24. The trial is designed to prove the equivalence of treatment modalities. A statistic test is used for evaluation, including the Kaplan-Meier-method. When all 4 study arms contain 116 BCCs, a 2-group-test on the equivalence of ratios with a 1-sided significance level of 0.05 will have a power of 80% to disprove the null hypothesis. The null hypothesis is that standard and test method are not equivalent (ratio difference delta T - delta S ≥ 0.15). Then the alternative hypothesis is more probable, meaning that the ratios in both groups are equivalent supposed that the expected ratio difference is 0.07 and the ratio within the standard group is 0.03 (according to an expected recurrence rate of 3% in the surgical excision study arm).