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Oxaliplatin (OHP) is a reagent for the standard treatment of advanced and recurrent colorectal cancer (CRC), although OHP resistance mechanisms are not fully elucidated. We found that HCT116-derived OHP-resistant clones (HCT/OHPs), but not DLD1-derived OHP-resistant clones also were resistant to the other drugs used for CRC treatment (5-fluorouracil, irinotecan, and trifluorothymidine), and HCT/OHP-derived tumors were resistant to OHP treatment. Among the candidate genes derived from microarray analysis using the samples of HCT/OHP cells and HCT/OHP-derived tumors, Forkhead box Q1 (FOXQ1) was further assessed to validate OHP resistance and its association with clinicopathological features. In our 173 cohort and 587 TCGA samples, FOXQ1 was upregulated in most CRC tumors compared to normal colonic mucosa and associated with tumor location of the right-sided colon and KRAS/BRAF mutation status. Possible association with prognosis in advanced CRC in our cohort and with microsatellite instability and advanced stage in TCGA samples were indicated. Modification of FOXQ1 via siRNA knockdown and expression vector could not confirm the involvement of FOXQ1 in OHP resistance. In conclusion, our results indicates that FOXQ1 is upregulated in CRC and FOX1 expression is associated with tumor location and KRAS/BRAF mutation status, but is not involved in the OHP resistance mechanism.

Introduction In high sacrectomy, it is difficult to secure the lateral surgical margin and prevent severe postoperative complications. In this report, we present our unique surgical procedure using transanal total mesorectal excision for locally recurrent rectal cancer. Technique A 49-year-old woman was diagnosed with locally rerecurrent rectal cancer, which was located at the height of the S3 vertebra by preoperative imaging, and posterior pelvic exenteration concomitant with high sacrectomy below the S2 vertebra was planned. A multiaccess transperineal platform was placed to secure the lateral surgical margin using transperineal minimally invasive surgery during the perineal and sacral side procedure. Transperineal minimally invasive surgery has several clinical benefits over the conventional approach. For the perineal approach, a 2-team laparoscopic approach was performed. This surgical intervention with laparoscopic perineal assistance contributed to the completion of the dissection of the planned lateral surgical margin, such as the distal piriformis muscles and the sacrotuberous and sacrospinous ligaments, which are the most difficult areas to access in the lithotomy position. Regarding the sacral approach, it facilitated the dissection of the dorsal space of the sacrum; therefore, only a 7-cm transverse skin incision was required during sacrectomy. Small skin incisions and minimal dissection may reduce surgical site infections. Results The operative time was 933 minutes, with 80 mL of blood loss. There were no major complications, and pathologically confirmed curative resection was achieved. Conclusions Our new technique utilizing transanal total mesorectum excision is feasible to secure the lateral surgical margin with minimal skin incision and dissection and may prevent severe postoperative complications.

Tumour-Node-Metastasis (TNM) staging of colorectal cancer (CRC) needs further classification for better treatment because of disease heterogeneity. Although molecular classifications which are expensive and laborious are under study, cost and labour efficient subtyping is desirable. We assessed the combinations of preoperative tumour marker (TM) elevation and tumour lymphovascular invasion (LVI) as a solution. We used the pooled data of 7151 colon cancer (CC) patients and 4620 rectal cancer (RC) patients who received curative surgery between 2004 and 2008 in Japan. The best-matched subtyping for predicting relapse-free survival (RFS) was statistically selected using the c-index and Akaike’s information criterion. This subtyping (TM-LVI), which consisted of three categories by TM elevation status and severity of LVI status, was an independent prognostic factor for RFS of CC (stage IIa, IIIb, and IIIc) and RC (stage I, IIa, IIb, IIIa, and IIIb) and also for disease specific survival of CC (stage IIa, IIb, IIIb, and IIIc) and RC (all stage except for IIc). Although TM-LVI classified CRC patients into low and high recurrence risk groups, the application of adjuvant therapy was not accordance with the TM-LVI status. TM-LVI may be a cost and labour efficient subtyping of colorectal cancer for better treatment strategy.

Background/aim The difficulty of early diagnosis of colitis associated colorectal cancer (CACRC) due to colonic mucosal changes in long-standing ulcerative colitis (UC) patients is often experienced in daily clinical practice. Noninvasive objective monitoring for cancer development is advantageous for optimizing treatment strategies in UC patients. We aimed to examine the epigenetic alterations occurring in CACRC, focusing on DNA hypermethylation of CpG islands. Materials and methods The level of DNA methylation in CpG cites was compared between CACRC and the counterpart non-tumorous mucosa using Infinium HumanMethylation 450K BeadChip. Results Our subjects included 3 males and 3 females (median age, 49.5 years). The 450K CpG site DNA methylation microarray revealed that the difference in β value (level of hypermethylation) was the highest for corcicotropin releasing hormone receptor 2 (CRHR2) between CACRC and counterpart non-tumorous mucosa. Conclusion Detection of hypermethylation of CRHR2 may be promising for cancer screening in UC patients.

Oxaliplatin (OHP) is a reagent for the standard treatment of advanced and recurrent colorectal cancer (CRC), although OHP resistance mechanisms are not fully elucidated. We found that OHP-resistant clones derived from HCT116, but not DLD1 were also resistant against the other drugs used for CRC treatment (5-fluorouracil, OHP, and trifluorothymidine) and their xenograft tumors were resistant against OHP treatment. Among the candidate genes derived from microarray analysis using the samples of OHP-resistant cells and their xenografts derived from HCT116, Forkhead box Q1 (FOXQ1) was further assessed for validation of OHP resistance and its association with clinicopathological features. Modification of FOXQ1 via siRNA knockdown and expression vector could not confirm the involvement of FOXQ1 in OHP resistance. In 173 CRC patients, FOXQ1 was upregulated in most CRC tumors compared to normal colonic mucosa. FOXQ1 expression was significantly different by tumor location of the right-sided colon cancer compared with left-sided and rectal cancer. Moreover, expression level was significantly associated with prognosis in advanced and recurrent patients. TCGA data also showed significant association of FOXQ1 expression with tumor location. Our results indicated that FOXQ1 expression is associated with tumor location of right-sided colon, but not with acquisition of OHP resistance in colorectal cancer.

