Surgical management and prognostic factors in patients with subungual melanoma

Forty-six cases of subungual melanoma were reviewed to identify significant clinicopathologic prognostic factors, determine the role of DNA content analysis in the biologic assessment of these tumors, and evaluate the effectiveness of amputation level, lymph node dissection (LND), and regional limb perfusion on the survival of these patients.

Subungual melanoma is a unique and rare subtype of melanoma, constituting only 1% to 3% of cases. Thus, little is known about prognostic factors and optimal management of patients with this disease. Moreover, the appropriate level of amputation and LND and limb perfusion in the management of subungual melanoma remain controversial.

Forty-six patients underwent amputation alone or in combination with LND and/or regional limb perfusion for primary subungual melanoma. The effects of these treatment modalities and the prognostic significance of patient and tumor-related variables, including DNA flow cytometric data, on overall survival were assessed.

Univariate statistical analysis identified six factors that significantly affected patient survival. They were stage at diagnosis (p = 0.0001), percentage of aneuploid cells (p = 0.01), presence of ulceration (p = 0.02) or bone invasion (p = 0.02), thickness of the primary lesion (p = 0.03), and percentage of cells in S-phase (p = 0.03). Multivariate analyses identified tumor stage and S-phase fraction as independent prognostic factors in these patients. Survival did not differ among patients who received amputation alone or those who underwent amputation in combination with LND or perfusion (p = 0.90); however, the use of limb perfusion reduced the incidence of locally recurrent disease. The level of amputation did not affect patient survival (p = 0.74) or the incidence of local recurrence.

The study identified several significant prognostic factors, including DNA flow cytometric parameters, in patients with subungual melanoma. In addition, it showed that conservative amputation of the affected digit at the level of the proximal interphalangeal or metacarpophalangeal/metatarsophalangeal joint appears to be safe, provided that clear margins are obtained. Although isolated limb perfusion may reduce the incidence of local recurrence, LND, or limb perfusion in the routine management of subungual melanoma remains controversial.