WEDNESDAY, Aug. 28, 2024 -- Most patients with basal cell carcinoma (BCC) or squamous cell carcinoma (SCC) have residual tumor at the time of Mohs micrographic surgery (MMS), including in some patients clinically appearing tumor-free following biopsy, according to a study published online Aug. 19 in the Journal of the American Academy of Dermatology.

Katherine G. Thompson, M.D., from Johns Hopkins University in Baltimore, and colleagues examined the percentage of cases in which residual tumor was histologically present at the time of MMS for BCC and SCC. Data were included for 483 MMS cases performed for biopsy-proven BCC and SCC (287 and 196 cases, respectively) between October 2022 and April 2023.

The researchers identified residual tumor in 83.3 and 66.8 percent of BCC and SCC, respectively, at the time of MMS. Residual histologic tumor was identified in 68.2 and 41.5 percent of BCC and SCC, respectively, in patients clinically appearing tumor-free following biopsy. The likelihood of residual tumor was significantly higher in men, high-risk sites, smaller biopsy sizes, and larger preoperative sizes.

"Future studies examining how to reliably identify cases in which no residual histologic tumor is present following biopsy could potentially allow patients in those select cases to avoid surgery in the future," the authors write.