Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina.
Memorial Healthcare System, Pembroke Pines, Florida.
Int J Radiat Oncol Biol Phys. 2021 May 1;110(1):237-248. doi: 10.1016/j.ijrobp.2020.09.054. Epub 2020 Dec 22.
Ultrahypofractionationed radiation therapy for prostate cancer is increasingly studied and adopted. The American Association of Physicists in Medicine Working Group on Biological Effects of Hypofractionated Radiotherapy therefore aimed to review studies examining toxicity and quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer and model its effect.
We performed a systematic PubMed search of prostate SBRT studies published between 2001 and 2018. Those that analyzed factors associated with late urinary, bowel, or sexual toxicity and/or quality of life were included and reviewed. Normal tissue complication probability modelling was performed on studies that contained detailed dose/volume and outcome data.
We found 13 studies that examined urinary effects, 6 that examined bowel effects, and 4 that examined sexual effects. Most studies included patients with low-intermediate risk prostate cancer treated to 35-40 Gy. Most patients were treated with 5 fractions, with several centers using 4 fractions. Endpoints were heterogeneous and included both physician-scored toxicity and patient-reported quality of life. Most toxicities were mild-moderate (eg, grade 1-2) with a very low overall incidence of severe toxicity (eg, grade 3 or higher, usually <3%). Side effects were associated with both dosimetric and non-dosimetric factors.
Prostate SBRT appears to be overall well tolerated, with determinants of toxicity that include dosimetric factors and patient factors. Suggested dose constraints include bladder V(Rx Dose)Gy <5-10 cc, urethra Dmax <38-42 Gy, and rectum Dmax <35-38 Gy, though current data do not offer firm guidance on tolerance doses. Several areas for future research are suggested.
针对前列腺癌的超分割放射治疗越来越受到研究和采用。为此，美国医学物理学家协会（AAPM）低分割放射治疗生物学效应工作组旨在审查研究立体定向体部放射治疗（SBRT）治疗前列腺癌后的毒性和生活质量，并建立模型以预测其效应。
我们对 2001 年至 2018 年间发表的前列腺 SBRT 研究进行了系统的 PubMed 检索。纳入并分析了与晚期尿、肠或性功能毒性和/或生活质量相关的因素的研究，并进行了正常组织并发症概率模型分析。对于包含详细剂量/体积和结局数据的研究进行了分析。
我们发现有 13 项研究分析了尿毒性，6 项研究分析了肠毒性，4 项研究分析了性功能障碍。大多数研究纳入了中低危前列腺癌患者，治疗剂量为 35-40Gy。大多数患者接受 5 个分次治疗，有几个中心使用 4 个分次治疗。研究终点各异，包括医生评分毒性和患者报告的生活质量。大多数毒性为轻度至中度（如 1-2 级），严重毒性（如 3 级或更高，通常 <3%）的总体发生率非常低。副作用与剂量学和非剂量学因素均有关。
前列腺 SBRT 总体上耐受性良好，其毒性的决定因素包括剂量学因素和患者因素。建议的剂量限制包括膀胱 V(Rx 剂量)Gy <5-10cc，尿道 Dmax <38-42Gy，直肠 Dmax <35-38Gy，但目前的数据并不能为耐受剂量提供明确的指导。建议开展多个未来研究领域。
