Working title: high dose rate intra-cavitary brachytherapy with cobalt 60 source for locally advanced cervical cancer: the Zimbabwean experience

Background and purpose
Cervical cancer is the fourth commonest cancer in women in the world with the highest regional incidence and mortality seen in Southern, Eastern and Western Africa. It is the commonest cause of cancer morbidity and mortality among Zimbabwean women. Most patients present with locally advanced disease that is no longer amenable to surgery. Definitive concurrent chemoradiation (CCRT), which is the use of external beam radiotherapy (EBRT) and weekly cisplatin, includes use of intracavitary brachytherapy, as the standard treatment. In the setting of this study, cobalt-60 (Co60)-based high dose rate brachytherapy (HDR-BT) has been in use since 2013. This study sought to review practices pertaining to use of brachytherapy in Zimbabwe, including timing with external beam radiotherapy, adverse effects and patient outcomes.

A retrospective analysis of data from records of patients with histologically confirmed cervical cancer treated with HDR-BT at the main radiotherapy centre in Zimbabwe from January 2013 to December 2014 was done. Outcome measures were local control, overall survival as well as gastro-intestinal and genito-urinary toxicity.

A total of 226 patients were treated with HDR-BT during the study period, with a 97% treatment completion rate. All patients received between 45-50Gy of pelvic EBRT. Seventy-four percent received concurrent platinum-based chemotherapy. In 52% of the patients, HDR-BT was started when they were still receiving EBRT. The commonest fractionation schedule used was the 7Gy × 3 fractions, once a week (87%). Clinical complete tumour response was achieved in 75% at 6 weeks post treatment, 23% had partial response. Follow-up rates at 1 year and 2 years were 40 and 19% respectively. Disease free survival at 1 year and 2 years was 94 and 95% respectively. Vaginal stenosis was the commonest toxicity recorded, high incidence noted with increasing age. Four patients developed vesico-vaginal fistulae and two patients had rectovaginal fistulae.

One hundred and seventeen patients patients started HDR-BT during EBRT course, with a treatment completion rate of 97%. The overall treatment duration was within 56 days in the majority of patients. Early local tumour control was similar for all the HDR-BT fractionation regimes used in the study, with a high rate (75%) of complete clinical response at 6 weeks post-treatment. Prospective studies to evaluate early and long-term outcomes of HDR-BT in our setting are recommended.