Analysis of risk factors for anastomotic leakage after lower rectal Cancer resection, including drain type: a retrospective single-center study.

BACKGROUND: We investigated the correlations between surgery-related factors and the incidence of anastomotic leakage after low anterior resection (LAR) for lower rectal cancer. METHODS: A total of 630 patients underwent colorectal surgery between 2011 and 2014 in our department. Of these, 97 patients (15%) underwent LAR and were enrolled in this retrospective study. Temporary ileostomy was performed in each patient. RESULTS: Anastomotic leakage occurred in 21 patients (21.7%). Univariate analysis showed a significant association between operative duration (p = 0.005), transanal hand-sewn anastomosis (p = 0.014), and operation procedure (p = 0.019) and the occurrence of leakage. Multivariate regression reanalysis showed that underlying disease (p = 0.044), transanal hand-sewn anastomosis (p = 0.019) and drain type (p = 0.025) were significantly associated with the occurrence of leakage. The propensity-score analysis showed that closed drainage were 6.3 times more likely to have anastomotic leakage than open drainage in relation to the amount of postoperative drainage (ml), according to the inverse probability of treatment-weighted analysis. CONCLUSIONS: Our results indicate that underlying disease, transanal hand-sewn anastomosis, and closed drain may be a risk and predictive factors for anastomotic leakage after LAR for lower rectal cancer. The notable finding was that closed drainage was related to the occurrence of anastomotic leakage and closed drainage was correlated with less volume of postoperative drain discharge than open drain.

Histopathological predictors for local recurrence in patients with T3 and T4 rectal cancers without preoperative chemoradiotherapy.

BACKGROUND AND OBJECTIVES: Identification of suitable predictors of local recurrence (LR) in patients with rectal cancer would be of clinical benefit. The aim of this study was to identify histopathological factors that could predict LR. METHODS: A total of 796 stage II/III patients with pT3 and pT4 rectal cancer who did not undergo preoperative chemoradiation were enrolled. LR was defined as intra-pelvic recurrence only. Histopathological factors related to LR were investigated. RESULTS: LR was found in 25 patients (6.1%) with stage II and 54 patients (13.9%) with stage IIIB/IIIC. In patients with stage II, distance of mesorectal extension (DME) >4 mm (P = 0.011) and positive venous invasion (P = 0.035) were independent factors that predicted LR. In patients with stage IIIB/IIIC, circumferential resection margin (CRM) ≤1 mm (P = 0.003) and positive lymphatic invasion (P = 0.006) were independent factors. The cumulative 5-year LR rate was higher (11.9%) in patients with a combination of DME > 4 mm and/or positive venous invasion for stage II (P < 0.001), and was also higher in patients with a combination of CRM≤1 mm and/or positive lymphatic invasion for stage IIIB and IIIC (22.2%; P < 0.002, and 34.3%; P < 0.006, respectively). CONCLUSIONS: Important histopathological predictors for LR in patients with pT3 and pT4 rectal cancer were different at each stage.

Technical tips for intersphincteric resection: how to take out the rectum.

Intersphincteric resection (ISR) is an ideal technique that preserves the anus, regardless of whether the internal anal sphincter is removed. However, it is difficult to dissect the anterior wall of the rectum from the adjacent organs. We herein describe a safe and useful ISR technique which draws out the rectum through the anus. The intersphincteric space (ISS) between the internal and external anal sphincter muscles was first transabdominally dissected. Next, the transanal dissection was advanced into the ISS bilaterally from the posterior side without dissecting the anterior wall of the anal canal, and the sigmoid colon and rectum were drawn out through the anus. Dissection between the anterior wall of the rectum and prostate/vagina could be easily performed under direct vision. This technique enables the dissection without any risk of a positive surgical margin or unexpected bleeding, and avoids injury to adjacent organs. This technique seems to be a safe and useful dissection technique for approaching the anterior wall of the anal canal.

External sphincter resection for lower rectal and anal canal adenocarcinoma: achieving anal preservation with oncological and functional satisfaction.

Intersphincteric resection (ISR) has recently been performed for very low rectal cancer, whereas abdominoperineal resection (APR) is typically reserved for cancers extremely close to the anal verge and/or when the depth of tumor invasion is suspected to involve the intersphincteric space. This is because impairment of anal function is considered unavoidable if the external sphincter (ES) is excised. We describe our technique of ISR with ES resection and discuss its outcomes. This surgical technique may offer major clinical advantages to selected patients and should be considered as an alternative to APR, although careful consideration of anal function is required.

