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Introduction: Total mesorectal excision is the standard treatment for clinical T2 (cT2) rectal cancer; however, this procedure can result in postoperative dysfunction, decreased quality of life, and stoma creation in some patients. We investigated neoadjuvant chemoradiotherapy (nCRT) plus local excision (LE) as an alternative treatment strategy for patients with cT2N0 rectal cancer. Method: Fifty-six patients with cT2N0M0 rectal cancer who exhibited the following characteristics (an anal verge of ≤8 cm, tumor size of 2) or S-1 (tegafur/gimeracil/oteracil; 80 mg/m2). Results: Fifty-five patients (98%) completed nCRT as planned. Histologically, the excision margin was negative in all patients, and four patients with ypT3 disease underwent total mesorectal excision. Recurrence was observed in 15 patients (27%), local recurrence in 7 (13%), and distant recurrence in 10 (18%). The salvage surgery was possible for the local recurrence group. The 5-year disease-free and overall survival rates were 68.4% and 84.9%, respectively. Multivariate analysis showed that only the tumor regression grade (TRG) was an independent risk factor for recurrence (p = 0.025). Although 7 (26%) out of 27 patients with a TRG of 3 or 4 developed local recurrence and 6 (22%) had distant metastasis, 25 patients with a TRG of 1 or 2 did not exhibit local recurrence, and only 1 (4%) experienced distant metastasis. Conclusion: nCRT plus LE may be an alternative treatment for patients with cT2N0 rectal cancer who achieved a TRG of 1 or 2. However, additional treatment was required in patients who achieved a TRG of 3 or 4.

Background: In patients with colorectal cancer, the rate of recurrence increases as the histologic stage progresses. However, the prediction of recurrence in individual patients is difficult. Many studies have reported on the relation between outcomes and tissue-infiltrating lymphocytes (TILs). The aim of our study was to clarify the relation between TILs and oncologic outcomes in patients with colon cancer using propensity score matching analysis. Methods: The study group comprised 513 patients with colon cancer who received curative resection. By using propensity score matching for sex, age, tumor location, T stage, N stage, histologic type, and adjuvant therapy as conventional prognostic factors, 61 patients with recurrence and 61 patients with no recurrence were selected. Hematoxylin-eosin staining and immunohistochemical staining using CD3, CD8, CD4, and FoxP3 were performed for lymphocytes in the primary tissue. The results were evaluated separately in the whole tumor, the central part, and the invasive margin. Results: The median follow-up period was 53 months. Among the 513 patients, 70 had recurrence and 443 had no recurrence. In the comparison of outcomes between the 61 patients with recurrence and the 61 patients with no recurrence, univariate analysis showed that the disease-free survival rate was significantly higher among the patients with positive TILs in the whole tumor and in the invasive margin (p = 0.016 and p = 0.012, respectively) and with CD8+ cells in the central part (p = 0.039) than among those with negative results. A multivariate analysis showed that TILs in the invasive margin (hazard ratio 1.81; 95% confidence interval, 1.03–3.05; p = 0.037) and CD8+ cell density in the central part (hazard ratio 1.76; 95% confidence interval, 1.07–2.93; p = 0.023) were prognostic factors that were independent from conventional prognostic factors. Conclusions: In patients with curatively resected colon cancer, TILs in the invasive margin and CD8+ cell density in the central part may be prognostic factors suggesting host antitumor immune response.

Background: Neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision surgery is a standard treatment for locally advanced rectal cancer (LARC). Tumor-infiltrating lymphocytes (TILs) have been reported to be associated with tumor response; however, this remains to be established. We previously reported that histological changes on biopsy specimens obtained 7 days after starting nCRT are strong predictors of response to nCRT. Methods: The subjects were 208 patients with LARC who received nCRT. TILs on hematoxylin-eosin staining together with immunohistochemical staining of lymphocyte surface markers including CD3, CD4, CD8, and FoxP3 were performed both on the biopsy specimens before and 7 days after starting nCRT. Results: The proportions of patients with high densities of CD3+, CD4+, CD8+, and FoxP3+ cells 7 days after starting CRT were significantly lower than the respective values before starting nCRT (p < 0.0001, p < 0.0001, p = 0.0023, and p = 0.0046). In biopsy specimens obtained before treatment, high-density CD4+ cells and FOXP3+ cells were significantly associated with tumor shrinkage rate. High-density FOXP3+ cells were significantly associated with marked tumor regression. In biopsy specimens obtained 7 days after starting treatment, high-density CD4+ cells were significantly associated with marked tumor regression, tumor regression grade 1, and tumor shrinkage rate. High-density FoxP3+ cells were significantly associated with marked tumor regression and tumor shrinkage rate. Conclusions: In patients who received nCRT for LARC, the evaluations of immunohistochemical staining for CD4+ and FOXP3+ TILs were more intimately related to histological response to CRT and tumor shrinkage rates in biopsy specimens obtained 7 days after starting treatment than in biopsy specimens obtained before CRT.

Background Seprafilm did not decrease small bowel obstruction (SBO), but significantly decreased reoperation in patients with inflammatory bowel disease. However, the preventive effect in colon cancer remains unclear. Methods We conducted a randomized controlled trial in patients with colon cancer. The study group comprised 345 patients with colon cancer. In the seprafilm group (n = 166), two sheets of seprafilm were inserted under a midline incision. Patients who were admitted and required decompression were considered to have SBO. Results The median follow-up was 61.9 months. Patient characteristics were well balanced. There was no significant difference in the incidence of SBO between the seprafilm group (7.8%) and the control group (10.6%) (P = .46). In patients who underwent reoperation, SBO occurred in a midline incision in one patient and at other sites in four patients in the seprafilm group as compared with two patients and five patients, respectively, in the control group. Multivariate analysis showed that only a history of laparotomy was an independent risk factor for SBO. Conclusions Seprafilm did not decrease SBO or reoperation in colon cancer. The incidence of SBO caused by adhesion to the midline incision was relatively low as compared with that caused by adhesion to other sites.

Background/aim Immune checkpoint inhibitors are mainly used for right-sided, microsatellite instability-high colorectal tumors. In this study, the effects of oral uracil-tegafur plus leucovorin (UFT/LV) chemotherapy on the gene expressions of four immunotherapy targets and the amounts of tumor-infiltrating lymphocytes (TILs) were investigated. Patients and methods Data of 260 patients with stage II or stage III colorectal cancer were analyzed. Gene expression and amount of TILs were evaluated using real-time reverse transcription polymerase chain reaction (CRT-PCR) assay and immunohistochemical staining, respectively. Results Expression of CTLA4 and LAG3 in tumor tissues was significantly increased after UFT/LV chemotherapy, but only in left-sided tumors. The percentage of high-TIL, high-CD3 and high-FoxP3 patients in the UFT/LV group was significantly higher than that in the control group, only in left-sided tumors. Conclusion The increase in TILs count, especially of CD3+ T cells and FoxP3+ regulatory T cells, after UFT/LV chemotherapy were specific to left-sided colorectal cancers.

