The impact of biopsy technique on upstaging, residual disease, and outcome in cutaneous melanoma

Background: After skin biopsy of malignant melanoma, the findings in the subsequent wide local excision (WLE) sometimes result in upgrading of the T-category. Herein, we examine the influence of biopsy technique on residual disease in melanoma WLE specimens and on upstaging. Methods: We performed a retrospective review of data from malignant melanoma patients who underwent sentinel lymph node biopsy between 1997 and 2010. Results: A total of 609 patients were biopsied by shave (51%), punch (19%), and excision (30%). Residual disease was seen in 240 patients (39%) at WLE, of whom 60% had undergone shave biopsy. Fifty-nine patients had a T-category upgrade after WLE (10% of all patients); 64% were sampled by shave. Seven percent of patients with a T-category upgrade had negative margins initially. Positive biopsy margin and greater thickness predicted T-category upgrade. Conclusions: Partial biopsy for melanoma resulted in more residual disease at WLE and a higher rate of T-category upgrade. Moreover, the presence of negative margins at biopsy did not ensure lack of residual disease.