Superficial Basal Cell Carcinoma (sBCC) and Bowen Disease (BD) are malignant skin tumors localised in the superficial epidermis. These tumors are highly prevalent in the caucasian population. Diagnosis of sBCC and BD is often delayed because the clinical manifestation may be discrete and lesions are sometimes wrongly diagnosed and treated as eczema. Once the diagnosis is established, the lesions may cover an extensive area, making surgical excision more difficult. At that moment, the physician can make use of less invasive techniques such as photodynamic therapy (PDT). Pretreatment with an ablative carbon dioxide (CO2) laser has recently been studied in order to enhance the skin penetration of the photosensitizer methyl aminolevulinate (MAL). This study compares the results of a full ablative and a fractional ablative CO2 laser mode as pretreatment of PDT in the management of sBCC and BD. Ablation of the upper epiderm of the cancer results in an deeper penetration of MAL. Fractional ablation is known to result in better wound healing compared to full ablative CO2 laser ablation, because only small skin columns are ablated instead of the entire epidermal layer. Patients with non operable sBCC or BD lesions covering an area of at least 5 cm2 or with the presence of two small separated lesions, will be investigated. Lesions greater than 5 cm2 are divided in two. After randomization, the half of the lesions will be pretreated with the full ablative CO2 laser, while the other half with the fractional ablative CO2 laser. Afterwards, the entire surface is treated with MAL-PDT. Such as in our current clinical practice, this treatment modality is repeated after a two week interval. Thus, every subject undergoes both treatment modalities, making within-patient comparison possible. The endpoints efficacy, pain, aesthetics and patient preference are investigated during twelve months of follow up.
