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Abstract Background To prevent local recurrence caused by exfoliated cancer cells caught in the suture line, intraoperative rectal washout during surgery can be performed to eliminate exfoliated cancer cells. However, the impact of neoadjuvant chemoradiotherapy on exfoliated cancer cells is not well known. This study aimed to identify positive rate of malignant cells in rectal washout fluids of neoadjuvant chemoradiotherapy patients and to determine if neoadjuvant chemoradiotherapy could affect exfoliated cancer cells. Methods A total of 105 patients who underwent rectal washout intraoperatively for distal sigmoid colon and rectal cancer from April 2020 to September 2021 were analyzed. The primary outcome was positive rate of malignant cells in rectal washout fluids of patients who had received neoadjuvant chemoradiotherapy. Results The positive rate of malignant cells in washout fluids of patients who had received neoadjuvant chemoradiotherapy was 0.0% and those who had not was 32.1%. The overall positive rate was 23.8%. In the positive group, tumor sizes were bigger (4.64 ± 1.68 cm vs. 3.64 ± 2.00 cm, p = 0.026) and more patients had a fungating tumor shown in preoperative colonoscopy (96.0% vs. 71.3%, p = 0.012). Although these factors did not show statistical significance in multivariable logistic regression analysis, fungating tumor showed a trend towards significance (OR: 7.28, 95% CI: 0.90-58.77, p = 0.063). Conclusions Our study suggests that neoadjuvant chemoradiotherapy could reduce exfoliated cancer cells, and rectal washout for the purpose of eliminating exfoliated cancer cells might be unnecessary in patients who have received neoadjuvant chemoradiotherapy.

Purpose Since the introduction of robotic surgery, robots for colorectal cancer have replaced laparoscopic surgery, and a single-port robot (SPR) platform has been launched and is being used to treat patients. We analyzed the learning curve and initial complications of using an SPR platform in colorectal cancer surgery. Methods We reviewed 39 patients who underwent SPR colectomy from April to October 2019. All surgeries were performed by the same surgeon using an SPR device. A learning curve was generated using the cumulative sum methodology to assess changes in total operation time, docking time, and surgeon console time. We grouped the patients into 3 groups according to the time period: the first 11 were phase 1, the next 11 were phase 2, and the last 17 were phase 3. Results The mean age of the patients was 61.28±13.03 years, and they had a mean body mass index of 23.79±2.86 kg/m2. Among the patients, 23 (59.0%) were male, and 16 (41.0%) were female. The average operation time was 186.59±51.30 minutes, the average surgeon console time was 95.49±35.33 minutes, and the average docking time (time from skin incision to robot docking) was 14.87±10.38 minutes. The surgeon console time differed significantly among the different phases (P

Abstract Background Previous investigations of transcriptomic signatures of cancer patient survival and post-therapy relapse have focused on tumor tissue. In contrast, here we show that in colorectal cancer (CRC) transcriptomes derived from normal tissues adjacent to tumors (NATs) are better predictors of relapse. Results Using the transcriptomes of paired tumor and NAT specimens from 80 Korean CRC patients retrospectively determined to be in recurrence or nonrecurrence states, we found that, when comparing recurrent with nonrecurrent samples, NATs exhibit a greater number of differentially expressed genes (DEGs) than tumors. Training two prognostic elastic net-based machine learning models—NAT-based and tumor-based in our Samsung Medical Center (SMC) cohort, we found that NAT-based model performed better in predicting the survival when the model was applied to the tumor-derived transcriptomes of an independent cohort of 450 COAD patients in TCGA. Furthermore, compositions of tumor-infiltrating immune cells in NATs were found to have better prognostic capability than in tumors. We also confirmed through Cox regression analysis that in both SMC-CRC as well as in TCGA-COAD cohorts, a greater proportion of genes exhibited significant hazard ratio when NAT-derived transcriptome was used compared to when tumor-derived transcriptome was used. Conclusions Taken together, our results strongly suggest that NAT-derived transcriptomes and immune cell composition of CRC are better predictors of patient survival and tumor recurrence than the primary tumor.

