RESUMEN
BACKGROUND: Basal cell carcinoma (BCC) is the most common type of skin cancer and incidence rates are increasing. Photodynamic therapy (PDT) is a frequently used treatment, especially for superficial BCC (sBCC). Two topical photosensitizing agents are currently used to treat sBCC, namely 5-aminolaevulinic acid (ALA) and its ester, methyl aminolaevulinate (MAL). Previous research showed a high efficacy for ALA-PDT using a twofold fractionated illumination scheme in which two light fractions of 20 J cm-2 and 80 J cm-2 were delivered 4 h and 6 h after ALA application. OBJECTIVES: To evaluate whether twofold ALA-PDT is superior to conventional MAL-PDT for sBCC. METHODS: We performed a single-blind, randomized, multicentre trial in the Netherlands. RESULTS: Overall, 162 patients were randomized either to conventional MAL-PDT or twofold ALA-PDT. After 12 months, a total of six treatment failures occurred following ALA-PDT and 13 treatment failures occurred following MAL-PDT. The 12-month cumulative probability of remaining free from treatment failure was 92·3% [95% confidence interval (CI) (83·7-96·5)] for ALA-PDT and 83·4% (95% CI 73·1-90·0) for MAL-PDT (P = 0·091). CONCLUSIONS: The twofold ALA-PDT scheme resulted in fewer recurrences, although the difference between both treatment groups was not statistically significant. However, ALA-PDT resulted in higher pain scores and more post-treatment side-effects compared with MAL-PDT.