Impact of TAS-102 dose reduction on severe neutropenia and survival outcomes in patients with metastatic colorectal cancer and prior chemotherapy-induced neutropenia.

The present study aimed to evaluate the impact of initial dose reduction of trifluridine/tipiracil (TAS-102) monotherapy on the incidence of severe neutropenia and overall survival (OS) in individuals with metastatic colorectal cancer, considering prior chemotherapy-induced severe neutropenia. Participants were classified into the following three groups: A group, individuals who did not experience severe neutropenia during previous chemotherapy and did not undergo dose reduction (n=61); B1 group, those who experienced severe neutropenia during previous chemotherapy and received an initial dose reduction of TAS-102 (n=28); and B2 group, those who experienced severe neutropenia but did not receive a dose reduction (n=88). Neutropenia severity, progression-free survival (PFS) and OS were compared among the groups. Notably, there was no significant difference in the incidence of grade 3 or higher neutropenia among the three groups during TAS-102 administration (P=0.958). The median OS times in the A group (n=61), B1 group (n=28) and B2 group (n=88) were 273 days (95% CI, 199-299), 285 days (95% CI, 202-NA) and 233 days (95% CI, 182-272), respectively (log-rank test, P=0.165). The median PFS times among the three groups were 133.0 days (95% CI, 98-153), 94.5 days (95% CI, 77-133) and 93.5 days (95% CI, 83-100), respectively (log-rank test, P=0.053). In conclusion, a proactive dose reduction at TAS-102 treatment initiation based on pre-existing severe neutropenia should be carefully considered, as it may not be necessary.