RECIST 1.1, Choi and mChoi criteria in the evaluation of tumor response in patients with metastatic colorectal cancer treated with Regorafenib and anti-PD-1 antibody

Abstract

PurposeNo comparative study on evaluating performance of radiological criteria has been investigated in metastatic colorectal cancer (mCRC) patients treated with the combination of Regorafenib and anti–programmed cell death 1(PD-1) antibody. We aimed to compare the performance of different radiological criteria in evaluating response in mCRC patients treated with the combination of Regorafenib plus anti-PD-1 antibody. MethodWe retrospectively recruited patients treated with Regorafenib and anti-PD-1 antibody in a single institution. Baseline and the first tumor evaluation of contrast-enhanced computed tomography (CE-CT) were assessed by three evaluation criteria: RECIST 1.1, Choi, modified Choi (mChoi). Overall survival (OS) was defined as endpoint event. ResultsTwenty-three mCRC patients [age: 58.8 ± 10.6 years, 18 (78.3 %) males] were assessed. The median overall survival was 11.8 months. According to RECIST 1.1, 8 (34.8 %) patients were stable disease (SD) and 15 (65.2 %) were progressive disease (PD). According to Choi and mChoi, 5 (21.7 %) and 1(4.3 %) patient was responders, respectively. All non-PD patients showed significantly better overall survival than PD patients by all criteria. According to Choi, those identified as responders showed better overall survival than non-responders though significant statistics were not reached (P=0.262). ConclusionsRECIST 1.1, Choi and mChoi criteria could identify survival benefit from Regorafenib plus anti-PD-1 antibody in mCRC patients. However, the value of responders detected by Choi remains to be validated in further studies.