Purpose

Conventional imaging rarely localizes the site(s) of prostate cancer recurrence in patients undergoing evaluation for salvage radiation therapy (sRT) after radical prostatectomy (RP). LOCATE (NCT02680041) was a prospective, multicenter study investigating the impact of ¹⁸F-fluciclovine positron emission tomography and computed tomography (PET/CT) on the management of patients with biochemical recurrence of prostate cancer after curative-intent radiation or RP and negative or equivocal conventional imaging. Our objective was to determine the impact of ¹⁸F-fluciclovine PET/CT on treatment decisions for men planning to undergo sRT for biochemical recurrence post-RP.

Methods and Materials

We conducted a subgroup analysis of post-RP patients enrolled in LOCATE who were planning to undergo sRT with or without hormonal therapy based on prescan documentation. ¹⁸F-Fluciclovine PET/CT was performed according to standardized procedures. The treatment plan postscan was compared with the prescan plan, and Fisher exact test was used to determine the impact of prescan prostate-specific antigen (PSA) and Gleason sum (GS) on positivity and anatomic patterns of uptake.

Results

A total of 114 patients (median prescan PSA 0.42 [interquartile range, 0.3-1.1] ng/mL) met selection criteria (54% of patients in LOCATE). Forty-eight (42%) had ¹⁸F-fluciclovine-avid lesions. Twelve patients (11%) had positive findings only in the prostate bed, 24 (21%) had positivity only in the pelvis (prostate bed or pelvic nodes), and 24 (21%) had extrapelvic findings. PSA >0.5 ng/mL and GS ≥8 were associated with a higher risk of extrapelvic positivity (P < .05).

Postscan, 55 (48%) patients had a management change; 37 (32%) had a change in overall treatment approach (ie, omission of sRT); and 18 (16%) had sRT target modification.

Conclusions

¹⁸F-Fluciclovine PET/CT is positive in nearly half of patients planning to undergo post-RP sRT with negative/equivocal conventional imaging, with findings frequently leading to changes in management. PSA >0.5 ng/mL and GS ≥8 are associated with a higher risk of extrapelvic positive findings.

中文翻译：

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根治性前列腺切除术后生化复发前列腺癌患者的 18F-氟氯乙烯正电子发射断层扫描和计划接受挽救性放射治疗：来自 LOCATE 的结果。

目的

在接受根治性前列腺切除术 (RP) 后接受挽救性放射治疗 (sRT) 评估的患者中，传统成像很少定位前列腺癌复发的部位。LOCATE (NCT02680041) 是一项前瞻性、多中心研究，旨在研究¹⁸ F-氟氯霉素正电子发射断层扫描和计算机断层扫描 (PET/CT) 对治疗性放疗或 RP 后前列腺癌生化复发患者的治疗和阴性或模棱两可的传统成像。我们的目标是确定¹⁸ F-fluciclovine PET/CT 对计划接受 sRT 以治疗 RP 后生化复发的男性治疗决策的影响。

方法和材料

我们对参加 LOCATE 的 RP 后患者进行了亚组分析，这些患者计划根据扫描前记录进行 sRT 联合或不联合激素治疗。¹⁸ F-氟氯霉素 PET/CT 根据标准化程序进行。将扫描后治疗计划与扫描前计划进行比较，并使用 Fisher 精确检验来确定扫描前前列腺特异性抗原 (PSA) 和 Gleason sum (GS) 对阳性和解剖摄取模式的影响。

结果

共有 114 名患者（中位扫描前 PSA 0.42 [四分位距，0.3-1.1] ng/mL）符合选择标准（54% 的患者在 LOCATE）。48 个 (42%) 有^{18 个}F-fluciclovine-avid 病变。12 名患者 (11%) 仅在前列腺床中有阳性结果，24 名 (21%) 仅在骨盆（前列腺床或盆腔淋巴结）中有阳性结果，24 名 (21%) 有盆腔外发现。PSA > 0.5 ng/mL 和 GS ≥ 8 与较高的盆腔外阳性风险相关 ( P < .05)。

扫描后，55 (48%) 名患者进行了管理变更；37 (32%) 名患者的整体治疗方法发生了变化（即省略了 sRT）；和 18 (16%) 有 sRT 目标修改。

结论

¹⁸ F-Fluciclovine PET/CT 在计划接受 RP 后 sRT 且常规成像阴性/模棱两可的近一半患者中呈阳性，其发现经常导致管理发生变化。PSA > 0.5 ng/mL 和 GS ≥8 与较高的盆腔外阳性结果风险相关。