Does Residual Invasive Disease in Wide Local Excision after Diagnosis with Partial Biopsy Technique Influence Survival in Melanoma? Matched-Pair Analysis of Multicenter Selective Lymphadenectomy Trial I and II.

BACKGROUND: Current guidelines recommend excisional/complete biopsy for melanoma diagnosis, owing to high rates of residual disease found at wide local excision (WLE) after partial biopsy techniques. We sought to determine any survival disadvantage associated with the presence of residual invasive melanoma in the WLE after diagnosis with a partial biopsy technique. STUDY DESIGN: Data were examined from Multicenter Selective Lymphadenectomy Trials I and II (MSLT-I and -II), 2 large melanoma trials. Patients diagnosed with excisional/complete biopsy were excluded. Clinicopathologic characteristics, melanoma-specific survival (MSS), distant disease-free survival (DDFS), and disease-free survival (DFS) of those with residual invasive melanoma in the definitive WLE and those with no residual melanoma were compared. Matched pairing was used to reduce variability between groups. RESULTS: From 1994 through 2014, 3,939 patients were enrolled in these trials and 874 (22%) were diagnosed using partial biopsy techniques. Of these, 399 (46%) had residual tumor in the WLE. Only 6 patients had residual tumor in their WLE resulting in T-upstaging of their tumor. Match-pairing formed two cohorts (1:1) of patients with and without residual invasive tumor after WLE. A total of 514 patients were paired; 288 (56%) males, 148 (28.8%) aged 60 or older, 192 (37.4%) with truncal melanomas, 214 (41.6%) had Breslow thickness 2 mm or greater, and 376 (73.2%) had positive sentinel nodes. Kaplan-Meier analysis showed no statistical difference in 10-year MSS (73.6% ± 3.3% vs 73.9% ± 3.7%, p = 0.891), DDFS (68.7% ± 3.4% vs 65.3% ± 4.0%, p = 0.548), or DFS (59.6% ± 3.7% vs 59.4% ± 3.9%, p = 0.783). CONCLUSIONS: Survival in patients with primary melanoma does not appear to be worse in patients who undergo a partial biopsy technique and are later found to have residual invasive tumor in the WLE specimen