Predicting Trifluridine/Tipiracil Treatment Outcomes in Refractory Metastatic Colorectal Cancer Patients: A Multicenter Exploratory Analysis

Introduction. There are no recommended biomarkers to identify patients with refractory metastatic colorectal cancer (mCRC) who would benefit the most from trifluridine/tipiracil (TTP). The exploratory analysis of the RECOURSE trial revealed that patients with low tumor burden and indolent disease derive greater benefit in terms of both progression-free (PFS) and overall survival (OS). Nevertheless, the final answer on the TTP real impact on the well-being of patients with late-stage mCRC will come from real-world data.Methods. The aim of this retrospective exploratory study was to investigate the effectiveness of TTP in mCRC with regard to the duration of standard treatment and other influencing variables. The study included 260 patients from the three largest Croatian oncology centers who began treatment with TTP in the third or fourth line between 2018 and 2020.Results. The median OS and PFS for the entire cohort were 6.53 and 2.50 months, respectively. Patients with more aggressive disease, defined as those whose time to progression on the first two lines of standard therapy was less than 18 months, had significantly shorter PFS (2.40 vs. 2.57 months, HR 1.34 95%CI 1.03-1.84). There was also a tendency towards shorter OS (6.10 vs. 6.30 months, HR 1.32, 95%CI 0.99-1.78) but without statistical significance. Patients with ECOG PS 0, without liver metastases, and with RAS mutation had both longer OS and PFS. No influence was detected from other variables including age, sex, primary tumor location, and tumor burden.Conclusion. With regard to the results of the previously conducted trials, the study concludes that indolent disease, good general condition, and absence of liver metastases are positive predictive factors for TTP treatment.