Clinicopathological evaluation of anoxic mucosal injury in strangulation ileus.

BACKGROUND: In patients with strangulation ileus, the severity of bowel ischemia is unpredictable before surgery. To consider a grading scale of anoxic damage, we evaluated the pathological findings and investigated predictive factors for bowel gangrene. METHODS: We assessed 49 patients with strangulation ileus who underwent a laparotomy between January 2004 and November 2012. Laboratory tests and the contrast computed tomography (CT) were evaluated before surgery. According to the degree of mucosal degeneration, we classified anoxic damages into the following 3 grades. Ggrade 1 shows mild mucosal degeneration with extended subepithelial space. Grade 2 shows moderate degeneration and mucosal deciduation with residual mucosa on the muscularis mucosae. Grade 3 shows severe degeneration and mucosal digestion with disintegration of lamina propria. RESULTS: Resected bowel specimens were obtained from the 36 patients with severe ischemia, while the remaining 13 patients avoided bowel resection. The mucosal injury showed grade 1 in 11 cases, grade 2 in 10 cases, and grade 3 in 15 cases. The patients were divided into two groups. One group included grade 1 and non-resected patients (n = 24) while the other included grades 2 and 3 (n = 25). When comparing the clinical findings for these groups, elevated creatine kinase (P = 0.017), a low base excess (P = 0.021), and decreased bowel enhancement on the contrast CT (P = 0.001) were associated with severe mucosal injury. CONCLUSION: In strangulation ileus, anoxic mucosal injury progresses gradually after rapid spreading of bowel congestion. Before surgical intervention, creatine kinase, base excess, and bowel enhancement on the contrast CT could indicate the severity of anoxic damage. These biomarkers could be the predictor for bowel resection before surgery.

A Case of Immediate Anastomotic Leakage After Low Anterior Resection for Rectal Cancer.

A man in his seventies was referred to our hospital for radical therapy for advanced rectal cancer with multiple liver metastases. A colonic stent had already been placed in his rectum at the previous hospital because of malignant colorectal obstruction, so our therapeutic strategy was to perform systematic chemotherapy after resection of the primary tumor. Laparoscopic low anterior resection with a covering stoma was performed under general anesthesia. At about one hour after the surgery, the patient had sudden abdominal pain with watery diarrhea, and a similar discharge from his drainage tube. We suspected peritonitis caused by bowel perforation and emergency surgery was performed. The operative findings showed that his peritonitis was caused by anastomotic leakage from the rectum. Radical lavage of the abdominal space and reconstruction of colostomy was performed. The patient gradually recovered and we were able to start systematic chemotherapy at one month after the surgery. Anastomotic leakage immediately after anterior resection caused by watery diarrhea is rare, and it may be concerned with several issues. The covering stoma is intended to stop anastomotic leakage but it cannot prevent all cases of leakage especially when obstruction is present. We recommend that preventive measures be taken against anastomotic leakage, including intraoperative leakage tests or anal decompression tube placement.

Non-invasive Monitoring of Pouchitis After Total Proctocolectomy Using Fecal Calprotectin Levels.

BACKGROUND: Fecal calprotectin (FC) is the most widely used marker for evaluating the disease activity of ulcerative colitis (UC). However, studies on FC in pouchitis after total proctocolectomy are scarce. We aimed to examine the correlations between the FC level and clinical findings and Pouchitis Disease Activity Index (PDAI) in UC patients who underwent total proctocolectomy (TP) with ileal pouch-anal canal anastomosis (IPAA) or ileal pouch-anal canal anastomosis (IACA). METHODS: Between April 2008 and March 2018, 15 patients, consisting of 8 males and 7 females, with an average age at operation of 46.5 years, participated in this study. The average observation period was 68.3 months. The subjects underwent FC level measurements and endoscopic examinations. RESULTS: The mean FC level was 418.69 µg/g (range: 10-1650 µg/g). Pouchitis was found in one (6.6%) patient, as detected by endoscopy. Among the 15 cases, FC levels were positively correlated with white blood cell count as well as albumin and C-reactive protein levels. There was a significant positive correlation between the PDAI score and FC levels (p<0.05). The median FC level was 111 mg/g in those with pouchitis, which was significantly higher than the 16 mg/g in those without pouchitis (p<0.05). Moreover, a significant positive correlation was found between the endoscopic findings of inflammation and FC levels (p<0.00005). CONCLUSION: FC levels were correlated with the PDAI score, blood testing data, and endoscopic findings, suggesting that the FC level could be a useful index of postoperative pouchitis and ileal pouch condition in patients undergoing TP with IPAA as UC treatment.

