ALA-PDT (20% aminolevulinic acid + blue light) Delivers 100% Histologic Clearance in Facial cSCC in situ

In the single-center, investigator-initiated, open-label NCT06159842 study, patients with biopsy-confirmed facial cutaneous squamous cell carcinoma in situ (cSCCis/Bowen disease) received 2 cycles of 20% aminolevulinic acid (ALA), a topical prodrug converted to protoporphyrin IX to enable photodynamic tumor cell kill, followed by blue-light activation 28 days apart (n=32 enrolled; n=30 completed). At end of treatment (8 weeks after the second treatment, with mandated excision), complete histologic clearance was 100% and clinical clearance before excision was also 100% (40% by day 49; remainder by day 69). Tolerability was favorable (mild erythema/flaking; 1 case temporary hyperpigmentation; mean pain 2.71/10; no treatment-related serious AEs reported)—notably less morbidity than surgery (excision/Mohs) but without any recurrence/readout yet, which is the key benchmark where surgery typically performs best.