Abstract
Introduction: Regorafenib and TAS-102 are two orally-administered drugs used to treat refractory metastatic colorectal cancer (mCRC). This study was performed to explore any differences between different therapy sequences: TAS-102 first or regorafenib first. Patients and methods: This is a retrospective and real-practice study in mCRC patients treated according to the ESMO guidelines. They received TAS-102 first (regorafenib second, TR) or regorafenib first (TAS-102 second, RT) at standard doses. Responses to therapy and toxicities were evaluated by RECIST and CTCAE v4.0, respectively. Associations between clinical and pathologic variables and different therapy sequences were evaluated by χ2-test. p <0.05 was considered statistically significant. A description of any differences in overall survival (OS) between TR and RT was the primary outcome. OS curves were depicted through the Kaplan−Meier product limit. All statistical analyses were performed by the Excel software and MedCalc® version 20.112. Results: Sixty-five patients were analyzed. Twenty-eight received regorafenib before TAS-102, 37 vice versa. Responsiveness to first-line chemotherapy as well as disease control were not different between RT and TR patients. G4 toxicities were very rare. The three most common G1/G2 toxicities with regorafenib were fatigue, anemia, and cutaneous rash; anemia, fatigue, and neutropenia with TAS-102. Compliance to treatment was lower in TAS-102 patients compared to regorafenib. Interestingly, analysis of OS showed a significant difference at Log Rank test (p = 0.0366) in favor of TR (median OS: 4.5 months) compared to RT (median OS: 3.0 months; HR: 0.55; 95% CI: 0.31−0.96). Conclusions: we found a significant difference in terms of survival in favor of the TR sequence of treatment. Larger studies are needed to confirm these data and explore specific biomarkers predicting the correct sequence of oral drugs in the treatment of refractory mCRC patients.