Mucosal melanomas (MM) of the female genital tract are rare a. We aimed to study the prognostic factors of vulvar and vaginal locations of MM.
A multicenter, retrospective cohort study conducted between 01/01/2000 and 01/06/2019.
Of the 33 patients included 25 (75.8%) had vulvar (VuM) and eight (24.2%) vaginal melanomas (VaM). VaMs were deeper: median Breslow index: 17.5 mm [3.5-22] versus 4.3 mm [0.35-18] (p = 0.013). Average follow-up was 24.0 ± 59.8 months. Twenty-six patients (78.8%) experienced recurrence. Disease-free survival was 52.9% at 1 year (64.7% for VuM and 14.3% for VaM) and 8.4% at 3 years (11% for VuM and 0% for VaM) (p = 0.002). Median time to the first recurrence was 9.01 months [CI95%: 2.07-56.71]. VaM recurred earlier than VuM (3.12 months [CI95%: 2.07-12.49] versus 17.72 [CI95%: 3.58-56.71], p = 0.011). VaM had a higher risk of recurrence (HR = 5.64 [CI95%: 2.01-15.82], p = 0.001) in multivariate analysis. Overall survival was 88.5% at 1 year (100% for VuM and 50% for VaM), and 59.4% at 3 years (69.3% for VuM and 25% for VaM). Women with VaM died earlier: median specific death occurrence of 8.76 months [CI95%: 6.54-24.72] versus 39.61 [CI95%: 21.89-209.21], p = 0.013 (HR = 5.08 [CI95%: 1.39-18.60], p = 0.014). A lesion size ≥3 cm was associated with an increased risk of mortality (HR = 8.45 [CI95%: 1.60-44.52], p = 0.012). In multivariate analysis, vaginal location remained an independent and predictive variable of a higher risk of specific death (HR = 8.56 [CI95%: 1.95-37.64], p = 0.005).
A vaginal location of MM is associated with a poorer prognosis than a vulvar location.

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