Inverse effect of mucinous component on survival in stage III colorectal cancer

Although mucinous adenocarcinoma (MAC) is has been recognized as a separate entity in colorectal cancer (CRC), adenocarcinoma with a mucinous component (ACM) remains poorly understood.

The association of MAC and ACM with disease-free survival (DFS) and overall survival (OS) was examined using the Cox proportional hazard model in 425 consecutive stage III CRCs.

Compared with conventional adenocarcinoma (CAC), patients with MAC exhibited independently worse DFS (hazard ratio [HR], 2.64; 95% CI, 1.21-5.80; P = 0.014) and OS (HR, 3.56; 95% CI, 1.53-8.30; P = 0.003). Unexpectedly, ACM was significantly associated with worse OS than CAC (P = 0.002), despite having a similar DFS to CAC. Further, ACM patients after recurrence exhibited significantly worse OS than CAC patients (P < 0.001), similar to MAC.

Although ACM is similar to CAC with regard to estimated risk of recurrence, the outcome is extremely poor once recurrence occurs and is identical to MAC; one of the most aggressive phenotypes of stage III CRC. Thus, both MAC and ACM are adverse prognostic factors for OS.