Postoperative results and complications of fecal diversion for anorectal Crohn's disease.

PURPOSE: Fecal diversion is a less-invasive technique that can alleviate symptoms in patients with refractory anorectal Crohn's disease. However, complications, including recurrence of residual anorectal Crohn's disease, may develop. We aimed to evaluate the postoperative results and complications associated with fecal diversion in patients with refractory anorectal Crohn's disease. METHODS: We enrolled 1218 Crohn's disease patients who underwent laparotomy at our institute. We retrospectively analyzed the clinical features of 174 patients who underwent fecal diversion for refractory anorectal Crohn's disease, complications of the diverted colorectum, and the incidence and risk factors for proctectomy after fecal diversion. RESULTS: After fecal diversion, 74% of patients showed improved symptoms. However, bowel continuity restoration was successful in four patients (2.2%), and anorectal Crohn's disease recurred in all patients. Seventeen patients developed cancer with a poor prognosis. The rate of conversion to proctectomy after fecal diversion was 41.3%, and the risk factors included rectal involvement (p = 0.02), loop-type stoma (p < 0.01), and the absence of treatment with biologics after fecal diversion (p = 0.03). CONCLUSION: Fecal diversion for refractory anorectal Crohn's disease can improve clinical symptoms. Patients with rectal involvement or loop-type stoma have a greater risk of requiring proctectomy following fecal diversion. The administration of biologic may decrease the rate of proctectomy.

[Surgical treatment for ulcerative colitis in patients over 70 years of age].

The clinical course of 104 patients with ulcerative colitis who underwent primary surgery at ≥70 years was retrospectively examined. Pre- and postoperative patient conditions determined the choice of surgical procedure. Approximately half of the patients underwent restorative proctocolectomy, resulting in relatively good defecation function. In addition, the long-term outcomes of patients who underwent permanent ileostomy were favorable. However, the postoperative complication and mortality rates were high in all patients, including those with low preoperative performance status due to long-term hospitalization. In this patient population, surgery should be conducted before decreased performance status due to long-term hospitalization.

[A case of ulcerative colitis complicated by disseminated intravascular coagulation that improved markedly after surgery].

A 57-year-old man presenting with severe ulcerative colitis (UC) complicated by disseminated intravascular coagulation (DIC) was referred to our hospital. Since it was difficult to improve DIC immediately with any medical treatment, total proctocolectomy, ileoanal canal anastomosis, and ileostomy were performed on the patient. Soon after the surgery, his platelet count and coagulability improved, and he recovered from DIC. Thus, when the cause of DIC is probably UC itself, and medical treatment has limited efficacy in improving the DIC, surgery should be performed as soon as possible to eliminate the cause of DIC, considering the general condition of the patient.

Clinicopathological and prognostic evaluations of anorectal cancer after fecal diversion for patients with Crohn's disease.

PURPOSE: Colorectum diversion with a proximal stoma is often the preferred surgical approach in patients with Crohn's disease-related anorectal lesions or refractory colitis. To date, few studies have assessed the incidence and prognosis of cancer in the diverted anorectal segments. This study aimed to evaluate the clinical characteristics and prognosis of anorectal cancer associated with Crohn's disease following fecal diversion. METHODS: This was a retrospective study based on medical records of patients diagnosed with Crohn's disease between 1999 and 2020. It was conducted at Yokohama Municipal Citizen's Hospital. Patients diagnosed with anorectal cancer following fecal diversion were identified, and their prognosis was the primary outcome measure. RESULTS: Among 1615 patients, 232 patients (14%) underwent colorectum diversion. Of those 232 patients, 11 were diagnosed with anorectal cancer following fecal diversion, ten were diagnosed with advanced cancer, 10 underwent abdominoperineal resection, and eight died. 1 could not undergo resection due to multiple lung metastasis and died. The overall five-year survival rate in patients diagnosed with anorectal cancer following fecal diversion was 20%. CONCLUSION: Crohn's disease-associated anorectal cancer following fecal diversion was challenging to diagnose early, and patients had a poor prognosis even after curative resection. Early abdominoperineal resection may be considered for patients with Crohn's disease who cannot benefit from cancer screening and surveillance due to difficulty accessing the anorectal stricture via endoscopy.

