Analysis of neutropenia as a predictive factor of the efficacy of trifluridine-tipiracil treatment

Trifluridine-tipiracil (TAS-102), an oral cytotoxic agent used in adult patients with refractory metastatic colorectal cancer (mCRC), has been associated with neutropenia (chemotherapy-induced neutropenia) (CIN)). We evaluated the efficacy and safety of TAS-102 in a group of 45 mCRC patients (median age 66 years) in Huelva province, Spain, in a retrospective, multicenter observational study. We showed that the association between TAS-102 and CIN can be used as a predictor of efficacy. 20% (9/45) of patients with an Eastern Cooperative Oncology Group (ECOG) score of 2 had received at least one previous chemotherapy treatment. Overall, 75.5% (34/45) and 28.9% (13/45) had received anti-VEGF and anti-EGFR monoclonal antibodies, respectively. Additionally, 80% (36/45) of patients had received third-line treatment. The mean treatment period, duration of overall survival (OS), and duration of progression-free survival (PFS) were 3.4, 12, and 4 months, respectively. A partial response was seen in 2 patients (4.3%), and disease stabilization was observed in 10 patients (21.3%). Neutropenia was the most frequent grade 3 - 4 toxicity (46.7%; 21/45). Other findings were anemia (77.8%; 35/45), all grades of neutropenia (73.3%; 33/45), and gastrointestinal toxicity (53.3%; 24/45). The dose of TAS-102 needed to be reduced in 68.9% (31/45) of patients, whereas treatment needed to be interrupted in 80% (36/45) of patients. Grade 3 - 4 neutropenia was a positive prognostic factor for OS (p = 0.023). A retrospective evaluation shows that grade 3 - 4 neutropenia is an independent predictor of treatment response and survival in patients undergoing routine treatment for mCRC, but this finding needs confirmation in a prospective study.