Prognostic Significance of Mucinous Histologic Subtype on Oncologic Outcomes in Patients With Colorectal Cancer

PURPOSE Mucinous adenocarcinomas account for about 10% of all colorectal cancers. This study aimed to investigate the prognostic impact of mucinous histologic subtype on oncologic outcomes in patients with colorectal cancer. METHODS This retrospective study was performed at two large tertiary university hospitals. We analyzed the characteristics, prognostic factors, and survival of patients with colorectal cancer who were treated and followed up between 2000 and 2013. RESULTS Totally, 144 of 1,268 patients with a colorectal adenocarcinoma (11.4%) had mucinous histologic subtype. Statistically significant results found in this research are as follows: Mucinous histologic subtype tended to present in younger patients and to have larger tumor size, higher histologic grade, higher node stage, larger number of positive nodes, and higher rate of perineural invasion compared to nonmucinous histologic subtype. On the univariate analysis, mucinous subtype was a prognostic factor for disease-free and overall survival. On the multivariate analysis, primary tumor location, node stage and lymphatic-vascular invasion were independent prognostic factors for the local control rate. Rectal tumor location, higher disease stage, tumor grade II, and presence of lymphatic-vascular invasion had negative influences on disease-free survival, as did rectal tumor location, higher disease stage and presence of lymphatic-vascular invasion on overall survival. CONCLUSION Mucinous histologic subtype was associated with some adverse pathologic features in patients with colorectal cancer; however, it was not an independent prognostic factor for oncologic outcome.