BACKGROUND HDR brachytherapy alone is effective for the treatment of localised prostate cancer when given in 2-4 or more fractions. Single dose treatment has been explored in small cohort studies to date. This paper reports a large patient population with localised prostate cancer treated with single dose HDR brachytherapy delivering 19 Gy providing early outcome data from this approach. PATIENTS AND METHODS Seven centres across the UK collaborated in this national protocol to deliver 19 Gy to the PTV defined by the prostate capsule and a 3 mm expansion with clearly defined planning constraints for the urethra and rectum. Entry criteria allowed all risk groups provided PSA ≤40 µg/L and staging investigations were negative for metastases. The primary end point was biochemical relapse free survival (bRFS) defined using the Phoenix definition. Toxicity was measured using CTCAE v4.0. RESULTS A total of 441 patients were entered with median follow up 26 months (range 2-56). Median age was 73 (range 54-84) and 10% were low risk, 65% intermediate risk and 25% high risk. ADT was received by 37.6% overall and 90% of high risk patients for a median period of 6 months. Three year bRFS was overall 88%: this was 100% in low risk, 86% in intermediate risk and 75% in high risk. Only Gleason score was an independent predictor of bRFS. Relapse in 25 patients was assessed radiologically and occurred in the prostate in 15 of these, 11 of whom had localised prostate relapse only. Acute toxicity was low with no grade 3 or 4 events; there were two cases of late urinary stricture and two grade 3 late rectal events. CONCLUSION This is the largest cohort of single dose HDR brachytherapy patients treated with a single dose published to date. It shows that with 19 Gy there is 100% bRFS at 3 years in low risk patients but results in intermediate and high risk groups are less encouraging falling to 86% and 75% at 3 years with relapse predominantly in the prostate. Limited by the short follow up period of this study, the long-term outcomes of this single dose HDR approach remains uncertain. It is important to have close ongoing surveillance of this cohort as the data matures.

中文翻译：

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单剂量高剂量率 (HDR) 近距离放射治疗 (BT) 作为局部前列腺癌的单一疗法：英国国家队列研究的早期结果

背景 当分 2-4 次或更多次给药时，单独的 HDR 近距离放射治疗可有效治疗局部前列腺癌。迄今为止，已经在小型队列研究中探索了单剂量治疗。本文报告了大量使用单剂量 HDR 近距离放射疗法治疗的局限性前列腺癌患者群体，提供 19 Gy 的早期结果数据。患者和方法 英国的七个中心在该国家协议中合作，向由前列腺包膜定义的 PTV 提供 19 Gy，并在尿道和直肠明确定义规划约束的情况下进行 3 mm 扩张。进入标准允许所有风险组提供 PSA ≤ 40 µg/L 并且分期调查对转移呈阴性。主要终点是使用 Phoenix 定义定义的生化无复发生存 (bRFS)。使用 CTCAE v4.0 测量毒性。结果 共有 441 名患者进入，中位随访时间为 26 个月（范围 2-56）。中位年龄为 73 岁（范围 54-84），10% 为低风险，65% 为中度风险，25% 为高风险。37.6% 的患者和 90% 的高危患者接受了 ADT，中位时间为 6 个月。三年 bRFS 总体为 88%：低风险为 100%，中风险为 86%，高风险为 75%。只有格里森评分是 bRFS 的独立预测因子。25 名患者的复发进行了放射学评估，其中 15 名发生在前列腺中，其中 11 名仅发生局部前列腺复发。急性毒性低，无 3 或 4 级事件；有 2 例晚期尿道狭窄和 2 例 3 级晚期直肠事件。结论 这是迄今为止发表的最大单剂量 HDR 近距离放射治疗患者队列。结果表明，19 Gy 的低危患者在 3 年时的 bRFS 为 100%，但中危和高危组的结果不太令人鼓舞，3 年时分别下降到 86% 和 75%，复发主要发生在前列腺。受限于本研究的短期随访，这种单剂量 HDR 方法的长期结果仍不确定。随着数据的成熟，对这一群体进行密切的持续监测非常重要。受限于本研究的短期随访，这种单剂量 HDR 方法的长期结果仍不确定。随着数据的成熟，对这一群体进行密切的持续监测非常重要。受限于本研究的短期随访，这种单剂量 HDR 方法的长期结果仍不确定。随着数据的成熟，对这一群体进行密切的持续监测非常重要。