The authors present the findings of a retrospective, single-institution review of all patients with biopsy confirmed subungal melanomas over a period of 96 years in Mayo Clinic. Parameters examined were general demographics, level of digit amputation, disease recurrence, overall survival, Breslow thickness (for cases after 1970), lymph node involvement and distant metastases. Standard statistical methods, including multivariate analysis were utilised for data analysis. One hundred and twenty-four patients were included in the study, with a mean age of 58 years and mean follow-up from time of surgery 9.4 years. Almost all patients (96.7%) presented with symptoms and the majority had local disease only (83.9%). Melanoma subtypes were nodular (34.9%), acral lentiginous (32.6%), superficial spreading (23.2%) and amelanotic (11.6%). Mean Breslow thickness was 3.1mm. Clark level 4 was the most common (53.4%). Most of the patients (52.4%) were men. Majority of lesions (63.7%) were located on the hand, with the thumb most commonly affected (33.8%). On the feet, the great toe (25%) was the commonest site. Amputation was performed in 93.5% of patients. Most common level of amputation on the thumb was the proximal phalanx or metacarpophalangeal joint (43.9%), while on the fingers it was at the middle phalanx or proximal interphalangeal joint (39.4%). Amputations of the hallux were commonest (38.5%) at the proximal phalanx or the metatarsophalangeal joint; lesser toes were most commonly amputated as ray or transmetatarsal resections (24.1%). Resection level was not significantly associated with overall survival, disease-specific survival or progression-free survival on any of the digits on the hand and foot. Overall survival was 60.5% at five years’ post surgery and 28.3% at 20 years. For patients after 1970, Breslow thickness ≤1mm was associated with 89.5% overall survival at five years and 42.8% at 20 years after surgery, 1-4mm with 62.2% at five years and 27.5% at 20 years and >4mm with 47.6% at five years and 22.7% at 20 years. This study is limited by its retrospective nature, however, it is very well designed and its results robustly analysed. It adds to the existing literature on surgical management and long-term survival of patients with subungal melanomas and convincingly shows that there is no statistically significant correlation between distal amputations and overall survival in cases with histologically free margins.
Surgical management of subungal melanoma
Reviewed by Mark Butterworth and Nikolaos Arkoulis
Surgical management of subungal melanoma.