Investigation of clinicopathological characters and gene expression features in colorectal signet-ring cell carcinoma utilizing CMS classification.

Signet ring cell carcinoma (SRCC) is a rare pathological type of colorectal cancer, of which the clinicopathological features and genetic background have not yet been fully investigated. Previous research has focused on the optimization of colorectal cancer treatment utilizing consensus molecular subtyping (CMS). However, it is not known what type of CMS would be designated to SRCC treatment. In the current study, of 1,350 patients diagnosed with colorectal cancer who underwent surgery, 14 were diagnosed with SRCC. The case-control cohort that fit the clinical background of the SRCC case was constructed. Statistical comparison between the SRCC group and the case-control cohort was performed among clinicopathological variables. SRCC and well to moderately adenocarcinoma case mRNA were submitted to microarray analysis and CMS analysis. Compared with the case-control cohort, the SRCC group was located more in the right-sided colon, the lymphatic invasion was more severe and the peritoneal dissemination was more frequent. The cancer-specific survival and the progression-free survival were significantly worse in the SRCC group compared with the case-control cohort. Microarray and CMS analysis identified that one SRCC case was significantly well assigned in the CMS 4 group and the other case was assigned in the CMS 1 group. Gene set analysis revealed the upregulation of EMT related genes and the downregulation of fatty acid, glycolysis, differentiation, MYC, HNF4A, DNA repair genes. In conclusion, the clinical characteristics of SRCC are severe but there is a possibility of the presence of different phenotypes according to CMS analysis.

Challenges in staging systems for colorectal cancer: clinical significance of metastatic lymph node number in colorectal cancer and mesorectal extension in rectal cancer.

In many countries, treatment for cancer is performed based on staging systems in which the degree of cancer development is defined objectively. A common staging system is thus needed to compare outcomes. The staging system for colorectal cancer in Japan has been made to enhance consistency with the TNM classification, and the categorization of metastatic lymph nodes and depth of invasion have been revised in recent years. Although these are important factors that determine disease stage, relationships between each factor and recurrence have shown differing prognoses. In our retrospective study, the prognosis of a group with only one metastatic lymph node was significantly better compared to a group with > or = 2 metastatic lymph nodes. In addition, rectal cancer with mesorectal extension >5 mm showed low relapse-free survival rates and high recurrence rates. The validity of staging systems should thus be inspected from various perspectives.

Quercetin Suppresses Proliferation of Liver Cancer Cell Lines In Vitro.

BACKGROUND/AIM: We investigated the anti-proliferative effect of quercetin on liver cancer cell lines. MATERIALS AND METHODS: Thirteen liver cancer cell lines were cultured followed by treatment with varying concentrations of quercetin (0-100 µM) or quercetin and 5-FU, and the cell viability was analysed by the MTT assay. Flow cytometry was also used to examine cell cycle progression after treatment with quercetin. RESULTS: The addition of quercetin resulted in a dose- and time-dependent suppression of cell proliferation. In some cell lines, treatment with quercetin and 5-FU caused an additional or synergistic effect. Most cell lines displayed cell cycle arrest at different phases of the cell cycle. CONCLUSION: Quercetin inhibits the proliferation of liver cancer cells via induction of apoptosis and cell cycle arrest.

Mesocolic hernia following retroperitoneal laparoscopic radical nephrectomy: A case report.

INTRODUCTION: Small bowel obstruction (SBO) caused by an internal hernia through a mesocolon after retroperitoneal laparoscopic nephrectomy (RLN) is rare. PRESENTATION OF CASE: A 66-year-old man who had undergone RLN with bladder cuff excision for a left renal pelvic cancer. After the surgery, he experienced SBO repeatedly. Contrast-enhanced computed tomography (CT) and gastrografin contract radiography through a long tube showed an internal hernia through the mesocolon to the retroperitoneal space where the resected left kidney had been located. We performed a subsequent surgery for the internal hernia. Postoperative course was uneventful and currently he has no recurrence of herniation 6 months post-operatively. DISCUSSION: Mesenteric defects that cause an internal hernia can be created inadvertently during RLN when the colon is mobilized medially, and the kidney is being detached from retroperitoneum. The removal of a kidney leads to a potential retroperitoneal space to which small intestine can migrate. While there is no absolute necessity in mobilizing the colon during the retroperitoneal laparoscopic approach, there is still a risk of making mesocolic defects directly in the retroperitoneal space. CONCLUSION: We need to perform operations with sufficient anatomical knowledge of retroperitoneal fascia and careful surgical techniques. The critical thing to prevent an internal hernia following RLN is to close the mesenteric defects intraoperatively. It is also important to suspect an internal hernia and do proper examinations promptly when patients had the symptoms of SBO after nephrectomy.