Background: FOLFIRI plus bevacizumab have been widely used as first-line treatment for metastatic colorectal cancer (mCRC). Pharmacokinetics and pharmacodynamics suggested a low dose of irinotecan given as a long-term infusion is expected to enhance antitumor activity. We conducted a randomized phase II study to compare oral S-1 with a 24-h infusion of irinotecan plus bevacizumab versus FOLFIRI plus bevacizumab. Methods: The subjects comprised 120 chemotherapy-naïve patients with mCRC. The study group received a 24-h infusion of irinotecan at a dose of 125 mg/m2 on days 1 and 15, combined with oral S-1 80 mg/m2 on days 1–14 (24h-SIRI/B). The FOLFIRI/B group received irinotecan at a dose of 150 mg/m2, 5-fluorouracil given at a dose of 400 mg/m2 as a bolus injection and at a dose of 2,400 mg/m2 as a 46-h infusion, and 200 mg/m2 leucovorin on days 1 and 15. Bevacizumab was given at a dose of 5.0 mg/kg on days 1 and 15 in both groups. Treatment was repeated every 4 weeks. The primary endpoint was 1-year progression-free survival (PFS). Secondary endpoints were PFS, response rates (RR), overall survival (OS), and adverse events (AEs). Results: From December 2013 through January 2018, 120 patients were randomly assigned, 61 patients to the 24h-SIRI/B and 59 patients to the FOLFIRI/B. The median follow-up period was 22.8 months. The 1-year PFS rate was 43.14% in the 24h-SIRI/B arm and 19.15% in the FOLFIRI/B arm (HR = 0.312 [95%CI 0.13–0.78], p = 0.01). The median PFS was 10.2 months (95%CI 8.8–14.3) and 10.0 months (95%CI 7.4–11.0), and the median OS was 29.7 months (95%CI 22.9–43.9) and 28.8 months (95%CI 18.4-ND), respectively (p = 0.3758, p = 0.8234). The overall RR was 86.3 and 61.7%, respectively (p = 0.0053). AEs were similar. Conclusions: Our results show that the 24h-SIRI/B regimen is an effective and reasonably well-tolerated regimen for the first-line treatment of mCRC.

Regorafenib and trifluridine/tipiracil (TAS-102) are novel antitumor agents for patients with refractory metastatic colorectal cancer. However, it is unclear which patients may derive a survival benefit from these drugs in real-life clinical practice. We evaluated retrospectively the efficacy and safety of regorafenib and TAS-102 at a single institution between June 2013 and November 2015. Cox regression analysis was carried out to obtain predictive scores (the nearest integers of hazard ratio) for survival benefit. Forty-four patients treated with regorafenib or TAS-102 were included in the analysis; among them, 17 received crossover treatment. The median overall survival (OS) was 9.1 months for regorafenib and 9.3 months for TAS-102, and the corresponding values after crossover were 7.1 and 5.3 months, respectively. OS was not correlated to relative dose intensity, but was proportional to the total administered dose of each drug. Adverse events were tolerable even after crossover. We identified three variables as significant for prediction of OS with good discrimination (C-statistic=0.70): Poor Eastern Cooperative Oncology Group performance status, time since diagnosis of metastatic disease ≤18 months, and previous chemotherapy continued ≥2 months beyond progression were all predictors of poor OS. Regorafenib and TAS-102 can be recommended for patients with better performance status and slow progression of metastatic disease. Optimal survival benefit was provided by prompt administration of either drug after failure of previous chemotherapy, with flexible titration to the optimal dose for each individual patient.

Background/aim The standard treatment for rectal cancer is neoadjuvant chemoradiotherapy (nCRT) followed by surgery. Mucinous carcinoma responds poorly to nCRT. In some patients, mucin lakes (MLs) are induced by nCRT. Identifying whether MLs are induced or originally present would be of great importance. Patients and methods We studied 20 patients with MLs (CRT-MC group) among 205 patients who received nCRT. Among 88 patients who did not receive nCRT, we studied 9 patients with mucinous carcinoma (non-CRT-MC group) and 18 patients with MLs in differentiated adenocarcinoma (non-CRT-AC group). Tumors were stained with high iron diamine-Alcian blue (HID-AB) and MUC1 staining. Results Rate of AB>HID staining of cancer cells was significantly higher in the CRT-MC group than in non-CRT-MC group (p=0.0004). Rate of MUC1 staining in MLs was significantly higher in the CRT-MC group (p=0.0254). Conclusion nCRT can induce qualitative changes in mucinous components, however, other methods are required to distinguish induced components from originally existing components.

Background Mucinous rectal carcinoma has been reported to have a lower survival rate and a poorer histologic response to chemoradiotherapy(CRT). Magnetic resonance imaging (MRI) can accurately evaluate the amount of mucin pools (MP) in primary cancer tissue. We compared the degree of MP on MRI before and after CRT with the histologic findings of resected specimens to investigate the predictors of response to CRT. Methods The study group comprised 205 patients with rectal adenocarcinoma who received preoperative CRT. MPs were measured on MRI before and after CRT and in resected specimens. The degree of MP was classified into five classes according to the MP area ratio: 0%, class I; 1 to 19%, class II; 20 to 49%, class III; and 50% or higher, class IV. Results The degree of MP on MRI was largely unchanged after CRT; however, the MP on MRI after CRT was underestimated in 26.3% of patients as compared with that in resected specimens. A pathological complete response was obtained in patients who initially had no MP or had an MP ratio of less than 20%. The tumor volume was significantly greater, and the rates of tumor shrinkage and T downstaging were significantly lower in patients who had an MP area ratio of 20% or higher before CRT than in those who had an MP area ratio of less than 20%. Conclusions The MP area ratio measured on MRI before treatment was closely associated with the response to CRT and is a potentially useful predictor of treatment response.

In rectal cancer who received chemoradiotherapy, the number of Lymph nodes (LNs) required remains unclear. We conducted a randomized controlled trial to determine whether preoperative tattooing increases the number of LNs and enhances the detection rate of metastatic LNs.Eighty patients with rectal cancer who received chemoradiotherapy were randomly assigned to receive no tattooing (C group) or to receive tattooing (T group).The number of LNs was significantly higher in the T group (13.3 ± 7.4, mean ± SD) than in the C group (8.8 ± 5.9, p 0.001), however, the number of positive LNs did not differ (0.5 ± 1.3 vs. 0.5 ± 1.1, p = 0.882). The long-axis diameter of LNs was significantly smaller in the T group than in the C group (3.4 ± 1.8 vs. 3.9 ± 2.3 mm, p 0.001), however, the long-axis diameter of positive LNs did not differ.Tattooing increased the number of retrieved LNs by 51%, however, there was no increase in the number of positive LNs.

