MALIGNANT-MELANOMA OF THE VULVA TREATED BY RADICAL HEMIVULVECTOMY - APROSPECTIVE-STUDY OF THE GYNECOLOGIC-ONCOLOGY-GROUP

Background. Beginning in 1983, the Gynecologic Oncology Group (GOG) co nducted a prospective clinicopathologic study of primary malignant mel anoma of the vulva. The objectives of this study were to determine the relationship of histopathologic parameters and microstaging to the In ternational Federation of Gynaecology and Obstetrics (FIGO) staging an d prognosis. Methods. All patients with primary untreated malignant me lanoma of the vulva and no history of previous or subsequent other pri mary invasive malignancy were eligible for study entry. All patients w ere required to have modified radical hemivulvectomy as minimal therap y. Groin dissection was optional. Histopathologic specimens were revie wed for capillary space involvement, Clark's level, Breslow's depth of invasion, cell type, and melanin distribution. Patient characteristic s were analyzed in their relationship to groin node status and recurre nce-free interval. Results. Between 1983 and 1990, 81 patients were en tered in the study. Of these, 71 were evaluable. Thirty-four patients underwent radical hemivulvectomy, and 37 patients underwent radical vu lvectomy. In addition, 56 patients underwent groin node dissection. Th e factors that were independently correlated with groin node status we re: capillary lymphatic space involvement (P = 0.0001) and central pri mary tumor location (i.e,, bilateral/clitoral/T3) (P = 0.003). The oth er factors that were significant-clinical tumor size, vulvar staging ( FIGO), GOG performance status, and Breslow's depth of invasion-were no t independent predictors of positive nodes. The factor with the highes t significant correlation with recurrence-free interval was the 1992 s taging system of the American Joint Committee on Cancer (AJCC) for mal ignant melanoma of the skin. Using multiple regression, ATCC stage was the only independent prognostic factor. In the absence of AJCC stage, Breslow's depth of invasion was the most prognostic.Conclusion. The b iologic behavior of vulvar melanoma is similar to other nongenital cut aneous malignant melanoma.