Sinusoidal Obstruction Syndrome and Postoperative Complications Resulting from Preoperative Chemotherapy for Colorectal Cancer Liver Metastasis.

BACKGROUND/AIM: The aim of this study was to investigate the effects of preoperative chemotherapy on the healthy, metastasis-free part of the liver in colorectal cancer patients with liver metastasis, and the relationship between chemotherapy and postoperative complications. PATIENTS AND METHODS: Our study included 90 cases of colorectal cancer liver metastasis resected after preoperative chemotherapy. The patients were divided into three groups according to the received chemotherapy regimen: 20 cases received mFOLFOX6, 54 cases a combination of mFOLFOX6 with bevacizumab, and 16 cases a combination of mFOLFOX6 and cetuximab or panitumumab. RESULTS: The mean numbers of sinusoidal injuries for each chemotherapy type were compared. The group treated with the combination of mFOLFOX6 and bevacizumab showed a lower extent of sinusoidal injury relative to other groups; this intergroup difference became increasingly remarkable as the number of chemotherapy cycles increased. Complications of various extents were found in all three groups, but no significant differences were observed between the three groups. CONCLUSION: In cases where preoperative chemotherapy was extended over a long period, combined use of bevacizumab was thought to be effective because of stabilization of disturbed liver hemodynamics resulting from sinusoidal injury suppression effects, allowing effective distribution of anti-cancer agents to tumors.

Efficacy of the combined use of bevacizumab and irinotecan as a postoperative adjuvant chemotherapy in colon carcinoma.

We evaluated the efficacy of anti-human VEGF antibody (bevacizumab) with or without irinotecan (CPT-11) against lung metastases in which neovascularization was already induced, as a postoperative adjuvant therapy using orthotopically implanted colon cancer in rat. The high VEGF productive KM12SM human colon cancer cells were injected into the cecal wall. At 5 weeks after the injection, the cecum was removed including the tumor. Then, 5 mg/kg of bevacizumab and 40 mg/kg of CPT-11 were administered, alone or in combination, intravenously once a week for 3 weeks, from day 15 after the cecal removal. The results show that the incidences of macroscopic and/or microscopic lung metastases in the bevacizumab-alone group (B) and in the combination group (C) were significantly lower (B, p=0.001 and C, p=0.037) than that in the control group at day 35 after the cecal removal. The number of lung metastases in B was 0.8+/-0.8 (p=0.024) and in C 2.4+/-1.8 (p=0.060), each value lower than the 12.4+/-4.2 of the control group. The growth of a subcutaneously implanted tumor was significantly inhibited in the combination group compared to either the CPT-alone (p=0.003) or the bevacizumab-alone groups (p=0.027). Apoptosis was significantly (p<0.001) induced in the combination group. In conclusion, a beneficial effect of bevacizumab against postoperative lung metastases may be expected even after the establishment of neovascularization in metastatic foci in nude rat. The results from the present subcutaneously implanted tumor model suggested that a higher efficacy may be expected when bevacizumab is combined with the cytotoxic agent CPT-11, compared to bevacizumab alone, against tumors with a variety of VEGF production levels in clinical situations.

Mina53 nuclear localization is an important indicator of prognosis in patients with colorectal cancer after adjuvant chemotherapy.