Abstract Continuous wound infusion with local anesthesia is an effective method for reducing postoperative pain after laparoscopic colorectal surgery. However, most subcutaneous local anesthesia is delivered through continuous injection, which can be inconvenient for patients. This study compared the effectiveness of postoperative pain relief from the application of a local poloxamer 407-based ropivacaine hydrogel (Gel) to the incision site with continuous infusion-type ropivacaine administration (On-Q) in patients undergoing laparoscopic colorectal surgery. This prospective, randomized, non-inferiority study included 61 patients who underwent laparoscopic colorectal surgery with an incision length of 3–6 cm. All 61 patients were randomly assigned to the Gel group (poloxamer 407-based 0.75% ropivacaine, 22.5 mg) or the On-Q group (0.2% ropivacaine, 4 mg/hour for two days). Postoperative analgesia was induced in all patients with intravenous patient-controlled analgesia (IV-PCA). The outcome measures, which were assessed for 72 h after surgery, included the total amount of fentanyl consumed via IV-PCA (primary endpoint), and the amount of rescue analgesia (pethidine) and postoperative pain intensity assessed using a numeric rating scale (NRS) [secondary endpoints]. The Gel was administered to 31 patients and On-Q was used for 30 patients. There was no significant difference in the total usage of fentanyl between the two groups (Gel group, 1623.98 mcg; On-Q group, 1595.12 mcg; P = 0.806). There was also no significant difference in the frequency of analgesic rescue medication use (P = 0.213) or NRS scores (postoperative 6 h, P = 0.860; 24 h, P = 0.333; 48 h, P = 0.168; and 72 h, P = 0.655) between the two groups. The Gel, which continuously delivers a local anesthetic to operative sites, can thus be considered an effective device for analgesia and pain relief for midline incisions in laparoscopic colorectal surgery.

Summary: Predicting cancer recurrence is essential to improving the clinical outcomes of patients with colorectal cancer (CRC). Although tumor stage information has been used as a guideline to predict CRC recurrence, patients with the same stage show different clinical outcomes. Therefore, there is a need to develop a method to identify additional features for CRC recurrence prediction. Here, we developed a network-integrated multiomics (NIMO) approach to select appropriate transcriptome signatures for better CRC recurrence prediction by comparing the methylation signatures of immune cells. We validated the performance of the CRC recurrence prediction based on two independent retrospective cohorts of 114 and 110 patients. Moreover, to confirm that the prediction was improved, we used both NIMO-based immune cell proportions and TNM (tumor, node, metastasis) stage data. This work demonstrates the importance of (1) using both immune cell composition and TNM stage data and (2) identifying robust immune cell marker genes to improve CRC recurrence prediction. The bigger picture: Colorectal cancer is a significant global public health issue, and accurately predicting its recurrence remains a challenge despite advances in screening and treatment. Accurate recurrence prediction is crucial for clinicians to make informed decisions about treatment and follow-up care, leading to timely interventions that may improve outcomes and potentially prolong survival. In this study, we present a method that combines immune cell information with clinical data to enhance the accuracy of recurrence risk prediction. The predictive performance of the method was validated using two independent cohorts of patients with colorectal cancer of different races. Our approach has implications for both clinical practice and research, as it helps to suggest treatment strategies by predicting recurrence risk and identifying potential therapeutic targets based on immune cell information.

Purpose Various clinical practice guidelines recommend at least 12 regional lymph nodes should be removed for resected colon cancer. According to a recent study, the lymph node yield (LNY) in colon cancer surgery in the last 20 years has tended to increase from 14.91 to 21.30. However, it is unclear whether these guidelines adequately reflect recent findings on the number of harvested lymph nodes in colon cancer surgery. The aim of this study is to assess the impact of an LNY of more than 25 on survival in right-sided colon cancer. Methods We included 285 patients who underwent a right hemicolectomy during the period from January 2010 through December 2015. Patients were divided into two groups (

Abstract Patients with pathologic complete response (pCR) achievement can consider local excision or “watch and wait” strategy instead of a radical surgery. This study analyzed the predictive factors of pCR in rectal cancer patients who underwent radical operation after neoadjuvant chemoradiotherapy (nCRT). This study also analyzed the recurrence patterns in patients who achieved pCR and the oncologic outcomes and prognostic factors by ypStage. Between 2000 and 2013, 1,089 consecutive rectal cancer patients who underwent radical resection after nCRT were analyzed. These patients were classified into two groups according to pCR. The clinicopathologic and oncologic outcomes were analyzed and compared between the two groups. Multivariate analysis was conducted on factors related to pCR. The proportion of patients achieving pCR was 18.2% (n = 198). The pCR group demonstrated earlier clinical T and N stages, smaller tumor size, better differentiation, and a lower percentage of circumferential resection margin (CRM) involvement than did the non-pCR group. The prognostic factors associated with poorer disease-free survival were high preoperative carcinoembryonic antigen levels, non-pCR, poor histology, lymphatic/perineural invasion, and involvement of CRM. Multivariate analysis revealed that clinical node negativity, tumor size

