Prognostic significance of perioperative chemotherapy on resectable colorectal mucinous adenocarcinoma liver metastasis.

BACKGROUND: Mucinous adenocarcinoma (MAC) is an uncommon subtype of colorectal cancer (CRC). For colorectal cancer liver metastasis (CRLM), perioperative chemotherapy (PCT) has been developed to improve the rate of resection and reduce the rate of early recurrence; however, its impact on long-term outcomes in MAC is unclear. METHODS: From 1999 to 2016, 442 patients with CRLM were retrospectively reviewed, all of whom underwent CRC resection and liver metastasis resection. Among them, 34 were MAC, and the others were non-MAC. A total of 102 non-MAC patients with CRLM who underwent surgery at the same period were matched with 34 MAC patients in a ratio of 3:1 by using a random number table for analysis. RESULTS: Clinicopathologic characteristics for the MAC group (n=34) and non-MAC group (n=102) had no statistical difference. Both recurrence free survival (RFS) and overall survival (OS) did not significantly differ between the two groups. Nevertheless, in the non-MAC group, OS was fundamentally prolonged in patients with PCT compared to those who didn't have PCT (P=0.031). CONCLUSIONS: In this study, PCT had a survival benefit on non-MAC patients with CRLM while MAC patients with resectable CRLM do not benefit from PCT. When developing treatment like PCT or surgery alone for CRLM, mucinous histology should be considered as an important influence factor.