Tumor recurrence 5 years after treatment of cutaneous basal cell carcinoma and squamous cell carcinoma.

For most cutaneous basal cell and squamous cell carcinomas (nonmelanoma skin cancers (NMSCs)), data are insufficient to permit evidence-based choices among treatments. To compare tumor recurrence after treatments, we conducted a prospective cohort study of consecutive patients with primary NMSCs treated with the most common treatments, in two practices in 1999-2000. Recurrence was determined from medical records by observers blinded to treatment type. Follow-up was available for 1,174 patients with 1,488 tumors (93.8%) at median 7.4 years; of these tumors, 24.3% (N=361) were treated with destruction with electrodessication/curettage, 38.3% (N=571) with excision, and 37.4% (N=556) with histologically guided serial excision (Mohs surgery). The overall 5-year tumor recurrence rate (95% confidence interval) was 3.3% (2.3, 4.4). Unadjusted recurrence rates did not differ after treatments: 4.9% (2.3, 7.4) after destruction, 3.5% (1.8, 5.2) after excision, and 2.1% (0.6, 3.5) after Mohs surgery (P=0.26), and no difference was seen after adjustment for risk factors. In tumors treated only with excision or Mohs surgery, the hazard of recurrence was not significantly different, even after adjustment for propensity for treatment with Mohs surgery. These data indicate that common treatments for NMSCs were at least 95% effective, and further studies are needed to guide therapeutic choices for different clinical subgroups.