[3 min read] Are negative margins in BCC biopsies an accurate predictor of residual disease?

Pathology reports of basal cell carcinoma biopsies often contain comments of positive or negative margins, with only one to two per cent of the margin evaluated. A recent study sought to determine the negative predictive value of basal cell carcinoma biopsy margin status on the absence of residual basal cell carcinoma in the corresponding excision.

From institutional archives, researchers collected basal cell carcinoma biopsies with negative margin readings that had subsequent excisions. For excisions read as negative for residual basal cell carcinoma, the excision blocks were sectioned at 150-μm intervals until exhausted.

Of 143 cases that met criteria, 34 (24 per cent) were found to contain residual basal cell carcinoma in the corresponding excision leading to a negative predictive value of 76 per cent. In 31 of 34 (91 per cent) of these cases, the residual histologic subtype was superficial.

The study concluded that negative margins in a basal cell carcinoma biopsy are a poor predictor of residual disease in the patient. It recommended that clinicians treat these lesions, and that pathologists who comment on margin status of basal cell carcinoma biopsies consider adding a caveat to reflect these findings.

Read more recent research on non-melanoma skin cancer.

Willardson, Hal Bret et al. Predictive value of basal cell carcinoma biopsies with negative margins: A retrospective cohort study. Journal of the American Academy of Dermatology, Volume 79, Issue 1, Pages 42-46.

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