Usually systemic photosensitizers (PS) require a long period of incubation (48-96h) after systemic admission. On the
other hand clearing from healthy skin needs weeks or months. Severe side effects on skin are possible in case of
uncontrolled light exposure. Topical PDT may solve this problem, but deep portions may not be sufficiently sensitized,
resulting in a survival of some tumor cell population after PDT and recurrence. The same problem counts for actinic
keratosis and Bowen's disease, but with even worse consequences as a resulting infiltrating growing squamous cell
carcinoma (SCC) is likely to produce metastatic lesions. Light dosimetry is crucial also. Wavelenght, fluence and total
energy may influence outcome of any PDT substantially.
17 patients with Bowen's disease or BCC where treated using a novel systemic PS (Fotolon®) and 665nm light from a
diode laser. Follow up time ranges between 2.5 and 1 years after treatment. 2 patients received a second PDT, in 15
patients one treatment was efficient. We found a remissions in 1, local control in 2 and no evidence of disease in 14
patients. Significant fluorescence was noted in all lesions. With a light protection protocol for only 48 hours no severe
side effects where seen. One patient developed mild redness of sunlight exposed skin sites 24h after being discharged
from light protection protocol.
In comparison with currently available topical PS Fotolon® offers some important advantages as secure photosenzitation
of deep portions, single treatment, high selectivity combined with a high cure rate. In comparison with currently
available systemic PS Fotolon® offers short incubation time, high selectivity and short time of elimination, while
efficiency was comparable to HPD (hematoporphyrin-derivate) PDT combined with ALA-5 PDT and without need for
additional local PS-application for PDD.