Vijai Simha1, Bhavana Rai2, Firuza D Patel1, Rakesh Kapoor1, Suresh C Sharma1, Oinam A Singh1, Veenu Singla3, Bhaswanth Dhanireddy1, Sushmita Ghoshal1. 1. Department of Radiotherapy and Oncology and Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India. 2. Department of Radiotherapy and Oncology and Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Electronic address: bhavana1035@gmail.com. 3. Department of Radio Diagnosis, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Abstract
PURPOSE: To evaluate the long-term disease control and toxicity to the organs at risk after dose-escalated image-based adaptive brachytherapy (BT) in cervical cancer. METHODS AND MATERIALS: Sixty patients of cervical cancer were treated with external radiotherapy 46 Gy in 23 fractions with weekly cisplatin and MRI-guided BT 7 Gy × 4 fractions with a minimum dose of 85.7 Gy (EQD2) to the high-risk clinical target volume (HRCTV). The BT dose was initially prescribed to point A and plans were optimized to ensure coverage of both point A and HRCTV while maintaining doses to the organs at risk within the recommended constraints. Patients were followed up clinically every three months for the first two years and six months thereafter. Toxicity scoring for urinary and bowel symptoms was done using CTCAE version 3.0. RESULTS: The mean doses to the point A and D90 HRCTV were 85.5 (±2.75) Gy and 98.4 (±9.6) Gy EQD2 respectively. The mean 2 cc EQD2, the bladder, rectum, and sigmoid were 90.6 Gy, 70.2 Gy, and 74.2 Gy respectively. The overall survival at a median followup of 49.8 months was 91.66%. Six (10%) patients developed grade 3 gastrointestinal toxicity. One patient developed grade 3 bladder toxicity. The incidence of bladder, rectal, and sigmoid toxicity increased significantly with doses >85 Gy, 66 Gy, and >71 Gy EQD2 respectively. CONCLUSIONS: While the incidence of grade 3-4 toxicity was low (8.3% for gastrointestinal toxicity and 1.6% for bladder), the threshold for development of grade 1-2 bladder and rectal toxicity was lower than the doses recommended by the GEC-ESTRO group. By adhering to volume-based prescriptions, there is scope of further reduction in toxicity to organs at risk.
PURPOSE: To evaluate the long-term disease control and toxicity to the organs at risk after dose-escalated image-based adaptive brachytherapy (BT) in cervical cancer. METHODS AND MATERIALS: Sixty patients of cervical cancer were treated with external radiotherapy 46 Gy in 23 fractions with weekly cisplatin and MRI-guided BT 7 Gy × 4 fractions with a minimum dose of 85.7 Gy (EQD2) to the high-risk clinical target volume (HRCTV). The BT dose was initially prescribed to point A and plans were optimized to ensure coverage of both point A and HRCTV while maintaining doses to the organs at risk within the recommended constraints. Patients were followed up clinically every three months for the first two years and six months thereafter. Toxicity scoring for urinary and bowel symptoms was done using CTCAE version 3.0. RESULTS: The mean doses to the point A and D90 HRCTV were 85.5 (±2.75) Gy and 98.4 (±9.6) Gy EQD2 respectively. The mean 2 cc EQD2, the bladder, rectum, and sigmoid were 90.6 Gy, 70.2 Gy, and 74.2 Gy respectively. The overall survival at a median followup of 49.8 months was 91.66%. Six (10%) patients developed grade 3 gastrointestinal toxicity. One patient developed grade 3 bladder toxicity. The incidence of bladder, rectal, and sigmoid toxicity increased significantly with doses >85 Gy, 66 Gy, and >71 Gy EQD2 respectively. CONCLUSIONS: While the incidence of grade 3-4 toxicity was low (8.3% for gastrointestinal toxicity and 1.6% for bladder), the threshold for development of grade 1-2 bladder and rectal toxicity was lower than the doses recommended by the GEC-ESTRO group. By adhering to volume-based prescriptions, there is scope of further reduction in toxicity to organs at risk.