Long-term follow up of ALA 10% gel and red-light photodynamic therapy for the treatment of squamous cell carcinoma in situ.

Photodynamic Therapy (PDT) with 10% aminolevulinic acid (ALA) gel and narrow-band red light has been previously shown to be safe and effective for the treatment of squamous cell carcinoma in situ (SCCis) on the trunk and extremities. However, there is a paucity of data in the literature evaluating long-term disease recurrence after PDT. Hence, we performed a follow-up study in which nine of the original twelve patients from our pilot study returned 29-40 months after their last PDT treatment. All patients were clinically clear of disease and only one of seven patients biopsied had residual disease, indicating a long-term clearance rate of 88%. Cosmetic outcomes and patient satisfaction were favorable. Our data supports that red-light PDT with 10% ALA gel can achieve long-term clinical and histopathologic disease clearance and is a viable alternative to surgery for select SCCis.