Factors associated with effectiveness of trifluridine/tipiracil versus regorafenib in patients with pretreated metastatic colorectal cancer (mCRC).

Abstract

137 Background: Trifluridine/tipiracil (T) and regorafenib (R) are indicated for patients with refractory mCRC. Currently, no biomarkers are used to select which patient will benefit from which treatment. Methods: We retrospectively evaluated 212 patients who received T and/or R. Different factors associated with progression-free survival (PFS) and overall survival (OS) were analyzed. Results: T received 132, R 52, both drugs 28 patients. Median age was 64 (range 28-83), male 64%, PS 0 37%, median line of treatment 3, characteristic was similar between treatment groups. Median follow-up was 16.5 months. Median OS for T was 10.2, for R 6.9 months, P = 0.03. Factors significantly associated with OS were: ≥ 24 months from diagnosis of mCRC (0.49, P < 0.001), PS 0 (HR 1.54, P = 0.007), baseline WBC < 8 × 109/L (HR 0.47, P < 0.001), normal baseline CRP (HR 0.47, P < 0.001), ≥ 3 months from last therapy (fluoropyrimidine for T, anti-VEGF for R) (HR 0.66, P = 0.006). We developed a scoring system TASREG from these factors, 1 point for each factor, the overall score was the sum of these points and patients were divided into 3 groups: high risk group with 0 to 1 point, intermediate with 2 to 3, favorable with 4 or more points. OS for all patients according to risk group was 4.6 for high risk, 7.9 intermediate, 11.8 months favorable risk (P < 0.001). Score was also significant for T and R group evaluated separately. Score was also significant for PFS. Factors associated with OS specific for T were neutropenia G≥2 (HR 0.34, P < 0.001); for R normal baseline LDH (HR 0,40. P < 0.001), no liver metastases (HR 0.45, P = 0.002), non-synchronous disease (HR 0,40, P < 0.001). Conclusions: We could find factors associated with better outcomes for both treatment groups and factors specific for T or R. TASREG is simple prognostic tool for patients with refractory mCRC.