van Delft LCJ, et al. - Recurrences following noninvasive therapy for basal cell carcinoma (BCC) may become a “more aggressive” histologic subtype, so researchers assessed the proportion of patients with a nonsuperficial treatment failure following noninvasive therapy for superficial BCC in this observational study. Using data from a single blind, noninferiority, randomized controlled trial (March 2008-August 2010) with 5-year follow-up in patients with primary superficial BCC treated with methylaminolevulinate–photodynamic therapy, 5-fluorouracil, or imiquimod, they identified that within the first 3 months posttreatment, most aggressive treatment failure recurrences occur after noninvasive therapy for superficial BCC. This suggests a probable underdiagnosis of more aggressive components in the primary tumor rather than transformation.