Prognostic significance of BRAF and NRAS mutations in melanoma: a German study from routine care

Abstract Background Hotspot mutations of the oncogenes BRAF and NRAS are the most common genetic alterations in cutaneous melanoma. Specific inhibitors of BRAF and MEK have shown significant survival benefits in large phase III trials. However, the prognostic significance of BRAF and NRAS mutations outside of clinical trials remains unclear. Methods The mutational status of BRAF (exon 15) and NRAS (exon 2 and 3) was determined in melanoma samples of 217 patients with pyrosequencing and Sanger sequencing. The genotypes were correlated with clinical outcomes and pathologic features of the primary tumors. Time to disease progression was calculated with the cumulative incidence function. Survival analyses were performed with Kaplan-Meier estimates and Cox proportional hazards regression analysis. Relative survival was calculated with the Ederer-II method. Treatment with BRAF and MEK inhibitors and immune checkpoint blockade (ICB) was allowed. Results Mutations in BRAF and NRAS were identified in 40.1 and 24.4% of cases, respectively. Concurrent mutations in both genes were detected in further 2.3%. The remaining 33.2% were wild type for the investigated exons (WT). BRAF mutations were significantly associated with younger age at first diagnosis (p < 0.001) and truncal localization of the culprit primary (p = 0.002). The nodular subtype was most common in the NRAS cohort. In addition, NRAS-mutant melanoma patients showed a higher frequency of nodal relapse (p = 0.013) and development of metastatic disease (p = 0.021). The time to loco-regional nodal relapse was shortest in NRAS-mutant melanoma (p = 0.002). Presence of NRAS mutation was an independent risk factor for disease progression in multivariate analysis (HR 2.01; 95% CI 1.02 – 3.98). BRAF-mutant melanoma patients showed a tendency for better overall and relative survival. Genotype was not a consistent risk factor in multivariate analysis. Instead, positive sentinel lymph node status (HR 2.65; 95% CI 1.15 – 6.10) and treatment with ICB in stage IV disease (HR 0.17; 95% CI 0.06–0.48) were significant multivariate risk factors. Conclusions NRAS-mutant tumors tended to behave more aggressively particularly in early stages of the disease in this high-risk melanoma population. Treatment with immune checkpoint blockade improved survival in stage IV disease in a real-world setting

Additional file 3: Figure S2. of Prognostic significance of BRAF and NRAS mutations in melanoma: a German study from routine care

Time to event analyses after patients with other malignancies than melanoma were excluded (n = 179). The times to loco-regional relapse and metastatic disease were assessed with the cumulative incidence function. Indicated p-values were calculated with the Gray’s test. Overall and relative survival were computed with the Kaplan-Meier and Ederer-II method, respectively. The p-value for overall survival was calculated with the log-rank test. (PDF 358 kb

Additional file 1: of Prognostic significance of BRAF and NRAS mutations in melanoma: a German study from routine care

Table S1. Primer sequences for PCR of the genes BRAF (exon 15), NRAS (exon 2), and NRAS (exon 3). Table S2. Probes for pyrosequencing of the genes BRAF (exon 15), NRAS (exon 2), and NRAS (exon 3). (DOCX 14 kb

Additional file 2: Figure S1. of Prognostic significance of BRAF and NRAS mutations in melanoma: a German study from routine care

Kaplan-Meier estimates for overall survival according to disease stage. Patients were staged according to the current staging system of AJCC from 2009 at primary diagnosis to internally validate the dataset. The survival curves showed a clear and significant stratification from stage I to stage IV. The indicated p-value was calculated with the log-rank test. (PDF 287 kb

Prognostic factors and treatment outcomes in 444 patients with mucosal melanoma

Background: Mucosal melanoma (MM) is a rare but diverse cancer entity. Prognostic factors are not well established for Caucasians with MM. Patients and methods: We analysed the disease course of 444 patients from 15 German skin cancer centres. Disease progression was determined with the cumulative incidence function. Survival times were estimated with the Kaplan-Meier method. Prognostic parameters were identified with multivariate Cox regression analysis. Results: Common anatomic sites of primary tumours were head and neck (MMHN, 37.2%), female genital tract (MMFG, 30.4%) and anorectal region (MMAN, 21.8%). MMAN patients showed the highest vertical tumour thickness (p = 0.001), had a more advanced nodal status (p = 0.014) and a higher percentage of metastatic disease (p = 0.001) at diagnosis. Mutations of NRAS (13.8%), KIT (8.6%) and BRAF (6.4%) were evenly distributed across all tumour site groups. Local relapses were observed in 32.4% and most commonly occurred in the MMHN group (pZ0.016). Male gender (p = 0.047), advanced tumour stage (p = 0.001), nodal disease (p = 0.001) and incomplete resection status (p = 0.001) were independent risk factors for disease progression. Overall survival (OS) was highest in the MMFG group (p = 0.030) and in patients without ulceration (p = 0.004). Multivariate risk factors for OS were M stage at diagnosis (p = 0.002) and incomplete resection of the primary tumour (p = 0.001). Conclusion: In this large series of MM patients in a European population, anorectal MM was associated with the poorest prognosis. (C) 2017 Elsevier Ltd. All rights reserved