PROTON RADIOTHERAPY OF SKIN CARCINOMAS

At the Proton Medical Research Center, University of Tsukuba, we perfo rmed a pilot study of proton-beam radiotherapy in 12 patients with the following types of carcinoma: Bowen's disease (4), oral verrucous car cinoma (5), and squamous cell carcinoma (3). They received total doses of 51-99.2 Gy in fractions of 2-12.5 Gy. All of the tumours responded well to the treatment. All four lesions of Bowen's disease, three of the five oral verrucous carcinomas, and the three squamous cell carcin omas completely regressed following irradiation. Two squamous cell car cinomas recurred during the followup period. One recurrent squamous ce ll carcinoma was successfully treated by a salvage surgical operation, and in the other case the patient refused further therapy. In two ver rucous carcinomas there was 90% regression of tumour volume. No severe radiation-related complication occurred. As proton radiotherapy produ ces good local tumour control without significant morbidity to the sur rounding normal tissues, it may prove to be a useful therapeutic modal ity for the treatment of skin carcinomas.