Low adoption rate of iRECIST guidelines in recurrent gynecologic cancer patients treated with immune modulators

연구배경: Two immune modulators, pembrolizumab (pembro) and nivolumab (nivo), have been used in the treatment of recurrent gynecologic cancers since November 2017. Currently, iRECIST (modified RECIST 1.1 for immune modulators) is available for response evaluation in clinical trials and practice also. We aimed to present real-world experience with pembro and nivo regarding response evaluation in our hospital. 대상 및 방법: We identified patients with recurrent gynecologic cancer treated with immune modulators between November 2017 and May 2020. Through the review of patients’ medical records, clinico-pathologic characteristics, and response data were collected. Tumor response was evaluated by both the RECIST 1.1 and iRECIST guidelines. 결과: In total, 79 patients were identified. Excluding 33 who were enrolled in clinical trials, 7 with melanoma, and 5 with sarcoma, 34 (31 for pembro and 3 for nivo) were included in this analysis. Currently, pembro/nivo treatment was still ongoing in 11 patients. The number of ovarian, cervical, and endometrial cases were 20 (58.8%), 11 (32.4%), and 3 (8.8%), respectively. Mean patient age was 58.6 years, and median treatment lines and cycles for pembro/nivo were 5 (range, 3-9) and 3 (range, 1-18), respectively. Three patients (8.8%) died during pembro/nivo treatment owing to worsened disease status, and four patients (11.8%) were lost to follow-up without any Imaging. All the remaining 27 patients received CT scans after first 3 cycles of pembro/nivo, and underwent tumor response assessment: applying RECIST 1.1, PR, SD, and PD were observed in 7.4%, 18.5%, and 74.1%, respectively. Of the PD cases, 55.0% (11/20) stopped further pembro/nivo at the patient and physician’s decision. However, the other nine (45.0%) continued pembro/nivo treatment in accordance with iRECIST; they were assessed as iUPD and received additional cycles (median total cycles, 9 [range, 4-18]). Of these, only two showed iCPD on follow-up CT scans done within 8 weeks after iUPD. The best overall response was iPR for one and iSD for six. 결론: Less than half of recurrent gynecologic cancer patients who showed RECIST 1.1 PD in their first imaging continued pembro/nivo treatment. Our study demonstrate the necessity of follow-up imaging for confirmation of progression, rather than direct discontinuation of the immune modulator, as recommended by the iRECIST.