Simha Vijai, Rai Bhavana, Patel Firuza D, Kapoor Rakesh, Sharma Suresh C, Singh Oinam A, Singla Veenu, Dhanireddy Bhaswanth, Ghoshal Sushmita
Department of Radiotherapy and Oncology and Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Department of Radiotherapy and Oncology and Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Brachytherapy. 2018 Mar-Apr;17(2):345-351. doi: 10.1016/j.brachy.2017.09.008.
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.
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.
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.
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.
评估基于图像的剂量递增自适应近距离放射治疗（BT）后宫颈癌的长期疾病控制情况以及对危及器官的毒性。
60例宫颈癌患者接受外照射放疗，23次分割，总量46 Gy，每周联合顺铂，并行MRI引导下的BT，分4次给予7 Gy，高危临床靶区（HRCTV）的最小剂量为85.7 Gy（等效剂量2，EQD2）。BT剂量最初处方至A点，并对计划进行优化，以确保A点和HRCTV均得到覆盖，同时将危及器官的剂量维持在推荐限制范围内。患者在最初两年每三个月进行一次临床随访，此后每六个月随访一次。使用CTCAE 3.0版对泌尿系统和肠道症状进行毒性评分。
A点和HRCTV的D90的平均剂量分别为85.5（±2.75）Gy和98.4（±9.6）Gy EQD2。2 cc的平均EQD2，膀胱、直肠和乙状结肠分别为90.6 Gy、70.2 Gy和74.2 Gy。中位随访49.8个月时的总生存率为91.66%。6例（10%）患者出现3级胃肠道毒性。1例患者出现3级膀胱毒性。当EQD2分别>85 Gy、66 Gy和>71 Gy时，膀胱、直肠和乙状结肠毒性的发生率显著增加。
虽然3 - 4级毒性的发生率较低（胃肠道毒性为8.3%，膀胱毒性为1.6%），但1 - 2级膀胱和直肠毒性发生的阈值低于GEC - ESTRO组推荐的剂量。通过遵循基于体积的处方，有可能进一步降低对危及器官的毒性。