[Pregnancy and delivery in patients with Crohn's disease who had a history of abdominal surgery].

OBJECTIVE: A few studies have focused on pregnancy and childbirth in patients with Crohn's disease (CD) who had a history of abdominal surgery. The objective of this study is to analyze the problems of pregnant patients with CD with a history of abdominal surgery. METHODS: The rates of pregnancy-related complications and adverse birth outcomes were retrospectively analyzed in 29 patients with CD (45 pregnancies) with previous intestinal surgery. RESULTS: In this study, the following outcomes were observed:normal births occurred in 55.6% of the pregnancies, preterm births in 13.3%, and spontaneous abortions in 20.0%. The vaginal birth and cesarean section rates were 45.7% and 40.0%, respectively. The rate of low-birth weight infants was 14.3%. CONCLUSION: Overall, patients with CD with previous abdominal surgery can conceive and give birth. However, care needs to be taken to avoid preterm birth, spontaneous abortion, low birth weight, and cesarean delivery.

[A case of a patient with Crohn's disease who had vaginal delivery after abdominoperineal resection for severe anorectal complications].

We report the case of a young female patient with Crohn's disease case who had vaginal delivery after abdominoperineal resection for severe perianal disease. The patient had Crohn's disease with anorectal complications for 13 years and underwent abdominoperineal resection for anorectal stenosis, complex anal fistula, and rectovaginal fistula in her early twenties. Seven years later, she got pregnant and gave birth to a healthy boy by vaginal delivery. No recurrence of Crohn's disease was observed during the perinatal period. There is no curative treatment for severe anorectal complications, which may be necessary for young patients to undergo abdominoperineal resection. Further studies are needed to determine the effects of Crohn's disease with anorectal complications on pregnancy and childbirth in affected patients.

The role of apical lymph node metastasis in right colon cancer.

BACKGROUND: The role of apical lymph node (APN) metastasis in colorectal cancer remains controversial. The main purpose of this study is to explore the prognostic value of APN metastasis in patients with right colon cancer. METHODS: This is a retrospective study of patients with stage III right colon cancer between April 2007 and December 2016. Patients who underwent resection of right colon cancers with D3 lymph node dissection were divided into APN-positive (APN+) and APN-negative (APN-) groups according to the postoperative pathological presence or absence of APN metastasis. Relapse-free survival (RFS) and overall survival (OS) between groups were compared after Cox regression analysis and 1:1 propensity score matching (PSM). RESULTS: A total of 254 patients were included in this study: 28 (11.0%) were APN+ and 226 (89.0%) were APN-. Before matching, the rates of elevated carcinoembryonic antigen (CEA), T3-4 tumor invasion, and N2 lymph node metastasis were significantly higher in the APN+ group (CEA ≥ 5 ng/mL, 53.6% vs. 37.6%, p < 0.001; T3-4, 92.9% vs. 85.4%, p < 0.001; N2 metastasis, 57.1% vs. 20.4%, p < 0.001), and APN+ tumors were associated with significantly higher postoperative relapse rates (39.3% vs. 21.2%; p = 0.03), especially with lung metastases (14.3% vs. 4.0%; p = 0.019), which conferred worse RFS (p = 0.013), although OS was similar (p = 0.078). However, after PSM, there were no apparent between-group differences in RFS (p = 0.29) or overall survival rate (p = 0.637). The Cox regression analysis indicated that lymphatic vessel infiltration and depth of invasion were independent risk factors for OS, while APN+ status was not a significant predictor for RFS or OS. CONCLUSIONS: APN metastasis was not a prognostic indicator for RFS or OS in right colon cancer. However, APN+ patients with elevated CEA levels and deeper tumor invasion should be closely monitored for lung metastasis during postoperative follow-up.

