Reflectance confocal microscopy confirms residual basal cell carcinoma on clinically negative biopsy sites before Mohs micrographic surgery: A prospective study.

Abstract

Biopsy specimens from patients with basal cell carcinoma (BCC) can present to surgery with no clinically residual tumor, complicating treatment decisions. To evaluate reflectance confocal microscopy (RCM) for the assessment of residual BCC following biopsy. Consecutive patients with biopsy-proven BCC and no clinical evidence of residual tumor who had been referred for Mohs micrographic surgery were included. Biopsy sites were imaged with a handheld RCM device. On the basis of RCM evaluation, cases were labeled RCM positive or RCM negative. Mohs micrographic surgery was performed in all cases; margins and 15-μm serial vertical sectioning were evaluated. A total of 61 patients were included (mean age, 61.7 years [standard deviation, 12.2 years]; range, 37-87 years); 60.7% were women. The mean lesion size was 5.1 mm (range, 3-12 mm); 73.8% of patients were positive on RCM, and 68.9% had residual BCC on histopathologic examination. The rates of RCM sensitivity, specificity, positive predictive value, and negative predictive value were 92.8%, 68.4%, 86.6%, and 81.2%, respectively. Three cases of BCC (high-risk, infiltrative, and basosquamous) were missed with use of RCM. When high-risk subtypes were excluded (n = 5), sensitivity and negative predictive value were both 100%. RCM can miss deep-seated residual tumor. RCM is a valuable tool for the evaluation of residual BCC following biopsy, with the potential to reduce unnecessary surgical procedures.