Population-based analysis of the prevalence of BRAF mutation in patients diagnosed with cutaneous melanoma and its significance as a prognostic factor.

Abstract

The prevalence of BRAF mutation has been reported in between 38% and 48% of melanoma patients, based on mainly Stage III or metastatic melanoma, however, information based on population-based studies is scarce. We performed a population-based retrospective cohort study to determine the prevalence of the BRAF mutation in patients diagnosed with in situ and infiltrating cutaneous malignant melanoma in the province of Girona between 2009 and 2011. Using the database of the Girona Cancer Registry, we performed BRAF mutation analysis based on paraffin-embedded tissue. This data was then correlated with other known clinical and histological prognostic factors for survival. We found 286 incident cases of cutaneous melanoma in the Girona Cancer Registry database. Excluding missing cases, BRAF-mutated patients constituted 38.9% of "in situ" melanoma cases and 53.8% of invasive melanoma cases. Five-year relative survival was not statistically different between BRAF-mutated patients (93.6%; 95%CI: 87.1-100.5) and non-mutated patients (84.3%, 95%CI: 75.3-94.8). Only stage was significant as a prognostic factor for survival based on multivariate analysis. From our population-based study, we conclude that BRAF mutation is not an independent prognostic factor for melanoma survival.