Left colon as a novel high-risk factor for postoperative recurrence of stage II colon cancer.

BACKGROUND: It is not clear whether stage II colon and rectal cancer have the same risk factors for recurrence. Thus, the purpose of this study was to identify the risk factors for postoperative recurrence in stage II colorectal cancer. PATIENTS AND METHODS: We retrospectively analyzed the data of 990 patients who had undergone radical surgery for stage II colorectal cancer. Patients' pathological features and characteristics including age, sex, family history, body mass index, tumor diameter, gross type of tumor, infiltration degree (T3/T4), tumor grade, perineural invasion, vascular invasion, lymphatic invasion, pathologic examination of lymph node number, and preoperative carcinoembryonic assay (CEA) level was compared between patients with and without recurrence. Finally, the prediction of the left and right colons was analyzed. RESULTS: The mean ages of the colon cancer and rectal cancer patients were 69.5 years and 66.4 years, respectively. In total, 508 (82.1%) and 285 (76.8%) patients were treated laparoscopically for colon cancer and rectal cancer, respectively, with median follow-up periods of 42.2 months and 41.8 months, respectively. Forty-four recurrences occurred in both the colon cancer (7.1%) and rectal cancer (11.9%) groups. The preoperative serum CEA level and T4 infiltration were significantly higher in recurrent colorectal cancer patients. The postoperative recurrence rate of left colon cancer (descending colon, sigmoid colon) was higher than that of right colon cancer (cecum, ascending colon, transverse colon) (OR 2.191, 95% CI 1.091-4.400, P = 0.027). In COX survival factor analysis of colon cancer, the left colon is one of the independent risk factors (risk ratio 5.377, 95% CI 0.216-0.88, P = 0.02). In disease-free survival (DFS), the left colon has a relatively poor prognosis (P = 0.05). However, in the COX analysis and prognosis analysis of OS, no difference was found between the left colon and the right colon. CONCLUSION: Preoperative CEA and depth of infiltration (T4) are high-risk factors associated with recurrence and are prognostic factors in stage II colorectal cancer. Left colon is also a risk factor for postoperative recurrence of stage II colon cancer.

[A case of ulcerative colitis in an 86-year-old woman undergoing restorative proctocolectomy with ileal pouch-anal canal anastomosis].

An 86-year-old woman was diagnosed with ulcerative colitis (UC) in the 1970s. A colonoscopy performed 40 years thereafter revealed a 0-Is lesion in the upper rectum, and pathological examination showed well-differentiated adenocarcinoma. The lesion was diagnosed as colitic cancer based on the pathological findings and the 40-year interval since the diagnosis of total colitis type of UC. The patient was in good overall health with good anal function, based on the clinical examination and manometric study;she wished to undergo sphincter-preserving operation. Restorative proctocolectomy with ileal pouch-anal canal anastomosis that preserved the anal canal mucosa was performed. The postoperative course was good, with a defecation frequency of 4-5 times/day without fecal incontinence, and the patient resumed her preoperative lifestyle with very few alterations. Even in elderly patients aged >80 years who have UC, restorative proctocolectomy is feasible for those in good general health and with relatively good anal function, determined based on the daily defecation activity and anal manometry.

[A Case of Upper Urinary Tract MALT Lymphoma with Remarkable Thickness of Renal Pelvis and Ureter Wall].