Introduction It has been considered difficult to achieve en bloc resection in cases of locally advanced rectal cancer with lateral pelvic sidewall invasion. The present study demonstrates a novel surgical procedure for these tumors. Technique There are 3 avascular planes of the retroperitoneum in the pelvic sidewall. Two visceral pelvic fasciae, namely the ureterohypogastric fascia and umbilical prevesical fascia, and the parietal pelvic fascia can be identified. In addition, the key structures of these fasciae, the ureter, umbilical artery, and external iliac vessels, can be identified transperitoneally before any dissection. Thus, these 3 avascular planes can be dissected without resorting to dissection of the retrorectal space. The key steps to this technique are: 1) after dissection from the side opposite to the site of tumor invasion to the dorsal side of the rectum, the avascular planes of the retroperitoneum among the 3 above-mentioned fasciae are dissected; and 2) the retrorectal space and pelvic sidewall space are connected by sharp dissection. Results Recognizing the 3 above-mentioned fasciae enables the dissection of the avascular planes of the pelvic sidewall, which helps to achieve en bloc dissection in cases of locally advanced rectal cancer with lateral pelvic sidewall invasion. Conclusion The pelvic sidewall could be divided into 3 areas based on the visceral pelvic fasciae, which has helped to achieve en bloc dissection in cases of locally advanced rectal cancer with lateral pelvic sidewall invasion.

Circulating microRNAs (miRNAs) are considered promising biomarkers for diagnosis, prognosis, and treatment efficacy of diseases. However, usefulness of circulating miRNAs as biomarkers for hereditary gastrointestinal diseases have not been confirmed yet. We explored circulating miRNAs specific for patients with familial adenomatous polyposis (FAP) as a representative hereditary gastrointestinal disease. Next-generation sequencing (NGS) indicated that plasma miR-143-3p, miR-183-5p, and miR-885-5p were candidate biomarkers for five FAP patients compared to three healthy donors due to moderate copy number and significant difference. MiR-16-5p was considered as an internal control due to minimum difference in expression across FAP patients and healthy donors. Validation studies by real-time PCR showed that mean ratios of maximum expression and minimum expression were 2.2 for miR-143-3p/miR-16-5p, 3.4 for miR-143-3p/miR-103a-3p, 5.1 for miR-183-5p/miR-16-5p, and 4.9 for miR-885-5p/miR-16-5p by using the samples collected at different time points of eight FAP patients. MiR-143-3p/16-5p was further assessed using specimens from 16 FAP patients and 7 healthy donors. MiR-143-3p was upregulated in FAP patients compared to healthy donors (P = 0.04), but not significantly influenced by clinicopathological features. However, miR-143-3p expression in colonic tumors was rare for upregulation, although there was a significant difference by existence of desmoid tumors. MiR-143-3p transfection significantly inhibited colorectal cancer cell proliferation compared to control microRNA transfection. Our data suggested regulation of miR-143-3p expression differed by samples (plasma or colonic tumors) in most FAP patients. Upregulation of plasma miR-143-3p expression may be helpful for diagnosis of FAP, although suppressive effect on tumorigenesis seemed insufficient in FAP patients.

FR901464 (FR) was first described as an anticancer drug and later identified as a modulator of splicing factor 3B subunit 1 (SF3B1). Although the effectiveness of splicing modulators has been investigated in colorectal cancer (CRC) cells, their usefulness in animal experiments has not been confirmed. The association of SF3B1 with CRC progression and the influence of FR on transcriptional activity in CRC has not been fully elucidated. FR showed strong cytotoxicity against CRC cell lines, SF3B1-mutated cancer cell lines, and human fibroblasts with IC50 values less than 1 ng/ml. FR-resistant clones derived from HCT116, DLD1, Lovo, and CT26 cells showed IC50 values greater than 100 ng/ml. SF3B1 sequencing demonstrated low frequencies of SF3B1 mutations in CRC and mutations in codon 1074 of exon 22 in all FR-resistant clones. Unlike hematological malignancies, SF3B1 expression was not associated with CRC progression. Although FR showed significant growth inhibition in a xenograft model of RKO cells, severe toxicity was also induced. These data indicated CRC might be a suitable target of FR unless toxicity occurs. Microarray analysis and real-time quantitative PCR demonstrated downregulation of genes associated with Fanconi anemia (BRCA1 and BRCA2) and 28 driver oncogenes. These data suggested combination treatment of FR with other anticancer drugs whose sensitivity is associated with genes affected by FR treatment. Combination treatment with PARP1 inhibitor olaparib, whose sensitivity was enhanced by BRCA 1/2 deficiency, showed synergistic effects in CRC cells. Our data indicates the potential of FR in combination therapy rather than monotherapy for CRC treatment.

// Tomoki Yamano 1 , Shinichi Yamauchi 2 , Kiyoshi Tsukamoto 1 , Masafumi Noda 1 , Masayoshi Kobayashi 1 , Michiko Hamanaka 1 , Akihito Babaya 1 , Kei Kimura 1 , Chihyon Son 1 , Ayako Imada 1 , Shino Tanaka 1 , Masataka Ikeda 1 , Naohiro Tomita 1 , Kenichi Sugihara 2 and Japanese Study Group for Postoperative Follow-up of Colorectal Cancer 1 Division of Lower GI Surgery, Department of Surgery, Hyogo College of Medicine, Hyogo, Japan 2 Division of Colorectal Surgery, Department of Surgery, Tokyo Medical and Dental University, Tokyo, Japan Correspondence to: Tomoki Yamano, email: yamanot@hyo-med.ac.jp Keywords: colorectal cancer; curative surgery; follow-up; recurrence; survival Received: March 02, 2018 Accepted: April 12, 2018 Published: May 22, 2018 ABSTRACT Background: The follow-up schedule for colorectal cancer patients after curative surgery is inconsistent among the guidelines. Evaluation of time to recurrence (TTR) and survival after recurrence (SAR) may provide evidence for appropriate follow-up. Methods: We assessed 3039 colon cancer (CC) and 1953 rectal cancer (RC) patients who underwent curative surgery between 2007 and 2008. We evaluated the pre- and post-recurrent clinicopathological factors associated with TTR and SAR in each stage of CC and RC. Results: The recurrence rates of stages I, II, and III were 1.2%, 13.1%, and 26.3%, respectively, for CC, and 8.4%, 20.0%, and 30.4%, respectively, for RC. In CC patients, high carcinoembryonic antigen (CEA) level and lymphovascular invasion were independent predictors of short TTR. In RC patients, metastatic factors (liver metastasis in stage III) and venous invasion (stage III) were independent predictors of short TTR. The prognostic factors of SAR were age (stage II CC and stage III RC), female gender (stage III RC), high CEA level (stage II RC), histological type (stage III CRC), nodal status (stage III CC), recurrence within 1 year (stage III RC), M1b recurrence (stage II CRC), local recurrence (stage II CC), and no surgical resection after recurrence (stage II and III CRC). Conclusions: The follow-up schedule for stage I should be different from that for the other stages. We recommend that intensive follow-up is appropriate in stage III CC patients with undifferentiated adenocarcinoma or N2 nodal status, stage II RC patients with high preoperative CEA level, and stage III RC patients.

