ABSTRACT
BACKGROUND/AIM: TAS-102 has led to a significant improvement in overall survival (OS) and progression-free survival (PFS) of patients with metastatic colorectal cancer (mCRC). Neutropenia is the most common adverse event and an important factor impacting chemotherapy continuation. In this retrospective study, factors associated with grade ≥3 neutropenia, that is frequently observed in TAS-102-treated patients, were examined. PATIENTS AND METHODS: The medical records of 41 patients with CRC who received TAS-102 between October 2014 and June 2017 at the Fukuoka University Hospital were retrospectively reviewed. Response rate, PFS, OS, and adverse events were analyzed using KRAS mutation, administration method, concomitant drug administration, neutrophil-to-lymphocyte ratio (NLR), and Onodera's prognostic nutritional index (Onodera's index) as a stratification factors. RESULTS: Both PFS and OS were significantly higher with TAS-102 plus bevacizumab combination therapy. Biweekly administration (7.1%) was associated with significantly less neutropenia compared to normal administration (44.4%). DCR with biweekly administration was better than that with normal administration, although without statistical significance. No significant difference was observed in OS rates between the biweekly and normal administration regimens; however, the biweekly regimen was associated with significantly prolonged PFS. By multivariate analysis, a significant difference was noted in the Onodera's index for OS and in the administration method and NLR for PFS. CONCLUSION: Biweekly administration without a change in the drug dose intensity was associated with reduced neutropenia in patients with mCRC. The effects and adverse events of TAS-102 were associated with concomitant drug administration, administration method, and nutritional status.
