 years (range 60-84). All patients received a single 20Gy radiation dose, and surgery was performed either 24-72 hours after RT (SPORT group, n=5) or on average 95 days after RT in the SPORT-DS group (range 75-133 days; n=8). All patients underwent partial mastectomy with sentinel lymph node biopsy. Histologically, all tumors were invasive ductal carcinomas, except for one invasive micropapillary carcinoma and one invasive tubular carcinoma (both in the SPORT group). Tumor bed changes, similar to what is observed in the post-neoadjuvant chemotherapy setting, were identified in all but one patients in the SPORT-DS group (7/8 patients) but was not seen in the SPORT group (0/5 patients, p=0.005). Using the Miller-Payne system, there was no evidence of response in the SPORT cohort (grade 1/5 in all patients), while 6/8 patients in the SPORT-DS cohort had a partial pathological response (grade 3/5 in 2 patients and grade 4/5 in 4 patients, p = 0.02). No pCR were observed. Comparing Ki67 on the biopsy and surgical specimens, an average decrease of 7.5% in the SPORT group and 6.3% in the SPORT-DS group was observed (p=0.8). A significant lymphocytic infiltrate was not present in any case (stromal TILs Citation Format: Marie-Hélène Ngo, David Tiberi, Peter Vavassis, David Nguyen, Bernard Fortin, Mai-Kim Gervais, Lucas Sideris, Pierre Dubé, Guy Leblanc, Michel-Pierre Dufresne, Marie-Christine Guilbert, Michael Yassa. Single pre-operative radiation therapy (SPORT) trial for low risk breast cancer: A phase 1 study comparing pathological findings in immediate versus delayed surgery [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-12-07.

Background Therapeutic resistance is the main cause of death in metastatic colorectal cancer. To investigate genomic plasticity, most specifically of metastatic lesions, associated with response to first‐line systemic therapy, we collected longitudinal liver metastatic samples and characterized the copy number aberration (CNA) landscape and its effect on the transcriptome. Methods Liver metastatic biopsies were collected prior to treatment (pre, n = 97) and when clinical imaging demonstrated therapeutic resistance (post, n = 43). CNAs were inferred from whole exome sequencing and were correlated with both the status of the lesion and overall patient progression‐free survival (PFS). We used RNA sequencing data from the same sample set to validate aberrations as well as independent datasets to prioritize candidate genes. Results We identified a significantly increased frequency gain of a unique CN, in liver metastatic lesions after first‐line treatment, on chr18p11.32 harboring 10 genes, including TYMS, which has not been reported in primary tumors (GISTIC method and test of equal proportions, FDR‐adjusted p = 0.0023). CNA lesion profiles exhibiting different treatment responses were compared and we detected focal genomic divergences in post‐treatment resistant lesions but not in responder lesions (two‐tailed Fisher's Exact test, unadjusted p ≤ 0.005). The importance of examining metastatic lesions is highlighted by the fact that 15 out of 18 independently validated CNA regions found to be associated with PFS in this study were only identified in the metastatic lesions and not in the primary tumors. Conclusion This investigation of genomic‐phenotype associations in a large colorectal cancer liver metastases cohort identified novel molecular features associated with treatment response, supporting the clinical importance of collecting metastatic samples in a defined clinical setting., Graphical Abstract and Graphical Headlights Liver metastatic lesions from colorectal cancer patients were collected before and after first‐line standard chemotherapy and comprehensively profiled with the objective to assess the genomic impact of systemic therapy and investigate association with response and survival. This study allowed identification of novel CNAs having an impact on the transcriptome with a potential prognostic value in patients with colorectal cancer.

SCOPUS: ar.j, info:eu-repo/semantics/published

Pseudomyxoma Peritonei (PMP) and Peritoneal Mesothelioma (PM) are both rare peritoneal malignancies. Currently, affected patients may be treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy offering long-term survival or even cure in selected patients. However, many issues regarding the optimal treatment strategy are currently under debate. To aid physicians involved in the treatment of these patients in clinical decision making, the PSOGI executive committee proposed to create a consensus statement on PMP and PM. This manuscript describes the methodology of the consensus process. The Delphi technique is a reliable method for attaining consensus on a topic that lacks scientific evidence through multiple voting rounds which feeds back responses to the participants in between rounds. The GRADE system provides a structured framework for presenting and grading the available evidence. Separate questionnaires were created for PMP and PM and sent during two voting rounds to 80 and 38 experts, respectively. A consensus threshold of 51.0% was chosen. After the second round, consensus was reached on 92.9%-100.0% of the questions. The results were presented and discussed in the plenary session at the PSOGI 2018 international meeting in Paris. A third round for the remaining issues is currently in progress. In conclusion, using the Delphi technique and GRADE methodology, consensus was reached in many issues regarding the treatment of PM and PMP amongst an international panel of experts. The main results will be published in the near future.

