Adjuvant chemotherapy following concurrent chemoradiation (CRT) in patients with high-risk early-stage cervical carcinoma following radical hysterectomy: Results of NRG oncology/RTOG 0724/GOG-0724.

5504 Background: To assess the efficacy of adjuvant systemic chemotherapy following CRT for patients (pts) with high-risk early-stage cervical carcinoma. Methods: Pts with clinical stage IA2, IB, or IIA cervical carcinoma with at least one of the following high-risk features after radical hysterectomy: positive pelvic nodes, positive parametrium, and/or positive para-aortic nodes were stratified by intention to use brachy (yes v no), RT (Standard v IMRT); and RT dose (45 v 50.4 Gy) then randomized 1:1 to CRT or CRT and 4 cycles of adjuvant chemotherapy with paclitaxel and carboplatin (CRT + chemo). Primary endpoint was disease-free survival (DFS: death, local or regional failure, or distant mets). Reported secondary endpoints are OS (death due to any cause) and AEs (CTCAEv4). Sample size was 235 pts (50 DFS events, HR=0.47, corresponding to an increase in 4-year DFS from 80% to 90% for the CRT + chemo arm, 80% power, 1-sided log-rank α=0.05). Multivariable analysis (MVA) used Cox regression models. Results: From 9/16/2009 to 3/2/2022, this phase III international trial enrolled 236 pts, with 212 eligible/analyzed (109 CRT and 103 CRT + chemo). Median age was 46 yrs (min-max: 25-77) and median follow-up for all pts was 4.5 yrs (min-max: 0.02-12.8). Fifty-one percent of pts identified as white, 39% as Asian, and 6% Black. Most pts had squamous cell carcinoma (76%), with 18% adenocarcinoma and 5% adenosquamous. 56% of pts had open radical hysterectomy, 23% laparoscopic, and 22% robotic. Most pts had stage IB (87%) and 74% had positive pelvic nodes. Four (4%) pts on the CRT arm and 1 (1%) patient on CRT + chemo did not receive RT. The median (min-max) RT dose delivered was 50.4 Gy (7.2-60.4). Four pts (2 on each arm) did not receive concurrent cisplatin and 27 (26%) pts did not receive adjuvant carboplatin and paclitaxel on the CRT + chemo arm. Grade 3 and 4 events occurred in 36% and 7% of CRT pts; 44% and 21% in the CRT + chemo arm. There were 50 failures, 26 and 24 on the CRT and CRT + chemo arms, respectively, with 4-yr DFS estimates of 76% (90% CI: 69%, 83%) and 77% (90% CI: 70%, 84%) for the CRT and CRT + chemo arms, respectively (HR=1.05 90% CI: 0.65, 1.68, p=0.56). Thirty-seven of 50 first failures were distant 74%, 20 (40%) and 17 (34%) in CRT and CRT + chemo arms, respectively. On MVA, factors that were statistically significant for worse DFS were receiving vaginal brachy (p<0.0001), RT dose ≥50 Gy (p=0.0021), and adenocarcinoma histology (p=0.03). Pts receiving brachy had close or positive margins. The estimated 4-yrs OS is 87% (90% CI: 82%, 93%) and 89% (90% CI: 84%, 94%) for the CRT and CRT +chemo arms, respectively (HR=0.91 90% CI: 0.49 to 1.69; 1-sided log-rank p=0.40). Conclusions: The addition of systemic chemotherapy following CRT didn't improve DFS or OS in cervical cancer patients with high-risk factors after radical hysterectomy. Clinical trial information: NRG Oncology/RTOG 0724/GOG-0724.