The results of the study support the use of nerve blocks as pain relief during PDT of field cancerization on the forehead and scalp, although individual considerations must be taken into account to find the most adequate pain-relieving method for each patient.

The results imply that there is no significant difference in transdermal penetration of ALA and MAL in tumour tissue. Detectable levels of drug were not obtained in almost 50% of the lesions where catheters were situated 1-1.9 mm in the lesion. Curettage was not found to affect the interstitial concentration, indicating that penetration of drug indeed might be a problem when treating BCCs thicker than 1 mm.

Nerve blocks provide efficient pain relief during PDT when treating patients with field cancerization of the forehead. Nerve blocks were not found to affect the clinical outcome of PDT, and were generally well tolerated by the patients.

Pain is the most common side-effect of photodynamic therapy (PDT). Our main objective was to identify pain predictors in PDT. In total, we performed 658 treatments on 377 patients at our department during 2004. Larger sized treatment areas were the strongest pain predictor, and actinic keratoses were more painful to treat than basal cell carcinomas and Bowen's disease. The most sensitive areas to treat were the face and scalp. Gender and age did not influence pain. Although treatment outcome was not our primary objective, 62% of 95 superficial basal cell carcinomas that were followed for 3 years showed complete clearance. Also, perforation of nodular basal cell carcinomas did not lead to better clinical results. In conclusion, the size of the treatment area, the diagnosis and the lesion location influence pain during PDT. Nevertheless, there is a large variance in visual analogue scale assessment within each group, thereby limiting the ability to predict pain.

Compared with IMIQ, PDT treatment obtained a higher rate of AK clearance at 3-month follow-up and achieved shorter-lasting, but more intense, short-term skin reactions.