Preliminary results of a ⁶⁸Ga‐PSMA PET/CT prospective study in prostate cancer patients with occult recurrence: Diagnostic performance and impact on therapeutic decision‐making

Abstract

Background In this prospective study (NCT03443609), we investigated the impact of 68Ga‐PSMA‐11 PET‐CT on the treatment plan and therapeutic response obtained for patients with prostate cancer (PCa) presenting a recurrence with a low rising PSA. Methods One hundred thirty hormone‐naive (PSA < 1.5 ng/mL) patients were enrolled. All patients received radical treatment. PET images were recorded 1 and 2 hours after injection of tracer and interpreted by two independent nuclear physicians. Six months after treatment ended, a PSA assay was requested to evaluate the therapeutic efficacy of the treatment based on PSMA results. Results Data analysis for the first 52 included patients has been completed. 68Ga‐PSMA‐11–positive lesions were detected in 38/52 (73.1%) patients. Ninety‐four lesions were detected as follows, 53/94 in lymph nodes (56.4%), 25/94 in bone (26.6%), and 12/94 into the prostate bed (12.7%). Detection rates were 58%, 81%, and 82% for serum PSA levels lower than 0.25 ng/mL, between 0.25 to ≤ 0.69 ng/mL and 0.70 ng/mL, respectively. As a result of the PSMA PET‐CT, therapeutic management changed in 38/52 patients (73.1%). Patients had undetectable serum PSA levels after treatment guided by 68Ga‐PSMA‐11 PET‐CT results in 10/52 (19.2%) cases and with a PSA decrease of over 60% in 18/52 (34.6%) patients. Conclusion Whilst our patient population presented a very low PSA level, preliminary results of the 68Ga‐PSMA PET‐CT study showed recurrence localization in more than half of the patients and this had a major clinical impact, as it resulted in treatment change in more than half of the patients and a significant decrease in PSA levels in a third of patients.

Clinical impact of PSMA PET in biochemically recurrent prostate cancer; a review of the literature

“…Ultimately 16 studies were included in the review (Tab. 2; [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]). Twelve studies reported outcomes using [ 68 Ga]-PSMA-11 PET, while four studies reported data on other PSMA-tracers.…”

“…The pooled data of all patients included in this review show an overall change of management in 861 of 1899 patients (45%). Nine studies, including 729 patients, reported sufficient data to extract the kind of change in management [20,24,26,27,29,33,36,38,40]. In 332 (46%) of these 729 patients a change in management was seen.…”

The Roach Equation: Value of Old Clinical Tools in the Era of New Molecular Imaging

“…More recent studies in which all patients underwent extended pelvic lymph node dissection appeared to confirm the accuracy of the Roach equation (9). PSMA PET and fluciclovine 18 F PET studies have demonstrated the role of molecular imaging in physician decision making among patients with biochemical recurrence as well as in the upfront setting among patients with intermediate-and high-risk prostate cancer at the time of initial diagnosis (10)(11)(12)(13)(14).…”

(Radio)Theranostic Patient Management in Oncology Exemplified by Neuroendocrine Neoplasms, Prostate Cancer, and Breast Cancer

“…PSMA PET has demonstrated strong impact on therapy planning and clinical decision making with treatment regimen adjustment in 27%-77% of patients [136][137][138][139][140][141][142][143][144] [120]. Since then numerous original research and review articles have pointed out that the PSMA imaging using PET/CT is a sensitive, specific, safe, efficient and reproducible diagnostic method allowing visualization of local disease, lymph node, bone, and visceral organ lesions with high detection rate, and it has positive predictive value [121][122][123][124][125][126][127][128].…”

“…PSMA PET has demonstrated strong impact on therapy planning and clinical decision making with treatment regimen adjustment in 27%-77% of patients [136][137][138][139][140][141][142][143][144] Tc-PSMA scintigraphy has minimally less noise than posttherapy scanning and can be used for imaging follow-up in out-patient setting. GM 5 geometric mean; MIP 5 maximum-intensity projections; p.i.…”