Prognostic Value of BRAF and KRAS Mutation in Relation to Colorectal Cancer Survival in Iranian Patients: Correlated to Microsatellite Instability.

PURPOSE: To evaluate the prognostic role of BRAF and KRAS mutations after adjustment for microsatellite instability (MSI) in Iranian colorectal cancer (CRC) patients. METHODS: BRAF and KRAS mutations and MSI status were assessed in 258 Iranian subjects with CRC. Two hundred fifty-eight consecutive stages I-IV CRC patients, who underwent surgical resection of adenocarcinoma from 2012 to 2016, were enrolled in the research. Pyrosequencing and Cast-PCR methods were used to the detection of KRAS and BRAF mutations. Kaplan-Meier and Cox regression were employed to estimate hazard ratios (HR) for the association between BRAF and KRAS mutation and overall survival (OS). RESULTS: KRAS and BRAF mutations were detected in 36 (14%) and 15 (5.8%) cases of 258 patients with CRC, respectively. BRAF mutations that all comprised V600E and KRAS mutations was found in codon 12 and 13 (80.6% and 19.4%), respectively. KRAS mutations were detected in 19 (15.4%) patients of 123 microsatellite stable (MSS) CRC and it is significantly associated with tumor location and metastasis. BRAF and KRAS mutant vs. wild type of BRAF and KRAS, 5-year OS was 73.3% vs. 82.3% and 83.3% vs. 81.5% (long-rank P > 0.05), respectively. KRAS mutant vs. KRAS-wild-type tumors in MSS/MSI-L status CRC patients, 5-year OS was 78.9% vs. 90.4% (long-rank p = 0.046). CONCLUSION: The present study revealed that BRAF and KRAS mutations were not related to the worse overall survival, while KRAS mutation can be a prognostic factor for overall survival in sporadic microsatellite-stable (MSS) status in Iranian CRC patients.

Polyp detection rate and pathological features in patients undergoing a comprehensive colonoscopy screening.

AIM: To identify the prevalence, and clinical and pathologic characteristic of colonic polyps among Iranian patients undergoing a comprehensive colonoscopy, and determine the polyp detection rate (PDR) and adenoma detection rate (ADR). METHODS: In this cross-sectional study, demographics and epidemiologic characteristics of 531 persons who underwent colonoscopies between 2014 and 2015 at Mehrad gastrointestinal clinic were determined. Demographics, indication for colonoscopy, colonoscopy findings, number of polyps, and histopathological characteristics of the polyps were examined for each person. RESULTS: Our sample included 295 (55.6%) women and 236 (44.4%) men, with a mean age of 50.25 ± 14.89 years. Overall PDR was 23.5% (125/531). ADR and colorectal cancer detection rate in this study were 12.8% and 1.5%, respectively. Polyps were detected more significantly frequently in men than in women (52.8% vs 47.2%, P < 0.05). Polyps can be seen in most patients after the age of 50. The average age of patients with cancer was significantly higher than that of patients with polyps (61.3 years vs 56.4 years, P < 0.05). The majority of the polyps were adenomatous. More than 50% of the polyps were found in the rectosigmoid part of the colon. CONCLUSION: The prevalence of polyps and adenomas in this study is less than that reported in the Western populations. In our patients, distal colon is more susceptible to developing polyps and cancer than proximal colon.