Is Microsatellite Instability Really a Good Prognostic Factor of Colorectal Cancer?

PURPOSE: The aim of this study was to investigate the clinicopathologic features of and the prognosis for colorectal cancers (CRCs) with microsatellite instabilities (MSIs). METHODS: Between 2006 and 2009, genotyping was performed on 245 patients with stage II/III CRCs to establish the MSI status. The clinicopathologic differences and the prognostic value of MSI were analyzed. The median follow-up period was 38 months (range, 7-68 months). RESULTS: Of the total 245 patients, 20 (8.2%) had MSI-high (H) and 225 (91.8%) had MSI-low (L) or stable (S) CRCs. Adjuvant chemotherapies were performed on 101 stage II (87.8%) and 107 stage III patients (82.3%). Patients with MSI-H CRCs more frequently had a family history of colon cancer (10% vs. 2.7%, P = 0.003), more frequently had a cancer located at the proximal colon (90.0% vs. 19.1%, P < 0.0001), and more often showed a mucinous phenotype or poor differentiation (35.0% vs. 7.1%, P = 0.001). Despite less frequent lymph node metastasis (25% vs. 55.6%, P = 0.01), the number of retrieved lymph nodes was higher (26.3 +/- 13.1 vs. 20.7 +/- 1.2, P = 0.04) in the MSI-H group. The overall survival and the disease-free survival (DFS) did not differ with respect to MSI status. However, in the stage II subgroup, the DFS for patients with MSI-H CRCs was significantly worse (72.2% vs. 90.7%, P = 0.03). The multivariate analysis performed on this subgroup revealed that MSI-H was an independent poor prognostic factor (adjusted hazard ratio, 4.0; 95% confidence interval, 1.0-15.6, P = 0.046). CONCLUSION: MSI-H CRCs had distinct clinicopathologic features, and MSI-H was an independent poor prognostic factor in stage II CRCs. Considering the majority of stage II patients were administrated adjuvant chemotherapy, the efficacy of adjuvant chemotherapy for treating MSI CRCs might be different from that for treating MSI-L/S tumors.

Incidence and Risk Factors of Parastomal Hernia

PURPOSE: Among the various stoma complications, the parastomal hernia (PSH) is the most common. Prevention of PSH is very important to improve the quality of life and to prevent further serious complications. The aim of this study was to analyze the incidence and the risk factors of PSH. METHODS: From January 2002 and October 2008, we retrospectively reviewed 165 patients who underwent an end colostomy. As a routine oncologic follow-up, abdomino-pelvic computed tomography was used to examine the occurrence of the PSH. The associations of age, sex, body mass index (BMI), history of steroid use and comorbidities to the development of the PSH were analyzed. The median duration of the follow-up was 36 months (0 to 99 months). RESULTS: During follow-up, 50 patients developed a PSH and the 5-year cumulative incidence rate of a PSH, obtained by using the Kaplan-Meier method, was 37.8%. In the multivariate COX analysis, female gender (hazard ratio [HR], 3.29; 95% confidence interval [CI], 1.77 to 6.11; P < 0.0001), age over 60 years (HR, 2.37; 95% CI, 1.26 to 4.46; P = 0.01), BMI more than 25 kg/m2 (HR, 1.8; 95% CI, 1.02 to 3.16; P = 0.04), and hypertension (HR, 2.08; 95% CI, 1.14 to 3.81; P = 0.02) were all independent risk factors for the development of a PSH. CONCLUSION: The 5-year incidence rate of a PSH was 37.8%. The significant risk factors of a PSH were as follows: female gender, age over 60 years, BMI more than 25 kg/m2, and hypertension. Using a prophylactic mesh during colostomy formation might be advisable when the patients have these factors.

Effectiveness of Adjuvant Chemotherapy with 5-FU/Leucovorin and Prognosis in Stage II Colon Cancer

PURPOSE: The aims of this study were to investigate the survival results and the prognostic factors of adjuvant chemotherapy in stage II colon cancer in the sparsity of Korean data. METHODS: From 1993 to 2006, 363 curatively resected pathologic stage II colon cancer patients were enrolled. Six cycles of adjuvant chemotherapy was performed: intravenous bolus 5-fluorouracil (5-FU) 500 mg/m2 with leucovorin 20 mg/m2 for 2 hours daily for 5 days, followed by a 3-week resting period (n = 308). Fifty-five patients received only curative surgery. A high risk of recurrence was defined as the presence of one or more of the following factors: T4 tumor, lympho-vascular invasion, perineural invasion, perforation, obstruction, retrieved lymph node < 12, and poorly differention. The median follow-up period was 68 months (1 to 205 months). RESULTS: The five-year overall survival (OS) rate was 90.1%, and the five-year disease-free survival (DFS) rate was 84.7%. Among high-risk patients, the OS and the DFS rates of the treatment group were significantly higher than those of the non-treatment group (OS: 90.6% vs. 69.1%, P < 0.0001; DFS: 85.9% vs. 54.1%, P < 0.0001). Among low-risk patients, the survival results of the treatment group were also significantly superior (OS: 97.7% vs. 88.2%, P < 0.0001; DFS: 93.0% vs. 80.0%, P = 0.001). In the multivariate analysis, adjuvant chemotherapy was a significantly favorable prognostic factor for overall survival (hazard ratio, 0.41; 95% confidence interval, 0.22 to 0.75; P = 0.004). CONCLUSION: In our population, adjuvant chemotherapy showed superior survival to curative surgery alone and significantly reduced the risk of death. A nationwide multicenter randomized trial is needed.