Inflammatory bowel disease (IBD) increases the risk of colorectal cancer, known as colitis-associated cancer (CAC). It is still unclear what driver mutations are caused by chronic inflammation and lead to CAC development. To get insight into this issue, we investigated somatic alterations in CAC. We performed exome sequencing of 22 fresh CACs and targeted sequencing of 43 genes on 90 archive specimens from Japanese CAC patients, of which 58 were ulcerative colitis (UC) and 32 were Crohn’s disease (CD). Consistently with the previous reports, TP53 was commonly mutated (66%) whereas APC, KRAS and SMAD4 were mutated less frequently (16%, 11% and 11%, respectively). Mucinous CD-CACs in the anus, an Asian-specific subtype of CD-CAC, had less somatic mutations in our target genes. We also found that RNF43, a negative regulator of the Wnt signaling, was somatically mutated in a significant fraction of CACs (10 of 90; 11%). Two lines of evidence indicated that somatic mutations of RNF43 were related to chronic inflammation. First, somatic mutations of RNF43 were significantly associated with longer duration of IBD. Second, clinico-pathological features suggested many of the APC-mutated CACs were actually sporadic colorectal cancer whereas RNF43-mutated CACs did not have this tendency. RNA-Seq analysis showed that RNF43-mutated CACs had elevated expression of c-Myc and its target genes, suggesting that RNF43 is a bona fide driver of CAC development. This study provides evidence that somatic mutation of RNF43 is the driver genetic alteration that links chronic inflammation and cancer development in about 10% of CACs.

Lynch syndrome (LS) and familial adenomatous polyposis (FAP) are major sources of hereditary colorectal cancer (CRC) and are associated with other malignancies. There is some heterogeneity in management strategies in Japan. We undertook a survey of management of hereditary CRC in hospitals that are members of the Japan Society of Colorectal Cancer Research. One hundred and ninety departments responded, of which 127 were from designated cancer care hospitals (DCCHs) according to the Japanese government. There were 25 488 operations for CRC in these departments in 2015. The DCCHs performed better with regard to usage of Japan Society of Colorectal Cancer Research guidelines, referring new CRC patients for LS screening, and having in-house genetic counselors and knowledge of treatment for LS. There were 174 patients diagnosed with LS and 602 undergoing follow-up in 2011-2015, which is fewer than the number expected from CRC operations in 2015. These numbers were not affected by whether the institution was a DCCH. Universal screening for LS was carried out in 8% of the departments. In contrast, 541 patients were diagnosed with FAP and 273 received preventive proctocolectomy/colectomy in 2011-2015. The DCCH departments undertook more surgery than non-DCCH departments, although most of the management, including surgical procedures and use of non-steroidal anti-inflammatory drugs, was similar. Management of desmoid tumor in the abdominal cavity differed according to the number of patients treated. In conclusion, there was heterogeneity in management of LS but not FAP. Most patients with LS may be overlooked and universal screening for LS is not common in Japan.

Data on long-term outcomes of familial adenomatous polyposis (FAP) are unclear in Japan because a nationwide registry system is lacking. We assessed overall survival, incidence of neoplasms, fecal incontinence, and postoperative follow-up status of patients with FAP treated surgically in our hospital. In total, 154 patients with FAP who underwent radical surgery from 1981 to 2017 in our department were available for the questionnaire. Sixty-five patients, 36 of whom were followed at our hospital, were assessed using clinical records and the questionnaire. The median follow-up time was 187 months (interquartile range, 93.5–296 months). The median age at surgery was 36 years (range, 12–69 years). The 5-, 10-, 15-, and 20-year overall survival rate was 100%, 98%, 95%, and 89%, respectively. All five deaths were caused by diseases other than colorectal cancer. FAP-related neoplasms comprised 23 colorectal cancers, five duodenal cancers, three gastric cancers, five thyroid cancers, two ileal pouch cancers, and nine desmoid tumors. The incidence of desmoid tumors was significantly associated with the operation date. The duration from radical surgery to neoplasm onset significantly differed by neoplasm type. Forty-five of 54 patients (excluding those who died or underwent ileostomy) developed fecal incontinence (median Wexner score of 8). Surgical procedures involving hand-sewn sutures with rectal mucosal stripping were significantly associated with fecal incontinence and the Wexner score. Fifty-eight of the 60 surviving patients underwent follow-up examinations. Overall survival was favorable. Fecal incontinence depended on the surgical procedures. Most patients continued to receive follow-up examinations. No. 3112 by Institutional Review Board of Hyogo College of Medicine

The aim of this study was to investigate the influence of chemoradiotherapy (CRT) on nutritional status and the association between changes in nutritional status and clinical outcomes (treatment completion, adverse events, perioperative complications, and relapse-free survival [RFS]) in patients with locally advanced rectal cancer (LARC).In this multicenter, phase II study, 41 patients with LARC underwent CRT for 5 wk, followed by a 6- to 8-wk interval before surgery. Body weight, body mass index (BMI), lean body mass, serum albumin, and prealbumin levels were measured before (pre-), during, and after CRT, and before surgery. Changes in these data and scores on the Malnutrition Universal Screening Tool (MUST) were calculated based on pre-CRT status.Twelve patients (29.3%) experienced body weight loss (BWL) ≥5% (defined as malnutrition) after CRT (P0.001) and before surgery (P = 0.035). Significant changes were seen in serum albumin levels and BMI during and after CRT (P0.001), and in MUST scores after CRT (P = 0.003) and before surgery (P = 0.035). Treatment completion was significantly associated with BWL (P = 0.028), MUST score (P = 0.013), and decreased serum albumin level (P = 0.001) after CRT. Regarding adverse events, MUST score before surgery (P = 0.009) and serum albumin level after CRT (P = 0.002) were significantly associated with diarrhea severity. Serum albumin level during CRT was associated with the onset of neutropenia (P = 0.005). No association was found between BWL and RFS.These findings suggest that malnutrition and changes in nutritional status are not only commonly observed after CRT, but also associated with treatment completion and adverse events.

