Surgical Management of Subungual Melanoma

Abstract

Optimal surgical management of subungual malignant melanoma (SMM) has been debated. Our tumor registry was reviewed for surgically treated cases of SMM from 1914 to 2010. Resection levels were compared with outcome. During a 96-year period, 124 cases of SMM were identified (65 men and 59 women). Mean age at diagnosis was 58 years. Mean length of symptoms before diagnosis was 2.2 years. Lesions occurred on the hand (n = 79) and foot (n = 45). The thumb (33.8%) and hallux (25.0%) were affected most. At diagnosis, most had local (83.9%) and regional nodal involvement (12.9%). Mean follow-up was 9.4 years.Mean Breslow depth was 3.1 mm. Amputations were most commonly performed on the thumb at the proximal phalanx or metacarpophalangeal joint (43.9%), and on the hallux at the proximal phalanx or metatarsophalangeal joint (69.0%).Disease progression occurred in 61 (49.2%) patients, and most commonly occurred as regional nodal (62.3%) and distant metastasis (42.6%). Disease progression-free survival rates at 5, 10, and 15 years were 57.1%, 49.9%, and 47.0%, respectively. Fifty-three patients died of melanoma-related causes. Disease-specific survival rates at 5, 10, and 15 years after surgery were 59.3%, 49.3%, and 45.2%. Overall survival rates at 5, 10, and 15 years were 60.5%, 43.8%, and 33.1%.In 116 patients who underwent amputation, resection level outcome analysis with univariate and multivariate analysis adjusting for tumor depth and clinical involvement demonstrated that level of resection was not significantly associated with progression-free, overall, or disease-specific survival. Diagnosis of subungual melanoma is often delayed and carries a poor prognosis. Conservative resections are warranted as resection level does not influence outcome when histologically free margins are obtained. Amputation through the proximal phalanx or the metatarsophalangeal joint is required in the hallux and toes. Fingers require resection through the distal interphalangeal joint. For the thumb, although resection through the interphalangeal joint proved adequate, secondary efforts should be directed toward maximizing function and quality of life. Function-preserving resections in the thumb with nail removal, partial distal phalanx resection, and volar flap reconstruction are easily performed and preserve length, maximize joint and sensory function, and improve cosmesis.