Advanced mucinous colorectal cancer – epidemiology, prognosis and efficacy of chemotherapeutic treatment

Background: Occasionally, patients with colorectal cancer are diagnosed with a mucinous subtype of the disease. Although well known, the clinicopathological significance of this histological finding remains controversial. As of today, none of the current guidelines for treatment of colorectal cancer differentiate treatment with respect to mucinous or non-mucinous cancer. Due to the lack of substantiated data, best treatment approaches remain unclear and mucinous subtype of CRC is mostly treated along the lines of recommendations for adenocarcinoma of the colon.

Methods: We investigated an East-Bavarian cohort of 8758 patients suffering from colorectal cancer. These included 613 (7.0%) patients with a mucinous subtype and eligible for the analysis of characteristics in clinical course and evaluation of efficacy of common chemotherapy protocols.

Results and conclusion: Mucinous CRC was found to be predominantly right sided (p < 0.001), to occur with a preponderance in women (p < 0.001), and being more dedifferentiated (grading) at diagnosis (p < 0.001). An association of younger age at first diagnosis, previously reported by other groups, with mucinous CRC could not be confirmed. Patients with non-mucinous CRC demonstrated poorer survival (p = 0.049). Further subgroup analysis demonstrated that this was mostly due to a significantly poorer outcome in patients with rectal carcinoma (p = 0.029). Chemotherapeutic treatment showed comparable efficacy for mucinous and non-mucinous cancers in both an adjuvant and palliative setting for colon cancer patients (p < 0.001 – 0.005).