Purpose This study assessed the incidence of malnutrition caused by preoperative chemoradiotherapy (CRT) in rectal cancer patients, which is seemingly underestimated; however, malnutrition affects treatment tolerability, postoperative complications, including anastomotic leakage (AL), and oncological outcomes. Methods Between January 2008 and December 2014, 54 consecutive patients with T3–4, N0–2, M0–1 resectable rectal cancer received CRT comprising 45 Gy radiotherapy and S-1 alone or with irinotecan for 5 weeks and then underwent curative surgery with diverting or permanent stomas 6–8 weeks after CRT. We assessed malnutrition after completion of CRT (5–6 weeks after CRT start date) and at surgery (11–14 weeks after CRT start date), defining weight loss as ≥5 % of pre-CRT weight; this definition differs from commonly used criteria for adverse events. We evaluated the incidence of malnutrition associated with CRT and influence of malnutrition on treatment tolerability, AL, and disease-free survival (DFS). We also assessed the influence of CRT on the rate of postoperative complications by comparing the study group with 61 patients who had undergone excision with diverting or permanent stomas alone. Results Malnutrition was observed in 51 % of patients after CRT and in 29 % at surgery. Malnutrition after CRT was associated with treatment tolerability, and malnutrition at surgery was significantly associated with AL, which significantly influenced DFS in stage 1–3 patients. Conclusion Malnutrition caused by CRT is common and is associated with treatment tolerability and AL. Nutritional assessment and support seem indispensable for the rectal cancer patients receiving CRT.

We experienced 2 cases of pelvic recurrence from rectal cancer. These patients received radiofrequency ablation(RFA) therapy. Case 1 was a 76-year-old man who underwent intersphincteric resection for lower rectal cancer in October 2013. In May 2015, the patient received systemic chemotherapy for multiple lung metastases and pelvic local recurrence. In January 2017, RFA was performed to reduce the pain of the pelvic recurrence. Immediately after RFA, the pain markedly reduced, and 2 months after treatment, the patient discontinued his pain therapy. Case 2 was a 48-year-old man who underwent Hartmann 's procedure for ulcerative colitis with rectal cancer in November 2011. In July 2012, we performed abdominoperineal resection for rectal cancer that developed in the remnant rectum. In November 2012, he received systemic chemotherapy for multiple lung metastases and pelvic recurrence. In addition, we performed stereotactic radiotherapy(SRT)for the pelvic recurrence. In May 2016, because he developed bilateral hydronephrosis and painful pelvic recurrence, we performed bilateral nephrostomy and RFA for the painful pelvic recurrence. After RFA, pain reduced, but he developed a pelvic abscess that was treated by CT-guided drainage. He underwent complete ablation for the recurrent pelvic mass 2 years after RFA but died of exacerbation of multiple lung metastases. CT-guided RFA for painful pelvic recurrence from rectal cancer can be considered a feasible and effective treatment to reduce pain.

Despite the recent advancement of the treatment including endoscopic resection, surgery, and systemic chemotherapy, mortality rate of colorectal cancer(CRC) has been increasing in Japan. Therefore, the strategy for CRC should be focused to both the early diagnosis by efficient screening and prevention. The screening using fecal occult blood test and subsequent total colonoscopy has been recognized as a gold standard of CRC screening, however, the checkup rate of these examinations is still very low in Japan. It is considered to be important to improve this checkup rate and now, the new modalities, such as computed tomographic colonography or capsule colon endoscopy, are expected to be involved in the clinical practice of CRC screening.

The purpose of the present study was to assess the efficacy and toxicity of preoperative chemoradiotherapy using irinotecan against locally advanced lower rectal cancer according to UDP-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms. Between 2009 and 2016, 46 patients with resectable rectal cancer (T3-T4, N0-N2, M0) received preoperative chemoradiotherapy consisting of 80 mg/m2 per day tegafur/gimeracil/oteracil (S-1; days 1-5, 8-12, 22-26, and 29-33), 60 mg/m2 per day irinotecan (days 1, 8, 22, and 29), and 45 Gy radiation (1.8 Gy/day, 5 days per week for 5 weeks). Six to eight weeks after completing chemoradiotherapy, total mesorectal excision was carried out. Patients with UGT1A1 polymorphisms were divided into WT (n = 26), heterozygous (n = 15), and homozygous (n = 5) groups, the latter including double heterozygosities. We evaluated associations between clinical characteristics, including UGT1A1 polymorphisms, and chemoradiotherapy efficacy and toxicity. Incidence rates of grade 3+ neutropenia and diarrhea were 17.0% and 30.4%, respectively. Relative dose intensity was 89.3%. Pathological complete response rate (grade 3) was 26.1%, and the good response (grade 2/3) rate was 84.8%. UGT1A1 polymorphisms were significantly associated with neutropenia and pathological good responses, but not with diarrhea. UGT1A1 polymorphism was the only predictive factor for pathological good responses. Our results indicate that UGT1A1 polymorphism is a predictive factor to determine the clinical efficacy of preoperative chemoradiotherapy and hematological toxicity induced by chemoradiotherapy using irinotecan in locally advanced rectal cancer patients.

A 67-year-old woman was diagnosed with cecal cancer, para-aortic lymph node metastasis, peritoneum dissemination, and left breast cancer. We administered mFOLFOX6 plus panitumumab for cecal cancer and an aromatase inhibitor for her breast cancer. She received 7 courses of systemic chemotherapy and showed a partial response. She additionally received 5 courses of mFOLFOX6 plus panitumumab. We performed ileocecal resection, sigmoidectomy, right oophorectomy, dissection of the para-aortic lymph nodes, and peritoneal dissemination. The histopathological findings revealed adenocarcinoma, ypT3, ypN0, ycM0, ypStage II (therapeutic effect Grade 2). One month later, she underwent an enforced left breast segmental resection and sentinel lymph node biopsy(0/2). The results of the pathological examination indicated no residual cancers (therapeutic effect Grade 3). The patient is now in good health and was administered S-1 as an outpatient.

Case 1: 63-year-old woman received abdominoperineal resection with lateral lymph node dissection for rectal cancer in 2008. After adjuvant chemotherapy, she suffered from lung metastasis and received partial pneumonectomy in 2012. However, chemotherapy was performed again for lung metastasis and mediastinal lymph nodes in 2013. Radiofrequency ablation (RFA)was performed to lung metastasis in 2016 due to ineffectiveness of chemotherapy. Case 2: 81-year-old man received Hartmann's procedure for rectal cancer with lung and liver metastasis in 2012. After 6 months of chemotherapy, liver partial resection and pulmonary partial resection were performed. In spite of additional chemotherapy, He received partial pneumonectomy in 2013. In 2014, he restart chemotherapy due to lung metastasis. In 2016, he received RFA for lung metastasis because of ineffectiveness of chemotherapy. After that, he received g-knife for brain metastasis. He is going to receive RFA for another lung metastasis.

