Clinicopathological Demographics of Malignant Melanoma of the Vulva and Vagina in Japan

Abstract

Objective: Malignant melanomas of the vulva (VuM) and vagina (VaM) represent a unique subgroup of rare malignant melanomas with critical biological properties and treatment differing from that of other cancers. In Japan, adequate surveys on these have not been performed. The objective of this study was to elucidate the clinicopathological demographics and the outcomes of VuM and VaM in Japan.Methods: This retrospective observational study included women with invasive VuM or VaM, identified from older medical records in Japan. Clinical data were collected and the Kaplan-Meier method was used to analyze progression-free survival (PFS) and overall survival (OS). Univariate and multivariate regression models were used to identify factors significantly related to survival.Results: A total of 217 patients were identified: 109 (50.2%) with VuM and 108 (49.8%) with VaM. The median PFS was 16.8 months in patients with VuM (95% confidence interval [CI] 23.1-87.7) and 15.6 months in patients with VaM (95% CI 8.4-12.6). The median OS was 43.9 months (95% CI 60-138) and 31.1 months (95% CI 24.8-45.3) in patients with VuM and VaM, respectively. Multivariate analysis showed that a >III American Joint Committee on Cancer (AJCC) disease stage (hazard ratio [HR] = 2.063; 95% CI = 0.995-4.278) was associated with poorer PFS, and unknown surgical margin was the only independent factor influencing OS (HR = 2.188; 95% CI = 1.203-3.977).Conclusions: The overall outcomes of VuM and VaM remain poor in Japan. The AJCC stage and the surgical margin are significant predictors of survival.