Cendales Ricardo, Alwers Elizabeth, Cifuentes Javier, Bobadilla Ivan, Torres Felipe, Arbelaez Juan, Gaitan Armando, Cortes Helber, Acevedo Yenny, Quintero Paulo, Vasquez Jaider
Centro de Control de Cancer Ltda., Bogota, Colombia.
J Contemp Brachytherapy. 2015 Feb;7(1):10-6. doi: 10.5114/jcb.2015.48838. Epub 2015 Feb 4.
High-dose-rate (HDR) brachytherapy has been accepted as an effective and safe method to treat prostate cancer. The aim of this study was to describe acute toxicity following HDR brachytherapy to the prostate, and to examine the association between dosimetric parameters and urinary toxicity in low-risk prostate cancer patients.
Patients with low-risk prostate cancer were given HDR brachytherapy as monotherapy in two 12.5 Gy fractions. Planning objectives for the planning target volume (PTV) were V100% ≥ 90% and V150% ≤ 35%. Planning objectives for organs at risk were V75% ≤ 1 cc for the bladder, rectum and perineum, and V125% ≤ 1 cc for the urethra. Toxicity was assessed three months after treatment using the Common Terminology Criteria for Adverse Events.
Seventy-three patients were included in the analysis. Thirty-three patients (45%) reported having any type of toxicity in the three months following HDR brachytherapy. Most toxicity cases (26%) were grade 1 urinary toxicity. Mean coverage index was 0.89 and mean V100 was 88.85. Doses administered to the urethra were associated with urinary toxicity. Patients who received more than 111.3% of the prescribed dose in 1 cc of the urethra were four times more likely to have urinary toxicity compared to patients receiving less than 111.3% (OR = 4.71, 95% CI: 1.43-15.6; p = 0.011).
High-dose-rate brachytherapy administered as monotherapy for prostate cancer proved to be a safe alternative treatment for patients with low-risk prostate cancer. Urinary toxicity was associated with the dose administered to 1 cc and 0.1 cc of the urethra and was remarkably inferior to the reported toxicity in similar studies.
高剂量率（HDR）近距离放射治疗已被公认为治疗前列腺癌的一种有效且安全的方法。本研究的目的是描述前列腺HDR近距离放射治疗后的急性毒性，并研究低风险前列腺癌患者剂量学参数与泌尿毒性之间的关联。
低风险前列腺癌患者接受HDR近距离放射治疗作为单一疗法，分两次给予12.5 Gy剂量。计划靶体积（PTV）的计划目标为V100%≥90%且V150%≤35%。危及器官的计划目标为膀胱、直肠和会阴的V75%≤1 cc，尿道的V125%≤1 cc。治疗三个月后使用不良事件通用术语标准评估毒性。
73例患者纳入分析。33例患者（45%）报告在HDR近距离放射治疗后的三个月内出现任何类型的毒性。大多数毒性病例（26%）为1级泌尿毒性。平均覆盖指数为0.89，平均V100为88.85。给予尿道的剂量与泌尿毒性相关。在1 cc尿道中接受超过规定剂量111.3%的患者发生泌尿毒性的可能性是接受低于111.3%患者的四倍（OR = 4.71，95% CI：1.43 - 15.6；p = 0.011）。
对于低风险前列腺癌患者，HDR近距离放射治疗作为单一疗法被证明是一种安全的替代治疗方法。泌尿毒性与给予1 cc和0.1 cc尿道的剂量相关，且明显低于类似研究中报告的毒性。