Cancer associated fibroblasts are an important and highly heterogeneous component of the tumor microenvironment. Here the authors identify PRRX1 as a master transcription factor determining a fibroblast lineage with myofibroblastic phenotype, associated with unfavourable prognosis in several cancer types.

Recently, abdominoperineal resection (APR) using a robot has been demonstrated in other studies. However, there has been no report on APR for rectal cancer using the single-port robot (SPR) platform. In response to this research gap, we described the clinical experience of APR using a SPR. From April 2019 to March 2020, APR using a SPR platform was performed in a total of 4 patients. Three patients had a transumbilical approach, and 1 patient had a transstoma site approach. The average operation time was 307 minutes, and the patient docking time to the SPR platform was 133.5 minutes. There were no complications during the operation, and no laparoscopy or open conversion. No reoperation occurred within 30 days. Mild postoperative complications occurred in 2 patients. We found that APR has safety and feasibility in surgery using an SPR platform. There was no intraoperative event and severe postoperative complications.

Purpose Identification of type I protein arginine methyltransferase (PRMT) substrates and their functional significance during tumorigenesis is becoming more important. The present study aimed to identify target substrates for type I PRMT using 2-dimensional (2D) gel electrophoresis (GE) and 2D Western blotting (WB). Methods Using immunoblot analysis, we compared the expression of type I PRMTs and endogenous levels of arginine methylation between the primary colorectal cancer (CRC) and adjacent noncancerous tissues paired from the same patient. To identify arginine-methylated proteins in HCT116 cells, we carried out 2D-GE and 2D-WB with a type I PRMT product-specific antibody (anti-dimethyl-arginine antibody, asymmetric [ASYM24]). Arginine-methylated protein spots were identified by mass spectrometry, and messenger RNA (mRNA) levels corresponding to the identified proteins were analyzed using National Center for Biotechnology Information (NCBI) microarray datasets between the primary CRC and noncancerous tissues. Results Type I PRMTs and methylarginine-containing proteins were highly maintained in CRC tissues compared to noncancerous tissues. We matched 142 spots using spot analysis software between a Coomassie blue (CBB)-stained 2D gel and 2D-WB, and we successfully identified 7 proteins that reacted with the ASYM24 antibody: CACYBP, GLOD4, MAPRE1, CCT7, TKT, CK8, and HSPA8. Among these proteins, the levels of 4 mRNAs including MAPRE1, CCT7, TKT, and HSPA8 in CRC tissues showed a statistically significant increase compared to noncancerous tissues from patients using the NCBI microarray datasets. Conclusion Our results indicate that the method shown here is useful in identifying arginine-methylated proteins, and significance of arginine modification in the proteins identified here should be further identified during CRC development.

Abstract Background Young patients with colorectal cancer (CRC) exhibit poor prognoses compared to older patients due to the difficulty in early diagnosis and treatment. However, the underlying molecular characteristics are still unclear. Methods We conducted a comprehensive analysis of 49 CRC patients without hereditary CRC using the whole-exome and RNA sequencing with tumor and matched normal samples. A total of 594 TCGA samples and 4 patient-derived cells were utilized for validation. Results Consensus molecular subtype 4 (CMS4) (53.85%) and CMS2 (38.46%) were enriched in the young (≤ 40 years) and old (> 60 years) age groups, respectively. A CMS4-associated gene, platelet-derived growth factor receptor α (PDGFRA), was significantly upregulated in young patients with CRC (FC = 3.21, p = 0.0001) and was negatively correlated with age (p = 0.0001, R = − 0.526). Moreover, PDGFRA showed a positive co-expression with metastasis-related genes in young CRC patients. In vitro validation confirmed that young patient-derived cells (PDCs) showed an enriched expression of PDGFRA compared to old PDCs and a reduced proliferation rate by knockdown of PDGFRA. Furthermore, young CRC patients were more sensitive to regorafenib, a PDGFRA-targeting drug, than old CRC patients. Conclusions Our study suggests that CRC in young patients is associated with CMS4 and PDGFRA. In addition, PDGFRA may serve potential of novel therapeutic strategies and represent a predictive biomarker of response to regorafenib for young CRC patients.

