Safety of an oral anticancer agent (trifluridine/tipiracil combination tablet) in patients with advanced and recurrent colorectal cancer.

We retrospectively studied the safety of trifluridine/tipiracil combination tablet (TAS-102) monotherapy in patients with advanced and recurrent colorectal cancer. Adverse events to TAS-102 monotherapy were observed in 22 out of 23 cases (95.7%). The most frequent adverse events were neutropenia (69.6%), nausea (53.2%), and malaise (30.4%). Treatment was postponed in 54 (59.3%) out of 91 courses, and in 34 (66.7%) of these 54 courses, the delay in treatment was due to bone marrow suppression. Seven patients with peritoneal metastases suffered from nausea, whilst none of the patients without peritoneal metastases had nausea (p = 0.0139). Nausea and vomiting during a previous chemotherapy cycle was significantly associated with nausea after TAS-102 treatment (p = 0.0007), and the treatment cycles were significantly longer in patients with grade 3 or 4 neutropenia (p = 0.0061). Our results suggest that the incidence of nausea was higher in patients treated with TAS-102. Therefore, it is important to inform patients of the risk of these toxicities and to provide enhanced supportive care. Moreover, we recommend that, for patients with repeated treatment postponement due to neutropenia, the dosage should be fixed based on therapeutic efficacy and prognosis.