Analysis of combined HDR Brachytherapy and external beam radiotherapy in the treatment of carcinoma of cervix

Abstract

This study is designed to evaluate dosimetric and radiobiological aspects of the treatments of carcinoma of cervix treated with HDR brachytherapy in combination of external beam radiotherapy. 49 patients with carcinoma of cervix treated with external beam radiotherapy plus HDR brachytherapy were included in the analysis. FIGO classification was used for staging of the tumor and were of stage II - IIIB. ICRU-38 definitions of dose points specifications were used to determine doses and BED values at different points. Some other points, for bladder and rectum have also been defined during the planning of these patients to see their relevance in planning and reporting and found that the bladder and rectum complications have significant correlation with BED values of the points which have received higher dose. The ICRU reference volume, calculated with respect to the point A dose, had positive correlation with locoregional control and is a good predictor in 2D planning done with orthogonal films. The doses and corresponding BEDs at different point of lymphatic trapezoid do not reveal any correlation with neither complication nor with local control. The ICRU bladder and rectum reference points do not have any bearing with complications hence cannot be considered as good predictors. While on the other hand the ICRU reference volume calculated with respect to the point A dose and corresponding tumor control probability have positive correlation with clinical outcome hence is considered to be a good clinical predictor.