Objective: The National Comprehensive Cancer Network (NCCN) guidelines recommend local excision and observation as standard treatment for selected patients with clinical T1N0M0 rectal cancer. In patients with pathological T1 (pT1) rectal cancer who received local excision, the local recurrence rate is at least 10%. We studied oncological outcomes in patients with pT1 rectal cancer who received chemoradiotherapy (CRT) after local excision. Methods: Local excision was performed in 65 patients with clinical T1N0M0 rectal cancer (≤8 cm from the anal verge, tumor size < 30 mm, well or moderately differentiated adenocarcinoma). The patients received CRT (40 or 45 Gy in 1.8–2.0 fractions with concurrent oral UFT [tegafur/uracil] or S-1 [tegafur/gimeracil/ote­racil]) after confirmation of pT1 and negative margins. Results: Patients who had pT2 cancer or who did not provide informed consent were excluded. The remaining 50 patients additionally received CRT. The CRT was completed in 48 patients (96%). The median follow-up period was 71 months. Local recurrence occurred in 1 patient (2%). Distant metastases occurred in 3 patients (6%). The 5-year disease-free survival rate was 86%, and the 5-year overall survival rate was 92%. Conclusions: Our study suggested that multidisciplinary treatment with local excision plus CRT can be used as a treatment option in selected patients with clinical T1N0M0 rectal cancer.

Objective: We previously reported that the largest diameter of retrieved lymph nodes (LNs) correlates with the number of LNs and is a prognostic factor in stage II colon cancer. We examine whether T, B, and natural killer (NK) cells in LNs are related to the number of LNs and survival. Methods: The subjects comprised 320 patients with stage II colon cancer. An LN with the largest diameter was selected in each patient. The positive area ratios of cells that stained for CD3 and CD20, and the numbers of CD56-positive cells were measured. Results: The CD3-positive area ratio was 0.39 ± 0.08 and CD20-positive area ratio was 0.42 ± 0.10. The mean number of CD56-positive cells was 19.3 ± 22.7. The area ratios of B cells and T cells and the number of NK cells were significantly related to the sizes of the largest diameter LNs. The number of NK cells significantly correlated with the number of LNs and was an independent prognostic factor. On multivariate analysis, pathological T stage (T4 or T3; HR 4.71; p < 0.001) and the number of CD56-positive cells (high or low; HR 0.22; p < 0.001) were found to be independent prognostic factors. Conclusions: The number of NK cells in the largest diameter LNs can most likely be used as a predictor of recurrence.

Objectives: The histologic response to neoadjuvant chemoradiotherapy (nCRT) has been intimately related to outcomes in locally advanced rectal cancer. Serum carcinoembryonic antigen (CEA) levels change after nCRT and after surgery as compared with before nCRT. Methods: The subjects were 149 patients with locally advanced rectal cancer who received nCRT between 2005 and 2013. The patients were divided into 4 groups according to the serum CEA levels: group 1, 55 patients with negative serum CEA levels before nCRT; group 2, 41 patients with positive serum CEA levels before nCRT that became negative after nCRT; group 3, 37 patients with positive serum CEA levels after nCRT that became negative after surgery; and group 4, 16 patients with positive serum CEA levels after nCRT as well as after surgery. Results: Pathological complete response, T downstaging, and tumor shrinkage were significantly higher in group 1 than in other groups. Disease-free survival was significantly poorer in group 4. The lack of a decrease in the serum CEA level in group 4 was most likely attributed to the persistence of micrometastases outside the resection field. Conclusions: Changes in serum CEA levels measured before nCRT, after nCRT, and after surgery can be used to reliably predict the histologic response to nCRT and outcomes.

Rectal washout is performed in rectal cancer surgery to eliminate exfoliated cancer cells. Before rectal washout, a cross-clamp should generally be placed distal to the tumor. In some patients with lower rectal cancer, however, the tumor cannot be adequately isolated. We, therefore, hypothesized that neoadjuvant chemoradiotherapy (nCRT) can decrease the number of exfoliated cancer cells even after the rectal washout including tumors. We prospectively studied 86 patients with rectal cancer who underwent proctectomy after nCRT. A cross-clamp was applied proximal to the tumor, and the rectum was washed with 2000 mL of physiological saline solution. The initial 100 mL used to wash the rectum was collected as a pre-washout sample. After the rectum was washed with the remaining 1900 mL, the solution remaining in the rectum was collected as a post-washout sample. Cells classified as class IV or higher according to the papanicolaou classification were considered to indicate a positive diagnosis. The cytological diagnosis was positive in pre-washout samples in 21 patients (24%) and post-washout samples in two patients (2%). In patients with rectal cancer, nCRT may decrease the number of exfoliated cancer cells in the rectum, and rectal washout including the tumor may be oncologically acceptable.

Background: Colorectal neuroendocrine carcinoma (NEC) is a rare disease, and mixed cases with colorectal adenocarcinoma also exist. The histogenesis of this disease remains unclear. We studied the numbers of neuroendocrine marker-positive cells in adenocarcinoma tissue and in normal ­mucosal tissue to investigate the relation between adenocarcinoma and NEC and to discuss the histogenesis of NEC. Methods: We studied a total of 354 curatively resected cases of stage II or III colon cancer and 36 cases of rectal cancer treated at the Tokai University Hospital between 2007 and 2012. Adenocarcinoma tissue and normal mucosal tissue were immunohistochemically stained with chromogranin A, synaptophysin, and CD56. Cases in which neuroendocrine marker-positive cells were found in cancer tissue were defined as positive. In normal mucosa, the numbers of positive cells per 15 high-power fields (HPF) were counted. Results: Among the 390 cases, 181 cases had right sided colon cancer, 173 cases had left sided colon cancer, and 36 cases had rectal cancer. The rates of positive staining for chromogranin A, synaptophysin, and CD56 were significantly higher in the right sided colon than in the left sided colon, consistent with the preferred sites of NEC as reported previously. Cells positive for chromogranin A and synaptophysin in normal mucosa were significantly more common in the rectum and the left sided colon than in the right sided colon. No site-specific differences were found for CD56. Conclusions: Neuroendocrine marker-positive cells in colorectal cancer tissue are more common in the right sided colon, whereas neuroendocrine marker-positive cells in normal mucosa are more common in the rectum. These results suggest that NEC may arise from preceding adenocarcinomas.