A 78-year-old man was referred to Tsukuba University Hospital for right hydronephrosis. He had undergone ureteroscopy and ureteral stenting in another hospital, but no tumor was revealed in renal pelvis and ureter. The urinary cytology was negative. Computed tomography (CT) revealed remarkable thickening of right renal pelvis and ureter wall. CT also showed para-aortic, iliac, supraclavicular and mediastinal lymph node (LN) swelling. 18F-fluoro-2-deoxy-D-glucose positron emission tomography (PET) revealed high uptake at thickened right renal pelvis and ureter wall and enlarged LNs. The soluble interleukin-2 receptor was elevated to 1,110 U/ml (normal range: 613 U/ml). Those findings suggested that the malignant lymphoma originated from the renal pelvis and ureter rather than urothelial cancer. Therefore we performed open biopsy of iliac LN and periureteral tissue. The pathological diagnosis was mucosa associated lymphoid tissue (MALT) lymphoma. The patient was trasferred to the department of hematology, and treated with rituximab and bendamustine. After 6 courses of chemotherapy, swelling of renal pelvis, ureter and LN was markedly reduced. The ureteral sent could be removed. MALT lymphoma of the upper urinary tract is extremely rare and pretreatment diagnosis is difficult. In 8 of 11 reported cases, the diagnosis was made by nephroureterectomy. In our cases, open biopsy could avoid nephroureterectomy.

[Diagnosis and treatment of six patients with Crohn's disease complicated by recto-perineal-urethral fistula].

Recto-perineal-urethral fistula caused by Crohn's disease is a rare, for which fundamental treatment has not been established yet. We analyzed the clinical characteristics, diagnosis, treatment, and prognosis of six male patients with anorectal lesions caused by Crohn's disease. Three patients were treated with abdominoperineal resection and the other three with rectal excision without anastomosis. Excluding one case, which presented worsening immediately after surgery, symptoms of urethral fistula improved without urethral stenosis, dysuria, or sexual dysfunction. Recto-perineal-urethral fistula is currently treated with various treatment modalities, including colostomy and drug therapy. Although the evaluation of these modalities is required, abdominoperineal resection or rectal excision without anastomosis may be a valuable treatment option because these approaches improve the urethral fistula while sparing the urethra without any significant complications.

A case of Crohn's disease complicated with simultaneous double cancers of the small bowel.

A case of Crohn's disease complicated with simultaneous double cancers of the small bowel is reported. The patient is a 66-year-old man who had suffered from Crohn's disease for 20 years. He underwent surgery to identify the source of repeated episodes of intestinal obstruction. Two short segments of strictures and proximal dilatations were found in the distal ileum. Therefore, we performed an en bloc resection of the two stenotic sections instead of strictureplasty. Histological examination of the resected specimen revealed not only Crohn's disease but also a well-differentiated adenocarcinoma within each of the two strictures. One had invaded to the muscular layer and the other to the subserosal layer. In cases of Crohn's disease with longstanding stenosis, the probability of carcinoma should be considered.

A Study of the Right Colonic Vascular Anatomy: Correlations between Veins and Arteries.

OBJECTIVES: Few studies have examined the correlations between the arteries and veins of the right colon. In this study, we aimed to use high-resolution CT scans to understand the vascular anatomy of Henle's gastrocolic trunk and review the terminology describing the arteries and veins of the right colon. METHODS: This retrospective study has examined patients who underwent laparoscopic colectomy for right colon cancer in a single institution in Japan. Scans from consecutive patients who underwent surgery between October 2017 and March 2020 (n = 165) were examined. Preoperative CT images were used to create multiplanar reformation images and volume rendering images. RESULTS: Among the 139 patients with Henle's gastrocolic trunk (GCT) present, arteries accompanying the accessory right colic vein (ARCV) were most common on the right branch of the middle colic artery (MCA) (71.2%), followed by the right colic artery (RCA) (19.4%); meanwhile, 9.4% of the patients had no accompanying arteries. Of patients with no accompanying arteries to the ARCV, RCA was present in 15.4%. Among the 26 patients with no GCT, the right colic vein (RCV) existed in 15 patients, with the artery accompanying the RCV most commonly being the right branch of the MCA (66.6%), followed by the RCA (33.3%). CONCLUSIONS: Irrespective of the presence of GCT, approximately 70% of the arteries accompanying the drainage vein from the right colon were the right branch of the MCA. We suggest that vascular branch formation be considered preoperatively in surgical management for right colon cancer.

