Target volume delineations for prostate cancer (PCa) salvage radiotherapy (SRT) after radical prostatectomy are usually drawn in the absence of visibly recurrent disease. 68Ga-labeled prostate-specific membrane antigen (PSMA-11) PET/CT detects recurrent PCa with sensitivity superior to standard-of-care imaging at serum prostate-specific antigen (PSA) values low enough to affect target volume delineations for routine SRT. Our objective was to map the recurrence pattern of PCa early biochemical recurrence (BCR) after radical prostatectomy with 68Ga-PSMA-11 PET/CT in patients with serum PSA levels of less than 1 ng/mL, determine how often consensus clinical target volumes (CTVs) based on the Radiation Therapy Oncology Group (RTOG) guidelines cover 68Ga-PSMA-11 PET/CT-defined disease, and assess the potential impact of 68Ga-PSMA-11 PET/CT on SRT. Methods: This was a post hoc analysis of an intention-to-treat population of 270 patients who underwent 68Ga-PSMA-11 PET/CT at 4 institutions for BCR after prostatectomy without prior radiotherapy at a PSA level of less than 1 ng/mL. RTOG consensus CTVs that included both the prostate bed and the pelvic lymph nodes were contoured on the CT dataset of the PET/CT image by a radiation oncologist masked to the PET component. 68Ga-PSMA-11 PET/CT images were analyzed by a nuclear medicine physician. 68Ga-PSMA-11-positive lesions not covered by planning volumes based on the consensus CTVs were considered to have a potential major impact on treatment planning. Results: The median PSA level at the time of 68Ga-PSMA-11 PET/CT was 0.48 ng/mL (range, 0.03-1 ng/mL). One hundred thirty-two of 270 patients (49%) had a positive 68Ga-PSMA-11 PET/CT result. Fifty-two of 270 (19%) had at least one PSMA-11-positive lesion not covered by the consensus CTVs. Thirty-three of 270 (12%) had extrapelvic PSMA-11-positive lesions, and 19 of 270 (7%) had PSMA-11-positive lesions within the pelvis but not covered by the consensus CTVs. The 2 most common 68Ga-PSMA-11-positive lesion locations outside the consensus CTVs were bone (23/52, 44%) and perirectal lymph nodes (16/52, 31%). Conclusion: Post hoc analysis of 68Ga-PSMA-11 PET/CT implied a major impact on SRT planning in 52 of 270 patients (19%) with PCa early BCR (PSA < 1.0 ng/mL). This finding justifies a randomized imaging trial of SRT with or without 68Ga-PSMA-11 PET/CT investigating its potential benefit on clinical outcome.