Modern management of colorectal cancer (CRC) with peritoneal metastasis (PM) is based on a combination of cytoreductive surgery (CRS), systemic chemotherapy, and hyperthermic intraperitoneal chemotherapy (HIPEC). Although the role of hipec has recently been questioned with respect to results from the PRODIGE 7 trial, the role and benefit of a complete CRS were confirmed, as observed with a 41-month gain in median survival in that study, and 15% of patients remaining disease-free at 5 years. Still, CRC with PM is associated with a poor prognosis, and good patient selection is essential. Many questions about the optimal management approach for such patients remain, but all patients with PM from CRC should be referred to, or discussed with, a PM surgical oncologist, because cure is possible. The objective of the present guideline is to offer a practical approach to the management of PM from CRC and to reflect on the new practice standards set by recent publications on the topic.

Literature on rectal anastomosis and diverting ileostomy in patients treated with hyperthermic intraperitoneal chemotherapy (HIPEC) is limited. This study assesses the safety of rectal anastomoses during cytoreductive surgery (CRS) and HIPEC, with and without fecal diversion, and its morbidity when performed.From January 2012 to January 2020, patients with peritoneal metastases who underwent CRS and HIPEC that required a rectal anastomosis were included in this single-hospital retrospective chart review.84 patients were included, of which 29 had a diverting loop ileostomy. The rectal anastomotic leak (AL) rate for the series was 8.3%. Factors associated with AL were male gender (p = 0.031) and increased BMI (p 0.0005). Diverting loop ileostomy was associated with a significant decrease of clinically significant rectal AL (0% vs 12.7%, p = 0.045). However, the 90-day readmission rate was higher in this group (37.9% vs 10.9%, p = 0.003). Stoma reversal surgery was performed for all patients, but 3 patients experienced AL (10.7%).This study suggests that creation of a diverting loop ileostomy may be an effective strategy to prevent symptomatic rectal AL following CRS with HIPEC. However, it is also associated with an increased readmission rate and increased risk of AL following reversal surgery.

Highlights • Full-thickness diaphragmatic infiltration with pleural effusion in advanced epithelial ovarian cancer is challenging. • Short-term control of malignant pleural effusion with HITAC for advanced epithelial ovarian cancer seems feasible. • Carboplatin is safe when used as HIPEC or HITAC agent for advanced epithelial ovarian cancer.

Background: The COVID-19 pandemic has put enormous pressure on hospital resources, and has affected all aspects of patient care. As operative volumes decrease, cancer surgeries must be triaged and prioritized with careful thought and attention to ensure maximal benefit for the maximum number of patients. Peritoneal malignancies present a unique challenge, as surgical management can be resource intensive, but patients have limited non-surgical treatment options. This review summarizes current data on outcomes and resource utilization to help inform decision-making and case prioritization in times of constrained health care resources. Methods: A rapid literature review was performed, examining surgical and non-surgical outcomes data for peritoneal malignancies. Narrative data synthesis was cross-referenced with relevant societal guidelines. Peritoneal malignancy surgeons and medical oncologists reviewed recommendations to establish a national perspective on case triage and mitigating treatment strategies. Results and Conclusions: Triage of peritoneal malignancies during this time of restricted health care resource is nuanced and requires multidisciplinary discussion with consideration of individual patient factors. Prioritization should be given to patients where delay may compromise resectability of disease, and where alternative treatment options are lacking. Mitigating strategies such as systemic chemotherapy and/or surgical deferral may be utilized with close surveillance for disease stability or progression, which may affect surgical urgency. Unique hospital capacity, and ability to manage the complex post-operative course for these patients must also be considered to ensure patient and system needs are aligned.

