FLAME试验（NCT01168479）表明，在中高危前列腺癌患者中，对前列腺内病变进行等同毒性的局部增强能够改善5年无病生存率（DFS）。虽然对于总肿瘤体积的近最小剂量（D98%）与治疗效果的改善有关，但仔细观察显示对于所有患者来说可能并非如此。因此，我们研究了与局部增强效益相关的危险因素是否可被识别。我们描述了526名FLAME试验患者中的临床特征分布和高危因素的数量，与D98%相关。我们使用罚型Cox回归建立了预测模型。为了研究不同患者亚组的潜在效益，我们比较了基于模型的5年DFS预测，假设采用标准全腺放疗77 Gy，与假设使用额外的D98%为95 Gy的局部增强放疗的预测之间的差异。 高危因素患者在接受D98% > 85 Gy的120名患者组中得到了很好的代表，并且与接受77 Gy的组相比，复发情况较少。应用模型模拟标准剂量77 Gy时，我们预测了GG1级患者有着较高的DFS，而具有高危特征的患者似乎显示出较低的DFS。当模拟D98%为95 Gy时，所有危险组均显示出较高的DFS水平。 我们的结果表明，在标准剂量77 Gy下，GG1级患者已经显示出了较低的失败率，局部增强的附加效益有限。相反，具有高危特征的患者，特别是GG4或5级，显示出了较低的5年DFS，局部增强可能会显著改善这一情况。这表明对于这些患者来说，达到较高的局部增强剂量可能会特别有益。 版权所有 © 2023 Elsevier Inc. 保留所有权利。

The FLAME trial (NCT01168479) showed that isotoxic focal boosting to the intraprostatic lesion(s) in patients with intermediate- and high-risk prostate cancer improves 5-year disease-free survival (DFS). Although the near-minimum dose to the gross tumor volume (D98%) was associated with improved outcomes, a closer look suggested that this might not be the same for all patients. Therefore, we investigated whether risk factors that are associated with a benefit of focal boosting can be identified.We described the distribution of clinical characteristics and the number of high-risk factors with respect to the D98% in 526 FLAME trial patients. We used penalized Cox regression to develop a prediction model. To investigate a potential benefit in patient subgroups, we compared the model-based predictions of 5-year DFS assuming standard whole-gland radiation therapy of 77 Gy to the predictions assuming an additional focal boost with D98% of 95 Gy.Patients with high-risk factors were well represented in the group of 120 patients that received D98% > 85 Gy and showed fewer recurrences compared with the group that received 77 Gy. Applying the model simulating a standard dose of 77 Gy, we predicted a high DFS for grade group (GG) 1 patients, whereas patients with high-risk characteristics appeared to show a low DFS. All risk groups showed a high level of DFS when simulating D98% of 95 Gy.Our results suggest that GG 1 patients already show a low level of failure at a standard dose of 77 Gy, limiting the additional benefit of focal boosting. In contrast, patients with high-risk characteristics, especially GG 4 or 5, show a low 5-year DFS, while focal boosting might improve this substantially. This suggests that reaching a high focal boost dose may be particularly beneficial for these patients.Copyright © 2023 Elsevier Inc. All rights reserved.