Long-term outcomes following Foscan®-PDT of basal cell carcinomas

In a previous publication we showed that mTHPC-PDT (Foscan®-PDT) is an effective treatment of basal cell carcinomas (BCCs) in "difficult to treat" locations and presented optimized treatment parameters to reduce costs and side effects. Now we present long-term results of the same study population.

Following PDT of a total of 460 BCCs in 117 subjects, the patients/lesions were followed-up for a mean duration of 42 (range: 2-72) months. Two patients dropped out of follow-up; 13 patients died of unrelated causes. Recurrences were treated either by repeated PDT or other established methods.

The sustained clearance rate was 93.7% and the overall treatment success rate was 90.7%. Kaplan-Meier analysis revealed an estimated recurrence free fraction of patients at 5 years of 95.1%, 92.4%, 85.1%, and 74.0% for the four different photosensitizer dose groups (0.06-0.15, 0.05, 0.04, and 0.03 mg/kg). High-risk lesions (recurrences, thickness >3 mm) recurred more often than low-risk ones, and recurrences mostly (>50%) occurred during the first year of follow-up.

Long-term outcomes of high-dose (0.06-0.15 mg/kg) and reduced-dose (0.05 mg/kg) Foscan®-PDT in "difficult to treat" BCCs compare favorably with other methods, even in high-risk lesions (recurrent and/or thick lesions). A recommended combination of treatment parameters for low-dose therapy seems to be: 0.05 mg/kg Foscan®, 24 hours drug-light interval (DLI), fluence ≥40 J/cm(2) . Prospective randomized studies are needed to look into low-dose mTHPC-PDT of BCCs in more detail and to directly compare it with other treatments.