Management of Transected Invasive Melanoma: A Single Institution Retrospective Review

BACKGROUND Deep transection of invasive melanoma precludes accurate measurement of Breslow depth, which may affect tumor staging. OBJECTIVE To determine the frequency of upstaging of transected invasive melanomas after excision, characterize the impact on National Comprehensive Cancer Network (NCNN)-recommended treatment, and determine predictors of subsequent upstaging. MATERIALS AND METHODS A retrospective review of invasive melanomas between January 2017 and December 2019 at a single institution. Deeply transected biopsy reports were compared with subsequent excisions to calculate the frequency of upstaging. RESULTS Three hundred sixty (49.6%) of 726 invasive melanomas identified were transected. Forty-nine (13.6%) transected tumors had upstaging that would have altered NCCN-recommended management. "Broadly" transected tumors had upstaging that would have resulted in a change in the management in 5/23 cases (21.7%) versus 2/41 cases (4.9%) for "focally" transected tumors (p = .038). Breslow depth increased by 0.59 mm on average for "broad" transection versus 0.06 mm for "focal" transection (p =< .01). Of the 89 transected pT1a melanomas, specimens with gross residual tumor or pigment after biopsy were upstaged in 8/17 (47.1%) of cases versus 5/72 (6.9%) of specimens without (p =< .01). CONCLUSION Upstaging of deeply transected invasive melanomas that would alter NCCN-recommended management occurred in 13.6% of cases. Broad transection and gross residual tumor or pigment after biopsy predicted higher likelihood of upstaging.