Summary: Predicting colorectal cancer recurrence after tumor resection is crucial because it promotes the administration of proper subsequent treatment or management to improve the clinical outcomes of patients. Several clinical or molecular factors, including tumor stage, metastasis, and microsatellite instability status, have been used to assess the risk of recurrence, although their predictive ability is limited. Here, we predicted colorectal cancer recurrence based on cellular deconvolution of bulk tumors into two distinct immune cell states: cancer-associated (tumor-infiltrating immune cell-like) and noncancer-associated (peripheral blood mononuclear cell-like). Prediction model performed significantly better when immune cells were deconvoluted into two states rather than a single state, suggesting that the difference in cancer recurrence was better explained by distinct states of immune cells. It indicates the importance of distinguishing immune cell states using cellular deconvolution to improve the prediction of colorectal cancer recurrence.

Background: Depth of tumor is a risk factor for lymph node metastasis in rectal cancer, but impact of yield pathologic T (ypT) stage on lymph node involvement in rectal cancer remains unclear. The aim of this study was to evaluate the correlation between ypT stage and lymph node metastasis. Methods: From January 2010 to December 2015, 602 patients who were diagnosed with rectal cancer and treated with neoadjuvant chemoradiotherapy (CRT) followed by radical operation were reviewed retrospectively. The correlations between ypT stage and lymph node status and survival were evaluated. Results: On pathology, 179 (29.7%) patients exhibited regional lymph node metastasis. Lymph node metastasis was seen in 8.5% of ypT0 patients, 20% of ypT1, 18.4% of ypT2, 47.5% of ypT3, and 27.3% of ypT4. Positive lymph node metastasis was correlated with ypT stage. In addition, the difference of lymph node metastasis in ypT stage subgroups was statistically significant ( p

BackgroundBevacizumab is a humanized monoclonal antibody against vascular endothelial growth factor and is used in combination with first-line chemotherapy in the treatment of metastatic colorectal cancer. One of the side effects of bevacizumab is gastrointestinal perforation. This study was designed to identify the effect of bevacizumab in intestinal anastomosis site healing.MethodsFrom January 2010 to December 2020, patients diagnosed with stage IV colorectal cancer treated with palliative chemotherapy or chemoradiotherapy followed by radical surgery were retrospectively reviewed. Clinical signs or symptoms and computed tomography were tools used for diagnosing anastomosis site leakage. The patients were divided into two groups, the bevacizumab group (n = 136) and the non-bevacizumab group (n = 124).ResultsAmong the 260 patients 14 (5.4%) patients were diagnosed with anastomosis site leakage. In the bevacizumab group, 13 (9.6%) patients were diagnosed with anastomotic leakage. In the non-bevacizumab group, 1 (0.8%) patient was diagnosed with anastomotic leakage. Anastomosis site leakage was significantly higher in the bevacizumab treatment group (P < 0.001). In the bevacizumab group, period of drug discontinuation before surgery was factor associated with anastomosis site leakage in multivariable analysis (P = 0.031).ConclusionStage IV colorectal patients treated with bevacizumab before radical surgery for primary cancer should be carefully observed of anastomosis site leakage after surgery, and the period of drug discontinuation before surgery should be longer than 5 weeks to avoid anastomosis site leakage.

Purpose The survival benefit of neoadjuvant chemotherapy (NAC) prior to surgical resection in colorectal cancer with liver metastases (CRCLM) patients remains controversial. The aim of this study was to compare overall outcome of CRCLM patients who underwent NAC followed by surgical resection versus surgical treatment first. Methods We retrospectively analyzed 429 patients with stage IV colorectal cancer with synchronous liver metastases who underwent simultaneous liver resection between January 2008 and December 2016. Using propensity score matching, overall outcome between 60 patients who underwent NAC before surgical treatment and 60 patients who underwent surgical treatment first was compared. Results Before propensity score matching, metastatic cancer tended to involve a larger number of liver segments and the primary tumor size was bigger in the NAC group than in the primary resection group, so that a larger percentage of patients in the NAC group underwent major hepatectomy (P < 0.001). After propensity score matching, demographic features and pathologic outcomes showed no significant differences between the 2 groups. In addition, there was no significant difference in short-term recovery outcomes such as postoperative morbidity (P = 0.603) and oncologic outcome, including 3-year overall survival rate (P = 0.285) and disease-free survival rate (P = 0.730), between the 2 groups. Conclusion NAC prior to surgical treatment in CRCLM is considered a safe treatment that does not increase postoperative morbidity, and its impact on oncologic outcome was not inferior.