Background Anal cancer is a rare cancer with chemoradiation being the mainstay of treatment for locoregional presentation. In North America, the most common subtype is anal squamous cell carcinoma (epidermoid). A surgical approach is considered for persistent or recurrent anal disease and systemic chemotherapy for metastatic disease. We are presenting a unique case of recurrent anal cancer with isolated peritoneal malignancy, an oligometastatic state which is rare in itself. It was treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. There are currently no clear guidelines for the aforementioned presentation. The discussion drew on the feasibility and safety of this approach. Case presentation A 68-year-old woman diagnosed with an epidermoid anal cancer (stage 3B) was initially treated with chemoradiation therapy (Standard Nigro Protocol) in 2014. At the 5-year mark post-treatment, she was diagnosed with a recurrent anal epidermoid cancer in the form of isolated peritoneal carcinomatosis proven by biopsy. After declining systemic chemotherapy, she underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy with Mitomycin-C©. Peritoneal carcinomatosis index was evaluated at 10, and intraoperative frozen sections were positive for carcinoma of epidermoid origin compatible with anal cancer. A completeness of cytoreduction score of 0 was achieved during the cytoreductive surgery, and her hospital course was unremarkable. She remains disease-free 12 months later. Conclusions To our knowledge, this is the first case reporting the disease presentation of anal cancer with oligometastatic dissemination to the peritoneum. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy were performed. Thus far, this approach seems to be a safe and feasible option for short-term control of the disease.

Background and objectives Complete cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) have been proven to lengthen survival in appendiceal peritoneal carcinomatosis (PC-A). The aim of this study was to analyze survival results of this therapy in our institution over the last 10 years. Methods Data was retrospectively reviewed and analyzed. Treatment consisted of CRS plus HIPEC with oxaliplatin. Ronnett's histologic classification was used (peritoneal mucinous carcinomatosis (PMCA), PMCA with intermediate features (PMCA-I) and disseminated peritoneal adenomucinosis (DPAM)). Overall survival (OS) and disease-free survival (DFS) estimates were calculated using Kaplan–Meier survival curves. Results 109 patients with PC-A underwent laparotomy with curative intent. Of those, 92 underwent CRS plus HIPEC. Median follow-up was 42 months. The 5 and 10-year OS rates for the HIPEC group were 82.2% and 76.5%. The 5 and 10-year OS estimates for DPAM and PMCA-I subgroups were 100% and 100%, 78.1% and 72.9%, respectively. For the PMCA subgroup, the 3 and 5-year OS were 61.4% and 40.1%, respectively. The 5 and 10-year DFS estimates were 71.9% and 42.7%. Conclusion CRS plus HIPEC with oxaliplatin represent an effective therapeutic approach for PC-A. Long term OS estimates for patients treated at our institution are encouraging.

International audience; BACKGROUND:The impact of the location of colorectal cancer on patient outcomes has been reported in several settings. The objective of this study was to assess the prognostic impact of the location of the primary colon cancer among patients with colorectal cancer peritoneal metastases undergoing complete cytoreductive surgery.METHODS:Using the prospectively maintained clinical and biological digestive peritoneal metastasis database of the BIG-RENAPE network, we identified 796 patients treated by a complete cytoreductive surgery between January 2004 and January 2017 for colorectal cancer peritoneal metastases in 16 different institutions. The 2 primary endpoints were overall survival and progression-free survival. To evaluate the impact on overall survival and progression-free survival of potential prognostic factors (including the location of the primary colorectal cancer), these factors were included in univariate and multivariate Cox proportional hazard models.RESULTS:Right-sided colorectal cancers were more often BRAF mutated and had microsatellite instability, whereas the frequency of RAS mutation was similar between right-sided and left-sided colorectal cancers. After a median follow-up time of 3.3 years, there was no significant difference in overall survival or progression-free survival according to tumor side. The lack of effect of tumor location on overall survival and progression-free survival was consistent across subgroups.CONCLUSION:Among patients undergoing complete cytoreductive surgery for peritoneal metastases, the site of the primary colorectal cancer was not associated with differences in progression-free survival or overall survival. Tumor side should not be used as a stratification factor in trials of colorectal cancer peritoneal metastases and should not be used in the selection process of patients for cytoreductive surgery.

