Treatment Outcomes in Patients Receiving Regorafenib for Metastatic Colon Cancer

Abstract

Objectives: To review the treatment outcomes of patients with chemorefractory metastatic colorectal cancer receiving the multikinase inhibitor regorafenib. Methods: This was a retrospective cohort study including patients who received regorafenib after failure of standard irinotecan-and oxaliplatin-based chemotherapy with or without biologics from 2016 to 2018 in a single centre in Hong Kong. Results: Fourteen patients met the inclusion criteria. All had good general condition (i.e., Eastern Cooperative Oncology Group score 1). Seven patients had received bevacizumab previously. Median progression-free survival (PFS) was 12.4 weeks and median overall survival (OS) was 26.5 weeks. Eight patients had grade ≥3 adverse events and 10 (71.4%) required temporary treatment suspension. The commonest grade ≥3 adverse events were palmarplantar erythrodysaesthesia and fatigue (both 28.6%). Patients with a carcinoembryonic antigen drop of ≥50% from baseline enjoyed longer PFS, though not to a significant extent. OS was longer for left-sided primary tumours (202 vs. 57 days, p = 0.001). Two patients with good performance after progression received trifluridine-tipiracil. Their median OS was 400 days. Conclusion: Our experience with regorafenib monotherapy for patients with chemorefractory metastatic colorectal cancer was comparable to the landmark trials. The grade ≥3 adverse events were frequent, and dose reduction or treatment delay was required. Potentially favourable prognostic factors included a left-sided primary tumour and a carcinoembryonic antigen drop from baseline. Those who received further treatment after regorafenib enjoyed reasonably long survival. Treatment after regorafenib with newer strategies should be considered in those who remain functional.