Incidence of residual basal cell carcinoma in patients who appear tumor free after biopsy

Basal cell carcinoma (BCC) biopsy sites often heal with no clinical evidence of residual tumor. The purpose of our study is to determine whether such patients require further therapy. If biopsies can be curative, health care costs can be reduced by avoiding unnecessary surgery. We prospectively evaluated 41 consecutive subjects with 42 biopsy-confirmed BCCs who appeared disease free. Each biopsy site was excised and processed by the Mohs micrographic technique. The tissue block was sectioned horizontally at 30-micrometer intervals until exhausted. Sections were stained and examined microscopically for residual tumor. Tumor was identified in 28 (66%) of 42 cases. No statistically significant relationship was found between the presence or absence of residual tumor and the following variables: age, sex, tumor location, biopsy technique, histopathologic subtype, scar size, time from biopsy to surgery, and extent of inflammation in histologic sections. Our data suggest that patients with small (< 1 cm) primary BCCs that appear to be completely removed after a biopsy procedure are at risk for recurrence without further treatment.