Subungual Melanoma: A Systematic Review

Background:  Subungual melanoma is a relatively rare disease that carries a poor prognosis.  Several retrospective studies have been conducted, but incidence, recurrence, and survival rates vary greatly depending on the investigation (1-4). Current guidelines also offer little insight as to the specific surgical management of subungual melanoma (5). We aim to utilize a systematic review to better appraise this pathology and to examine applicable surgical interventions.

Material and Methods: A systematic literature review using MEDLINE to identify all English language, human citations for original research related to subungual melanoma published between 1965 and 2012 was completed. Data formally extracted from each article included demographics, duration of follow up, location of the disease, treatments utilized, trauma and diagnostic delay, staging and pathology, incidence, recurrence, and five-year survival. Individual study data from the categories were pooled for analysis.

Results:  Sixteen studies met the established criteria for the systematic review including 669 patients. The mean affected age was 47.2 years, and the male to female ratio was comparable. Overall incidence was 3.03%. The thumb and the hallux were the most frequently affected digits. Average delay to diagnosis was 18.7 months. Fifty nine percent of lesions were with ulceration.  PIP joint was the principal level of finger amputation occurring 63% of the time.  The majority of studies did not demonstrate a survival difference in distal versus proximal digit amputation. Weighted mean overall five-year survival was 46%. When controlled for stage, mean five-year survival for stage I disease was 55%, and stage II or greater disease was a dismal 35%.

Conclusion:  Subungual melanoma is an insidious disease that has substantial importance. There is often a marked delay in diagnosis. Earlier recognition of this disease will likely improve survival.  No current evidence demonstrates improved survival with proximal amputation. Node dissection should be reserved for clinically positive nodes and for positive lymph node biopsy until additional data is available.