Abstract

Objective

We aimed to report the 2-year results of stereotactic body radiation therapy for prostate cancer and identify the clinical and dosimetric factors that predict acute genitourinary toxicities.

Methods

We retrospectively reviewed the medical records of patients with non-metastatic prostate cancer treated at Toyota Memorial Hospital between 2017 and 2020. The patients were treated with stereotactic body radiation therapy with a total dose of 36.25 Gy in five fractions on consecutive weekdays. While low-risk patients received radiotherapy alone, intermediate- to high-risk patients also received androgen deprivation therapy.

Results

We analysed a total of 104 patients, including 10, 60 and 34 low-, intermediate- and high-risk patients, respectively. The median follow-up duration was 2 years. We did not observe biochemical/clinical recurrence, distant metastasis or death from prostate cancer. One patient died of another cause. Grade 2 acute genitourinary toxicity was observed in 40 (38%) patients. Age (P = 0.021), genitourinary toxicity of grade ≥1 at baseline (P = 0.023) and bladder mean dose (P = 0.047) were significantly associated with the incidence of grade 2 acute genitourinary toxicity. The cut-off value of 65 years for age and 10.3 Gy for the bladder mean dose were considered the most appropriate. Grade 2 acute gastrointestinal toxicity was observed in five (5%) patients. None of the patients experienced grade ≥3 acute or late toxicity.

Conclusions

Stereotactic body radiation therapy is feasible for Japanese patients with prostate cancer, with acceptable acute toxicity. Age, genitourinary toxicity at baseline and bladder mean dose predict grade 2 acute genitourinary toxicity.

中文翻译：

---

日本局部前列腺癌患者的立体定向放射治疗：急性泌尿生殖系统毒性的 2 年结果和预测因素

摘要

客观的

我们旨在报告前列腺癌立体定向放射治疗的 2 年结果，并确定预测急性泌尿生殖系统毒性的临床和剂量学因素。

方法

我们回顾性地回顾了 2017 年至 2020 年在丰田纪念医院接受治疗的非转移性前列腺癌患者的医疗记录。这些患者在连续工作日接受了总剂量为 36.25 Gy 的立体定向放射治疗，分五次进行。低危患者仅接受放疗，中高危患者也接受雄激素剥夺治疗。

结果

我们共分析了 104 名患者，分别包括 10、60 和 34 名低风险、中风险和高风险患者。中位随访时间为 2 年。我们没有观察到前列腺癌的生化/临床复发、远处转移或死亡。一名患者死于其他原因。在 40 名 (38%) 患者中观察到 2 级急性泌尿生殖系统毒性。年龄（P  = 0.021），基线时≥1级的泌尿生殖毒性（P  = 0.023）和膀胱平均剂量（P = 0.047) 与 2 级急性泌尿生殖系统毒性的发生率显着相关。年龄的 65 岁和膀胱平均剂量的 10.3 Gy 的临界值被认为是最合适的。在五名 (5%) 患者中观察到 2 级急性胃肠道毒性。没有患者出现≥3 级急性或晚期毒性。

结论

立体定向放射治疗对日本前列腺癌患者是可行的，具有可接受的急性毒性。年龄、基线泌尿生殖毒性和膀胱平均剂量可预测 2 级急性泌尿生殖毒性。