Department of Haematology, Oncology and Radiation Physics, Skane University Hospital, Lund, Sweden; Department of Clinical Sciences, Faculty of Medicine, Oncology and Pathology, Lund University, Lund, Sweden.
Department of Haematology, Oncology and Radiation Physics, Skane University Hospital, Lund, Sweden; Department of Clinical Sciences, Faculty of Medicine, Oncology and Pathology, Lund University, Lund, Sweden.
Int J Radiat Oncol Biol Phys. 2020 May 1;107(1):143-151. doi: 10.1016/j.ijrobp.2020.01.022. Epub 2020 Jan 28.
To study the relationships between absorbed dose to penile base structures and erectile dysfunction (ED) in patients treated with ultrahypofractionated (UHF) radiation therapy (RT) or conventionally fractionated (CF) RT for prostate cancer.
This dose-response study comprises 673 patients (57%) of the 1180 per-protocol patients included in the HYPO-RT-PC trial (median follow-up 5, years), where patients were randomized to CF (39 × 2.0 Gy, 8 weeks) or UHF (7 × 6.1 Gy, 2.5 weeks). No androgen deprivation therapy was allowed. Only patients with erectile function sufficient for intercourse at baseline and complete RT data were included in this study. Erectile function was assessed by physician at regular follow-ups. The main endpoint was severe ED (ED). The penile bulb (PB) and crus were retrospectively delineated on the treatment planning computed tomography scans. Dose-volume descriptors were derived from EQD2 converted dose matrices (α/β = 3 Gy). Univariable and multivariable Cox proportional hazard regression and logistic regression were used to find predictors for ED.
No significant difference in ED was found between CF and UHF. During the follow-up period, ED occurred in 27% of the patients in both treatment groups. Average (median) PB mean dose, D was 24.5 (20.2) in CF and 18.7 (13.1) Gy in UHF. Age was the only significant predictor for ED in Cox analyses. All dose-volume variables contributed significantly in univariable logistic regression at 2-year follow-up. Age and near maximum dose (D) were significant predictors for ED in multivariable logistic regression analyses at both 1 and 2 years.
The frequency of ED was similar in the CF and UHF treatment groups. Age at radiation therapy was the strongest predictor for ED, followed by dose to PB, and was most evident for younger patients. We propose D <50 Gy and D <20 Gy to the PB as the primary objectives to be applied in the treatment planning process.
研究接受超低分割（UHF）放射治疗（RT）或常规分割（CF）RT 治疗前列腺癌的患者中，阴茎基部结构吸收剂量与勃起功能障碍（ED）之间的关系。
这项剂量反应研究包括 HYPO-RT-PC 试验中 1180 名符合方案患者中的 673 名患者（57%）（中位随访时间为 5 年），这些患者被随机分配到 CF（39×2.0 Gy，8 周）或 UHF（7×6.1 Gy，2.5 周）组。不允许使用雄激素剥夺疗法。只有在基线时有足够性交能力且有完整 RT 数据的患者才被纳入本研究。医生在定期随访中评估勃起功能。主要终点是严重 ED（ED）。在治疗计划 CT 扫描上回顾性勾画阴茎球（PB）和阴茎脚。从 EQD2 转换的剂量矩阵中得出剂量-体积描述符（α/β=3 Gy）。使用单变量和多变量 Cox 比例风险回归和逻辑回归来寻找 ED 的预测因子。
CF 和 UHF 之间的 ED 发生率无显著差异。在随访期间，两组患者中 ED 的发生率均为 27%。CF 组和 UHF 组的平均（中位数）PB 平均剂量 D 分别为 24.5（20.2）Gy 和 18.7（13.1）Gy。年龄是 Cox 分析中 ED 的唯一显著预测因子。在单变量逻辑回归中，所有剂量-体积变量在 2 年随访时均有显著贡献。年龄和最大剂量（D）附近是多变量逻辑回归分析中 1 年和 2 年 ED 的显著预测因子。
CF 和 UHF 治疗组的 ED 发生率相似。放射治疗时的年龄是 ED 的最强预测因子，其次是 PB 剂量，在年轻患者中更为明显。我们建议将 D<50 Gy 和 D<20 Gy 作为主要目标应用于治疗计划过程。