Background Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin (OX) is the standard of care for selected patients with peritoneal carcinomatosis of colorectal origin. Because 5-FU is mandatory to improve efficacy of OX when used by systemic route, several teams now empirically combine intravenous (IV) 5-FU with HIPEC OX, but this practice has yet to be supported by preclinical data. Using a murine model, we studied the impact of IV 5-FU on peritoneal absorption of HIPEC OX. Methods Under general anesthesia, 24 Sprague-Dawley rats were submitted to 4 different doses of IV 5-FU (0, 100, 400 and 800 mg/m2) and a fixed dose of HIPEC OX (460 mg/m2) perfused at 40 °C during 25 min. At 25 min, samples in different compartments were harvested (peritoneum, portal vein and systemic blood) and the concentrations of 5-FU and OX were measured by high performance liquid chromatography. Results Peritoneal absorption of OX was significantly higher (17.0, 20.1, 34.9 and 38.1 nmol/g, p Conclusion IV 5-FU enhances peritoneal absorption of HIPEC OX. The most efficient dose of IV 5-FU to be used in combination with HIPEC OX seems to be 400 mg/m2.

BACKGROUND AND OBJECTIVES Pemetrexed is an appealing agent to use for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). However, the optimal method of pemetrexed delivery still remains undefined. Using a murine model, we compared the use of open and closed abdomen techniques on the absorption of intraperitoneal (IP) pemetrexed in different compartments. METHODS Eleven Sprague-Dawley rats were submitted to a fixed dose of IP pemetrexed (1000 mg/m2 ) at a perfusion temperature of 40°C during 25 min according to two techniques: open and closed. At the end of perfusion, samples in different compartments were harvested and the concentrations of pemetrexed were measured by high performance liquid chromatography. RESULTS Absorption of IP pemetrexed in portal and systemic blood was significantly higher using the open compared to the closed abdomen technique (93.17 vs 52.50 µg/mL, P