We had 2 cases of liver-limited and unresectable liver metastases from colorectal cancer with RAS mutations. These patients received hepatic arterial infusion chemotherapy(HAI), finally achieving pCR. Case 1 was a 76-year-old female with rectosigmoid cancer and multiple liver metastases. We underwent anterior resection for primary lesion. After surgery, the patient had received first-line and second-line systemic chemotherapy for the multiple liver metastases. The patient achieved SD and had Grade 3 neutropenia. We then performed HAI as third-line chemotherapy and we therefore underwent hepatectomy. The results of the pathological examination after hepatectomy pCR and is currently alive without cancer recurrence for 61 months. Case 2 was a 53-year-old male with sigmoid colon cancer and multiple liver metastases. We underwent sigmoidectomy with laparoscopic assistance. Three months after surgery, we underwent resection of the lateral segment of the liver under laparoscopy. This patient had cancer recurrence in the remnant liver at 6 months after surgery and had received first-line systemic chemotherapy. The patient had Grade 3 neutropenia after 1 course of chemotherapy and showed no improvement. We then performed HAI as second-line chemotherapy, and we therefore underwent hepatectomy. The results of the pathological examination after hepatectomy were pCR and he is currently alive without cancer recurrence for 30 months.

Introduction The aim of this study was to compare the short- and long-term outcomes between short-course radiotherapy with delayed surgery (SRT-delay) and a standard conventional chemoradiotherapy (CRT) regimen. Methods Two collaborating institutions adopted different regimens; the SRT-delay regimen was selected by Meiwa Hospital and the CRT regimen was selected by Hyogo College of Medicine. The inclusion criteria were T3 middle and low rectal cancer patients treated with radical surgery after preoperative therapy. The median follow-up period was 44 months (range, 12–85). Results From 2007 to 2013, 104 patients were treated using the SRT-delay regimen and 61 patients were treated using the CRT regimen. The pretreatment characteristics of the 2 groups were not significantly different. The sphincter-preserving rate (93.3%, 85.2%), T downstaging (37.5%, 37.7%), ypN(−) (74.0%, 67.2%), postoperative complications and the bowel, and urinary and sexual functioning of the SRT-delay regimen were noninferior to those of the CRT regimen. The 3-year local recurrence-free survival, recurrence-free survival, and overall survival in the SRT-delay and CRT groups were 90.6% and 90.6% ( P = .764), 83.8% and 78.3% ( P = .687) and 96.0% and 92.8% ( P = .833), respectively. Conclusion The SRT-delay regimen was noninferior in terms of the downstaging effect, and oncologic and functional outcomes compared with the CRT regimen for T3 middle and low rectal cancer.

Here, we report the case of a 40-year-old male with a giant intra-abdominal desmoid tumor (DT). He was followed up for familial adenomatous polyposis since age 17 years because of positive family history. Three years before admission, he was diagnosed with an inoperable intra-abdominal DT. He underwent surgery for peritonitis and received hormone and cyclooxygenase-2-inhibitor therapies. Eventually, the DT enlarged and perforated the abdominal wall. He presented with malnutrition, >5 L/week of effusion, anemia due to bleeding, pain, and a foul odor, all of which were attributed to the malignant wound. He was referred to our department for chemotherapy with dacarbazine plus doxorubicin. Chemotherapy after admission proved to be intolerable and ineffective. To relieve the patient’s condition, we applied Mohs’ paste on the tumor surface. Thereafter, the volume of effusion decreased to

Oncolytic virotherapy using adenoviruses has potential therapeutic benefits for a variety of cancers. We recently developed MOA5, a tumor-specific midkine promoter-regulated oncolytic vector based on human adenovirus serotype 5 (Ad5). We modified the binding tropism of MOA5 by replacing the cell-binding domain of the Ad5 fiber knob with that from another adenovirus serotype 35 (Ad35); the resulting vector was designated MOA35. Here we evaluated the therapeutic efficacies of MOA5 and MOA35 for human osteosarcoma. Midkine mRNA expression and its promoter activity was significantly high in five human osteosarcoma cell lines, but was restricted in normal cells. Very low levels of adenovirus cellular receptor coxsackievirus/adenovirus receptor (CAR) (Ad5 receptor) expression were observed in MNNG-HOS and MG-63 cells, whereas high levels of CAR expression were seen in the other osteosarcoma cell lines. By contrast, CD46 (Ad35 receptor) was highly expressed in all osteosarcoma cell lines. Infectivity and in vitro cytocidal effect of MOA35 was significantly enhanced in MNNG-HOS and MG-63 cells compared with MOA5, although the cytocidal effects of MOA5 were sometimes higher in high CAR-expressing cell lines. In MG-63 xenograft models, MOA35 significantly enhanced antitumor effects compared with MOA5. Our findings indicate that MOA5 and MOA35 allow tailored virotherapy and facilitate more effective treatments for osteosarcoma.

Background: Combination oxaliplatin and capecitabine therapy is recommended to treat advanced small bowel adenocarcinoma (SBA). However, SBA is rare, and limited preclinical studies and randomized clinical trials have been conducted. Methods: A patient-derived xenograft (PDX) was established from an advanced SBA patient with liver metastasis and peritoneal metastasis. Growth inhibition by oxaliplatin, irinotecan, 5-fluorouracil (5-FU), and 5-FU in combination with oxaliplatin, irinotecan, or paclitaxel was assessed using the PDX. Drug sensitivity against oxaliplatin, irinotecan, 5-FU, and paclitaxel was assessed using SBA cells from the PDX. The patient’s clinicopathological and genetic features were compared with the PDX to evaluate it as a preclinical model. Results: 5-FU, but not oxaliplatin and irinotecan showed statistically significant growth inhibition compared to control group (P = 0.0024). Among the combination treatment with 5-FU, oxaliplatin showed the highest tumor growth inhibition rate of 0.84 or 1.1, which was 0.46 for irinotecan and 0.49 for paclitaxel, respectively. IC50 of SBA cells was significantly lower against oxaliplatin and higher against paclitaxel compared with colon cancer cell line HT29. These results corresponded to the clinical response to FOLFOX (folinic acid+5-FU+oxaliplatin) and FOLFIRI (folinic acid+5-FU+irinotecan). PDX pathological and genetic features resembled those of the patient. Conclusions: We established a preclinical model comprising the PDX from SBA and SBA cells from the PDX. This model showed that the combination of oxaliplatin and 5-FU was a reasonable standard therapy for advanced SBA. A preclinical model comprising PDX and tumor cells from PDX seems to be useful for rare tumors including SBA. Citation Format: Tomoki Yamano, Jihyung Song, Kei Kimura, Akihito Babaya, Michiko Hamanaka, Kozo Kataoka, Naohito Beppu, Masafumi Noda, Masataka Ikeda, Naohiro Tomita. A patient-derived xenograft model demonstarates the effectiveness of combined oxaliplatin and 5-fluorouracil for advanced small bowel adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1053.

