Historically, toxicity concerns have existed in patients with large prostate glands treated with radiation therapy, particularly brachytherapy. There are questions whether this risk extends to stereotactic body radiation therapy (SBRT). In this retrospective review, we examine clinical outcomes of patients with prostate glands ≥100 cc treated curatively with SBRT. We retrospectively analyzed a large institutional database to identify patients with histologically confirmed localized prostate cancer in glands ≥100 cc, who were treated with definitive-robotic SBRT. Prostate volume (PV) was determined by treatment planning magnetic resonance imaging. Toxicity was measured using Common Terminology Criteria for Adverse Events, version 5.0. Many patients received the Expanded Prostate Cancer Index Composite Quality of Life questionnaires. Minimum follow-up (FU) was 2 years. Seventy-one patients were identified with PV ≥100 cc. Most had grade group (GG) 1 or 2 (41% and 37%, respectively) disease. All patients received a total dose of 3500 to 3625 cGy in 5 fractions. A minority (27%) received androgen deprivation therapy (ADT), which was used for gland size downsizing in only 10% of cases. Nearly half (45%) were taking GU medications for urinary dysfunction before RT. Median toxicity FU was 4.0 years. Two-year rates of grade 1+ genitourinary (GU), grade 1+ gastrointestinal (GI), and grade 2+ GU toxicity were 43.5%, 15.9%, and 30.4%, respectively. Total grade 3 GU toxicities were very limited (2.8%). There were no grade 3 GI toxicities. On logistic regression analysis, pretreatment use of GU medications was significantly associated with increased rate of grade 2+ GU toxicity (odds ratio, 3.19; = .024). Furthermore, PV (analyzed as a continuous variable) did not have an effect on toxicity, quality of life, or oncologic outcomes. With early FU, ultra large prostate glands do not portend increased risk of high-grade toxicity after SBRT but likely carry an elevated risk of low-grade GU toxicity.

中文翻译：

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立体定向全身放射治疗治疗超大（≥100 cc）腺体前列腺癌

从历史上看，接受放射治疗（尤其是近距离放射治疗）的大前列腺患者一直存在毒性问题。有人质疑这种风险是否会延伸到立体定向放射治疗 (SBRT)。在本回顾性综述中，我们检查了接受 SBRT 治愈性治疗的前列腺≥100 cc 患者的临床结果。我们回顾性分析了一个大型机构数据库，以确定经组织学证实的腺体≥100 cc的局限性前列腺癌患者，并接受了明确的机器人 SBRT 治疗。前列腺体积（PV）通过治疗计划磁共振成像确定。使用不良事件通用术语标准 5.0 版测量毒性。许多患者收到了扩展前列腺癌指数综合生活质量调查问卷。最短随访时间 (FU) 为 2 年。 71 名患者的 PV ≥100 cc。大多数人患有级别组 (GG) 1 或 2（分别为 41% 和 37%）疾病。所有患者均分 5 次接受 3500 至 3625 cGy 的总剂量。少数人 (27%) 接受雄激素剥夺疗法 (ADT)，该疗法仅在 10% 的病例中用于缩小腺体尺寸。近一半 (45%) 在放疗前服用 GU 药物治疗泌尿功能障碍。中位毒性 FU 为 4.0 年。 1+ 级泌尿生殖 (GU)、1+ 级胃肠道 (GI) 和 2+ GU 毒性的两年发生率分别为 43.5%、15.9% 和 30.4%。 3 级 GU 总毒性非常有限 (2.8%)。没有出现 3 级胃肠道毒性。在逻辑回归分析中，治疗前使用 GU 药物与 2+ 级 GU 毒性发生率增加显着相关（比值比，3.19；= .024）。此外，PV（作为连续变量分析）对毒性、生活质量或肿瘤结果没有影响。对于早期 FU，超大前列腺并不预示 SBRT 后高级别毒性风险增加，但可能会增加低级别 GU 毒性风险。