Metvix PDT in Participant With "High Risk" Basal Cell Carcinoma

Photodynamic therapy (PDT) is the selective destruction of abnormal cells through light activation of a photosensitiser in the presence of oxygen. These cells accumulate more photosensitiser than normal cells. The photosensitiser generates reactive oxygen species upon illumination. For skin diseases, there has been an increasing interest in using precursors of the endogenous photoactive porphyrins. The most commonly used precursors have been 5-aminolevulinic acid (ALA) and its derivatives. The present test drug, Metvix®, contains the methyl ester of ALA, which penetrates the lesions well and shows high lesion selectivity . BCC is a highly frequent skin malignancy, and accounts for approximately 75% of all non-melanoma skin cancers. It is the most common cancer in humans. Several non-pharmacological treatment modalities are used for BCC, including excision surgery, curettage and electrodesiccation, cryosurgery and more advanced modalities like radiation therapy, plastic surgery with reconstruction and Moh's surgery. The treatment used depends on the type, size, depth and localisation of the BCC lesion. Treatment options for BCC give good response rates in the majority of participants but are inadequate in a small group of participants defined as "high-risk" BCC. In this particular participant group, even a moderate complete response rate with good cosmetic results may be considered beneficial, since the number of participant who have to receive more advanced therapy with the possibility of high morbidity and poor cosmetic outcome was reduced. Even a partial response is of clinical interest since the remaining tumour was require less extensive surgery. In the case of treatment failure, Metvix PDT does not interfere with the use of other treatment modalities. The variable "complete response" after one or two Metvix treatment cycles was used as the basis for the justification of sample size.