The aim of this study was to investigate the status of the c­Myc­related molecule Mina53 and the clinical impact of Mina53 nuclear localization in patients with stage II and III colorectal cancer (CRC). Patients (n=250) who underwent complete resection of CRC at our department were enrolled in this study, and tissue microarray samples were constructed from resected specimens. Mina53 expression in the nuclei of tumor cells was analyzed using immunohistochemistry (IHC). Patients were classified into Mina53 nuclear localization­-positive and ­negative groups, and statistical correlations with clinicopathological factors were investigated. Relapse­free survival (RFS) was compared using the Kaplan­Meier method and the Cox proportional hazard model. Tumor recurrence was significantly higher in the Mina53­positive group than in the Mina53­negative group. Moreover, in RFS analysis, patients in the Mina53­positive group exhibited significantly poorer prognosis than patients in the Mina53­negative group. In the univariate analysis, histological type, adjuvant chemotherapy status, carcinoembryonic antigen (CEA) status, and Mina53 status were prognostic factors for RFS. Furthermore, in the subgroup analysis, patients in the Mina53­positive group with stage III disease treated with adjuvant chemotherapy exhibited significantly poorer prognosis in RFS than patients in the Mina53­negative group. In the univariate and multivariate analyses, histological type and Mina53 status were significantly associated with RFS. Thus, our findings revealed that Mina53 was an important indicator of prognosis in patients with stage III CRC treated with adjuvant chemotherapy.

Oral fluoropyrimidines may not reduce the risk of postoperative recurrence in colorectal cancer associated with mesenteric lymph node metastasis.

To clarify the efficacy and problems of postoperative adjuvant chemotherapy using oral fluoropyrimidines, the clinicopathological data of 307 colorectal cancer patients treated with or without postoperative chemotherapy were analyzed retrospectively. Patients in the chemotherapy group (n=188) who underwent curative resection were followed by administration of oral fluoropyrimidine. The other 119 patients underwent surgery alone. The disease-free survival rates were compared between the two groups. The disease-free survival rate in the chemotherapy group was significantly higher than that in the surgery alone. However, no significant difference in disease-free survival rate was found for those with tumors that were associated with mesenteric lymph node involvement and tumors with a high grade of lymphatic invasion or high grade of venous invasion. Postoperative adjuvant chemotherapy using oral fluoropyrimidines such as UFT (litegafur +4:uracil) and 5'-DFUR (doxifluridine) might not reduce the risk of recurrence in colorectal cancer with mesenteric lymph nodes involvement.

Perineural Invasion Is a Prognostic Factor and Treatment Indicator in Patients with Rectal Cancer Undergoing Curative Surgery: 2000-2011 Data from a Single-center Study.

BACKGROUND/AIM: The aim of the present study was to investigate whether perineural invasion (PNI) was a prognostic index for patients who underwent curative surgery for Dukes' grade B and C rectal cancer. PATIENTS AND METHODS: A total of 645 patients with rectal cancer between January 2000 and December 2011; 363 with Dukes' B or C stages who did not undergo chemoradiotherapy were reviewed. RESULTS: Of 363 patients, 83 (22.9%) were PNI-positive. The 5-year overall survival and disease-specific survival rates were significantly worse for patients with PNI-positive Dukes' B or C disease compared to those with PNI-negative disease. There was no significant difference in the recurrence pattern (hematogenous or lymphatic spread), but patients with PNI-positive disease had a significantly higher rate of recurrence compared to those with PNI-negative disease (p<0.001). CONCLUSION: PNI was a significant prognostic factor in rectal cancer, and the PNI status in primary rectal cancer pathology specimens should be considered for therapy stratification.

The MMP-9 expression determined the efficacy of postoperative adjuvant chemotherapy using oral fluoropyrimidines in stage II or III colorectal cancer.

BACKGROUND: The aim of this study was to determine any correlation between the efficacy of postoperative adjuvant chemotherapy using oral fluoropyrimidines and the matrix metalloproteinase 9 (MMP-9) expression in primary colorectal cancer tissues. PATIENTS AND METHODS: The data on 307 patients with colorectal cancer at stage II or III, who underwent potentially curative resection with lymphadenectomy, were reviewed. Of these, 188 received postoperative administration of oral fluoropyrimidines such as UFT and 5'-DFUR (chemotherapy group), while the other 119 patients underwent surgery alone (surgery-alone group). Immunostaining for MMP-9 was performed using surgical specimens of all 307 primary tumors and 18 recurrent tumors. RESULTS: Overall, MMP-9 was positively expressed in the primary tumor in 44% of patients. Multivariate analysis revealed that the MMP-9 expression was a worse prognostic factor with a second highest hazard ratio for recurrence. The disease-free survival rate in the chemotherapy group was significantly higher than that in the surgery-alone group. However, no significant difference in disease-free survival rate between the two groups was found in patients with a tumor positive for MMP-9. There was a strong positive correlation of MMP-9 expression between the primary tumors and the recurrent liver or lung tumors. CONCLUSIONS: The efficacy of postoperative adjuvant chemotherapy using oral fluoropyrimidines such as UFT and 5'-DFUR may not be as great for patients with a tumor positive for MMP-9 having a greater risk to postoperative recurrence.

