Brachytherapy Doses and Late Rectal and Bladder Toxicities for Cervical Cancer Patients: A Case Study of a Radiotherapy Centre in Zambia

The purpose of this study was to analyse the International Commission of Radiation Unit (ICRU) point doses delivered to the urinary bladder and rectum with ultrasound based intracavitary brachytherapy and to evaluate late toxicity relative to the equivalent total doses delivered in 2 gray per fraction of equivalent dose (EQD2) for bladder and rectum using point based methods of reporting. This study was conducted using a quantitative retrospective research design which looked at three hundred and thirty three women who received external beam radiation therapy (EBRT) + brachytherapy (BT) between 2009 to 2013. The patients were aged 25 years and above the median age was 48. The median follow-up was 24 months and 58% of patients received 50 Gray in 25 fractions with 24 Gray in 3 fractions of BT and 42% received 46 Gray in 23 fractions to the pelvis with 26 Gray in 4 fractions of BT. BT was delivered with ring and tandem applicators. The results showed no correlation between late toxicity for rectum and total EQD2 to ICRU rectal points rs =0.1. For bladder the null hypothesis that there was no association between EQD2 and late toxicity grade for bladder was rejected and the alternative hypothesis that there was association between EDQ2 and late toxicity grade for bladder accepted, rs= 0.013. The mean rectal and urinary bladder doses at ICRU points were 59.8 % (4.5 Gy) and 62% (4.6 Gy) which was below the ICRU 38 recommended dose of lower than 80% of maximum dose to the rectum and bladder of the prescribed dose to point A.