Effect of neutropenia on survival outcomes of patients with metastatic colorectal cancer receiving trifluridine/tipiracil plus bevacizumab.

Trifluridine (FTD)/tipiracil (TPI) plus bevacizumab (Bev) is a promising late-line treatment in metastatic colorectal cancer (mCRC). Although chemotherapy-induced neutropenia (CIN) is a well-known predictor of FTD/TPI efficacy, whether CIN is a predictive marker of efficacy for FTD/TPI + Bev remains unclear. Thus, the present study aimed to investigate the clinical outcomes of FTD/TPI + Bev and the predictive markers of its efficacy. Clinical data of patients with mCRC who received FTD/TPI + Bev at the Cancer Institute Hospital between January 2017 and August 2020 were retrospectively collected. Disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety were assessed. In addition, subgroup analyses of prognostic and predictive efficacy markers were performed. In total, 94 patients (median age, 60.0 years; age range, 32-82 years; 37 men and 57 women) were included in the present study. The DCR was 44.7%, the median PFS time was 2.9 months (2.3-4.1 months) and the median OS time was 10.0 months (7.3-11.1 months). Grade 3 or 4 CIN within the first cycle of treatment occurred in 27.7% of patients, which was significantly associated with a longer PFS time than those who did not develop CIN [3.8 months (2.3-8.4 months) vs. 2.7 months (1.8-4.0 months); P=0.008]. Furthermore, the DCR was higher in patients with grade 3 or 4 CIN within the first cycle of treatment than those without CIN (61.5 vs. 38.2%; P=0.07). Multivariate Cox regression analysis revealed that grade 3 or 4 CIN within the first cycle of treatment are independent predictors for a longer PFS time (P=0.01). Taken together, the results of the present study suggest that grade 3 or 4 CIN within the first cycle of treatment are early predictors of the efficacy of FTD/TPI + Bev.