Morbidity following low-dose-rate selectron therapy for cervical cancer

The Christie Hospital installed a Selectron afterloading machine in 1979. By early 1982 it became apparent that patients treated for carcinoma of the cervix using the Selectron had developed a high incidence of morbidity compared with patients treated by the standard Manchester radium technique. Initially, the majority opinion was that the patients had been overdosed, because little or no allowance had been made for the higher dose rate of 137Cs. The results of investigation suggest, however, that the main factor responsible for the morbidity was a change in technique, previously unrecognised, in that the rigid 137Cs applicators facilitate the use of a much higher proportion of long intrauterine tubes and larger vaginal components than used to be the case with radium. The evidence for this and the probable mechanism of the resulting damage are discussed.