BACKGROUND The aim of the study was to evaluate acute side effects after extremely hypofractionated intensity-modulated radiotherapy (IMRT) with stereotactic body radiation therapy (SBRT) for definitive treatment of prostate cancer patients. PATIENTS AND METHODS Between February 2018 and August 2019, 205 low-, intermediate- and high-risk prostate cancer patients were treated with SBRT using "CyberKnife M6" linear accelerator. In low-risk patients 7.5-8 Gy was delivered to the prostate gland by each fraction. For intermediate- and high-risk disease a dose of 7.5-8 Gy was delivered to the prostate and 6-6.5 Gy to the seminal vesicles by each fraction with a simultaneous integrated boost (SIB) technique. A total of 5 fractions (total dose 37.5-40 Gy) were given on every second working day. Acute radiotherapy-related genitourinary (GU) and gastrointestinal (GI) side effects were assessed using Radiation Therapy Oncology Group (RTOG) scoring system. RESULTS Of the 205 patients (28 low-, 115 intermediate-, 62 high-risk) treated with SBRT, 203 (99%) completed the radiotherapy as planned. The duration of radiation therapy was 1 week and 3 days. The frequencies of acute radiotherapy-related side effects were as follows: GU grade 0 - 17.1%, grade I - 30.7%, grade II - 50.7%, grade III - 1.5%; and GI grade 0 - 62.4%, grade I-31.7%, grade II-5.9%, grade III-0%. None of the patients developed grade ≥ 4 acute toxicity. CONCLUSIONS SBRT with a total dose of 37.5-40 Gy in 5 fractions appears to be a safe and well tolerated treatment option in patients with prostate cancer, associated with slight or moderate early side effects. Longer follow-up is needed to evaluate long-term toxicity and biochemical control.

中文翻译：

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临床局限性或局部晚期前列腺癌患者确定立体定向放射治疗 (SBRT) 后的急性副作用：一项单一机构的前瞻性研究。

背景 本研究的目的是评估极大分割调强放射治疗 (IMRT) 与立体定向体部放射治疗 (SBRT) 对前列腺癌患者进行彻底治疗后的急性副作用。患者与方法 2018 年 2 月至 2019 年 8 月期间，205 名低、中、高风险前列腺癌患者使用“Cyber​​Knife M6”直线加速器接受 SBRT 治疗。在低风险患者中，每部分向前列腺输送 7.5-8 Gy。对于中危和高危疾病，采用同步综合增强 (SIB) 技术，每部分向前列腺输送 7.5-8 Gy 的剂量，向精囊输送 6-6.5 Gy 的剂量。每隔一个工作日给予总共 5 次分次（总剂量 37.5-40 Gy）。使用放射治疗肿瘤学组 (RTOG) 评分系统评估急性放射治疗相关的泌尿生殖 (GU) 和胃肠道 (GI) 副作用。结果 SBRT 治疗的 205 名患者（28 名低危、115 名中危、62 名高危）中，203 名（99%）按计划完成了放疗。放射治疗的持续时间为 1 周零 3 天。急性放疗相关副作用的频率如下：GU 0 级 - 17.1%，I 级 - 30.7%，II 级 - 50.7%，III 级 - 1.5%；GI 0-62.4%，I-31.7%，II-5.9%，III-0%。没有患者出现≥4级急性毒性。结论 SBRT 总剂量为 37.5-40 Gy，分 5 次，对于前列腺癌患者来说似乎是一种安全且耐受性良好的治疗选择，并伴有轻微或中度的早期副作用。