Background: To prevent surgical site infection (SSI) in colorectal surgery, the combination of mechanical bowel preparation (MBP), oral antibiotic bowel preparation (OABP), and the intravenous antibiotics have been proposed as standard treatment. We conducted an RCT comparing the incidence of SSI between MBP + OABP and OABP alone after receiving a single dose of intravenous antibiotics. Methods: The study group comprised 254 patients who underwent elective surgery for colon cancer. Patients were randomly assigned to receive MBP + OABP and intravenous antibiotics (MBP + OABP group) or to receive OABP and intravenous antibiotics (OABP alone group). Results: Overall, 125 patients in MBP + OABP group and 126 patients in OABP alone group were eligible. Incisional SSI occurred in 3 patients (2.4%) in MBP + OABP group, and 8 patients (6.3%) in the OABP-alone group. Organ/space SSI developed in 0 patients (0%) and in 4 patients (3.2%) in each group respectively. The OABP-alone group was thus not shown to be noninferior to the MBP + OABP group in the incidences of incisional SSI or organ/space SSI. Other infectious complications developed in 7 patients (5.6%) and in 6 patients (4.8%) in each group, indicating the non-inferiority of OABP alone to MBP + OABP. Conclusions: MBP combined with oral antibiotics and intravenous antibiotics remains standard in elective colon cancer surgery.

Objective: The histologic response to neoadjuvant chemoradiotherapy (CRT) has been intimately related to outcomes in locally advanced rectal cancer. However, reliable prognostic factors have yet to be established. Subjects and Methods: The study group comprised 198 patients with locally advanced rectal cancer who received CRT. A modified classification based on the combination of ypStage and tumor regression grade (TRG) was developed. ypStage II with TRG 2 was classified as ypTRGstage IIA, and ypStage II with TRG 3 or 4 was classified as ypTRGstage IIB. ypStage 0 and ypStage I were classified as ypTRGstage I, and ypStage III was classified as ypTRGstage III. Results: The 5-year disease-free survival (DFS) was 83% in ypTRGstage I, 86% in ypTRGstage IIA, 57% in ypTRGstage IIB, and 60% in ypTRGstage III (p = 0.0001). The 5-year DFS in ypTRGstage IIA did not differ significantly from that in ypStage 0 (p = 0.865) or ypStage I (p = 0.585). The 5-year DFS in ypStage IIB did not differ from that in ypStage III (p = 0.912). Multivariate analysis showed that ypTRGstage was an independent risk factor for DFS. Conclusion: A modified classification allows patients with ypStage II locally advanced rectal cancer to be clearly divided into two groups: responders and nonresponders.

In recent years, there have been many reports about the efficacy of stenting for central bronchial stenosis. When central bronchial stenosis is due to metastasis of a malignant tumor to the trachea and/or bronchi (endobronchial metastasis: EM), it is classified as "narrow EM" and "broad EM." [1] We managed two patients in whom bilateral stent placement was required for narrow and broad EM arising from colorectal cancer. Case 1: In September 2011, a 66-year-old man underwent low anterior resection for advanced colorectal cancer associated with unresectable liver metastasis. The liver metastasis became resectable after chemotherapy, with two resection procedures and radiofrequency ablation (RFA) being performed. Thereafter, lung metastasis occurred and a tumor in the left lung was resected. In May 2015, he developed respiratory distress. CT identified multiple lesions protruding into the lumen of the trachea and the left and right main bronchi. There was no evidence of mediastinal relapse or local relapse at the resection margin, and tumors were only detected in the tracheobronchial walls. Accordingly, narrow EM was diagnosed. An expandable metallic stent (EMS) was placed on the right side where stenosis was more severe, and radiation therapy was conducted for the non-stented tumors. The patient died 8 months later. Case 2: A 69-year-old woman had undergone laparoscopic right hemicolectomy and adjuvant chemotherapy for Stage lllb cancer of the ascending colon. Due to subsequent elevation of tumor markers, PET-CT was conducted and abnormal uptake was seen in the apex of the right lung and right upper abdomen. Both lesions were resected, and omental and lung metastases were diagnosed. She received treatment with UFT / calcium folinate, but relapse occurred at the resection margin in the right lung. At 7 years and 5 months after initial surgery, she complained of respiratory distress at an outpatient visit. CT demonstrated displacement of the trachea and right main bronchus due to enlargement of upper mediastinal lymph nodes. There was also severe stenosis of the right main bronchus due to tumor infiltration. Because there was both infiltration from local recurrence after resection and upper mediastinal lymph node enlargement, broad EM was diagnosed. An EMS was placed at the site of severe stenosis in the right main bronchus. Similar to Case 1, radiation therapy was also conducted, but respiratory distress occurred after 3 months due to tumor re-growth at the stent margin. Accordingly, stent-in-stent placement was performed and her respiratory symptoms improved. However, superior vena cava syndrome occurred 1 month later and the patient died. We consider that placing an EMS is effective in patients with tracheal stenosis due to EM that is judged to be an oncological emergency.

613 Background: FOLFOX or FOLFIRI plus Bev is a first-line treatment for MCRC. Recent studies have confirmed that oral S-1 combined with Iri and Bev is equivalent to FOLFIRI plus Bev. Iri is usually administered as a short-term 90-min. infusion. However, the cytocidal activity is S-phase specific, and carboxylesterases, that convert Iri into SN-38, are less likely to become saturated when Iri is given as a long-term infusion. Therefore, a low dose of Iri given as a long-term infusion is expected to enhance antitumor activity. We conducted a randomized phase II study to compare this regimen with FOLFIRI plus Bev. Methods: The subjects comprised 120 chemotherapy-naïve patients with MCRC. The study group received 24-hr infusion of Iri at a dose of 125 mg/m2 on days 1 and 15, combined with oral S-1 80 mg/m2 on days 1 to 14. The FOLFIRI group received Iri at a dose of 150 mg/m2, 5-FU given at a dose of 400 mg/m2 as a bolus injection and at a dose of 2400 mg/m2 as a 46 hr-infusion, 200 mg/m2 of leucovorin on days 1 and 15. Bev was given at a dose of 5.0 mg/kg on days 1 and 15 in both groups. Treatment was repeated every 4 weeks. The primary endpoint was the 1 y progression-free survival (PFS). Secondary endpoints were PFS, response rates (RR), overall survival (OS), and adverse events (AEs). Results: From October 2013 through December 2017, a total of 61 patients assigned to receive IRIS plus Bev (the A group) and 59 patients assigned to receive FOLFIRI plus Bev (the B group) were included in the analysis. The 1y RFS was 37.3% in the A group and 17.0% in the B group (p = 0.0281). The PFS was 10.2 mon in the A group and 10.0 mon in the B group, and the median OS was 27.0 mon and 28.6 mon, respectively (p = 0.26, p = 0.68). RR was significantly higher in the A group (87.0%) than in the B group (61.7%) (p = 0.005). The main grade 3 or 4 AEs were neutropenia (27.8%) and diarrhea (11.1%) in the A group and neutropenia (23.4%) and leukopenia (6.4%) in the B group. Conclusions: Our results showed that Iri, given biweekly as a 24-hour infusion in combination with oral S-1 and Bev, is a highly effective and well-tolerated regimen for the first-line treatment of MCRC. Clinical trial information: UMIN000014664.