Subtotal colectomy for refractory ulcerative colitis with COVID-19 infection; a first case report in Japan.

We report a 60-year-old male who was transferred to our hospital for the operation because of refractory ulcerative colitis (UC). He was diagnosed to be infected with COVID-19 for SARS-CoV-2 PCR test positive at the time of transfer. We determined emergency operation because his general condition was poor such as malnutrition and ADL decline due to exacerbation of UC and air embolization by central venous catheter removal. He underwent subtotal colectomy with a sigmoid mucous fistula and ileostomy. He was well postoperatively. This is a first case report in Japan who underwent an operation for UC with COVID-19 infection.

The Significance of Lateral Lymph Node Metastasis in Low Rectal Cancer: a Propensity Score Matching Study.

BACKGROUND: The indications for lateral lymph node dissection (LLND) in rectal cancer have been controversial. The purpose of this study was to clarify the significance of lateral lymph node metastasis in low rectal cancer. METHODS: This was a retrospective study at a high-volume cancer center in Japan. In this study, 40 patients with pathologically positive LLN (LLN+) were matched with 175 negative (LLN-) patients by propensity score matching (PSM). COX regression analysis was used to identify independent risk factors related to prognosis. The relapse-free survival rate (RFS) and overall survival rate (OS) of the 2 groups before and after matching were analyzed. RESULTS: Of the 64 patients undergoing LLND, 40 (62.5%) patients had LLN+ disease. The LLN+ patients showed deeper infiltration of the primary tumor than the LLN- patients (T3-T4: 87.5% vs. 72.0%; p = 0.044), a greater number of metastatic lymph nodes (N2: 75.0% vs. 35.4%; p < 0.001), and a higher rate of local recurrence (30% vs. 9.1%; p < 0.001). Adjuvant chemotherapy was more common in the 40 LLN+ patients than in the 175 LLN- patients (70.0% vs. 46.8%; p = 0.008). After relapse, the rate of first-line chemotherapy administration for LLN+ patients was higher than that for the LLN- patients (62.5% vs. 29.5%; p = 0.005). The RFS of LLN+ patients was shorter than that of the LLN- patients (p = 0.005). After PSM, although more LLN+ patients received adjuvant chemotherapy than the LLN- patients (70.0% vs. 40.0%; p = 0.007), the local recurrence rate remained higher (30% vs. 10%; p = 0.025). The differences between RFS (p = 0.655) and OS rates (p = 0.164) of the 2 patient groups were not significant. CONCLUSION: Even after LLND, patients with LLN+ low rectal cancer still showed an elevated local recurrence rate. Controlling local recurrence by adjuvant chemotherapy alone is difficult, and the additional strategic treatments are needed.

Laparoscopic Surgery for Colorectal Cancer in Patients on Hemodialysis: A Propensity Score-matched Analysis.

BACKGROUND/AIM: Surgery on hemodialysis patients requires special attention, as the tissue of these patients is vulnerable and hemorrhagic. This study explored the feasibility of laparoscopic surgery for colorectal cancer in hemodialysis patients. PATIENTS AND METHODS: This was a retrospective study of patients who underwent laparoscopic surgery for colorectal cancer in a single institute from April 2007 to December 2016. RESULTS: A total of 2668 patients were included: 24 (0.9%) were on hemodialysis, and 2644 (99.1%) were not. After 1:1 propensity score matching, there were no significant differences in the short-term postoperative results, the disease-free survival rate (p=0.0813) or the cancer-specific survival rate (p=0.555). However, the overall survival rate was significantly lower in hemodialysis patients than in non-hemodialysis patients (p=0.0135). CONCLUSION: Standard laparoscopic operative procedures can be safely performed for hemodialysis patients, and there was no marked difference in the long-term oncological outcomes between the two groups.