Purpose Coronavirus disease 2019 (COVID-19) has affected many parts of daily life and healthcare, including cancer screening and diagnosis. The purpose of this study was to determine whether there was an upshift in the colorectal cancer stage at diagnosis due to delays related to the COVID-19 outbreak. Methods From January to June of each year from 2017 to 2020, a total of 3,229 patients who were first diagnosed with colorectal cancer were retrospectively reviewed. Those enrolled from 2017 to 2019 were classified as the ‘pre-COVID’ group, and those enrolled in 2020 were classified as the ‘COVID’ group. The primary outcome was the rate of stage IV disease at the time of diagnosis. Results There was no statistically significant difference in the proportion of stage IV patients between the pre-COVID and COVID groups (P=0.19). The median preoperative carcinoembryonic antigen level in the COVID group was higher than in the pre-COVID group in all stages (all P

IntroductionObstruction in colon cancer is a well-known risk factor for worse oncologic outcomes. However, studies on differences in survival of patients with incomplete obstructive colon cancer (IOCC) by tumor location are insufficient. Thus, the aim of this study was to compare oncologic outcomes between IOCC and non-obstructive colon cancer (NOCC) according to tumor location.MethodsFrom January 2010 to December 2015, a total of 2,004 patients diagnosed with stage II or stage III colon adenocarcinoma who underwent elective colectomy were included (IOCC, n = 405; NOCC, n = 1,599). Incomplete obstruction was defined as a state in which colonoscopy could not pass through the cancer lesion but did not require emergent surgery, stent insertion, or stoma formation because the patient was asymptomatic without problem in bowel preparation. Kaplan–Meier method and log-rank tests were used to compare survival between IOCC and NOCC. Multivariable analysis was performed to determine which factors affected survivals.ResultsStage III IOCC patients showed significantly lower overall survival (OS) and recurrence-free survival (RFS). Stage II IOCC patients and stage III NOCC patients had similar survival curves. IOCC patients with tumors on the right side showed worse OS than other patients. In multivariable analysis, incomplete obstruction was an independent risk factor for worse OS and RFS in all stages. Tumor located at the right side in stage III was an independent risk factor for RFS (HR: 1.40, p = 0.030).ConclusionsPatients with IOCC showed significantly worse survival outcomes than those with NOCC. Stage II IOCC patients and stage III NOCC patients showed similar survival. Patients with stage III IOCC located at the right side showed significantly worse oncologic outcomes than those located at the left side. These results confirm that prognosis is different depending on the presence of incomplete obstruction and the location of the tumor, even in the same stage.

There are few studies on the prognostic impact of CEA level at the time of recurrence in recurrent colorectal cancer. The objective of this study was to evaluate the prognostic value of serum CEA levels at the time of recurrence in patients with recurrent colorectal cancer. Between 2007 and 2014, 962 consecutive recurrent patients for colorectal cancer were analyzed. These patients were divided into two groups according to CEA level at the time of recurrence (r-CEA): high r-CEA (≥5 ng/ml) (n = 428) and normal r-CEA (

Abstract Intersphincteric resection (ISR) is a surgical technique intended to avoid abdominoperineal resection (APR) in patients diagnosed with low-lying rectal cancer. However, the oncologic outcomes of minimally invasive ISR are still controversial. We analyzed the long-term oncologic outcomes of open and minimally invasive ISR. A total of 313 rectal cancer patients who underwent ISR between 2000 and 2014 were analyzed, including 147 in the open surgery group and 166 in the minimally invasive surgery (MIS) group. This study also analyzed 113 patients who received neoadjuvant chemoradiotherapy (nCRT) for advanced lower rectal cancer. Propensity score matching (PSM) was used to correct for differences between the two groups. 5-year disease-free survival (DFS) rate was the primary end point. The length of hospital stay was significantly shorter in the MIS group (9.6 vs. 11.8 days, p

