1. ¹Department of Dermatology, Erasmus MC, Rotterdam, The Netherlands
2. ²Department of Radiation Oncology, The Centre for Optical Diagnostics and Therapy, Erasmus MC, Rotterdam, The Netherlands

Correspondence: Dr Ellen R.M. de Haas, Department of Dermatology, Erasmus MC, PO Box 2040 (HP PB003), Rotterdam 3000CA, The Netherlands. E-mail: e.r.m.dehaas@erasmusmc.nl

Received 1 December 2005; Revised 3 April 2006; Accepted 23 May 2006; Published online 13 July 2006.

Abstract

Photodynamic therapy (PDT) of superficial basal cell carcinoma (sBCC) using topical 5-aminolevulinic acid (ALA) and a light fluence of 75–100 J cm^-2 yields unsatisfactory long-term results. In several animal models, illumination with two light fractions 2 hours apart was considerably more effective than single illumination. Response is further enhanced if the fluence of the first light fraction is reduced, although the cumulative fluence is maintained. We compared the response of sBCC to a single illumination and 2-fold illumination scheme in which two light fractions of 20 and 80 J cm^-2 are performed 4 and 6 hours after the application of a single dose of 20% ALA. We randomly assigned 154 patients with a total of 505 primary sBCC into two treatment groups. Two hundred and forty-three lesions were treated using a single illumination of 75 J cm^-2 at a fluence rate of 50 mW cm^-2. Fractionated PDT, at the same fluence rate, was performed on 262 lesions. The complete response (CR) following a 2-fold illumination scheme is significantly greater than that following a single light fraction (P=0.002, log-rank test). Twelve months after therapy, CR rate to a 2-fold illumination is 97%, whereas the CR to a single illumination is 89%.