Groin dissection in malignant melanoma

There is controversy about the extent of groin dissection necessary (whether superficial or radical) and about its utility when the deep nodes are affected.

A total of 198 groin dissections (1977-1991) were reviewed; 94 (48%) were superficial and 104 (52%) were radical dissections. Of 72 patients with palpable positive inguinal nodes, 31 (43%) had involvement of the deep nodes; of 39 patients with nonpalpable, histologically positive inguinal nodes, seven (18%) had or later manifested involvement of the deep nodes.

The mean number of positive nodes (median) in the group with clinically palpable disease was six (two), and in the group with occult disease the number was two (one). The estimated overall (disease-free) 5-year and 10-year survival rates for patients with negative nodes were 73% (67%) and 64% (58%), respectively, and for those with positive nodes they were 36% (27%) and 30% (23%), respectively. Survival was significantly poorer for patients with positive nodes (p < 0.0001). The respective 5-year and 10-year survival rates for patients with positive nodes and involvement of the inguinal nodes only were 41% (33%) and 36% (29%), and for those with involvement of the inguinal and deep nodes the rates were 28% (17%) and 19% (13%). Survival was significantly poorer for patients with deep node involvement (p = 0.006).

The survival rates after therapeutic groin dissection are substantial and unattainable with any other treatment at the present time. Incontinuity dissection of the deep nodes is advisable in the presence of palpable inguinal nodes, since the incidence of deep node involvement is considerable and the survival rate appreciable after removal of involved deep nodes.