Prognostic impact and risk factors of severe neutropenia in the early phase of treatment with trifluridine-tipiracil for metastatic colorectal cancer patients: a single-center retrospective study.

PURPOSE

We aimed to identify the risk factors for severe neutropenia in the early phase of trifluridine-tipiracil (FTD/TPI) treatment, and their impact on overall survival (OS).

METHODS

This single-center retrospective study included patients with unresectable metastatic colorectal cancer who were treated with FTD/TPI. The primary endpoint was OS, and the secondary endpoint was severe neutropenia during the first and second cycles of FTD/TPI. We assessed the association between outcomes and potential confounders using multivariate analysis.

RESULTS

Of the 77 total patients, 33 developed severe neutropenia during the first and second treatment cycles. In Cox hazard analysis, the independent factors associated with OS were neutropenia ≥ grade 1 during cycles 1 and 2 (adjusted hazard ratio 0.43; 95% confidence interval (CI) 0.21-0.87), combined treatment with bevacizumab (0.47; 95% CI 0.27-0.83), number of metastatic organs ≥ 3 (2.15; 95% CI 1.22-3.82), and time since diagnosis of metastasis until commencement of FTD/TPI < 18 months (1.94; 95% CI 1.13-3.33). Severe neutropenia during cycles 1 and 2 was not associated with OS (0.75; 0.44-1.27). The risk of severe neutropenia adjusted for initial dose reduction was defined as renal impairment with creatinine clearance (Ccr) of < 60 ml/min (adjusted odds ratio, 4.67; 95% CI, 1.38-15.80) and absolute neutrophil count (per 1000/μl, 0.47; 0.27-0.81).

CONCLUSION

The neutropenia ≥ grade 1 during cycles 1 and 2 of FTD/TPI is a predictor of favorable outcomes; however, the effect of severe neutropenia on OS was not clear. Renal impairment was also associated with severe neutropenia.