Department of Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany.
Acta Oncol. 2022 Jun;61(6):714-719. doi: 10.1080/0284186X.2022.2068968. Epub 2022 Apr 29.
Dosimetric and clinical comparison of two cohorts of Iridium-192 (Ir-192) and Cobalt-60 (Co-60) high-dose-rate brachytherapy (DR-BT) boost for localized prostate cancer.
Patients with localized prostate cancer receiving either Ir-192 or Co-60 high-dose-rate brachytherapy (HDR-BT) boost in combination with external beam radiotherapy (EBRT) in the period of 2002-2019 were evaluated for dosimetric differences, side effects, biochemical relapse-free survival (bRFS), metastasis-free survival (MFS), and overall survival (OS). EBRT, delivered in 46 Gy (D) in conventional fractionation, was followed by two fractions HDR-BT boost with 9 Gy (D) 2 and 4 weeks after EBRT. Genitourinary (GU)/gastrointestinal (GI) toxicity were evaluated utilizing the Common Toxicity Criteria for Adverse Events version 5.0 and biochemical failure was defined according to the Phoenix definition.
A total of 338 patients with a median follow-up of 101.8 (IQR 65.7-143.0) months were evaluated. At 10 years the estimated bRFS, MFS, and OS in our patient sample were 81.1%/71.2% (=.073), 87.0%/85.7% (=.862), and 70.1%/69.7% (=.998) for Ir-192/Co-60, respectively. Cumulative 5-year late grade ≥2 GU toxicity was 20% for Ir-192 and 18.3% for Co-60 (=.771). Cumulative 5-year late grade ≥2 GI toxicity was 5.8% for Ir-192 and 4.6% for Co-60 (=.610). Grade 3 late GU side effects were pronounced in the Ir-192 cohort with 8.1% 1.4% in the Co-60 cohort (=.01), which was associated with significantly lower dose to the organs at risk in the Co-60 cohort. PTV D was 9.3 ± 0.8 Gy 9.0 ± 1.1 Gy (=.027) for Ir-192 Co-60. PTV V and PTV V were not significantly different between both cohorts.
Co-60 brachytherapy sources are an effective alternative to Ir-192 in combined prostate HDR-BT boost + EBRT.
局部前列腺癌患者接受铱-192（Ir-192）和钴-60（Co-60）高剂量率近距离放射治疗（HDR-BT）加量的两组患者的剂量学和临床比较。
2002 年至 2019 年间，接受 Ir-192 或 Co-60 HDR-BT 加量联合外照射放疗（EBRT）治疗的局部前列腺癌患者，对剂量学差异、副作用、生化无复发生存（bRFS）、无转移生存（MFS）和总生存（OS）进行评估。EBRT 采用常规分割 46Gy（D），之后在 EBRT 后 2 周和 4 周时进行两次 9Gy（D）2 的 HDR-BT 加量。采用通用不良事件标准 5.0 评估泌尿生殖（GU）/胃肠道（GI）毒性，根据凤凰定义定义生化失败。
共评估了 338 例患者，中位随访时间为 101.8（IQR 65.7-143.0）个月。在 10 年时，我们患者样本的估计 bRFS、MFS 和 OS 分别为 81.1%/71.2%（=0.073）、87.0%/85.7%（=0.862）和 70.1%/69.7%（=0.998）。Ir-192/Co-60 的累积 5 年迟发性 2 级以上 GU 毒性分别为 20%和 18.3%（=0.771）。Ir-192 的累积 5 年迟发性 2 级以上 GI 毒性为 5.8%，Co-60 为 4.6%（=0.610）。在 Ir-192 组中，3 级迟发性 GU 副作用明显，而 Co-60 组为 1.4%（=0.01），这与 Co-60 组危险器官的剂量明显较低有关。PTV D 为 9.3±0.8Gy 和 9.0±1.1Gy（=0.027），Ir-192 和 Co-60 分别为 9.3±0.8Gy 和 9.0±1.1Gy（=0.027）。PTV V 和 PTV V 两组间无显著差异。
Co-60 近距离放射治疗源是 Ir-192 在联合前列腺 HDR-BT 加量+EBRT 中的有效替代物。
