PROSPECTIVE RANDOMIZED STUDY ON TWO DOSE FRACTIONATION REGIMENS OF HIGH DOSE RATE BRACHYTHERAPY FOR CARCINOMA CERVIX: COMPARISON OF CLINICAL RESPONSE AND COMPLICATIONS IN ORGANS AT RISK

Introduction: Cancer Cervix is treated with a combination of external beam radiotherapy and intracavitary brachytherapy. With the recent American Brachytherapy Society consensus guidelines for locally advanced carcinoma of the cervix, at least Equivalent Dose 2 > 80 Gy for patients with complete response or partial response with residual disease less than 4cm is recommended. For non responders or those with tumors larger than 4cm at the time of brachytherapy, tumor dose escalation to an Equivalent Dose 2 of 85-90 Gy is recommended to point A. Present study was designed to see the feasibility of these guidelines in terms of local tumor control and toxicities to rectum and bladder in our group of patients. Material and Methods: Fifty patients of biopsy proven cancer cervix were enrolled. After pre-treatment evaluation all patients were delivered external beam radiotherapy 50 Gy in 25 fractions at 200 cGy/day with concurrent cisplatin on weekly basis. Patients were then randomized into three applications (Group A), four applications (Group B) of HDR Brachytherapy of 6 Gy each so that total treatment time does not exceed 8 weeks. BED and LQED were calculated and assessment of response and complications were assessed. Statistical analysis was done using Chi square test. Results: Mean age of the patients was 50 years. No significant hematological toxicities and radiation reactions were seen during external beam radiotherapy. The mean BED of group A for tumor, rectum and bladder was 137.3 Gy, 112.53 Gy and 103.23 Gy respectively and of group B was 155.3 Gy, 120.98 Gy and 111.95 Gy respectively. The mean EQD2 in group A at tumor, rectum and bladder was 74 Gy, 54.08 Gy and 61.94 Gy respectively and in group B was 82 Gy, 59.18 Gy, and 66.60 Gy respectively. There was no statistically significant difference in local response and early and late bladder reactions in both the groups. Conclusion: In a follow up of six months we did not find any significant difference in toxicities of rectum and bladder. Long term follow up is needed to see for late rectal and bladder toxicities.