617 Background: Neuroendocrine carcinoma (NEC) is a rare disease and has been reported to most frequently arise in the right side of the colon. In the 2010 WHO classification, mixed adenoneuroendocrine carcinoma (MANEC) was defined as a neoplasm consisting of NEC and adenocarcinoma components. To clarify the histogenesis of NEC, we attempted to detect neuroendocrine marker-positive cells in cancer tissue and in the adjacent mucosa in patients with adenocarcinoma. Methods: The study group comprised 390 patients with Stage II or III colorectal adenocarcinoma between 2007 and 2012. Immunostaining was performed with anti chromogranin A, synaptophysin, and CD56 antibodies. Cases with positively stained cells in cancer tissue were defined as positive. In the adjacent mucosa, at least 5 cm from the tumor, the numbers of positive cells per 15 HPF were measured. Results: Tumor location was right side in 181 patients, left side in 173, and the rectum in 36 patients. Positive rates of Chromogranin A in cancer tissues were 23.7% in the right colon, 13.2% in the left colon, and 19.4% in the rectum. Those of synaptopysin were 35.3%, 21.9%, and 30.6%, respectively. Those of CD56 were 22.6%, 8.0%, and 16.7%, respectively. Positive rates of these three markers in right colon were significantly higher than those in left colon and rectum. (p = 0.0115, p = 0.0054, p = 0.0062). In the adjacent mucosa, the mean numbers of positive cells for chromogranin A were 62.2 ± 20.5 in the right colon, 131.9 ± 44.7 in the left colon, and 243.7 ± 60.2 in the rectum (p < 0.001). Those for synaptophysin were 47.7 ± 23.5, 95.3 ± 35.1, and 156.9 ± 56.8, respectively. (p < 0.001). There were no significant differences in the number of positive cells for CD56 among the sites (p = 0.295). Conclusions: In cancer tissue, the rate of positive staining for neuroendocrine marker-positive cells was higher in the right side of the colon, whereas in normal mucosa the rates of positive staining for these cells were higher in the sigmoid colon and the rectum. These results suggest that neuroendocrine marker-positive cells are an acquired characteristic of cancer tissue.

494 Background: In colon cancer, retrieval of less than 12 lymph nodes is a risk factor for recurrence. We previously reported that the long-axis diameter of the largest LNs (maximum LNs) is associated with a higher number of retrieved LNs and better outcomes in stage II disease (Int J Colorectal Dis 2015). Furthermore, the number of natural killer cells in the maximum LNs is associated with the number of retrieved LNs and lymph node size, and is an independent prognostic factor (Oncology 2018). We examined whether the long-axis diameter of maximum LNs with and without metastasis is a prognostic factor in stage III colon cancer. Methods: The study group comprised 190 patients with stage III colon cancer from 2005 to 2014. For each patient, one negative LN and one positive LN with the greatest long-axis diameter were selected, and the diameter was measured on H-E stained specimens. The endpoint of survival analysis was relapse free survival (RFS). The cut-off value (COV) was determined by using receiver operating characteristic curves. Results: The mean long-axis diameter of maximum negative and positive LNs were 8.5 ± 3.7 and 9.9 ± 4.9 mm, respectively. Factors related to the number of retrieved LNs were the tumor size (less than 4.3 cm, 13.5 ± 6.4; 4.3 cm or more, 16.6 ± 7.3; p = 0.004) and the long axis diameter of maximum negative LNs (< 8.1 mm, 13.4 ± 6.9; ≥ 8.1 mm, 17.6 ± 6.6; p < 0.001). Maximum negative LNs with a diameter of ≥ 8.1 mm was associated with significantly better RFS than maximum negative LNs with a diameter of < 8.1 mm (p = 0.020). The diameter of maximum positive LNs was not a prognostic factor. On multivariate analysis, the tumor size (≥ 4.3 cm/< 4.3 cm, HR 3.02; p < 0.001), venous invasion (absent/present, HR 0.41; p = 0.017), the number of LNs (≥ 12/< 12, HR 0.56; p = 0.043), and the diameter of maximum negative LNs (≥ 8.1 mm/< 8.1 mm, HR 0.45; p = 0.008) were independent prognostic factors. Conclusions: In stage III colon cancer, the long-axis diameter of negative maximum LNs was a prognostic factor. Enlarged negative LNs are caused by hyperplasia of cell components in LNs. The size of negative maximum LNs might reflect the tumor immunity of the host.

Purpose Preoperative chemoradiotherapy (CRT) using 5-fluorouracil (5-FU)-based chemotherapy is the standard of care for rectal cancer. The effect of additional chemotherapy during the period between the completion of radiotherapy and surgery remains unclear. Predictive factors for CRT may differ between combination chemotherapy with S-1 and with tegafur-uracil/leucovorin (UFT/LV). Methods The subjects were 54 patients with locally advanced rectal cancer who received preoperative CRT with S-1 or UFT/LV. The pathological tumor response was assessed according to the tumor regression grade (TRG). The expression levels of 18 CRT-related genes were determined using RT-PCR assay. Results A pathological response (TRG 1-2) was observed in 23 patients (42.6%). In a multivariate logistic regression analysis for pathological response, the overall expression levels of four genes, HIF1A, MTHFD1, GGH and TYMS, were significant, and the accuracy rate of the predictive model was 83.3%. The effects of the gene expression levels of GGH on the response differed significantly according to the treatment regimen. The total pathological response rate of both high-GGH patients in the S-1 group and low-GGH patients in the UFT/LV group was 58.3%. Conclusion Additional treatment with 5-FU-based chemotherapy during the interval between radiotherapy and surgery is not beneficial in patients who have received 5-FU-based CRT. The expression levels of four genes, HIF1A, MTHFD1, GGH and TYMS, in tumor tissues can predict the response to preoperative CRT including either S-1 or UFT/LV. In particular, the gene expression level of GGH in tumor tissues may be a useful biomarker for the appropriate use of S-1 and UFT/LV in CRT.

