802P Demography and clinical outcomes of adjuvant therapy in Spain: Results from GEM 1801 study

Approximately one-third of patients (pts) with stage III nodal disease will eventually develop metastatic disease and 17% will develop local unresectable relapse. The use of lymphadenectomy and adjuvant treatment (AT) for local disease is controversial. Here we present the demographic characteristics and clinical outcomes of those pts receiving AT other than interferon, included in the prospective observational study GEM 1801. From 2018 to 2019, 400 locally advanced / metastatic melanoma pts were included, 54 pts (13.5%) received AT. Pts receiving AT were stage IIIA-B (18.5%), IIIC (42.6%), IIID-IV (38.9%) at inclusion according to AJCC 8th ed. Median age was 51.6 y (range: 23.3-86.6), 59.3% were male, and 57.4% BRAF mutated. Resection of the sentinel lymph node (LN) was performed in 72.2%. The median of resected LN was 2 (range: 1-5), of which a median of 1 LN (range: 1-2) was positive. Lymphadenectomy was performed in 55.6% pts, with a median of 14 LN (range: 2-40) resected, of which a median of 0 LN (range: 0-42) was positive. Immunotherapy (IT) was the prefered AT in 44 (81.5%) pts, targeted therapy (TT) in 10 (18.5%). With median follow-up of 36.1 m (95% CI: 29.9-39.2), 24 pts (44.4,%) continued without evidence of disease and 25 pts (46.3%) relapsed (29.6% intra-AT, 16.7% post-AT), 9.3% Not Evaluable. The median relapse-free survival (RFS) was 36.6 m (95% CI: 28.9-44.3).After relapse 19 (76%) pts received subsequent systemic treatments, 9 (36%) pts IT, 8 (32%) TT, and 2 (8%) other. The 24-m OS rate was 85.7% (95% CI: 76.5-96.1). Stratified analysis of RFS and OS is depicted in the table.Table: 802P24-m RFS; % (95%CI)24-m OS; % (95%CI)Stage at diagnosisIIIA-B87.5 (67.3-100)87.5 (67.3-100)IIIC68.4 (50.4-92.9)94.7 (85.2-100)IIID - IV36.4 (20.9-63.2)77.3 (61.6-96.9)LymphadenectomyYes51.9 (36.1-74.6)85.2 (72.8-99.7)No70 (52.5-93.3)90 (77.8-100) Open table in a new tab Our data, as previously reported, suggest that lymphadenectomy previous to AT would have no impact on both RFS and OS in our population.