Purpose: Metastatic colorectal cancer (mCRC) is a significant global health burden. This retrospective study compared the effectiveness of trifluridine/tipiracil (FTD/TPI), regorafenib, and chemotherapy rechallenge for third-line mCRC treatment.
Materials and methods: We reviewed the medical records of 132 patients with mCRC treated with regorafenib, FTD/TPI, or a rechallenge with the initial chemotherapy regimen in a third-line setting from four different institutions. The primary end point was progression-free survival (PFS). Secondary end points were objective response rate and overall survival (OS) across the three treatment approaches.
Results: Twenty-nine patients received chemotherapy rechallenge, and 103 received FTD/TPI or regorafenib. Patients' characteristics were comparable, except for a lower number of left-sided primaries and KRAS wild-type tumors in the FTD/TPI-regorafenib group. The median PFS for the entire group was 3.0 months, and the median OS was 13.7 months. Chemotherapy rechallenge has resulted in a median PFS of 3.1 months and a median OS of 21.2 months, compared with 2.9 months (PFS) and 12.6 months (OS) for the FTD/TPI-regorafenib group. Multivariate analyses identified male sex and an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-1 as independent prognostic factors for better PFS, whereas chemotherapy rechallenge, localized stage at diagnosis, and an ECOG PS of 0-1 were significant prognostic factors for better OS.
Conclusion: This study suggests that chemotherapy rechallenge may provide a survival benefit in the third-line treatment of mCRC. However, patient characteristics, such as sex and ECOG PS, should also be considered in treatment decisions. Further prospective studies are required to confirm our findings.