High and sustained efficacy after two sessions of topical 5-aminolaevulinic acid photodynamic therapy for basal cell carcinoma: a prospective, clinical and histological 10-year follow-up study.

Background: Prolonged follow-up data on topical photodynamic therapy (PDT) in basal cell carcinoma (BCC) are necessary for a full evaluation of its effect and for comparison with conventional treatment methods.

Objectives: To assess 10-year long-term PDT efficacy in primary and recurrent BCC and to evaluate clinical and histopathological factors which may be associated with treatment failure.

Methods: We performed a longitudinal study on 60 histologically verified BCCs in 44 patients treated with curettage and one or two sessions of dimethylsulphoxide (DMSO)-supported topical 5-aminolaevulinic acid (ALA)-based PDT. Treated lesions were investigated by clinical and histopathological examination at regular intervals. The main outcomes were 10-year lesion complete response rate using a time-to-event analysis, histological treatment failure and cosmesis.

Results: Overall complete response rate for all lesions was 75% (95% confidence interval 64-87%); 60% after one and 87% after two treatment sessions. The response rate was 78% for primary lesions; 63% after one and 90% after two sessions. The cosmetic outcome was rated as good or excellent in 91-100% of evaluated cases. Treatment failure was documented in 15 (25%) of 60 lesions; clinical investigation identified 14 of them. All failures were noted within 3 years of treatment. Male gender, recurrent tumour and one treatment session were factors significantly associated with treatment failure. The only lesion larger than 2·0 cm relapsed.

Conclusions: Two sessions of DMSO-supported topical ALA-PDT and curettage can provide long-term effective treatment results with favourable cosmetic outcome in primary, small BCC.