The role of sentinel lymph node mapping in lower genital tract melanoma

Vulvar and vaginal melanomas are rare cancers of the female genital tract and account for 1% to 3% of all melanomas diagnosed in women. Due to the rarity of the disease, few data are available on the clinical and pathologic features of these cancers. Furthermore, treatment options are generally based on extrapolations of the information available for the more common cutaneous counterparts. Surgery represents the mainstay of treatment for lower genital tract melanoma. Moreover, the role of sentinel lymph node (SLN) assessment is controversial because no prospective data are available.

Data were collected from Medline, Embase, Web of Sciences and Scopus databases. On July 10, 2020, we used the search comprising the terms "vulvar melanoma," "genital melanoma" and "vulvovaginal melanoma" including only studies in which SLN biopsy was performed.

Ten retrospective studies have been found. No randomized trials have been reported. The studies included 132 patients while only 63 (47%) undergone SLN. 99mTC with or without blue dye followed by ultrastaging was highly accurate and is currently the gold standard. Mean detection rate was 98.3%. No clear evidence supported the execution of back lymphadenectomy (after SLN mapping), in fact, extrapolating data from cutaneous melanomas of other sites, completion of lymphadenectomy does not confer a melanoma-specific survival advantage.

Although the small amount of available data, sentinel lymph node procedure is feasible and capable of identifying patients who have occult lymph node metastases. However, the potential role of the sentinel lymph node procedure as an alternative method of lymph node staging in patients with vulvar or vaginal melanoma needs further investigation.