The expression of vascular endothelial growth factor determines the efficacy of post-operative adjuvant chemotherapy using oral fluoropyrimidines in stage II or III colorectal cancer.

The aim of this study was to determine any correlation between the efficacy of post-operative adjuvant chemotherapy using oral fluoropyrimidines and the vascular endothelial growth factor (VEGF) expression in primary colorectal cancer tissues. The data were reviewed retrospectively on 342 patients with colorectal cancer at stage II or III, who underwent potentially curative resection between 1988 and 1998. Of these, 225 received post-operative administration of oral fluoropyrimidines such as UFT and 5'-DFUR, while the other 117 patients underwent surgery alone. Immunostaining for VEGF was performed using colorectal tumours. Overall, VEGF was positively expressed in primary tumour cells in 48% of patients. The disease-free survival rate and the overall survival rate in the chemotherapy group were higher than those in the surgery-alone group, although not significantly. However, the disease-free survival rate and the overall survival rate were similar between the two groups in patients with a tumour positive for VEGF. Multivariate analysis revealed that the VEGF expression was an independent factor for post-operative recurrence, and the VEGF expression and post-operative adjuvant chemotherapy were an independent factor for overall survival, in addition to the lymph node metastasis and the venous invasion. In conclusion, the efficacy of post-operative adjuvant chemotherapy using oral fluoropyrimidines may not be as great for patients with a tumour positive for VEGF having a greater risk of post-operative recurrence. The results support further investigation on efficacy of molecular targeting therapy for VEGF in combination with oral fluoropyrimidines as post-operative adjuvant therapy in colorectal cancer positive for VEGF.

Nuclear Y-Box-binding Protein-1 Expression Predicts Poor Clinical Outcome in Stage III Colorectal Cancer.

BACKGROUND/AIM: Y-Box-binding protein-1 (YB-1), a DNA/RNA-binding protein, is an important oncogenic transcription and translation factor. We aimed to evaluate the relationships between nuclear YB-1 expression, epidermal growth factor receptor (EGFR) status, and poor clinical outcomes in patients with colorectal cancer (CRC). MATERIALS AND METHODS: Nuclear YB-1 expression was immunohistochemically analyzed in CRC tissues obtained from 124 patients who underwent curative resection between 2005 and 2008. Correlations between nuclear YB-1 expression, various clinicopathological characteristics, EGFR status, and prognostic factors were evaluated. RESULTS: High-grade nuclear YB-1 expression was detected in 62.9% of cases and was found to be an independent predictor of poorer overall survival (p<0.001) and relapse-free survival (p<0.001). A trend was also observed towards a positive correlation between nuclear YB-1 expression and EGFR status (p=0.051). CONCLUSION: Nuclear YB-1 expression is a useful prognostic biomarker that correlates with EGFR status in patients with CRC.

Prognostic factors after potentially curative resection in stage II or III colon cancer.

It is important to identify factors that are predictive of outcome after a curative resection in colon cancer in order to optimize adjuvant therapy. To investigate these prognostic factors we conducted a retrospective analysis of our clinicopathological data. A total of 190 patients with a pathological stage II or III colon cancer underwent potentially curative resection with lymphadenectomy at our hospital between 1990 and 1998. These patients received no preoperative chemotherapy, immunotherapy or radiotherapy. Postoperative adjuvant chemotherapy using oral fluoropyrimidines was performed in 127 patients, and the other 63 patients underwent surgery alone. Univariate and multivariate analyses for prognostic factors were carried out. The univariate analysis revealed that invasion to adjacent organs, N1-2, positive mesenteric lymph node metastasis (MLN+), lymphatic permeation (ly)1-3, venous invasion (v)1-3, and v2-3 were each significant factors indicating worse disease-free survival, and that N1-2, MLN+, ly1-3, v1-3 and v2-3 were each significant factors for worse overall survival. In the multivariate analysis, MLN+ and vl-3 were significant factors for worse disease-free survival, and for worse overall survival. In conclusion, stage II or III colon cancer patients positive for mesenteric lymph node metastasis or for venous invasion have a greater risk of recurrence and death after potentially curative resection. Postoperative adjuvant chemotherapy using oral fluoropyrimidines did not significantly reduce the risk of recurrence and death in these patients. More effective adjuvant chemotherapy than oral fluoropyrimidine should be considered, especially in such high-risk patients.