Negative Predictive Value of Biopsy Margins in Keratinocyte Carcinoma: A Literature Review

Pathologists sometimes include commentary on margin involvement in shave biopsy reports of keratinocyte carcinoma (KC). This practice can lead to confusion regarding the need for further treatment. There is limited literature evaluating the reliability of reported histologic margin status in shave biopsies of KC.

To evaluate the negative predictive value (NPV) of reported clear shave biopsy margins in basal and squamous cell carcinomas to determine whether this assessment is a reliable predictor of complete tumor removal.

A literature review was performed using the PubMed database. The data were compiled, NPVs were calculated by the tumor subgroup, and a statistical analysis was performed.

Four studies met inclusion criteria. Two hundred twenty-one KCs were identified (n = 221). All specimens had negative-reported histologic margins (39 squamous cell carcinoma [SCC] and 182 BCC). Fifty-five cases initially noted to have negative margins on biopsy were found to have residual tumor on subsequent analysis: 5 SCC and 50 BCC, translating to 12.8% of all SCC (5/39) and 27.5% for BCC (50/182). Negative predictive values were found to be 75.1% for all KCs, 87.2% for SCC, and 72.5% for BCC.

Negative histologic margin status on shave biopsy specimens of KC has a poor NPV and is an inadequate predictor for complete tumor removal.