Patterns of failure following the excision of in-transit lesions in melanoma and the influence of excisional margins

Background and Objectives: To describe the patterns of failure in patients with in-transit (IT) melanoma undergoing surgical excision. Methods: A retrospective review of patients who underwent their first IT lesion(s) resection between May 2005 and September 2014. Cumulative incidence of local failure (new lesion within 2 cm of IT resection) was estimated. Associations between clinicopathologic characteristics, local failure, and any recurrence were analyzed. Results: One hundred and thirty patients presented to our institution with IT disease over the study period and met the inclusion criteria. The 2-year cumulative incidence of local failure was 19.5%. Twenty-four patients developed disease within 2 cm of the resected IT disease; however, only eight were isolated local events. Cumulative incidence of local failure and of any disease differed with respect to less than 1 year disease-free interval (DFI) from primary melanoma to first IT event, and having greater than 1 IT lesion at presentation. Incidence of local failure was not found to differ with respect to gross margin greater than 5 mm, after adjusting for DFI and greater than 1 IT lesions. Conclusions: Patients with greater than 1 IT lesion and a DFI less than 1 year are at a higher risk of failure after surgical excision of a first IT event. Very few failures were isolated local disease within 2 cm of the IT resection scar, regardless of IT excision margin.