中文翻译：

---

前列腺癌根治术后前列腺癌生化复发的68Ga-PSMA-11 PET / CT定位在PSA水平低于1.0 ng / mL的患者中：对挽救性放疗计划的影响。

通常在不存在明显复发性疾病的情况下绘制前列腺癌根治术后前列腺癌（PCa）抢救放疗（SRT）的目标体积。68Ga标记的前列腺特异性膜抗原（PSMA-11）PET / CT在血清前列腺特异性抗原（PSA）值低到足以影响常规SRT的目标体积勾画时，可检测出复发性PCa，其敏感性优于医疗标准影像学。我们的目标是绘制血清PSA低于1 ng / mL的患者行68Ga-PSMA-11 PET / CT根治性前列腺切除术后PCa早期生化复发（BCR）的复发图谱，确定共识临床目标量的频率（根据放射治疗肿瘤学小组（RTOG）指南的CTV）涵盖了68Ga-PSMA-11 PET / CT定义的疾病，并评估了68Ga-PSMA-11 PET / CT对SRT的潜在影响。方法：这是一项对270例意向性治疗人群的事后分析，这些患者在4例前列腺癌切除术后未经事先放疗且PSA浓度低于1 ng / mL的BCR机构接受了68Ga-PSMA-11 PET / CT的患者。包括前列腺床和骨盆淋巴结在内的RTOG共识CTV由遮盖PET成分的放射肿瘤医师在PET / CT图像的CT数据集上绘制轮廓。核医学医师对68Ga-PSMA-11 PET / CT图像进行了分析。基于共识CTV的计划量未涵盖的68Ga-PSMA-11-阳性病变被认为对治疗计划具有潜在的重大影响。结果：68Ga-PSMA-11 PET / CT时的PSA中位数为0.48 ng / mL（范围0.03-1 ng / mL）。270例患者中的132例（49％）的68Ga-PSMA-11 PET / CT结果为阳性。270个中的52个（19％）至少有一个PSMA-11-阳性病变未被共识CTV覆盖。270例中有33例（12％）有盆腔外PSMA-11-阳性病变，而270例中有19例（7％）有骨盆内PSMA-11-阳性病变，但未被共识CTV覆盖。共有CTV以外的2个最常见的68Ga-PSMA-11-阳性病变部位是骨骼（23/52，44％）和直肠周围淋巴结（16/52，31％）。结论：事后对68Ga-PSMA-11 PET / CT的分析表明，对270例PCa早期BCR（PSA <1.0 ng / mL）患者中的52例（19％）的SRT计划产生了重大影响。这一发现证明了对有或没有68Ga-PSMA-11 PET / CT的SRT进行随机影像学试验的理由，以研究其对临床结局的潜在益处。270例中有33例（12％）有盆腔外PSMA-11-阳性病变，而270例中有19例（7％）有骨盆内PSMA-11-阳性病变，但未被共识CTV覆盖。共有CTV以外的2个最常见的68Ga-PSMA-11-阳性病变部位是骨骼（23/52，44％）和直肠周围淋巴结（16/52，31％）。结论：事后对68Ga-PSMA-11 PET / CT的分析表明，对270例PCa早期BCR（PSA <1.0 ng / mL）患者中的52例（19％）的SRT计划产生了重大影响。这一发现证明了对有或没有68Ga-PSMA-11 PET / CT的SRT进行随机影像学试验的理由，以研究其对临床结局的潜在益处。270例中有33例（12％）有盆腔外PSMA-11-阳性病变，而270例中有19例（7％）有骨盆内PSMA-11-阳性病变，但未被共识CTV覆盖。共有CTV以外的2个最常见的68Ga-PSMA-11-阳性病变部位是骨骼（23/52，44％）和直肠周围淋巴结（16/52，31％）。结论：事后对68Ga-PSMA-11 PET / CT的分析表明，对270例PCa早期BCR（PSA <1.0 ng / mL）患者中的52例（19％）的SRT计划产生了重大影响。这一发现证明了对有或没有68Ga-PSMA-11 PET / CT的SRT进行随机影像学试验的理由，以研究其对临床结局的潜在益处。共有CTV以外的2个最常见的68Ga-PSMA-11-阳性病变部位是骨骼（23/52，44％）和直肠周围淋巴结（16/52，31％）。结论：事后对68Ga-PSMA-11 PET / CT的分析表明，对270例PCa早期BCR（PSA <1.0 ng / mL）患者中的52例（19％）的SRT计划产生了重大影响。这一发现证明了对有或没有68Ga-PSMA-11 PET / CT的SRT进行随机影像学试验的理由，以研究其对临床结局的潜在益处。共有CTV以外的2个最常见的68Ga-PSMA-11-阳性病变部位是骨骼（23/52，44％）和直肠周围淋巴结（16/52，31％）。结论：事后对68Ga-PSMA-11 PET / CT的分析表明，对270例PCa早期BCR（PSA <1.0 ng / mL）患者中的52例（19％）的SRT计划产生了重大影响。这一发现证明了对有或没有68Ga-PSMA-11 PET / CT的SRT进行随机影像学试验的理由，以研究其对临床结果的潜在益处。