Early morphological change for predicting outcome in metastatic colorectal cancer after regorafenib

Background and Objective It is unclear whether early morphological change (EMC) is a predictive marker for regorafenib in metastatic colorectal cancer (mCRC). Therefore, the present study investigated whether EMC can predict the outcome of mCRC patients receiving regorafenib. Results This study evaluated 68 patients. Among 52 patients with lung metastasis, 16 (31%) had cavity formation (CF). The median progression-free survival (PFS) and overall survival (OS) in patients with/without CF were 4.2/2.4 months (p<0.01) and 9.2/6.5 months (p=0.09), respectively. Among 45 patients with liver metastasis, 14 (31%) had active morphological response (MR). The median PFS and OS in patients with/without active MR were 5.3/2.4 months (p<0.01) and 13.6/6.9 months (p=0.02), respectively. Overall, 25 patients (37%) had EMC. The median PFS and OS in patients with/without EMC were 5.3/2.1 months (p<0.01) and 13.3/6.1 months (p<0.01), respectively. Materials and Methods This retrospective study included mCRC patients with lung and/or liver metastases receiving regorafenib. CF in lung metastasis and MR in liver metastasis were evaluated at the first post-treatment computed tomography scan. EMC was determined as CF and/or active MR. We compared PFS and OS between patients with and those without EMC. Conclusions EMC could be a useful predictive marker for regorafenib in mCRC.