Use of a radon mould technique for skin cancer: results from the Peter MacCallum Cancer Institute (1975-1984).

During the period from 1975 to 1984, 642 patients had non-melanoma skin cancers (NMSC) treated by a radon mould technique following the principles of the Manchester system. The results of 77 out of 642 (12%) with histologically verified lesions are presented. The sites of the lesions were as follows: head and neck 25 (32%), upper limbs 38 (49%), lower limbs 13 (17%) and trunk one case only. The histological diagnosis was squamous cell carcinoma 48 (62%), basal cell carcinoma in 22 (29%) and other in seven (9%). There were nine out of 77 (12%) failures, four with persistent disease, which did not clear after initial treatment (and for whom the radon mould was an inappropriate choice of technique), and five (6%) recurrences after clearance of the initial lesion. There was a sharp rise in failures after 1979 when there was a change of radon supplier, but no calibration error was substantiated. It is clearly beneficial for institutions to cross-check the manufacturer's brachytherapy source data. There have been no further recurrences or any symptomatic late morbidity. This is a safe, effective and practical radiotherapeutic technique for superficial lesions (not exceeding a depth of 4 mm) in areas of poor radiation tolerance, and may obviate the need for a prolonged fractionated course of external-beam radiation in selected patients. Alternatives to radon are discussed.