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

BACKGROUND AND OBJECTIVE: 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. STUDY DESIGN/MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Optimization of treatment parameters for Foscan-PDT of basal cell carcinomas.

BACKGROUND AND OBJECTIVE: Basal cell carcinomas (BCCs) are the most common form of skin cancers with high and increasing incidence rates. Photodynamic therapy (PDT) with mTHPC (Foscan) has shown to be a promising treatment alternative with good cosmetic results. The current study was aimed to determine optimal treatment parameters for this indication. STUDY DESIGN/MATERIALS AND METHODS: mTHPC-PDT was performed in 117 patients with a total of 460 BCCs with diagnosis confirmed by scratch cytology. Treatment parameters were altered as follows: Foscan dose 0.03-0.15 mg/kg, drug-light interval (DLI) 1-96 hours, total energy density 20-120 J/cm(2). Outcomes were assessed 8 weeks post-PDT following WHO guidelines. RESULTS: The overall rate of complete remissions (CR) was 96.7% and the cosmetic outcome was very good. In the largest subgroup (n=80) where low-dose Foscan was applied (0.05 mg/kg mTHPC; 48 hours DLI; 50 J/cm(2) total energy density), a CR rate of 100% with a high and narrow 95% Confidence Interval of 0.955-1.000 was achieved. Smaller variations of the treatment parameters (i.e., reducing the photosensitizer dose to 0.04 mg/kg or shortening the DLI to 24 hours) yielded similarly good results. Side effects were encountered in 52 out of 133 PDT sessions. They were more common in patients who had received high drug doses (0.06-0.15 mg/kg) and comprised mostly pain and phototoxic reactions. Three patients developed severe sunburns with subsequent scarring at the injection site following bright sunlight exposure 15-19 days after photosensitizer administration. CONCLUSIONS: The presented data suggest that mTHPC-PDT with the treatment parameters mentioned above seems to be an effective treatment option for BCCs. If sensibly applied, it is well tolerated and provides mostly excellent cosmetic results. Long-term results are yet to be evaluated.