Effect of biopsy type on outcomes in the treatment of primary cutaneous melanoma.

BACKGROUND: Surgical excision remains the primary and only potentially curative treatment for melanoma. Although current guidelines recommend excisional biopsy as the technique of choice for evaluating lesions suspected of being primary melanomas, other biopsy types are commonly used. We sought to determine the impact of biopsy type (excisional, shave, or punch) on outcomes in melanoma.

METHODS: A prospectively collected, institutional review board-approved database of primary clinically node-negative melanomas (stages cT1-4N0) was reviewed to determine the impact of biopsy type on T-staging accuracy, wide local excision (WLE) area (cm(2)), sentinel lymph node biopsy (SLNB) identification rates and results, tumor recurrence, and patient survival.

RESULTS: Seven hundred nine patients were diagnosed by punch biopsy (23%), shave biopsy (34%), and excisional biopsy (43%). Shave biopsy results showed significantly more positive deep margins (P < .001). Both shave and punch biopsy results showed more positive peripheral margins (P < .001) and a higher risk of finding residual tumor (with resulting tumor upstaging) in the WLE (P < .001), compared with excisional biopsy. Punch biopsy resulted in a larger mean WLE area compared with shave and excisional biopsies (P = .030), and this result was sustained on multivariate analysis. SLNB accuracy was 98.5% and was not affected by biopsy type. Similarly, biopsy type did not confer survival advantage or impact tumor recurrence; the finding of residual tumor in the WLE impacted survival on univariate but not multivariate analysis.

CONCLUSIONS: Both shave and punch biopsies demonstrated a significant risk of finding residual tumor in the WLE, with pathologic upstaging of the WLE. Punch biopsy also led to a larger mean WLE area compared with other biopsy types. However, biopsy type did not impact SLNB accuracy or results, tumor recurrence, or disease-specific survival (DSS). Punch and shave biopsies, when used appropriately, should not be discouraged for the diagnosis of melanoma.