Preliminary clinical studies with PDT by topical TPPS administration in neoplastic skin lesions

Cutaneous photosensitization by topical administration of a porphyrin derivative has been previously reported from experimental studies. Preliminary clinical trials performed at the National Cancer Institute of Milan in the last six months have confirmed the feasibility of treating skin lesions by topical application of photosensitizers. Fourteen cases of basal cell carcinoma were treated by local administration of tetraphenylporphinesulphonate (TPPS), vehicled by azone. Later, the tumor was exposed to a wavelength of 630 nm from a dye laser. We noted complete remission, as documented by biopsies, in all tumors, with clinical thickness less than 2 mm, whereas partial remission was obtained in tumors with clinical thickness more than 2 mm. Our experience suggests the possibility of a routine treatment by this method for flat basal cell carcinoma and pre-malignant lesions, with remarkable advantages to conventional therapies. Our results have to be confirmed by increasing the number of cases and length of follow up; our short follow up does not allow us to make definitive claims regarding this therapy.