Adjuvant therapy for colorectal cancer (CRC) in patients aged ≥75 years is supported by inadequate evidence, although such patients are increasing in number worldwide.We assessed the influence of age and comorbidities on the prognosis of CRC in elderly patients using pooled data by the Japanese Study Group for Postoperative Follow-up of Colorectal Cancer. In total, 4598 patients (3304 with colon cancer and 1294 with rectal cancer) who underwent curative surgery from 2004 to 2006 were analysed with respect to age, Charlson comorbidity score (CS), tumour marker positivity, adjuvant therapy and prognosis.The number of patients aged64, 65-74 and75 years was 2007 (44%), 1614 (35%) and 977 (21%), respectively. Tumour location, tumour marker positivity, clinical stage, performance of adjuvant therapy, CS and overall survival (OS) were significantly different among these age groups (P 0.0001). Among patients aged ≥75 years with stage III CRC, 35% with colon cancer and 21% with rectal cancer received adjuvant therapy; these proportions were much lower than those in younger patients. Application of adjuvant therapy was dependent on the CS in patients aged ≤74 years, but not in older patients. Sex, the carcinoembryonic antigen concentration and adjuvant therapy were significantly associated with OS in elderly patients with stage III CRC.Age and comorbidities worsened the OS of patients with CRC who underwent curative surgery. However, patients aged ≥75 years were undertreated regardless of their CS despite the possibility of OS improvement by adjuvant therapy.

Cancer vaccine application is limited to specific cancer types because few cancer-associated antigens are known to induce tumor rejection. Accordingly, we assessed the utility of Ad881, an oncolytic adenovirus in which viral replication was strictly regulated by the cancer-specific midkine promoter, as a cancer vaccine in a murine colorectal cancer model lacking specific cancer-associated antigens. In CT26 and CMT93 cells, Ad881 (multiplicity of infection: 100 or 1,000) showed stronger cytotoxicity and oncolysis in vitro than its equivalent replication-defective adenovirus, Ad884. CT26 cells (1 × 104) infected with Ad881 (multiplicity of infection: 1,000) for 24 hours were suitable as vaccine antigens without tumor formation in our model. Repeated vaccinations, but not single vaccination, induced a greater prophylactic immune response. The percentage of mice that rejected the tumor challenge was 0, 4, and 38% after no vaccination, single vaccination, and repeated vaccinations, respectively. Immunogenic cell death marker high-mobility group box 1 protein (HMGB1) and adenosine triphosphate in culture medium were higher after Ad881 infection (24.3 ng/ml and 48.2 nmol/l, respectively) than after Ad884 infection (8.6 ng/ml and 15.4 nmol/l, respectively) or oxaliplatin treatment (3.7 ng/ml and 1.8 nmol/l, respectively). These results indicate that repeated whole cell vaccination using an oncolytic adenovirus may be a potent approach to evoke immunogenic cell death.

The aim of this study was to clarify the clinical aspects, histopathological features and prognosis of patients with rectal carcinoids, focusing on properties associated with metastasis, in order to gain insights into appropriate management. A total of 20 patients (15 males, 5 females; mean age, 54.9 years; range, 23-71) who underwent surgery for rectal carcinoid tumors at the Department of Colorectal Surgery, Hyogo College of Medicine, between May 2000 and January 2011 were analyzed. Ki-67 immunostaining was performed in 13 cases with available tumor tissue specimens. Of the 20 patients, a radical operation including rectal resection with a lymphadenectomy was performed in 16. The mean tumor size was 11.9 mm (3-25 mm) and lymph node metastasis was confirmed in 9 cases, including 3 with lesions no greater than 7 mm in diameter. Overall, 16 (80%) of the tumors were localized in the submucosal layer and 4 (20%) involved the proper muscle layer. Ki-67 labeling index and lymphovascular invasion were shown to be associated with lymph node and/or distant metastasis by multiple logistic regression analysis, but were not statistically significant in ANOVA findings. Lymph node metastasis from rectal carcinoids, even those smaller than 10 mm in diameter, was not a rare event. More attention should be given to decision-making, including the possibility of endoscopic resection for the treatment of rectal carcinoid tumors regardless of size.

症例は82歳の女性で，食欲不振と体重減少を主訴に近医にてCTを受けS状結腸癌を疑われた．精査目的で注腸検査を受け，検査後に腹痛が出現し翌日の画像検査でS状結腸穿孔によるバリウム腹膜炎の診断で当院紹介となった．緊急開腹術の所見で後腹膜腫瘍のS状結腸への浸潤と穿破によるバリウム腹膜炎，腫瘍による左尿管・左総腸骨動静脈の途絶，後腹膜腔に膿瘍形成を認めた．ハルトマン手術と左腎瘻造設を施行した．病理検査で後腹膜腫瘍は高分化扁平上皮癌であり原発巣を検索した．原発部位としては腎盂尿管が最も強く疑われたが確定診断には至らなかった．

819 Background: Preoperative chemoradiotherapy regimen using S-1 plus Irinotecan is still under clinical investigation. The aim of this study was to investigate the significance and the long-term outcomes of this regimen for locally advanced rectal cancer. Methods: Between 2009 and 2016, 81 patients underwent radical surgery after preoperative chemoradiotherapy. Radiotherapy was administered in total 45Gy with 1.8Gy/day for 25 days. S-1 was administered orally in a fixed daily dose of 80mg/m2 on days 1 to 5, 8 to 12, 22 to 26, and 29 to 33. Irinotecan was infused with dose of 80 mg/m2 on days 1, 8, 22, and 29. 6-9 weeks after the completion of the treatment, radical surgery was performed. The median follow-up was 35.3 months. Results: Of the 81 patients, 76 (93.8%) completed treatment of chemoradiotherapy. Relative dose intensity of CPT-11 was 92.8%, S-1 was 90.1%. 79 (97.5%) patients completed the radiotherapy. 18 patients (22.2%) had ≧Grade 3 hematologic toxicity (leukopenia; 15 patients, neutropenia; 16 patients ). 23 patients (28.3%) had ≧Grade 3 nonhematologic toxicity (diarrhea). In terms of the surgical procedure, 73 of 81 patients (90.1%) underwent sphincter-preserving surgery including 42 patients intersphincteric resection, and 8 patients (9.9%) underwent abdominoperineal resection. The tumor regression grade of 1/2/3(pCR) was 30/39/12(14.8%). In terms of long-term survival, 3-year local relapse-free survival rate was 96.7%, the recurrence-free survival rate was 71.6% and 3-year overall survival rate was 94.9%. Conclusions: Preoperative chemoradiotherapy using combined with Irinotecan as secondary drugs may result safe and feasible and accomplished favorable downstaging. This regimen was considered to be effective in patients with locally advanced rectal cancer.

