Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany; Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany; German Oncology Center.
Department of Radiation Oncology, German Oncology Center, University Hospital of the European University, Limassol, Cyprus.
Int J Radiat Oncol Biol Phys. 2022 Aug 1;113(5):1015-1024. doi: 10.1016/j.ijrobp.2022.04.048. Epub 2022 Jun 3.
Prostate-specific membrane antigen positron emission tomography (PSMA-PET) is increasingly used to guide salvage radiation therapy (sRT) in patients with prostate cancer and biochemical recurrence/persistence after prostatectomy. This work examined (1) metastasis-free survival (MFS) after PSMA-PET guided sRT and (2) the metastatic patterns on PSMA-PET images after sRT.
This retrospective, multicenter (9 centers, 5 countries) study included patients referred for PSMA-PET due to recurrent/persistent disease after prostatectomy. Patients with distant metastases (DM) on PSMA-PET before sRT were excluded. Cox regression was performed to assess the effect of clinical parameters on MFS. The distribution of PSMA-PET detected DM after sRT and their respective risk factors were analyzed.
All (n = 815) patients received intensity modulated RT to the prostatic fossa. In the case of PET-positive pelvic lymph nodes (PLN-PET) (n = 275, 34%), pelvic lymphatics had been irradiated. Androgen deprivation therapy had been given in 251 (31%) patients. The median follow-up after sRT was 36 months. The 2-/4-year MFS after sRT were 93%/81%. In multivariate analysis, the presence of PLN-PET was a strong predictor for MFS (hazard ratio, 2.39; P < .001). After sRT, DM were detected by PSMA-PET in 128/198 (65%) patients, and 2 metastatic patterns were observed: 43% had DM in sub-diaphragmatic para-aortic LNs (abdominal-lymphatic), 45% in bones, 9% in supra-diaphragmatic LNs, and 6% in visceral organs (distant). Two distinct signatures with risk factors for each pattern were identified.
MFS in our study is lower compared with previous studies, obviously due to the higher detection rate of DM in PSMA-PET after sRT. Thus, it remains unclear whether MFS is a surrogate endpoint for overall survival in PSMA PET-staged patients in the post-sRT setting. PLN-PET may be proposed as a new surrogate parameter predictive of MFS. Analysis of recurrence patterns in PET after sRT revealed risk factor signatures for 2 metastatic patterns (abdominal-lymphatic and distant), which may allow individualized sRT concepts in the future.
前列腺特异性膜抗原正电子发射断层扫描（PSMA-PET）越来越多地用于指导前列腺癌患者前列腺切除术后生化复发/持续患者的挽救性放疗（sRT）。本研究检查了（1）PSMA-PET 引导 sRT 后的无转移生存期（MFS）和（2）sRT 后 PSMA-PET 图像上的转移模式。
这项回顾性的多中心（9 个中心，5 个国家）研究纳入了因前列腺切除术后疾病复发/持续而接受 PSMA-PET 检查的患者。sRT 前 PSMA-PET 显示远处转移（DM）的患者被排除在外。采用 Cox 回归分析评估临床参数对 MFS 的影响。分析 sRT 后 PSMA-PET 检测到的 DM 的分布及其各自的危险因素。
所有（n=815）患者均接受了前列腺窝调强放疗。在 PSMA-PET 阳性的盆腔淋巴结（PLN-PET）（n=275，34%）的情况下，对盆腔淋巴结进行了照射。251 例（31%）患者接受了雄激素剥夺治疗。sRT 后中位随访时间为 36 个月。sRT 后 2/4 年 MFS 分别为 93%/81%。多因素分析显示，PLN-PET 的存在是 MFS 的强烈预测因素（危险比，2.39；P<.001）。sRT 后，128/198（65%）例患者通过 PSMA-PET 检测到 DM，观察到 2 种转移模式：43%的 DM 位于膈下主动脉旁 LN（腹部淋巴结），45%位于骨骼，9%位于膈上 LN，6%位于内脏器官（远处）。确定了每种模式的两个不同特征及其危险因素。
与以往研究相比，本研究中的 MFS 较低，显然是由于 sRT 后 PSMA-PET 中 DM 的检出率较高。因此，PSMA PET 分期患者 sRT 后 MFS 是否为总生存期的替代终点仍不清楚。PLN-PET 可作为预测 MFS 的新替代参数。sRT 后 PET 复发模式分析显示了 2 种转移模式（腹部淋巴结和远处）的危险因素特征，这可能允许未来采用个体化 sRT 概念。