Does signet ring cell carcinoma component signify worse outcomes for patients with colorectal cancer?

AIM: The purpose of this study was to elucidate the differences in clinical pathology and prognosis between signet ring cell carcinoma component and adenocarcinoma in colorectal cancer. MATERIALS AND METHODS: From April 2007 to December 2016, a total of 4348 patients with colorectal cancer underwent surgery, of which 3283 were included in the study. One patient was diagnosed with signet ring cell carcinoma (SRCC); 16 were diagnosed with signet ring cell carcinoma component (SRCCc); and 3266 patients were diagnosed with adenocarcinoma (ADC). We matched SRCCc and ADC with a propensity score of 1:3 and analyzed overall survival rates (OS) and cancer-specific survival rate (CSS) between the 2 groups before and after matching. RESULTS: Before matching, patients in the SRCCc group had more advanced cancer (stage III-IV: 87.5% vs 45.6%; P < .001), more perineural invasion (75.0% vs 44.2%; P = .013), and higher lymphatic invasion (87.5% vs 42.4%; P < .001) than those in the ADC group. Consequently, the OS (P < .001) and CSS (P = .049) of the SRCCc group were worse than the ADC group. Peritoneal metastasis was found in 4 (57%) patients with stage IV disease. However, after tumor staging and all background factors were matched, there were no significant differences in prognosis for OS (P = .127) and CSS (P = .932) between the 2 groups. CONCLUSION: SRCCc is more likely to be associated with lymphatic invasion and perineural infiltration than ADC, leading to significantly poorer survival outcomes. However, when all background factors are matched with ADC, the prognosis of SRCCc is not worse than ADC. Improving the treatment outcomes of peritoneal metastasis may be pivotal in the treatment of SRCCc.

Intestinal endometriosis treated by laparoscopic surgery: case series of 5 patients.

BACKGROUND: Intestinal endometriosis is rare and most frequently involves the rectum and sigmoid colon. CASE PRESENTATION: Here, we report a case series of 5 patients who underwent laparoscopic resection for intestinal endometriosis. None of the patients developed postoperative complications, and all were discharged at 5-8 days after surgery. The diagnosis of intestinal endometriosis is difficult to obtain before surgery. Only 2 of 5 patients were diagnosed preoperatively. Among 1 of the 2 patients, the symptoms at the time of menstruation were obvious. In patients with submucosal tumors, the preoperative diagnosis can be difficult. Additional imaging examinations at the time of menstruation might be useful for obtaining a diagnosis. D2 dissections were performed for 3 patients, because malignancy could not be ruled out as a preoperative diagnosis. The surgical findings of 1 patient did not appear to be endometriosis. Surgery for intestinal endometriosis usually encounters advanced pelvic adhesions and fibrosis. For patients undergoing sigmoidectomy, the mean operative time was 152 min and mean blood loss was 10 mL. For patients undergoing rectal resection, the mean operative time was 282 min and mean blood loss was 17 mL. Two cases had severe pelvic adhesions, and the residual rectum could not be straightened. Therefore, side-to-side anastomosis was performed. For intestinal endometriosis surgery, flexible planning for the anastomosis method used for residual intestine should be undertaken. CONCLUSION: Laparoscopic surgery for intestinal endometriosis was safe but technically difficult, because of fibrosis and adhesions. An accurate diagnosis should be attempted based on the clinical symptoms, imaging findings, and intraoperative findings. The method used for anastomosis should be decided on a case-by-case basis.

Persistent Descending Mesocolon as a Key Risk Factor in Laparoscopic Colorectal Cancer Surgery.