PurposeThe oncologic outcome of concurrent chemoradiotherapy (CCRT) after local excision in patients with high-risk early rectal cancer as compared with radical operation has not been reported. The aim of this study is to compare the oncologic outcome between radical operation and adjuvant CCRT after local excision for high-risk early rectal cancer.Materials and MethodsFrom January 2005 to December 2015, 266 patients diagnosed with early rectal cancer and treated with local excision who showed high-risk characteristics were retrospectively analyzed. Propensity score matching was applied in a ratio of 1:4, comparing the CCRT/radiotherapy (RT) (n = 34) and radical operation (n = 91) groups. Univariate and multivariate analyses were performed to identify prognostic factors for survival.ResultsThe median follow-up period was 112 months. The 5-year disease-free survival rate and the 5-year overall survival of the radical operation group were significantly higher than those of the CCRT/RT group after propensity score matching (96.7% vs. 70.6%, p

Purpose The impact of postoperative complications on long-term oncologic outcome after radical colorectal cancer surgery is controversial. The aim of this study was to examine the risk factors and oncologic outcomes of surgery-related postoperative complication groups. Methods From January 2010 to December 2010, 310 patients experienced surgery-related postoperative complications after radical colorectal cancer surgery. These stage I–III patients were classified into 2 subgroups, minor (grades I, II) and major (grades III, IV) complication groups, according to extended Clavien-Dindo classification system criteria. Clinicopathologic differences between the 2 groups were analyzed to identify risk factors for major complications. The diseasefree survival rates of surgery-related postoperative complication groups were also compared. Results Minor and major complication groups were stratified with 194 patients (62.6%) and 116 patients (37.4%), respectively. The risk factors influencing the major complication group were pathologic N category and operative method. The prognostic factors associated with disease-free survival were preoperative perforation, perineural invasion, tumor budding, and receiving neoadjuvant therapy. With a median follow-up period of 72.2 months, the 5-year disease-free survival rates were 84.4% in the minor group and 78.5% in the major group, but there was no statistical significance between the minor and major groups (P = 0.392). Conclusion Advanced cancer and open surgery were identified as risk factors for increased surgery-related major complications after radical colorectal cancer surgery. However, severity of postoperative complications did not affect disease-free survival from colorectal cancer.

BackgroundAlthough T4b is known to have worse oncologic outcomes, it is unclear whether it truly shows a worse prognosis. This study aims to compare the survival differences between T4a and T4b.MethodsPatients who were pathologically diagnosed with T3 and T4 colorectal adenocarcinoma from 2010 to 2014 were included (T3, n = 1822; T4a, n = 424; T4b, n = 67). Overall survival (OS) and cancer-specific survival (CSS) were compared between T4a and T4b using the Kaplan-Meier method and log-rank test.ResultsIn stage II, T4a had better OS and CSS than T4b (5-year OS, 89.5% vs. 72.6%; 5-year CSS, 94.4% vs. 81.7%, all p < 0.05), however, in stage III, there were no significant differences in survivals between groups (all p > 0.05). In multivariable analysis, T classification was not an independent risk factor for OS (p > 0.05). However, for CSS, when respectively compared to T3, T4b (HR 3.53, p < 0.001) showed a relatively higher hazard ratio than T4a (HR 2.27, p < 0.001).ConclusionsT4a showed more favorable OS and CSS than T4b, especially in stage II. Our findings support the current AJCC guidelines, in which T4b is presented as a more advanced stage than T4a.

