Effects of ue of a single HDR-ICBT treatment plan at orci for cervical cancer in subsequent fractions on dose delivered to organs at risk

Twenty one cervical cancer patients with tumour at stages IB to IIIB were used in this study. The study investigated the effects of use of a single treatment plan in subsequent treatment fractions in HDR-ICBT treatment of cervical cancer at ORCI on dose delivered to critical organs during treatment and the deviations of delivered from planned dose to critical organs and their association with applicator parking and sedation methods. The location of the applicator and critical organs during treatment plan was based on AP and LAT orthogonal radiographs. Assignment of 100% dose to the tumour volume allowed determination of percentage dose to critical organs on co-registered patient’s radiographs. The percentage doses delivered to bladder and rectum of selected patients during treatment in the second and third fractions were compared by using the first plan. With the exception of the rectum, the study showed that the percentage dose to critical organs for all patients was within the dose tolerance limit of ICRU recommendations. Only 1 patient in second fraction and 2 patients in the third fraction exceeded doses above tolerance limit to the rectum. As expected, the mean percentage dose difference in critical organs between planned and delivered dose increased with treatment fractions and were found to be highest in the third fraction for patients with cancer at late stages of development. From this study it was concluded that use of single treatment plan for subsequent fractions should be avoided for patients with cervical cancer at advanced stages of development and spinal anesthesia should replace local anesthesia to reduce applicator movement during treatment. This being a clinal study which involve patients, the permission to conduct it was granted by National Institute of Medical Research before the commencement of the study.