Objectives: Serum carcinoembryonic antigen (CEA) has been widely used for postoperative surveillance for colorectal cancer. However, serum CEA has a poor diagnostic accuracy for detecting recurrence. We tested the hypothesis that determining cutoff values according to the preoperative serum CEA levels would enhance the diagnostic accuracy. Methods: Serum CEA was measured before and 1-6 months after surgery in 783 patients with curatively resected colon cancer from 2005 through 2013. The cutoff values during surveillance were determined separately according to preoperative serum CEA levels. Results: In patients with negative preoperative serum CEA, the diagnostic accuracy for recurrence was 89.1% when a postoperative cutoff value was set at 5 ng/mL. However, in patients with positive preoperative serum CEA, the diagnostic accuracy was 58.4% when a postoperative cutoff value was set at 5 ng/mL, and was 75.6% when a cutoff value was set at 8 ng/mL. Among patients with positive preoperative serum CEA, the recurrence-free survival rate was significantly lower in patients with a serum CEA of ≥8 ng/mL than those with a serum CEA of p = 0.0018). Conclusions: The diagnostic accuracy of serum CEA for recurrence is enhanced by separately setting cutoff values according to preoperative serum CEA.

Background Rectal cancer is associated with a higher rate of surgical complications. The ability to predict the risk of complications before treatment would facilitate the design of personalized treatment strategies optimally suited for each patient. Methods We retrospectively studied 260 patients with rectal cancer who underwent radical surgery to examine the relations between complications and 5 types of risk scores. Results Complications developed in 56 patients (21.5%). Nineteen patients had infectious complications, 16 had intestinal obstruction, and 12 had other complications. Twelve patients out of 187 patients who received low anterior resection had anastomotic leakage. Estimation of Physiologic Ability and Surgical Stress Comprehensive Risk Score (E-PASS CRS) and Neutrophil-to-lymphocyte Ratio (NLR) were significantly related to all complications, infectious complications, and anastomotic leakage. Surgical Apgar Score was significantly related to infectious complications. Prognostic Nutritional Index was significantly related to all complications and intestinal obstruction. Colorectal Physiologic and Operative Severity Score for the Enumeration of Mortality and Morbidity was significantly related to all complications, and infectious complications. A multivariate analysis showed that body-mass index, E-PASS CRS, and NLR were independent risk factors for anastomotic leakage. In particular, NLR was the only score that could be evaluated before surgery. Conclusions Five types of risk scores were useful methods for evaluating the risks of complications in patients with rectal cancer. NLR is a score that can be evaluated before surgery and predicted the risk of anastomotic leakage, suggesting that it is useful for assessing the need for a diverting colostomy.

The case of a patient with asymptomatic double common bile duct that was identified by chance is presented. A 41-year-old man underwent esophagogastroduodenoscopy(EGD) as part of a regular health checkup, during which he was found to have an elevated lesion in the lesser curvature of the upper gastric corpus with bile draining from its tip. Further examination led to a diagnosis of double common bile duct from the left intrahepatic bile duct to the opening into the stomach. Morphological abnormalities of the biliary tree are commonly encountered in everyday gastroenterological practice, but a double common bile duct with an ectopic opening into the stomach is comparatively rare. It is also associated with an increased risk of developing cancer of the stomach or bile duct, and as such is a biliary abnormality that must be treated with caution. This case is reported together with a discussion of the literature.

A 74-year-old woman undergoing outpatient follow-up for reflux esophagitis and atrophic gastritis tested positive for Helicobacter pylori and underwent primary eradication therapy with lansoprazole (LPZ) 30 mg, amoxicillin (AMPC) 750 mg, and clarithromycin (CAM) 200 mg twice daily for 1 week in August 2012. A urea breath test (UBT) after this treatment revealed that eradication had failed. Secondary eradication therapy was carried out with esomeprazole (EPZ) 20 mg, AMPC 750 mg, and metronidazole (MNZ) 250 mg twice daily for 1 week, but this also failed. The third attempt at eradication consisted of EPZ 20 mg, AMPC 750 mg, and sitafloxacin (STFX) 100 mg twice daily for 1 week, but this also ended in failure. A fourth attempt using rabeprazole (RPZ) 20 mg (4 times daily) with MNZ 250 mg and STFX 100 mg twice daily for 2 weeks also failed, as did a fifth attempt in April 2015 using vonoprazan (VPZ) 20 mg, AMPC 750 mg, and MNZ 250 mg twice daily for 1 week. Eradication was finally successful after the sixth attempt, in which the patient was treated with vonoprazan 20 mg, MNZ 250 mg, and STFX 100 mg twice daily for 2 weeks.

790 Background: Neoadjuvant chemoradiotherapy (nCRT) is a standard of care for LARC. The serum CEA level is a predictor of the response to nCRT; however, the relation between CEA production immunohistochemically evaluated in cancer tissue and treatment response remains unclear. Methods: The study group comprised 145 patients with clinical Stage II/III rectal cancer who received nCRT followed by surgery from 2005 through 2013. The radiation dose was 40 to 45 Gy. UFT- or S-1-based chemotherapy was given concurrently. Surgery was performed 6 to 8 weeks after the completion of radiotherapy. Immunohistological CEA staining patterns in biopsy tissue obtained before nCRT were evaluated. Specimens in which the luminal cell membrane or the cytoplasm was strongly stained were defined as staining positive. The histologic response was evaluated on the basis of the pathological complete response (ypCR) rate, T downstaging, tumor regression grade (TRG), and tumor shrinkage rate on MRI. Results: CEA staining in biopsy specimens and serum CEA levels were both negative in 17 patients (11.7%) and both positive in 72 patients (49.7%). There was no relation between the groups (p = 0.174). In patients with negative CEA staining, the rates of ypCR, T downstaging, marked regression, and mean tumor shrinkage were 24.3%, 51.4%, 45.9%, and 72.3%, respectively. In patients with positive CEA staining, these rates were 11.1%, 48.1%, 37.0%, and 72.8%, respectively. CEA staining of cancer tissue was not significantly related to the ypCR rate, T downstaging, a marked regression rate, or the tumor shrinkage rate on MRI (p = 0.060, p = 0.849, p = 0.436, and p = 0.874, respectively). Patients with negative serum CEA levels before nCRT had significantly higher rates of ypCR, T downstaging, marked regression, and tumor shrinkage on MRI than did patients with positive serum CEA levels (p = 0.014, p = 0.006, p = 0.002, and p = 0.014, respectively). Conclusions: Serum CEA levels before nCRT were a significant predictor of the histologic response to nCRT; in contrast, tissue CEA staining before nCRT was unrelated to the histologic response to nCRT.

