Vulvar melanoma: is there a role for sentinel lymph node biopsy?

BACKGROUND: The objective of this study was to evaluate the author's recent, preliminary experience with the sentinel lymph node procedure in patients with vulvar melanoma and to compare this experience with treatment and follow-up of patients with vulvar melanomas who were treated previously at their institution.
METHODS: From 1997, sentinel lymph node procedure with the combined technique (99mTechnetium-labeled nanocolloid and Patente Blue-V) was performed as a standard staging procedure for patients with vulvar melanoma with a thickness > 1 mm and no clinically suspicious inguinofemoral lymph nodes. For the current study, clinicopathologic data from all 33 patients with vulvar melanoma who were treated between 1978 and 2000 at the University Hospital Groningen were reviewed and analyzed.
RESULTS: From January 1997 until December 2000, identification of sentinel lymph nodes was successful in all nine patients who were referred for treatment of vulvar melanoma. Three patients underwent subsequent complete inguinofemoral lymphadenectomy because of metastatic sentinel lymph nodes. In follow-up, groin recurrences (in-transit metastases) occurred in two of nine patients, both 12 months after primary treatment. Both patients had melanomas with a thickness > 4 mm and previously had negative sentinel lymph nodes. There was a trend toward more frequent groin recurrences in patients after undergoing the sentinel lymph node procedure (2 of 9 patients) compared with 24 historic control patients (0 of 24 patients; P = 0.06). Five of 33 patients developed local recurrences: Two patients had groin recurrences, and 11 patients developed distant metastases. Twelve patients died of vulvar melanoma. Seventeen patients with a median follow-up of 66 months (range, 9-123 months) are currently alive (overall survival rate, 52%).
CONCLUSIONS: Although the numbers were small, this study showed that the sentinel lymph node procedure is capable of identifying patients who have occult lymph node metastases and who may benefit from lymphadenectomy for locoregional control and prevention of distant metastases. However, the data also suggest that the sentinel lymph node procedure may increase the risk of locoregional recurrences (in-transit metastases), especially in patients with thick melanomas. The potential role of the sentinel lymph node procedure as an alternative method of lymph node staging in patients with vulvar melanoma needs further investigation only within the protection of clinical trials and probably should be restricted to patients with melanomas with intermediate thickness (1-4 mm).