Incidence of Melanoma in Pigmented Lesions Biopsied by Shave Technique
Mitchell D. Flurry, Rogerio I. Neves, MD.
Penn State Hershey, Hershey, PA, USA.
Biopsying any pigmented lesion has an inherent risk of diagnosing melanoma. For this reason, standard of care for surgeons is excisional biopsy of all pigmented lesions. However, dermatologic literature suggests shave biopsy may be appropriate and is therefore used by some dermatologists and other health care providers. The National Comprehensive Cancer Network’s (NCCN) current recommendations endorse that all patients undergo excisional biopsy of pigmented lesions unless suspicion of melanoma is low. Although controversial, shave biopsy is currently performed on pigmented lesions at many institutions as well as among the general medical community. This study's goal is to assess the incidence of melanoma for all shave biopsies and its impact in appropriate treatment for the patient.
A retrospective chart review was performed on all patients who had a shave biopsy performed for the diagnosis of a pigmented lesion at this institution from 1/1/2009 to 12/31/2009. Using an institutional database, a natural language search was conducted. The clinical history, pre-shave diagnosis, final diagnosis and comments were recorded. Comments included a positive or negative margin (deep and/or lateral), need for re-excision, and need for follow-up.
862 shave biopsies were performed during the 12-month study period. Of those, 64 (7.4%) were malignant (Malignant Melanoma, Lentigo Maligna Melanoma, Lentigo Maligna or Malignant Melanoma In-situ). Of the 64 melanomas shaved, 37 (57.8%) had a positive lateral margin and eight (12.5%) had a positive deep margin. Five (7.8%) of the shaved melanomas required an upstage in treatment. An additional 118 (13.7%) had atypical pathology prompting either re-excision or close clinical follow up. In total, 182 (21.1% of all) lesions were either malignant or had pathology warranting re-excision or follow-up.
Our results show that final pathology of 1 in every 13.5 pigmented lesions biopsied by shave technique will be malignant. Adding lesions with atypia on final pathology, 1 in every 5 pigmented lesions shaved will require definitive treatment, re-excision, or close clinical follow up. Additionally, in 12 months, 5 patients’ treatment was upstaged because of inadequate biopsy. Tumor thickness is the most important histologic factor in determining prognosis and treatment of melanoma. Unfortunately, partial thickness or shave biopsies are often unreliable at determining the full depth of a tumor. The possible consequences are twofold: an “upstage” in treatment resulting in more extensive surgery and higher costs, and exclusion from potentially life saving Clinical Trials as most require accurate tumor depth for inclusion. A clear trend can be seen indicating a high incidence of melanoma in the sample evaluated. Additionally, biopsy technique directly effected proper treatment in 0.6% of patients. This data suggests performing a shave biopsy should be avoided when evaluating a pigmented lesion. Additional review is necessary; however should the findings be consistent with the preliminary results, there would be compelling evidence to provoke a review of the current NCCN guidelines concerning initial evaluation of a pigmented lesion.
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