768 Background: Mucinous carcinoma has been reported to have a lower survival rate, a poorer histologic response to preoperative chemoradiotherapy (CRT) than non-mucinous differentiated adenocarcinoma. Mucinous carcinoma was difficult to diagnose on biopsy because mucinous components are mainly located inside the tumor. We therefore compared MRI findings before and after CRT with histologic findings of resected specimens to investigate the predictive factor of response to CRT. Methods: The study group comprised 205 patients with locally advanced rectal cancer (LARC) who received CRT (40 to 45 Gy) from January 2006 through December 2014. T2-weighted fast-spin echo MRI was used to show the area ratio of mucin lakes (ML) to the maximum cut surface of the primary tissue. The presence or absence of ML and the area ratio of ML on the maximum cut surface were evaluated. Results: The histologic type on preoperative biopsy was well-differentiated or moderately differentiated adenocarcinomas in 202 patients (98.5%), poorly differentiated adenocarcinoma in 2 patients (1.0%), and mucinous carcinoma in only 1 patient (0.5%). ML area ratio on MRI before treatment was less than 20% in 194 patients (94.6%), 20% to 50% in 4 patients (2.0%), 50% or more in 7 patients (3.4%). In 11 patients with ML area ratio of 50% or more in resected specimen, mucinous carcinoma was diagnosed in only one patient (14.3%). The tumor shrinkage rate was 74% in patients with ML area ratio of less than 20%, 54.5% with ML area ration of 20% to 50%, and 56.4% with ML area ratio of 50% or more. (p = 0.002) The rate of T-downstaging was significantly greater in patients with ML area ratio of less than 20% than those with ML area ratio of 20% or more. (58% vs. 27%, p = 0.047) The rates of pCR were 13% and 0%, however, the difference was not significant. (p = 0.21) Conclusions: Mucinous carcinoma is difficult to diagnose on biopsy before chemoradiotherapy. The diagnosis of mucin lakes on MRI before treatment may be useful for predicting the response to CRT.

822 Background: In stage II colon cancer, retrieval of less than 12 lymph nodes (LNs) is a risk factor for recurrence. We previously reported that the great long-axis diameter of the largest retrieved lymph nodes (maximum LNs) is associated with a higher number of retrieved LNs and better outcomes (Int J Colorectal Dis 2015). We examined whether the long-axis diameter of maximum LNs is a prognostic factor in node-positive stage III colorectal cancer. Methods: The study group comprised 260 patients (pts) with stage III disease who underwent curative resection from 2005 through 2014. Pts who underwent laparoscopic or emergency surgery were excluded. The long-axis diameter was measured on H-E stained specimens and one non-metastatic LN with the greatest long-axis diameter was selected. The cut-off value (COV) for the long-axis diameter was determined by using receiver ROC curves with recurrence or overall mortality as events. Results: Tumors were located in right colon in 86 pts (33%), left colon in 104 pts (40%), and rectum in 70 pts (27%). In pts with rectal cancer, 49 (70%) received chemoradiotherapy (CRT). The mean long-axis diameter was 8.0 ± 3.5 mm. Factors related to the long-axis diameter were tumor location (right colon 9.5 ± 3.8 mm, left colon 7.7 ± 3.4 mm, rectum 6.6 ± 2.4 mm, p < 0.001), CRT (absent 8.4 ± 3.6 mm, present 6.3 ± 2.3 mm, p < 0.001), TNM stage (IIIA 6.6 ± 3.0 mm, IIIB 8.0 ± 3.5 mm, IIIC 8.8 ± 3.7 mm, p = 0.025), and the number of retrieved LNs (less than 12, 6.5 ± 2.9 mm; 12 or more, 9.0 ± 3.5 mm, p < 0.001). The COV for the long-axis diameter from the ROC curves was 8.0 mm. A long-axis diameter of ≥8.0 mm (106 pts 41%) were associated with significantly better outcomes than a long-axis diameter of < 8.0 mm (154 pts 59%) (5y RFS: < 8.0 mm 57%, ≥8.0 mm 70%, p = 0.012). On multivariate analysis, sex (female/male, HR 0.61, p = 0.019), venous invasion (absent/present, HR 0.58, p = 0.042), TNM stage (IIIB/IIIA, HR 3.19, p = 0.021; IIIC/IIIA, HR 3.47, p = 0.033), and the long-axis diameter (≥8.0 mm/ < 8.0 mm, HR 0.55, p = 0.005) were independent prognostic factors. Conclusions: In pts with stage III colorectal cancer, the long-axis diameter of maximum LNs was a prognostic factor. The size of maximum LNs might thus reflect the tumor immunity of the host.

798 Background: Mucinous carcinoma (MC) has been defined as carcinoma with > 50% of tumor volume showing mucin pool (MP). The incidence of MC had been reported to be 4 to 12% of colorectal cancer and to be less effective for chemotherapy and CRT. The incidence of MC was 3 to 8% in rectal cancer treated with surgery alone and 13 to 24% in patients treated with CRT. These findings suggest that MP may be induced by CRT in some patients. We therefore compared the degree of MP in MRI findings before CRT, after CRT and in resected specimens. Methods: The study group comprised 205 patients with rectal cancer who received CRT (40 to 45 Gy) from 2006 through 2014. MPs on MRI were evaluated using T2-weighted fast-spin echo images, and the MP area ratios on maximum cross-section of the primary tumor were calculated. An MP area ratio of 0% was designated as class 0, 1 to 9% as class I, 10 to 29% as class II, 30 to 50% as class III, and 50% or higher as class IV. Results: On MRI before CRT, the MP area ratio was class 0 in 181 patients (88%), class I in 11 (5%), and class II or higher in 13 (6%). On MRI after CRT, the MP area ratio was class 0 in 186 patients (91%), class I in 4 (2%), and class II or higher in 15 (7%). The prevalence of MP classes did not change appreciably. The MP class evaluated on MRI before and after CRT changed by 2 or more levels in only 2 patients, both of whom had marked tumor shrinkage. Among 175 patients with an MP area ratio of class 0 or I in the resected specimens, the MRI findings after CRT were consistent with the findings of the resected specimens. However, the MP area ratio was underestimated by 2 or more levels on MRI in 14 (47%) of 30 patients who had an MP area ratio of class II or higher. A pathological complete response (pCR) was obtained in 24 patients (12%), all of whom had an MP area ratio of class 0 or I on MRI before CRT. No patient with an MP area ratio of class II or higher before CRT had a pCR. Conclusions: The degree of MP evaluated on MRI did not change during CRT. In patients who had an MP area ratio of > 10% in their resected specimens, the evaluation of MP on MRI was often underestimated. Patients with an MP area ratio of > 10% before CRT had a poor response to CRT, with no pCR.

