ALA-PDT using a twofold illumination scheme of 20 plus 80 J/cm(2) separated by a 2-h dark interval leads to high complete response rates at 2 years and can be regarded as an evidence-based treatment modality for superficial growing non-melanoma skin cancer and the (pre)malignant AK. The Rotterdam fractionated approach should be included in future guidelines.

Guidelines in dermatological oncological care are of reasonable quality according to the AGREE instrument. The domains in the AGREE instrument concern especially the methods of development of guidelines. The score according to AGREE can be improved by explicitly mentioning the different items. As clinical guidelines are regarded to be an important instrument to improve quality of care, improvements are needed.