PO06

Abstract

Purpose To compare the dosimetric parameters of IC/IS brachytherapy vs Intracavitary brachytherapy in carcinoma cervix. Methods and Materials Patients diagnosed as carcinoma cervix and treated with radical chemoradiation (50Gy in 25 fractions) were included for analysis. Brachytherapy was performed using fletcher style tandem and ovoid applicator with interstitial component. The dose prescribed was 21Gy to HRCTV, 7Gy per fraction for 3 fractions. Three plans were created for comparison. First plan was the approved plan using combined IC/IS technique. Second plan was intracavitary plan with dose prescribed to point A using standard loading. Third plan was optimised intracavitary plan with dose prescribed to HRCTV. The dosimetric parameters analysed were D90 to HRCTV and D2cc to the OAR's Results 12 patients were included in this study. 50% patients had HRCTV volume >30cc. The mean D90 HRCTV was 87.2Gy in IC/IS plan, 84Gy in standard loading plan and 81.6Gy in optimized intracavitary plan. For patients with residual HRCTV>30cc, there was a significant difference between the D90 HRCTV among the three plans (p value=0.018). The mean D2cc to the bladder was 78.6Gy in IC/IS plan,94.1Gy in standard loading plan and 88.2Gy in optimized intracavitary plan. The mean D2cc to the rectum was 70.2Gy in IC/IS plan, 87.9Gy in standard loading plan and 80.2Gy (p value=0.034) in optimized intracavitary plan. The mean D2cc to the sigmoid was 63.9Gy in IC/IS plan, 69.8Gy in standard loading plan and 66.2Gy in optimized intracavitary plan. 50% of patients had HRCTV D90 target coverage less than 85Gy in standard loading plan. 33% of OAR constraints were achieved in optimised intracavitary plan. For HRCTV volumes>30 cc, average dose escalation to the D90 HRCTV was 4.7Gy compared to optimised intracavitary plan and 2.8 Gy compared to a standard loading plan Conclusion IC/IS brachytherapy was dosimetrically superior to intracavitary brachytherapy in patients with residual disease post EBRT. To compare the dosimetric parameters of IC/IS brachytherapy vs Intracavitary brachytherapy in carcinoma cervix. Patients diagnosed as carcinoma cervix and treated with radical chemoradiation (50Gy in 25 fractions) were included for analysis. Brachytherapy was performed using fletcher style tandem and ovoid applicator with interstitial component. The dose prescribed was 21Gy to HRCTV, 7Gy per fraction for 3 fractions. Three plans were created for comparison. First plan was the approved plan using combined IC/IS technique. Second plan was intracavitary plan with dose prescribed to point A using standard loading. Third plan was optimised intracavitary plan with dose prescribed to HRCTV. The dosimetric parameters analysed were D90 to HRCTV and D2cc to the OAR's 12 patients were included in this study. 50% patients had HRCTV volume >30cc. The mean D90 HRCTV was 87.2Gy in IC/IS plan, 84Gy in standard loading plan and 81.6Gy in optimized intracavitary plan. For patients with residual HRCTV>30cc, there was a significant difference between the D90 HRCTV among the three plans (p value=0.018). The mean D2cc to the bladder was 78.6Gy in IC/IS plan,94.1Gy in standard loading plan and 88.2Gy in optimized intracavitary plan. The mean D2cc to the rectum was 70.2Gy in IC/IS plan, 87.9Gy in standard loading plan and 80.2Gy (p value=0.034) in optimized intracavitary plan. The mean D2cc to the sigmoid was 63.9Gy in IC/IS plan, 69.8Gy in standard loading plan and 66.2Gy in optimized intracavitary plan. 50% of patients had HRCTV D90 target coverage less than 85Gy in standard loading plan. 33% of OAR constraints were achieved in optimised intracavitary plan. For HRCTV volumes>30 cc, average dose escalation to the D90 HRCTV was 4.7Gy compared to optimised intracavitary plan and 2.8 Gy compared to a standard loading plan IC/IS brachytherapy was dosimetrically superior to intracavitary brachytherapy in patients with residual disease post EBRT.