The aim of this study was to compare the pathological response of mesorectal positive nodes between short-course chemoradiotherapy with delayed surgery (SCRT-delay) and long-course chemoradiotherapy (LC-CRT) in patients with rectal cancer. The resected primary tumor specimens following the two different approaches were assessed utilizing the tumor regression grade (TRG 0–4), and each positive lymph node was assessed according to the lymph node regression grade (LRG 1–3), with TRG 4 and LRG 3 indicating total regression. The lymph node sizes were measured to elucidate any correlation with LRG scores. Seventy-four patients with ypN-positive rectal cancer had 220 positive lymph nodes following the SCRT-delay, and 48 patients had 141 positive lymph nodes following the LC-CRT. The distribution of LRG 1/2/3 in the two groups was 123/72/25 and 60/31/50 (p

Background Extramural tumor deposits (TDs) and extracapsular lymph node involvement (ECLNI) are considered to be poor prognostic factors in patients with T3–4, N0–2, M0 colorectal cancer (CRC). Although TDs are known to have multiple origins and pleomorphic features, the prognostic significances of the different type of TDs have not yet been established. Methods We performed a retrospective review of 385 consecutive patients with T3–4, N0–2, M0 CRC who received curative resection at our institution between 2006 and 2012. We classified the TDs into two groups: invasive-type TD (iTD), which is characterized by the presence of lymphatic invasion, vascular invasion, perineural invasion, or undefined cancer cell clusters and nodular-type TD (nTD), which is characterized by a smooth or irregular-shaped tumor nodule other than an iTD. ECLNI was defined as invasion of cancer cells into capsular collagen tissues or adipose tissues beyond the capsular collagen. Multivariate analyses were used to assess the prognostic significance of iTD, ND, and ECLNI for relapse-free survival (RFS), disease-specific survival (DSS), and sites of recurrence. Results In patients without lymph node (LN) metastasis, the incidences of iTD and nTD were both in the range of 2–3 %. Conversely, in patients with LN metastasis, the incidences of iTD, nTD, and ECLNI were 31, 22, and 34 %, respectively. iTD, nTD, and ECLNI were all significant independent adverse factors for RFS in rectal cancer, and were all associated with pT, pN, and LN ratio. iTD was a significant independent adverse prognostic factor for DSS in rectal cancer, metastasis to the liver in colorectal cancer, and distant LN metastasis in colon cancer. ECLNI was a significant independent prognostic factor for RFS in colon cancer. Conclusions Classifying TDs and assessing ECLNI may help establish significant prognostic factors for patients with T3–4, N0–2, M0 CRC.

Tyrosinase-related protein-2 (TRP2) is a weak antigen expressed in murine and human melanomas. Induction of antibody (Ab) response and T-cell immunity toward TRP2 with DNA plasmid vaccines has not been efficient to date. Recent studies have suggested that a chemokine ligand for the CCR7 (CCL21) present on T-cells and dendritic cells is important in activating and regulating immunity. We investigated the effectiveness of CCL21 as an adjuvant with an HVJ anionic liposomal TRP2 DNA (plasmid) vaccine to enhance anti-TRP2 Ab, cytokines, delayed-type hypersensitivity, T-cell responses, and tumor protection against B16 melanoma cells. Induction of anti-TRP2 immunity depended mainly on cell-mediated immunity, which was regulated by timing and route of CCL21 administration with DNA vaccine. The optimum protocol was to administer CCL21 im 24 h before DNA vaccine at the same vaccination site. Two vaccinations (prime/boost) were essential for induction of strong anti-TRP2 cell-mediated immunity. CCL21 administration 3 days before or 24 h after DNA vaccine, simultaneous with DNA vaccine, or at different sites (iv, opposite leg) was not effective. This study demonstrated that CCL21 was an effective adjuvant to enhance TRP2-specific immunity induced by a plasmid DNA cancer vaccine.

Histone deacetylation and DNA methylation establish epigenetic modifications, which through chromatin remodeling may result in gene silencing. We hypothesized that chemokine receptors C-C chemokine receptor 7 (CCR7) and C-X-C chemokine receptor 4 (CXCR4) on melanoma cells undergo epigenetic regulation. We investigated whether a histone deacetylase inhibitor and a demethylating agent influence CCR7 and CXCR4 expression on melanoma cells. Initially, microarray analysis was done to screen changes in chemokine receptor expression on melanoma cells after treatment with trichostatin A (TSA) and 5-Aza-2-deoxycytidine (5-Aza). CCR7 and CXCR4 mRNA expression were uniformly altered and selected for further investigation. Quantitative real-time reverse transcription-PCR assay, immunohistochemistry, and Western blot analysis were used to assess changes in mRNA and protein expression induced by TSA and 5-Aza in melanoma lines. Cell migration assays were conducted to assess the effects of altered CCR7 and CXCR4 expression on cell function. Treatment with TSA or 5-Aza increased gene expression of both CCR7 and CXCR4 in melanoma lines. TSA was the strongest enhancer. With combined treatment, CCR7 and CXCR4 mRNA expression was also up-regulated. Immunohistochemistry after combined treatment showed enhanced staining of both CCR7 and CXCR4 compared with control cells. Melanoma cell migration in TSA- and 5-Aza-treated cells was 7- and 2-fold higher than control cells for CCR7 and CXCR4, respectively. In summary, a histone deacetylase inhibitor and a demethylating agent up-regulated CCR7 and CXCR4 expression on melanoma cells. This increase in chemokine receptor expression correlated with functional activity. Most importantly, we have identified an epigenetic mechanism that may endogenously regulate chemokine receptor expression on melanoma cells.

Purpose: The chemokine CC-ligand 21/secondary lymphoid tissue chemokine (CCL21/SLC) regulates the homing of naïve T cells and dendritic cells that express CC-chemokine receptor 7 (CCR7) from distant sites to lymphoid tissue such as lymph nodes. We hypothesized that CCL21/SLC regulates the migration of CCR7-bearing melanoma cells from a primary lesion to regional tumor-draining lymph nodes.Experimental Design: Quantitative real-time reverse transcriptase-PCR (qRT) assay and immunohistochemistry (IHC) were used to assess the level of CCR7 expression in melanoma cell lines and in primary and metastatic melanoma tumors. Cell migration assay using melanoma cell lines was performed under the induction of CCL21/SLC. The CCL21/SLC expression level in tumor-draining sentinel lymph nodes (SLNs) was assessed by both qRT assay and IHC.Results: Melanoma cell lines and tumors demonstrated heterogeneous expression of CCR7 mRNA by qRT assay. There was strong functional correlation between CCR7 mRNA expression and cell migration induced by CCL21/SLC. IHC evidence of CCR7 expression in primary melanomas significantly (P = 0.02) correlated with Breslow thickness. Assessment of SLN from 55 melanoma patients by qRT assay demonstrated that CCL21/SLC mRNA expression level was significantly (P = 0.008) higher in pathologically melanoma-negative SLNs than in melanoma-positive SLNs.Conclusions: This report demonstrates a potential mechanism for recruitment and homing of CCR7(+) metastatic melanoma cells to tumor-draining lymph nodes, which express CCL21/SLC. The study also suggests that lymph nodes bearing metastasis may suppress CCL21/SLC production.

