Emmett Louise, van Leeuwen Pim J, Nandurkar Rohan, Scheltema Matthijs J, Cusick Thomas, Hruby George, Kneebone Andrew, Eade Thomas, Fogarty Gerald, Jagavkar Raj, Nguyen Quoc, Ho Bao, Joshua Anthony M, Stricker Phillip
Department of Diagnostic Imaging, St. Vincent's Public Hospital, Sydney, Australia
The Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Sydney, Australia.
J Nucl Med. 2017 Dec;58(12):1972-1976. doi: 10.2967/jnumed.117.196683. Epub 2017 Jul 26.
Ga-PSMA (prostate-specific membrane antigen) PET/CT is increasingly used in men with prostate-specific antigen (PSA) failure after radical prostatectomy (RP) to triage those who will benefit from salvage radiation treatment (SRT). This study examines the value of PSMA-informed SRT in improving treatment outcomes in the context of biochemical failure after RP. We analyzed men with rising PSA after RP with PSA readings between 0.05 and 1.0 ng/mL, considered eligible for SRT at the time of PSMA. For each patient, clinical and pathologic features as well as scan results, including site of PSMA-positive disease, number of lesions, and a certainty score, were documented. Subsequent management, including SRT, and most recent PSA were recorded using medical records. Treatment response was defined as both PSA ≤ 0.1 ng/mL and >50% reduction in PSA. Multivariate logistic regression analysis was performed for association of clinical variables and treatment response to SRT. One hundred sixty-four men were included. PSMA was positive in 62% ( = 102/164): 38 of 102 in the prostatic fossa, 41 of 102 in pelvic nodes, and 23 of 102 distantly. Twenty-four patients received androgen-deprivation therapy (ADT) and were excluded for outcomes analysis. In total, 99 of 146 received SRT with a median follow-up after radiation treatment of 10.5 mo (interquartile range, 6-14 mo). Overall treatment response after SRT was 72% ( = 71/99). Forty-five percent ( = 27/60) of patients with a negative PSMA underwent SRT whereas 55% (33/60) did not. In men with a negative PSMA who received SRT, 85% ( = 23/27) demonstrated a treatment response, compared with a further PSA increase in 65% (22/34) in those not treated. In 36 of 99 patients with disease confined to the prostate fossa on PSMA, 81% ( = 29/36) responded to SRT. In total, 26 of 99 men had nodal disease on PSMA, of whom 61% ( = 16/26) had treatment response after SRT. On multivariate logistic regression analysis, PSMA and serum PSA significantly correlated with treatment response, whereas pT stage, Gleason score, and surgical margin status did not. PSMA PET is independently predictive of treatment response to SRT and stratifies men into a high treatment response to SRT (negative or fossa-confined PSMA) versus men with poor response to SRT (nodes or distant-disease PSMA). In particular, a negative PSMA PET result predicts a high response to salvage fossa radiotherapy.
镓-前列腺特异性膜抗原（PSMA）PET/CT越来越多地用于根治性前列腺切除术后出现前列腺特异性抗原（PSA）失败的男性，以筛选出能从挽救性放射治疗（SRT）中获益的患者。本研究探讨了基于PSMA的SRT在改善根治性前列腺切除术后生化失败情况下治疗效果的价值。我们分析了根治性前列腺切除术后PSA升高且PSA读数在0.05至1.0 ng/mL之间的男性，这些男性在PSMA检查时被认为符合SRT条件。记录了每位患者的临床和病理特征以及扫描结果，包括PSMA阳性疾病的部位、病变数量和确定性评分。使用病历记录后续治疗情况，包括SRT以及最近的PSA值。治疗反应定义为PSA≤0.1 ng/mL且PSA降低>50%。对临床变量与SRT治疗反应的相关性进行多因素逻辑回归分析。共纳入164名男性。PSMA阳性率为62%（n = 102/164）：102例中的38例位于前列腺窝，102例中的41例位于盆腔淋巴结，102例中的23例远处转移。24例患者接受了雄激素剥夺治疗（ADT），并被排除在结局分析之外。总共146例中的99例接受了SRT，放疗后的中位随访时间为10.5个月（四分位间距，6 - 14个月）。SRT后的总体治疗反应率为72%（n = 71/99）。PSMA阴性的患者中有45%（n = 27/60）接受了SRT，而55%（33/60）未接受。接受SRT的PSMA阴性男性中，85%（n = 23/27）显示出治疗反应，而未接受治疗的患者中65%（22/34）PSA进一步升高。在PSMA检查显示疾病局限于前列腺窝的99例患者中的36例中，81%（n = 29/36）对SRT有反应。总共99例男性中有26例在PSMA检查时有淋巴结疾病，其中61%（n = 16/26）在SRT后有治疗反应。多因素逻辑回归分析显示，PSMA和血清PSA与治疗反应显著相关，而pT分期、Gleason评分和手术切缘状态则无相关性。PSMA PET可独立预测SRT的治疗反应，并将男性分为对SRT治疗反应高（PSMA阴性或局限于前列腺窝）与对SRT反应差（淋巴结或远处疾病PSMA）两组。特别是，PSMA PET结果为阴性预示着对挽救性前列腺窝放疗反应良好。