804 Background: Multidisciplinary treatment had been a standard of care for locally advanced rectal cancer. Serum CEA had been reported as one of the predictive factors to CRT, however, serum CEA levels may change after CRT and surgery. We examined the relations of serum CEA before CRT, after CRT, and after surgery to histological response and outcomes. Methods: The subjects were 149 patients with cStage II or III adenocarcinoma of the rectum who underwent surgery after CRT from 2005 through 2013. A total dose of 40 to 45 Gy with concurrent oral UFT or S-1 was delivered. Surgery was performed 6 to 8 weeks after CRT. A serum CEA > 5 ng/mL was defined as positive. Patients with negative serum CEA before CRT were designated as group 1. Patients with positive serum CEA before CRT that became negative after CRT were designated as group 2. Patients with positive serum CEA after CRT that became negative after surgery were designated as group 3, and patients with positive serum CEA after CRT as well as after surgery were designated as group 4. The median follow-up period of the survivors was 60.4 months. Results: The numbers of patients in Groups 1, 2, 3, and 4 were 55 (37%), 41 (28%), 37 (25%), and 16 (11%), respectively. The incidences of pCR, T downstaging, and N downstaging did not differ significantly among the groups (p = 0.094, 0.060, and 0.346). Rates of marked regression (TRG Grade 1 or 2) were 55% in Group 1, 42% in Group 2, 16% in Group 3, 25% in group 4. The rates were significantly higher in groups 1 and 2 (p = 0.001).5y DFS was 76% in group 1, 75% in group 2, 77% in group 3, and 48% in group 4 and was significantly lower in group 4 (p = 0.024). 5y OS was 88% in group 1, 91% in group 2, 85% in group 3, and 68% in group 4 and was significantly lower in group 4 than that in groups 1 and 2 (p = 0.03, 0.019). Conclusions: In patients with rectal cancer who received CRT, changes in serum CEA levels before and after CRT and after surgery were intimately related to the histological response of the primary lesion. Patients who continued to have positive serum CEA levels after surgery had poor outcomes, strongly suggesting the presence of occult distant metastasis.

618 Background: In stage II colon cancer, patients with many retrieved LNs have good outcomes. We previously reported that the longest diameter of retrieved LNs correlates with the number of LNs and can be used as a prognostic factor (Int J Colorectal Dis 2015). LNs can be divided into three main regions, cortex, paracortex, and medulla, and consist mainly of T cells, B cells, NK cells, and histiocytes. We studied the relations of the T-cell, B-cell area ratios, and the number of NK cells in longest-diameter LNs to the number of retrieved LNs and outcomes. Methods: The subjects were 320 patients with stage II colon cancer who underwent curative resection. One LN with the maximum long-axis diameter was selected, and was immunostained with CD3 as a T-cell marker, CD20 as a B-cell marker, and CD56 as an NK-cell marker. Positive area ratio was determined by image analysis. The number of CD56-positive cells were examined and the mean number per 0.093 mm2was calculated. The relations were evaluated with the use of Spearman’s rank correlation coefficient. The cut-off values were calculated by ROC curve analysis. Results: The number of LNs was 14.8 ± 10.4 (mean ± SD). The CD3-positive area ratio was 0.39 ± 0.08. The CD20-positive area ratio was 0.42 ± 0.10. The number of CD56-positive cells was 9.9 ± 10.1. The correlation coefficients for the number of LNs with CD3-positive area ratio, CD20-positive area ratio, and the number of CD56-positive cells were respectively -0.07 (p = 0.220), 0.05 (p = 0.360), and 0.33 (p < 0.001). The number of LNs positively correlated with the number of CD56-positive cells. The median follow-up period was 118 months. Patients with a CD20-positive area ratio of 0.43 or greater (n = 160) had a significantly better survival (HR, 0.64; 95%CI, 0.44-0.92; p = 0.015). Patients with 3 or more CD56-positive cells (n = 276) had a significantly better survival (HR, 0.57; 95%CI, 0.37-0.93; p = 0.017). Conclusions: A high number of NK cells in longest-diameter LNs was associated with a higher number of retrieved LNs, a longer LN diameter, and better survival. NK cells in the longest LNs may reflect the host antitumor immune response in patients with Stage II colon cancer.

756 Background: Colorectal cancer patients with postoperative complications have poor long-term outcomes. Rectal cancer is associated with a higher incidence of complications than colon cancer. Reliable predictors of complications would facilitate determination of surgical procedures such as stoma creation. We examined the relations between five kinds of risk score and postoperative complications in patients(pts) with rectal cancer. Methods: The subjects were 261 pts with cStage II/III rectal cancer from 2003 to 2013. We categorized complications into all complications, leakage, infectious complications and intestinal obstruction. Estimation of physiologic ability and surgical stress comprehensive risk scores (E-PASS CRS), surgical Apgar scores (SAS), prognostic nutritional index (PNI), colorectal physiological and operative severity scores for the enumeration of mortality and morbidity (CR-POSSUM), and neutrophil-lymphocyte ratios (NLR) were assessed. Clavien-Dindo (CD) Grade 3a or higher requiring surgically invasive treatment were considered complications. For leakage, CD Grade 3b or higher were considered complications. Results: Complications occurred in 56 pts (21%), leakage (L) in 12 (14%), infectious complications (IC) in 19 (7%), and intestinal obstruction (IO) in 16 (6%). E-PASS CRS significantly correlated with all complications (OR 3.45; p < 0.001), IC (OR 0.26; p = 0.008), L (OR 4.94; p = 0.027), and IO (OR 3.92; p = 0.007). PNI correlated with all complications (OR 0.38; p = 0.002) and IO (OR 3.08; p = 0.024). NLR correlated with all complications (OR 0.40; p = 0.003), IC (OR 0.25; p = 0.004), L (OR 8.66; p < 0.001), and IO (OR 3.86; p = 0.007). SAS correlated with IC (OR 0.19; p = 0.004). CR-POSSUM correlated with all complications, (OR 2.26; p = 0.009), IC (OR 5.02; p < 0.001), and IO (OR 0.28; p = 0.014). Multivariate analysis revealed E-PASS CRS (OR 6.17 p = 0.020) and NLR (OR 7.11 p = 0.011) were independent risk factors for L. Conclusions: Five kinds of risk score were all useful for assessing the risk of complications in rectal cancer. NLR was the only risk factor for leakage that could be used before surgery. Our results suggest NLR might be an auxiliary means of evaluating the need for creation of diverting stoma.