BACKGROUND: Persistent descending mesocolon (PDM) is a rare colonic anatomical variant. However, PDM's impact on the technical aspects and outcomes of laparoscopic colorectal cancer resection are unclear. PATIENTS AND METHODS: This retrospective clinical cohort study was conducted at a high-volume cancer center in Japan to evaluate intra- and postoperative outcomes of laparoscopic colorectal cancer surgery in patients with (PDM+) or without (PDM-) PDM over the past 7 years. RESULTS: Between January 2012 and September 2019, 2,775 patients underwent laparoscopic colorectal cancer resection at our center, including 60 (2.1%) cases of PDM. Preoperative detection was achieved in only 5 patients (8.3%), 39 patients were men, and 21 patients were women. The average age was 67 years. Twenty patients had a history of prior abdominal surgery (33.3%), with little or no subsequent adhesions. The average duration of sigmoidectomy in PDM+ patients (n=17; 217.7±14.2 min) was significantly longer than that in PDM- patients (n=547; 176.2±2.4 min; p=0.003), as was average blood loss (32.3±10.6 ml vs. 16.7±2.8 ml; p=0.03). Likewise, average operative time for high anterior resection in PDM+ patients (n=11; 227.1±20.2 min) was significantly longer than that in PDM- patients (n=294; 195.6±3.0 min; p=0.048). Rates of postoperative anastomotic leakage and postoperative recurrence did not differ in both groups. In PDM+ patients, retention of left colic artery had no impact on proximal specimen margins or occurrences of anastomotic leakage. CONCLUSION: PDM prolongs operative times and increases bleeding in laparoscopic colorectal cancer surgery and should be considered a risk factor when encountered.

Mucinous Adenocarcinoma as a High-risk Factor in Stage II Colorectal Cancer: A Propensity Score-matched Study from Japan.

BACKGROUND/AIM: The purpose of this study was to investigate the clinical, pathological, and prognostic differences between adenocarcinoma (ADC) and mucinous adenocarcinoma (MUC) in colorectal cancer (CRC). PATIENTS AND METHODS: This was a retrospective study of a Japanese high-volume cancer Center over a 10-year period. From April 2007 to December 2016, a total of 3,296 patients with primary CRC were included in the study. The clinical characteristics of MUC and ADC were compared. Then, propensity score matching was performed according to a 1:2 ratio. Multivariate analysis was used for independent risk factors related to prognosis. The overall survival (OS) and disease-free survival (DFS) of 126 cases of MUC and 256 cases of ADC were studied, as well as the survival rate of each stage. RESULTS: MUC accounts for 3.82% of the total CRC. Compared to ADC, MUC is more common in female patients (47.62% vs. 38.77%; p=0.045), with higher carcinoembryonic antigen levels (56.35% vs. 34.95%; p<0.001), more ulcerative and infiltrative types (82.54% vs. 72.93%; p=0.016), higher incidence of perineural infiltration (51.59% vs. 41.04%; p=0.018), deeper infiltration (T3-T4: 90.48% vs. 65.84%; p<0.001), and more advanced cancer (stage III-IV: 59.52% vs. 44.79%; p=0.001). MUC is also more likely to recur (24.6% vs. 14.32%; p=0.001). Regarding the long-term survival rate, the OS (p<0.001) and DFS (p=0.05) is consequently worse. After propensity score matching, multivariate analysis showed that MUC was a common independent risk factor for DFS [odds ratio (OR)=4.277; 95% confidence interval (CI), 0.327-0.97; p=0.039], and also for OS (OR= 6.836; 95% CI, 0.274-0.831; p=0.009). In MUC, OS and DFS were still relatively worse (OS: p=0.017; DFS: p=0.038). However, only significant statistical differences were shown in stage II (OS: p=0.003; DFS: p=0.007). No significant differences were noted in the stages I, III, or IV. CONCLUSION: MUC is a high-risk factor for stage II CRC. Adjuvant chemotherapy should be routinely recommended for patients with MUC stage II, and special attention should be paid during their follow-up.