Radical radiotherapy for carcinoma cervix--preliminary experience with the microSelectron high dose rate machine.

Radiotherapy for uterine cervix carcinoma is an accepted treatment for all stages of invasive malignancy. The radiation modality is usually a combination of brachytherapy and external beam therapy for all except the most extensive tumours (stage IV--FIGO). Satisfactory results have been obtained in the Singapore General Hospital using low dose-rate radium applications in combination with cobalt teletherapy. Five year actuarial survival rates of 86.7% were obtained for FIGO stage I, 65.0% for stage II, 41.4% for stage III, 4.9% for stage IV with an overall rate of 54.0% for all stages. Corresponding 10-year rates were: 79.6%, 60.2%, 35.2%, 0% and 48.2%. Preliminary results of primary radiotherapy in 36 patients with cervical carcinoma treated by high dose-rate brachytherapy (microSelectron HDR) combined with 6MVP photons from a Siemens linear accelerator are presented. The patients were registered at the Mount Elizabeth Oncology Centre from November 1989 to December 1990 inclusive. The morbidity from high dose-rate therapy appears lower (9.1% for vaginal stenosis, 6.1% for non-severe proctitis) than for the radium series (4.1% and 20.8%) although the major complication rate appears similar (3% vs 2.8% respectively). The total failure rate is also lower at 19.4% for the HDR patients compared to 33.5% for the radium group. However, these rates are not strictly comparable as the HDR series consists of a small number of patients with limited follow-up. In the light of the data indicating acceptable morbidity with significant rate of early failure, the HDR brachytherapy doses have been increased whilst keeping within the limits set by other centres.