Background. Calpain, a cytosolic Ca 2+ -dependent proteinase, plays a pivotal role in cell injury. In this study, we investigated the effect of calpain-μ antisense oligonucleotide on oxidative stress induced-hepatocyte injury. Materials and methods. Hemagglutinating virus of Japan liposome complex with one of three types of antisense oligonucleotide (AS-1, AS-2, AS-3) or scramble oligonucleotide was added to the culture medium of HuH7 cells and incubated for 6 days. The expression of calpain-μ protein was examined by Western blotting. After the addition of tert-butyl hydroperoxide, bleb formation was examined by phase contrast microscopy, and cell viability was assessed by the release of lactate dehydrogenase. Results. Incubation of HuH7 cells with AS-2 resulted in a decrease in the amount of calpain on day 4 and a further decrease to almost undetectable levels on day 6, whereas scramble oligonucleotide had no effect. Bleb formation was observed 120 min after the addition of tert-butyl hydroperoxide in scramble oligonucleotide-treated cells as in untreated cells. In contrast, it was rarely observed in AS-2-treated cells. Lactate dehydrogenase release was significantly suppressed in AS-2-treated cells, compared with that in scramble oligonucleotide treated-cells. Conclusions. Our findings suggest that calpain activation is involved in the pathogenesis of oxidative stress injury and that transfection of calpain antisense may potentially protect against ischemia/reperfusion liver injury.

Background: Chronic inflammation is one of the major causes of carcinogenesis. Ulcerative colitis (UC) and Crohn’s disease (CD) increase the risk of colitis-associated cancer (CAC) development, and its biological and pathological characters are also distinct. However, the genetic mechanism of how chronic inflammation leads to CACs is still unclear. Methods: We obtained frozen tumor tissues from 21 CAC patients and performed exome or whole-genome sequencing of the matched tumor-normal samples. We enumerated recurrently mutated genes and selected 43 genes among them for target capture. We then performed targeted resequencing of 84 FFPE specimens from CAC tissues. Totally, we made genomic profiles of 105 CACs. Results: The most frequently mutated gene was TP53, whose mutation was found in 70 of 105 samples (67%), which is more prevalent in CACs than common colorectal cancers (CRCs). Somatic mutations of APC and KRAS were less prevalent (17 and 13 samples, respectively). Genes in the Wnt signaling pathway (APC, FBXW7, TCF7L2, and RNF43) were mutated in 31 samples, whereas those in the TGFβ pathway (TGFBR2, ACVR1B, SMAD2, SMAD4, LTBP4) were mutated in 25 samples. Mutational signature of CACs shows some differences from common CRCs. Conclusion: Our results confirmed genetic differences for cancer development between CACs and common CRCs. Frequent TP53 mutations and less frequent APC mutations are consistent with the idea of “de novo” carcinogenesis than adenoma-carcinoma sequence. The association between the mutations and clinical information are also discussed. Citation Format: Masashi Fujita, Nagahide Matsubara, Kazuhiro Maejima, Tomoki Yamano, Ikuo Matsuda, Seiichi Hirota, Hiroki Ikeuchi, Naohiro Tomita, Hidewaki Nakagawa. Genetic profiling of colitis-associated cancer indicates de novo carcinogenesis and the impact of chronic inflammation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1439. doi:10.1158/1538-7445.AM2017-1439

The purpose of this study was to analyze the influence of variations in clinical practice regarding the timing of surgery with short-course chemoradiotherapy with delayed surgery (SCRT-delay) for lower rectal cancer. A total of 171 patients with T3 N0-2 lower rectal cancer treated with SCRT-delay (25 Gy/10 fractions/5 days (S-1); days 1–10) were retrospectively evaluated. The median waiting period of 30 days was used as a discriminator (group A: waiting period, ≤30 days; group B: waiting period, ≥31 days). Preoperative treatment responses and oncological outcomes were analyzed. The mean waiting periods for groups A and B were 24.4 ± 5.3 and 41.4 ± 12.3 days, respectively. There were no statistically significant differences between the two groups in any of the clinical variables. The clinicopathological outcomes were as follows: T downstaging (43.5 vs 37.2 %; p = 0.400), negative yp N (67.1 vs 75.6 %; p = 0.218), pCR (7.1 vs 1.2 %; p = 0.119). The 5-year local recurrence-free survival (89.3 vs 87.6 %; p = 0.956), the recurrence-free survival (82.2 vs 78.8 %; p = 0.662), and the overall survival (88.5 vs 84.4 %; p = 0.741), all of which were similar between the two groups. The longer waiting period did not increase the tumor downstaging and not improve the oncological outcomes for T3 lower rectal cancer treated with SCRT-delay. In addition, considering that the impaired leukocyte response occurred during the sub-acute period, any time after the sub-acute period (day 12) up to 30 days after radiotherapy would be a suitable waiting period.

Background The response of positive mesorectal lymph nodes to chemoradiotherapy remains largely unstudied in patients with rectal cancer. The aim of this study was to investigate the requirements of the total regression of positive nodes treated with chemoradiotherapy. Methods The response of the primary tumor was evaluated according to the tumor regression grade (TRG 0−4) in resected specimens, and positive lymph nodes were assessed according to the lymph node regression grade (LRG 1−3), with TRG 4 and LRG 3 indicating total regression. We investigated the relationships among TRG, LRG, and the sizes of positive lymph nodes. Results Among 178 patients, 68 (38.2%) had 200 positive lymph nodes. We first investigated the relationship of positive nodes to TRG and LRG and found that the response of the primary tumor to chemoradiotherapy correlated with the response of positive nodes. Next, we investigated the correlation between LRG and the size of positive nodes. At TRG 1 and 2, LRG score was not correlated with the positive node size. In contrast, at TRG 3, LRG score was correlated with the size of positive nodes. Next, our assessment of the relationship between the sizes of positive nodes and complete degeneration to LRG 3 showed that the most accurate cut-off score on receiver-operator-characteristics curve analysis was 6 mm in maximum diameter for TRG 3. Conclusion The requirements of the total regression of positive nodes are 1) degeneration of the primary tumor to TRG 3 and 2) a positive node diameter of