Peritoneal recurrences after cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) for appendiceal and colorectal cancers are frequent. This study aimed to evaluate the safety, technical feasibility and perioperative and long-term outcomes of repeat CRS/HIPEC in patients with recurrent peritoneal carcinomatosis of colorectal and appendiceal origin.Data were collected from patients treated from 2000 to 2016 for recurrent peritoneal carcinomatosis from appendiceal or colorectal cancer with CRS/HIPEC at 2 specialist centres. Data on demographics, procedure details, morbidity and survival were recorded. Analyses compared the iterations of CRS/HIPEC to assess the safety and effectiveness of repeat surgery.Of all patients who underwent CRS/HIPEC in the 2 centres, 37 patients underwent a repeat procedure. Operative time was similar for the first and second surgeries (412.1 v. 412.5 min, p = 0.74) but patients had a significantly lower peritoneal carcinoma index score with the second surgery (21.8 in the first iteration v. 9.53 in the second iteration, p0.001) and significantly less blood loss (1762 mL in the first iteration v. 790 mL in the second iteration, p = 0.001). There was a nonsignificant decrease in grade III–IV complications and there was no 30-day mortality associated with repeat procedures. For patients with colorectal cancer, median disease-free survival was 9.6 months and median overall survival was 40 months. For patients with appendiceal cancer, median disease-free survival was 15 months and overall survival was 64.4 months.Repeat CRS/HIPEC procedures for recurrent appendiceal and colorectal peritoneal carcinomatosis are safe in well-selected patients, without increased morbidity or mortality, and they are associated with significant long-term survival, particularly for patients with appendiceal cancers. These results support the use of repeat CRS/HIPEC in these patients.Les récurrences péritonéales après une chirurgie cytoréductrice (CCR) et une chimiothérapie hyperthermique intrapéritonéale (CHIP) pour les cancers de l’appendice et colorectaux sont fréquentes. Cette étude visait à évaluer l’innocuité, la faisabilité technique et les résultats périopératoires et à long terme d’une reprise de CCR/CHIP chez les patients qui présentent une récurrence de carcinomatose péritonéale ayant son origine au niveau colorectal ou de l’appendice.Des données ont été recueillies sur des patients traités entre 2000 et 2016 pour une récurrence de carcinomatose péritonéale ayant son origine au niveau colorectal ou de l’appendice par CCR/CHIP dans 2 centres spécialisés. On a tenu compte des données démographiques, des détails des interventions, ainsi que de la morbidité et de la survie. Des analyses ont permis de comparer les premières et deuxièmes CCR/CHIP pour évaluer l’innocuité et l’efficacité des chirurgies répétées.De tous les patients soumis à des CCR/CHIP dans les 2 centres, 37 ont subi l’intervention de nouveau. Le temps opératoire a été similaire pour les premières et les deuxièmes chirurgies (412,1 c. 412,5 min, p = 0,74), mais les patients présentaient un score de carcinomatose péritonéale beaucoup plus bas lors de la deuxième chirurgie (21,8 pour la première intervention c. 9,53 pour la seconde, p0,001) et des pertes sanguines significativement moindres (1762 mL pour la première intervention c. 790 mL pour la seconde, p = 0,001). On a noté une diminution non significative des complications de grades III–IV et on n’a déploré aucune mortalité à 30 jours en lien avec la reprise de l’intervention. Pour les patients atteints d’un cancer colorectal, la survie médiane sans maladie a été de 9,6 mois et la survie médiane globale a été de 40 mois. Pour les patients atteints d’un cancer de l’appendice, la survie médiane sans maladie a été de 15 mois et la survie médiane globale a été de 64,4 mois.La reprise des CCR/CHIP pour les récurrences de carcinomatose péritonéale ayant leur origine au niveau colorectal ou de l’appendice est sécuritaire chez les patients soigneusement sélectionnés, sans accroissement de la morbidité ou de la mortalité, et elles sont associées à une survie à long terme significative, particulièrement chez les patients ayant un cancer de l’appendice. Ces résultats appuient la reprise des CCR/CHIP chez ces patients.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of peritoneal mesothelioma. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness of the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides the following multidisciplinary recommendations for the care of patients with peritoneal surface malignancies. This article focuses on the standards of a peritoneal surface malignancy center, standards of billing and coding, standards of operative reports for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, standards of cytoreductive surgery training, and standards of intraoperative chemotherapy preparation. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of ovarian neoplasms specifically related to the management of peritoneal surface malignancy. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, gynecologic oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The sentinel node biopsy following neoadjuvant chemotherapy (SN FNAC) study has shown that in node-positive (N+) breast cancer, sentinel node biopsy (SNB) can be performed following neoadjuvant chemotherapy (NAC), with a low false negative rate (FNR = 8.4%). A secondary endpoint of the SN FNAC study was to determine whether axillary ultrasound (AxUS) could predict axillary pathological complete response (ypN0) and increase the accuracy of SNB. The SN FNAC trial is a study of patients with biopsy-proven N+ breast cancer who underwent SNB followed by completion node dissection. All patients had AxUS following NAC and the axillary nodes were classified as either positive (AxUS+) or negative (AxUS−). AxUS was compared with the final axillary pathology results. There was no statistical difference in the baseline characteristics of patients with AxUS+ versus those with AxUS−. Overall, 82.5% (47/57) of AxUS+ patients had residual positive lymph nodes (ypN+) at surgery and 53.8% (42/78) of AxUS− patients had ypN+. Post NAC AxUS sensitivity was 52.8%, specificity 78.3%, and negative predictive value 46.2%. AxUS FNR was 47.2%, versus 8.4% for SNB. If post-NAC AxUS− was used to select patients for SNB, FNR would decrease from 8.4 to 2.7%. However, using post-NAC AxUS in addition to SNB as an indication for ALND would have led to unnecessary ALND in 7.8% of all patients. AxUS is not appropriate as a standalone staging procedure, and SNB itself is sufficient to assess the axilla post NAC in patients who present with N+ breast cancer.

Electrocautery (EC) is used during cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Using a murine model, we studied the effect of HIPEC on small bowel EC lesions and surrounding normal tissues.Thirty-two rats were divided into five groups: a control group with EC lesions; EC plus intraperitoneal heated 5% dextrose (D5W); EC plus oxaliplatin (OXA, 460 mg/m(2)); EC plus mitomycin C 10 mg/m(2) (MMC10); EC plus MMC 35 mg/m(2) (MMC35). EC lesions and surrounding tissue microvasculature were analysed after intravenous injection of fluorescein.In the ileum OXA significantly reduced EC lesions microvasculature compared with the control group; MMC10 caused greater reduction than the control, D5W and MMC35 groups. Surrounding tissue microvasculature was significantly reduced by MMC35 exposure when compared to the control, OXA or MMC10 groups. In the jejunum EC injuries exposed to OXA or MMC10 had significantly reduced microvasculature compared to the control, heated D5W and MMC35 groups. Surrounding tissue microvasculature was significantly reduced by MMC35 exposure when compared to the OXA group. There was no significant microvasculature difference between the EC lesions made before or after HIPEC.HIPEC with OXA and MMC10 potentiates small bowel wall EC injuries. MMC35 reduces surrounding unharmed tissue microvasculature. There was no effect of hyperthermia alone on microvasculature.

