Adjuvant Radiation Does Not Affect Locoregional Control Following Resection of Melanoma Satellitosis or In-Transit Disease.

BACKGROUND: This study evaluates the association of adjuvant radiation therapy (RT) with improved locoregional (LR) recurrence for resected melanoma satellitosis and in-transit disease (ITD). MATERIALS AND METHODS: Data were collected retrospectively for resected melanoma satellitosis/ITD from 1996 to 2017. RESULTS: 99 patients were identified. 20 patients (20.2%) received adjuvant RT while 79 (79.8%) did not. Mean follow-up in the RT group was 4.3 years and 4.7 years in the non-RT group. 80% of patients who underwent RT suffered a complication, most commonly dermatitis. Locoregional recurrence occurred in 9 patients (45%) treated with adjuvant RT and 30 patients (38%) in the non-RT group (P = 0.805). Median LR-DFS was 5.8 years in the RT group and 9.5 years in the non-RT group (P = 0.604). On multivariable analysis, having a close or positive margin was the only independent predictor of LR-DFS (HR 3.8 95% CI 1.7-8.7). In-transit disease was associated with improved overall survival when compared to satellitosis (HR 0.260, 95% CI 0.08-0.82). DISCUSSION: The use of adjuvant RT is not associated with improved locoregional control in resected melanoma satellitosis or ITD. Close or positive margin was the only treatment-related factor associated with decreased LR-DFS after surgical resection of satellitosis/ITD.