The treatment area (5x10 cm\^2) was treated at baseline and at 3 ,9 and 15 months visits. At baseline, the area was treated with fractionated Metvix® PDT treatment consisting of two treatment one week apart and at 3 ,9 and 15 months visits with single Metvix® PDT treatment. The participants were evaluated for occurrence of new lesions, lesion response and recurrence at 3 (not recurrence),9,15,21, and 27 months visits. New and recurrent lesions in the treated area were treated with Metvix® PDT treatment. Lesions with partial response in the treated area were re-treated with Metvix® PDT and lesions with no response were treated with lesion specific treatment at the discretion of the investigator.
In the contralateral control area (5x10 cm\^2), new and recurrent lesions and lesions in non-complete response were treated with lesion specific treatment at the discretion of the investigator at each study visit.