Purpose Although laparoscopic surgery is widely accepted in the treatment of colorectal cancer, conversion to open surgery is associated with the rate of unfavorable outcomes. The aim of this study was to determine the factors associated with open conversion from laparoscopic surgery for colorectal cancer. Methods A total of 3,002 patients who underwent laparoscopic colectomy as an initial plan for the treatment of colorectal cancer located from the sigmoid colon to the rectum were retrospectively evaluated between January 2009 and December 2018 at Samsung Medical Center in Korea. Risk factors significantly associated with open conversion were determined using univariate and multivariate regression models. Results Among the 3,002 patients, open conversion was performed in 120 patients (4%). Age >60 years (adjusted odds ratio [AOR], 2.370), preoperative bowel obstruction (AOR, 2.348), clinical T4 stage (AOR, 2.201), and serum carcinoembryonic antigen level >5 ng/mL (AOR, 2.289) were significantly associated with open conversion. Moreover, mucinous carcinoma was a significantly more frequent histopathologic type than adenocarcinoma (10.0% vs. 3.2%, P

We evaluated the predictive value of semiquantitative volumetric parameters derived from sequential PET/CT and developed a nomogram to predict pathological complete response (pCR) in patients with rectal cancer treated by neoadjuvant chemoradiotherapy (nCRT). From April 2008 to December 2013, among the patients who underwent nCRT, those who were taken sequential PET/CT before and after nCRT were included. MRI-based staging and semiquantitative parameters of PET/CT including standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were evaluated before and after nCRT. Multivariable analysis was performed to select significant predictors to construct a nomogram. Sensitivity, specificity, accuracy, and area under the receiver operating characteristics curve (AUC) of the model were evaluated to determine its performance. Among 137 eligible patients, 17 (12.4%) had pCR. All post-PET/CT parameters showed significant differences between pCR and non-pCR groups. Patients were randomly assigned to a training group (91 patients) and a validation group (46 patients). In multivariable analysis with the training group, post-CEA, post-MRI T staging, post-SUVmax, and post-MTV were significantly associated with pCR. There was no significant pre-nCRT variable for predicting pCR. Using significant predictors, a nomogram was developed. Sensitivity, specificity, accuracy, and AUC of the nomogram were 0.882, 0.808, 0.848, and 0.884 with the training group and 0.857, 0.781, 0.783, and 0.828 with the validation group, respectively. This model showed the better performance than other predictive models that did not contain PET/CT parameters. A nomogram containing semiquantitative post-PET/CT could effectively select candidates for organ-sparing strategies.

BACKGROUND: Signet-ring cell carcinoma (SRCC) is a very rare subtype of colorectal adenocarcinoma (COAD) with a poor clinical prognosis. Although understanding key mechanisms of tumor progression in SRCCs is critical for precise treatment, a comprehensive view of genomic alterations is lacking. MATERIALS AND METHODS: We performed whole-exome sequencing of tumors and matched normal blood as well as RNA sequencing of tumors and matched normal colonic tissues from five patients with SRCC. RESULTS: We identified major somatic alterations and characterized transcriptional changes at the gene and pathway level. Based on high-throughput sequencing, the pattern of mutations and copy number variations was overall similar to that of COAD. Transcriptome analysis revealed that major transcription factors, such as SRF, HNF4A, ZEB1, and RUNX1, with potential regulatory roles in key pathways, including focal adhesion, the PI3K-Akt signaling pathway, and the MAPK signaling pathway, may play a role in the tumorigenesis of SRCC. Furthermore, significantly upregulated genes in SRCCs were enriched for epithelial-mesenchymal transition genes, and accumulation of mucin in intracytoplasm was associated with the overexpression of MUC2. CONCLUSION: The results indicate that the molecular basis of colorectal SRCC exhibits key differences from that of consensus COAD. Our findings clarify important genetic features of particular abnormalities in SRCCs.

PurposeThis study aimed to compare short-term postoperative and oncologic outcomes of a transanal endoscopic total mesorectal excision (TME) to those of a transabdominal robotic TME.MethodsA total of 62 patients with rectal cancer underwent transanal (n = 26) or robotic (n = 36) TME between June 2013 and December 2014. After case-matching by tumor location and TNM stage, 45 patients were included for analysis. The median follow-up period was 21.3 months. Operative, histopathologic and postoperative outcomes and recurrences were analyzed.ResultsPatients younger than 60 years of age were more frequently observed in the robotic TME group (75.0% vs. 47.6%, P = 0.059), but tumor location, cT and cN category, and preoperative chemoradiotherapy were not different between the 2 groups. Estimated blood loss was greater in the transanal group (283 mL vs. 155 mL, P = 0.061); however, the operation time and the rate of a diverting ileostomy and subsequent ileostomy repair were not different between the groups. The proximal resection margin was longer in the transanal TME group (20.8 cm ± 16.0 cm, P = 0.030), but the distal resection margins, involvements of the circumferential resection margin, TME quality, numbers of retrieved lymph nodes, postoperative complications, including anastomotic leak and voiding difficulty, and recurrence rates for the 2 groups were not statistically different.ConclusionTransanal endoscopic and transabdominal robotic TME showed similar histopathologic and postoperative outcomes with the exception of the estimated blood loss and the proximal resection margin for a select group of patients.

