Prognostic factors in patients with advanced and recurrent colorectal cancer receiving last-line chemotherapy.

For patients with advanced/recurrent colorectal cancer, the trifluridine/tipiracil combination tablet (TAS 102) and regorafenib are last-line treatments. This study aimed to clarify prognostic factors in patients receiving last-line chemotherapy. Between April 2014 and December 2016, 47 patients received last-line chemotherapy at Ogaki Municipal Hospital, Japan. The primary outcome was overall survival. To determine factors associated with survival, those considered significant in the univariate analysis (p <0.10), were entered into a multivariate Cox proportional hazards model. KRAS type and the use of opioid formulations were independently and significantly associated with survival in the multivariate analysis. For patients with KRAS-wild relative to KRAS-mutation cancers, the hazard ratio for death was 0.478 (95% CI, 0.249-0.919; p = 0.03). For patients taking opioid formulations, relative to those not, the hazard ratio for death was 3.557 (95% CI, 1.032-12.257; p = 0.04). The median overall survival duration for patients with KRAS-wild (n = 24) and KRAS-mutation (n = 23) cancers were 223.5 days (range: 115-703) and 154 days (range: 51-503), respectively (p = 0.05). This finding provides a useful index to make an early decision on discontinuation of treatment and to guide decisions around agents to use in last-line chemotherapy.