Evaluation of treatment patterns in patients with BRAF-mutant cutaneous melanoma in adjuvant setting in real practice.

Abstract

e21573 Background: Mutation in BRAF is a crucial biomarker for treatment choice in patient with locally advanced or metastatic melanoma. In patient with BRAF wild-type (WT) melanoma aPD1 is the preferred treatment regimen. In patients with BRAF V600 mutant melanoma combined targeted therapy (cTT) could also be chosen as adjuvant treatment, which significantly improves OS. Methods: We conducted a retrospective continuous study of all melanoma patients, who were tested for BRAF mutation by RT-PCR in 2020 (COIVD-19 pandemic year) in our institution and analyzed adjuvant therapy options they received. Patient demographics, mutational status, disease stage, treatment regimens and treatment outcomes were collected from electronic medical records. Results: Between January 2020 and December 2020, tumor samples from 297 pts were tested for BRAF mutations. The mean pts age was 58.2 years (95% CI 51.2 to 60.3) and 130 (43.7%) were male. BRAF mutations were detected in 147 (49.5%) patients. Most common mutation was V600E (140 out of 147 samples, 88.4%) and V600K (13 out of 147, 8.84%). We also found K601N, K601E, L597R and V600M mutations (in one sample each). Among 150 BRAF wild type samples 44 were also tested for NRAS mutations and in 13 (29.54%) pts NRAS mutations were detected: Q61R – in 6 (46.15%) pts, Q61L – in 2 (15.38%) pts, Q61K – in 3 (23.08%) pts, G12E – in 1 (7.69%) pt, and G12D - in 1 (7.69%) pt . Also among 150 BRAF wild type samples 56 were tested for KIT mutations and only one sample were found to harbour D186V mutation . Among BRAF-positive pts at time of the genetic test performed stage I CM had 11 (7.48%) out of 147 pts, stage II - 13 (8.84%) pts, stage III - 67 (45.57%) pts, and stage IV - 43 (29.25%) pts. In 13 (8.84%) pts stage could not be clearly identified. In most cases (32 out of 67, 47.76%) monotherapy with aPD1 was given as adjuvant treatment in stage III pts where as only 6 (8.95%) patients received cTT, 7 pts (10.41%) received IFN-alfa and 22 pts (32.84%) received no or were given with other treatment (Table). Median DFS did not differ significantly between treatment cohorts. Conclusions: In our retrospective study we found that among stage III BRAF-mutant patients monotherapy with aPD1 was the most common adjuvant treatment regimen. In some patients with stage III disease IFN-alfa is still given. More studies are needed to define best adjuvant treatment for BRAF mutant stage III melanoma pts.[Table: see text]