Single-agent regorafenib is approved in Canada and in the US for patients with metastatic colorectal cancer (mCRC) who have failed previous lines of therapy1. Identification of prognostic biomarkers is crucial to ensure the best therapeutic strategies for mCRC patients. The goal of this clinical study (NCT01949194) was to explore putative molecular signatures of response and resistance to regorafenib in metastatic tumors and serial blood samples. We used a multi-omics approach to profile metastatic tumor tissues and serial blood samples from 47 mCRC patients who received single-agent regorafenib as second-line therapy after failing first-line therapy with an oxaliplatin or irinotecan-containing regimen with or without bevacizumab. Whole exome sequencing was performed to assess both the mutational and copy number (CN) landscapes of metastatic tissues from 29 patients and the transcriptome was interrogated using RNA sequencing. A 14-gene panel was used to profile serial plasma samples. Molecular aberrations were then correlated with lesion-specific treatment response using RECIST 1.1 and progression free survival (PFS) to investigate potential associations.The copy number aberration (CNA) landscape of metastatic tumors was assessed using Nexus Copy Number Software and 20 significant focal aberrations were identified using Genomic Identification of Significant Target in Cancer (GISTIC) test (q-bound Citation Format: Karen Gambaro, Maud Marques, Suzan McNamara, Mathilde Couetoux du Tertre, Cyrla Hoffert, Archana Srivastava, Sophie Mathieu, Anna schab, Thierry Alcindor, Adrian Langleben, Lucas Sideris, Mahmoud Adbelsalam, Mustapha Tehfe, Gerald Batist, Petr Kavan. A Phase II exploratory study to identify biomarkers prognostic of clinical response to regorafenib in patients with metastatic colorectal cancer who have failed first-line therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4325.

Background Peritoneal carcinomatosis (PC) from colorectal cancer is associated with poor prognosis. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has improved survival for patients with colorectal peritoneal carcinomatosis. However, standardization of HIPEC protocols, including which chemotherapeutic agent to use, is lacking in the literature. Therefore, we sought to report survival outcomes from colorectal cancer patients undergoing CRS/oxaliplatin-based HIPEC at our institution over the last 10 years. Methods Colorectal PC patients treated with CRS/oxaliplatin-based HIPEC 2004–2015 were included. Demographic, clinical, and oncologic data were abstracted from the medical record. Overall (OS) and disease-free survival (DFS) were calculated using Kaplan–Meier analysis. Univariate/multivariate Cox regression analysis was done. Results Laparotomy was performed in 113 patients for colorectal PC; 91 completed a curative intent CRS/HIPEC. At 3 and 5 years, OS for the CRS/HIPEC cohort was 75% and 55%, and DFS was 50% and 25%, respectively. On multivariate analysis, incremental increases in peritoneal carcinomatosis index (PCI) were associated with worse OS (p = 0.0001) and DFS (p = 0.0001). Grade III/IV complications were also associated with worse OS. Conclusions A standardized regimen of CRS and oxaliplatin-based HIPEC for colorectal PC is effective with favorable OS and DFS and acceptable complication rates.

Appendiceal neoplasms account for 1% of appendectomy specimens. Common subtypes include mucinous cystadenoma, adenocarcinoma, and neuroendocrine tumors (NETs). The simultaneous presence of appendicular mucinous and NETs is a rare event. Depending on the tumors' morphological distribution in the affected organ, they are qualified as either "collision" or "combined" tumours. We herein present the case of a 50-year-old male who presented with acute appendicitis and who was subsequently found to have pseudomyxoma peritonei (PMP) due to a perforated combined mucinous and neuroendocrine tumours. The patient was treated by right hemicolectomy and cytoreductive surgery (CRS) with oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC). He was cancer free 20 months later. Due to the limited clinical experience with this presentation, no formal recommendations exist as to its management other than those applicable to each cancer alone. The efficacity of treatment on the long-term prognosis on these combined tumors is yet to be elucidated.

