Abstract
AIM: Patients in clinical practice are relatively vulnerable compared to those enrolled in clinical trials. We focused on analyzing the pattern of regorafenib use in routine clinical practice, which included initial starting dose and follow-up schedule. We also evaluated the efficacy and safety according to clinical regimen. METHODS: We retrospectively reviewed the medical records of 134 Korean heavily pretreated metastatic colorectal cancer (mCRC) patients who had received regorafenib monotherapy as salvage treatment in routine clinical practice between January 2014 and January 2018. RESULTS: Among the 134 mCRC patients, the median age was 55 years (range, 22-80 years), and 51% had previously received four or more chemotherapy treatments. Thirty-eight (28.3%) patients had more than three metastatic lesions. As an initial starting dose, 120 mg regorafenib was mostly frequently used (n=65, 48.5%), followed by 80 mg (32.8%) and 160 mg (18.7%). The first follow-up after regorafenib initiation was most frequently at 28 days (45.5%), followed by 14 days (29.9%), 7 days (13.4%), and 21 days (11.2%). There was no significant difference in response rate according to initial dose of regorafenib (80 mg vs 120 mg vs 160 mg, 4.5% vs 1.5% vs 4.0%, P=0.596) or disease control rate (80 mg vs 120 mg vs 160 mg, 38.6% vs 29.2% vs 31.6%, P=0.299). Progression-free survival did not differ according to initial dose (80 mg vs 120 mg vs 160 mg, 2.8 months [95% CI 2.1-3.5] vs 2.2 months [95% CI 1.7-2.8] vs 1.9 months [95% CI 1.3-2.4], P=0.076). Grade 3/4 adverse events occurred in 17 (12.7%) patients and were not related to initial dose of regorafenib (P=0.126). CONCLUSION: Here, we present efficacy and safety data according to different initial doses of regorafenib in clinical practice. These data may provide useful information when using regorafenib for refractory mCRC in clinical practice.