Background: Zone based photodynamic therapy (PDT) is a promising treatment option for actinic keratosis, superficial basal cell carcinoma, and in-situ squamous cell carcinoma. PDT has similar cure rates to 5-fluorouracil and imiquimod. Objective: Determine if PDT zone treatments improve patient comfort, tolerance, retention, and offer less severe reactions as compared to full face treatments. Methods: 500 PDT patients were divided into full face (n = 250) versus zone treatments (n = 250). All subjects completed a post-treatment phone survey assessing tolerance of procedure. Retention rates and severe reactions were tracked. Results: Zone treatment resulted in a higher number of excellent responses for patient tolerance vs. full face treatment group (85 % vs. 39%,