The Pain Monitoring Device (PMD) monitor (Medasense Biometrics Ltd., Ramat Gan, Israel) uses the Nociception Level (NOL) index, a multiple parameter-derived index that has recently shown a good sensitivity and specificity to detect noxious stimuli. The aim of this study was to assess the latest version of the device (PMD200TM) on variations of the NOL response after standardized tetanic stimuli to study the correlation between remifentanil doses and NOL. Data from 26 patients undergoing midline laparotomy and receiving a desflurane-remifentanil-based anesthetic coupled with low thoracic epidural analgesia were analyzed. A standardized tetanic stimulus was applied to the forearm of the patients at different remifentanil infusion rates. The primary aim was to evaluate the correlation between post-tetanic stimulation NOL values from the PMD200 and remifentanil doses. The NOL index variations after experimental and clinical stimuli were also compared with heart rate (HR), mean arterial pressure (MAP), and Bispectral Index™ (BIS). A correlation between post-tetanic stimulation NOL values and remifentanil doses was found (r = −0.56; 95% confidence interval [CI], −0.70 to −0.44; P < 0.001). The NOL discriminated noxious from non-noxious states with the maximal Youden’s index value of the NOL receiver operating characteristic (ROC) curve showing a specificity of 88% (95% CI, 69.0 to 100) and sensitivity of 79.1% (95% CI, 56.2 to 95.5). The area under the NOL ROC curve (AUC, 0.9; 95% CI, 0.84 to 0.95) was significantly different from the other variables (P < 0.001 vs HR; P < 0.001 vs MAP; P < 0.001 vs BIS). The NOL value after noxious stimulus decreased with incremental remifentanil doses, showing a significant inverse correlation between the NOL index and opioid doses. The sensitivity and specificity of NOL to discriminate between noxious and non-noxious stimuli suggests its interesting potential as a monitor of nociception intensity during anesthesia. www.clinicaltrials.gov (NCT 02884778); 27 July, 2016.

Highlights • A tailgut cyst, also called retrorectal cystic hamartoma, is a rare congenital lesion that forms most commonly in the retrorectal space. • They are often misdiagnosed and can rarely transform into neuroendocrine tumours. • A complete surgical resection is required upon diagnosis, preferably by a posterior approach when feasible. • Final diagnosis is made with the histopathological examination of the resected mass and appropriate follow-up must be ensured., Introduction A tailgut cyst, also called retrorectal cystic hamartoma, is a rare congenital lesion that forms most commonly in the retrorectal space. It is presumed to arise from remnants of early embryogenesis. Presentation of Case The following report describes a unique case of a retrorectal cystic hamartoma in a 53 year-old French Canadian man with a history of low back pain. The tumour underwent malignant transformation into a well-differentiated neuroendocrine carcinoma three years after the beginning of symptoms. Discussion This condition can be found at any age, but occurs especially among middle-aged women. Not only is it frequently misdiagnosed, but also several complications associated to the cyst have been reported such as infection and malignant transformation. This is why complete surgical excision of the tailgut cyst is currently recommended.

Purpose An increasing proportion of patients (> 30%) with node-positive breast cancer will obtain an axillary pathologic complete response after neoadjuvant chemotherapy (NAC). If sentinel node (SN) biopsy (SNB) is accurate in this setting, completion node dissection (CND) morbidity could be avoided. Patients and Methods In the prospective multicentric SN FNAC study, patients with biopsy-proven node-positive breast cancer (T0-3, N1-2) underwent both SNB and CND. Immunohistochemistry (IHC) use was mandatory, and SN metastases of any size, including isolated tumor cells (ypN0[i+], ≤ 0.2 mm), were considered positive. The optimal SNB identification rate (IR) ≥ 90% and false-negative rate (FNR) ≤ 10% were predetermined. Results From March 2009 to December 2012, 153 patients were accrued to the study. The SNB IR was 87.6% (127 of 145; 95% CI, 82.2% to 93.0%), and the FNR was 8.4% (seven of 83; 95% CI, 2.4% to 14.4%). If SN ypN0(i+)s had been considered negative, the FNR would have increased to 13.3% (11 of 83; 95% CI, 6.0% to 20.6%). There was no correlation between size of SN metastases and rate of positive non-SNs. Using this method, 30.3% of patients could potentially avoid CND. Conclusion In biopsy-proven node-positive breast cancer after NAC, a low SNB FNR (8.4%) can be achieved with mandatory use of IHC. SN metastases of any size should be considered positive. The SNB IR was 87.6%, and in the presence of a technical failure, axillary node dissection should be performed. We recommend that SN evaluation with IHC be further evaluated before being included in future guidelines on the use of SNB after NAC in this setting.