Purpose The impact of obesity on the surgical outcomes of Asian patients undergoing laparoscopic colon surgery is not clear. The purpose was to evaluate the outcome of laparoscopic surgery in obese Asian patients with colon cancer. Methods We retrospectively reviewed the prospectively collected data of 1,740 consecutive patients who underwent laparoscopic surgery for colon cancer between January 2008 and December 2010. Patients were classified according to the categories proposed by the International Obesity Task Force, Non-obese (body mass index [BMI]

Purpose The purpose of this study was to investigate the distinctive clinicopathologic features and oncological survival outcomes of sporadic colorectal cancer in patients under the age of 30 years old. Methods From 1994 to 2013, total 15,206 patients underwent curative or palliative surgery for sporadic colorectal cancer in our institution. 235 patients (1.5%) were under 30 years of age. Patients who presented with metachronous cancers, recurrent cancers, hereditary nonpolyposis colorectal cancer, familial adenomatous polyposis and patients without a microsatellite instability (MSI) analysis were excluded. A total 79 pateints who were ≤30 years old with sporadic colorectal cancer were enrolled. Results Seven patients (8.9%) had family history of colorectal cancer. Location of the tumor was 23 (29.1%) in right colon, 29 (36.7%) in left colon, 27 (34.2%) in rectum. Young patients tend to present with a higher incidence of mucinous and signet ring cell tumors (15.2%), poorly differentiated tumors (11.4%) and advanced stage such as Stage III (31.6%), Stage IV (30.4%). microsatellite instability-high (MSI-H) was observed in 10 (12.7%), microsatellite stable (MSS)/ microsatellite instability-low (MSI-L) in 69 (87.3%). 66.7% (n=6) of the MSI-H tumors showed loss of hMLH1 expression; no MSS/MSI-L tumors showed hMLH1 loss. 5 years ovarall survival was 72.8%. Stage specific overall survival was 100% for stage I, 100% for stage II, 75.9% for stage III, 31.4% for stage IV. Conclusion Patients with sporadic colorectal cancer under the age of 30 seem to have poor outcome than older patients, because of characteristic clinical and biological behaviors. Early detection of colorectal cancer (CRC) confers survival benefit to young patients.

Purpose: For the treatment of locally advanced rectal cancer (LARC), research on primary lesions with mesorectal fascia (MRF) involvement is lacking. This study analyzed the clinical outcomes and efficacy of dose-escalated neoadjuvant concurrent chemoradiotherapy (NCRT) to patients with LARC involving MRF. Materials and Methods: We retrospectively reviewed 301 patients who were diagnosed with LARC involving MRF and underwent NCRT followed by total mesorectal excision (TME). Patients who received radiotherapy (RT) doses of =50.4 Gy were defined as the non-boost group, while =54.0 Gy as the boost group. Pathological tumor response and survival outcomes, including intrapelvic recurrence-free survival (IPRFS), distant metastases-free survival (DMFS) and overall survival (OS), were analyzed. Results: A total of 269 patients (89.4%) achieved a negative pathological circumferential resection margin and 104 (34.6%) had good pathological tumor regression grades. With a median follow-up of 32.4 months, IPRFS, DMFS, and OS rates at 5-years were 88.6%, 78.0%, and 91.2%, respectively. In the subgroup analysis by RT dose, the boost group included more advanced clinical stages of patients. For the non-boost group and boost group, 5-year IPRFS rates were 90.3% and 87.0% (p = 0.242), 5-year DMFS rates were 82.0% and 71.3% (p = 0.105), and 5-year OS rates were 93.0% and 80.6% (p = 0.439), respectively. Treatment related toxicity was comparable between the two groups (p = 0.211). Conclusion: Although this retrospective study failed to confirm the efficacy of dose-escalated NCRT, favorable IPRFS and pathological complete response was achieved with NCRT followed by TME. Further studies combining patient customized RT dose with systemic therapies are needed. [ABSTRACT FROM AUTHOR]