Predicting recurrence of basal-cell carcinomas treated by microscopically controlled excision: a recurrence index score.

Despite the high cure rate achieved for basal-cell carcinomas treated with microscopically controlled excision, recurrences do occur. To determine if lesions that are likely to recur may be predicted at the time of surgery, data from 5020 patients with 7010 basal-cell carcinomas treated with Mohs' technique were reviewed. Two thousand nine hundred sixty (2960) lesions with five-year follow-up were studied (overall recurrence rate = 2.6%). Sex and age of the patients, size and location of lesions, types of previous therapy, and the number of surgical stages of microscopically controlled excision were all found to correlate significantly with recurrence rate (p less than 0.01). Multiple regression analysis was performed to determine the relative contribution of each of these variables to predictability of recurrences by a weighted scoring system. The derived model delineated the lesions into no-risk, low-, medium-, and high-risk groupings (p less than 0.000001). Lesions in the high-risk group had a recurrence rate of 10.1%, almost four times greater than the average. More aggressive microscopically controlled excisions and closer follow-up care are indicated for those lesions that can be predicted to result in a high-risk score.