Duration of previous treatment as a prognostic factor in metastatic colorectal cancer treated with trifluridine/tipiracil.

We herein describe the findings from the trifluridine/tipiracil (TAS-102) Compassionate Use program in Latvia, set up prior to marketing authorization for the management of pretreated patients with metastatic colorectal cancer (mCRC). The efficacy and safety of TAS-102 in patients with refractory mCRC were evaluated in the phase III trial RECOURSE. A previous report confirmed neutropenia and duration of previous treatment for mCRC as prognostic factors in TAS-102 users. The aim of the present study was to analyze possible prognostic factors, such as neutropenia, in TAS-102 responders. A retrospective analysis of 14 patients who received TAS-102 chemotherapy in two institutions in Latvia (Clinic of Oncology of Pauls Stradins Clinical University Hospital and Oncology Centre of Riga East University Hospital) was performed. Grade 3-4 neutropenia was observed in 28% of the patients. In patients with grade 3-4 neutropenia the median progression-free survival (mPFS) was 7 months, whereas in those without neutropenia the mPFS was 5 months [hazard ratio (HR)=0.24, P=0.033]. In 64% of the patients, the duration of previous treatment was >18 months. In patients treated for >18 months from the start of first-line mCRC treatment the mPFS was 7 months, whereas in those treated for ≤18 months from the start of first-line mCRC treatment the mPFS was 5 months (HR=0.15, P=0.029). Therefore, a longer time from mCRC diagnosis until disease progression may be used to select chemotherapy-refractory mCRC patients for TAS-102 treatment. Furthermore, severe neutropenia may be considered as a surrogate marker for predicting TAS-102 treatment outcomes.