Abstract 4402: Survival impact of post-operative immunotherapy in resected stage III cutaneous melanomas in the checkpoint era

Abstract Introduction: Since 2015, immune checkpoint inhibitors have been approved as post-operative therapy for resected stage 3 cutaneous melanoma. This approval was a result of studies which demonstrated improved recurrence free survival. However, overall survival (OS) benefit has yet to be observed. We examine the OS of postoperative immunotherapy in stage 3 melanoma using real world data from the National Cancer Database (NCDB). Methods: Data was collected from the 2020 NCDB Participant Use File (October 2022 release). Patients were staged by both the 7th and 8th version of American Joint Committee on Cancers (AJCC). Those who underwent definitive surgery since 2016 and had sufficient pathologic data for staging were included. Patients who received systemic therapy prior to surgery were excluded. Patients were then sorted by the type of postoperative therapy started within 12 weeks from definitive surgery and classified into the no post-operative systemic therapy (NP) or postoperative immunotherapy (PI) groups. Survival time was calculated from the time of definitive surgery to last contact or death. OS was estimated by Kaplan-Meier method and compared by log-rank method. Results: 18,167 patients underwent surgery for stage 3 disease between 2016-2020. By AJCC v8 staging, 4,256 had Stage 3A disease, 3,752 stage 3B disease, 9,251 stage 3C disease, and 908 stage 3D disease. Median OS was not met in any stage 3 PI groups. The 36 - month landmark survival of all stage 3 subgroups is shown in Table 1. Only 13.3% of patient received PI in 2016. PI use increased to 24.8% in 2017, 43.8% in 2018, 46.8% in 2019, and 50.8% in 2020. Discussion: Using a large real-world database, we found that patients receiving post-operative immunotherapy in the checkpoint era have a significant survival benefit compared to those who did not. The benefit was significant in stage IIIB-C in AJCC v7 and Stage IIIC-D in AJCC v8. However, the benefit was not significant in stage 3A melanoma. Table 1. 36-month Landmark survival reported with 95% confidence interval for both AJCC versions No Post-Operative Immunotherapy Post-Operative Immunotherapy Given Stage Total Patients (n) n (%) 36- month survival % (95% CI) n (%) 36- month survival % (95% CI) p-value AJCC v 7 Stage 3 15272 Stage 3A 3818 2539 (66.5) 90 (89-91) 1141 (29.9) 91 (90-92) p=0.737 Stage 3B 4572 2990 (65.4) 78 (77-79) 1461 (32.0) 83 (82-94) p=0.001 Stage 3C 6882 4021 (58.4) 64 (63-65) 2637 (38.3) 73 (72-74) p<0.001 AJCC v 8 Stage 3 18167 Stage 3A 4256 2981 (70.0) 91 (90-92) 1145 (26.9) 93 (92-94) p=0.354 Stage 3B 3752 2255 (60.1) 84 (83-85) 1379 (36.8) 87 (86-88) p=0.057 Stage 3C 9251 5592 (60.4) 65 (64-66) 3372(36.5) 76 (75-77) p<0.001 Stage 3D 908 550 (60.6) 44 (42-46) 316 (34.8) 59 (56-62) p<0.001 Citation Format: Garo G. Hagopian, Christopher Grant, Danielle Brazel, Priyanka Kumar, Maki Yamamoto, James Jakowatz, Warren Chow, Thuy Tran, Justin Moyers. Survival impact of post-operative immunotherapy in resected stage III cutaneous melanomas in the checkpoint era. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4402.