Schmidt-Hegemann Nina-Sophie, Zamboglou Constantinos, Thamm Reinhard, Eze Chukwuka, Kirste Simon, Spohn Simon, Li Minglun, Stief Christian, Bolenz Christian, Schultze-Seemann Wolfgang, Bartenstein Peter, Prasad Vikas, Ganswindt Ute, Grosu Anca-Ligia, Belka Claus, Mayer Benjamin, Wiegel Thomas
Department of Radiation Oncology, University Hospital, Ludwig-Maximilians Universität (LMU) Munich, Munich, Germany.
Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Front Oncol. 2021 Oct 1;11:723536. doi: 10.3389/fonc.2021.723536. eCollection 2021.
68Ga-PSMA PET/CT is associated with unprecedented sensitivity for localization of biochemically recurrent prostate cancer at low PSA levels prior to radiotherapy. Aim of the present analysis is to examine whether patients undergoing postoperative, salvage radiotherapy (sRT) of the prostatic fossa with no known nodal or distant metastases on conventional imaging (CT and/or MRI) and on positron emission tomography/computed tomography (68Ga-PSMA PET/CT) will have an improved biochemical recurrence-free survival (BRFS) compared to patients with no known nodal or distant metastases on conventional imaging only.
This retrospective analysis is based on 459 patients (95 with and 364 without 68Ga-PSMA PET/CT). BRFS (PSA < post-sRT Nadir + 0.2 ng/ml) was the primary study endpoint. This was first analysed by Kaplan-Meier and uni- and multivariate Cox regression analysis for the entire cohort and then again after matched-pair analysis using tumor stage, Gleason score, PSA at time of sRT and radiation dose as matching parameters.
Median follow-up was 77.5 months for patients without and 33 months for patients with 68Ga-PSMA PET/CT. For the entire cohort, tumor stage (pT2 vs. pT3-4; p= <0.001), Gleason score (GS ≤ 7 vs. GS8-10; p=0.003), pre-sRT PSA (<0.5 vs. ≥0.5ng/ml; p<0.001) and sRT dose (<70 vs. ≥70Gy; p<0.001) were the only factors significantly associated with improved BRFS. This was not seen for the use of 68Ga-PSMA PET/CT prior to sRT (p=0.789). Matched-pair analysis consisted of 95 pairs of PCa patients with or without PET/CT and no significant difference in BRFS based on the use of PET/CT was evident (p=0.884).
This analysis did not show an improvement in BRFS using 68Ga-PSMA PET/CT prior to sRT neither for the entire cohort nor after matched-pair analysis after excluding patients with PET-positive lymph node or distant metastases a priori. As no improved BRFS resulted with implementation of 68Ga-PSMA PET in sRT planning, sRT should not be deferred until the best "diagnostic window" for 68Ga-PSMA PET/CT.
68Ga-PSMA PET/CT对于在放疗前低PSA水平下生化复发前列腺癌的定位具有前所未有的敏感性。本分析的目的是研究在传统成像（CT和/或MRI）以及正电子发射断层扫描/计算机断层扫描（68Ga-PSMA PET/CT）上均无已知淋巴结或远处转移的前列腺窝术后挽救性放疗（sRT）患者与仅在传统成像上无已知淋巴结或远处转移的患者相比，其无生化复发生存期（BRFS）是否会得到改善。
本回顾性分析基于459例患者（95例有68Ga-PSMA PET/CT，364例无）。BRFS（PSA < sRT后最低点 + 0.2 ng/ml）是主要研究终点。首先对整个队列进行Kaplan-Meier分析以及单因素和多因素Cox回归分析，然后在使用肿瘤分期、Gleason评分、sRT时的PSA和放射剂量作为匹配参数进行配对分析后再次进行分析。
无68Ga-PSMA PET/CT患者的中位随访时间为77.5个月，有该检查的患者为33个月。对于整个队列，肿瘤分期（pT2与pT3 - 4；p = <0.001）、Gleason评分（GS≤7与GS8 - 10；p = 0.003）、sRT前PSA（<0.5与≥0.5 ng/ml；p<0.001）和sRT剂量（<70与≥70 Gy；p<0.001）是与改善BRFS显著相关的唯一因素。sRT前使用68Ga-PSMA PET/CT未观察到这种情况（p = 0.789）。配对分析包括95对有或无PET/CT的前列腺癌患者，基于PET/CT的使用在BRFS上无明显差异（p = 0.884）。
本分析表明，无论是对于整个队列，还是在排除PET阳性淋巴结或远处转移患者后进行配对分析，sRT前使用68Ga-PSMA PET/CT均未改善BRFS。由于在sRT计划中实施68Ga-PSMA PET未使BRFS得到改善，因此sRT不应推迟至68Ga-PSMA PET/CT的最佳“诊断窗口”。
