Impact of long-term androgen deprivation therapy on PSMA ligand PET/CT in patients with castration-sensitive prostate cancer

Abstract

PurposeSince the introduction of PSMA PET/CT with 68Ga-PSMA-11, this modality for imaging prostate cancer (PC) has spread worldwide. Preclinical studies have demonstrated that short-term androgen deprivation therapy (ADT) can significantly increase PSMA expression on PC cells. Additionally, retrospective clinical data in large patient cohorts suggest a positive association between ongoing ADT and a pathological PSMA PET/CT scan. The present evaluation was conducted to further analyse the influence of long-term ADT on PSMA PET/CT findings.MethodsA retrospective analysis was performed of all 1,704 patients who underwent a 68Ga-PSMA-11 PET/CT scan at our institution from 2011 to 2017 to detect PC. Of 306 patients scanned at least twice, 10 had started and continued ADT with a continuous clinical response between the two PSMA PET/CT scans. These ten patients were included in the current analysis which compared the tracer uptake intensity and volume of PC lesions on PSMA PET/CT before and during ongoing ADT.ResultsOverall, 31 PC lesions were visible in all ten patients before initiation of ADT. However, during ongoing ADT (duration 42–369 days, median 230 days), only 14 lesions were visible in eight of the ten patients. The average tracer uptake values decreased in 71% and increased in 12.9% of the PC lesions. Of all lesions, 33.3% were still visible in six patients with a complete PSA response (≤0.1 ng/ml).ConclusionContinuous long-term ADT significantly reduces the visibility of castration-sensitive PC on PSMA PET/CT. If the objective is visualization of the maximum possible extent of disease, we recommend referring patients for PSMA PET/CT before starting ADT.

Prospective study on the effect of short-term androgen deprivation therapy on PSMA uptake evaluated with 68Ga-PSMA-11 PET/MRI in men with treatment-naïve prostate cancer

“…ADT is the gold standard treatment in patients with metastatic prostate cancer. The effect of continuous long-term ADT on reducing the visibility of castration-sensitive prostate cancer lesions on PSMA-PET has already been investigated; however, it is still uncertain if initiation of ADT could interfere with the staging results [17]. According to our preliminary findings, as none of the lesions disappeared during the observational period, ongoing short-term ADT does not represent a contraindication on performing a staging PSMA-PET.…”

Influence of androgen deprivation therapy on PSMA expression and PSMA-ligand PET imaging of prostate cancer patients

“…Although ADT has relevant impact on clinical practice, there is no consensus between imaging experts. We conducted a literature search on PubMed® and Google Scholar® in April 2019 and selected 19 papers (Table 1): 7 in vitro studies [3,4,[16][17][18][19][20], 2 in vivo studies [5,21], 4 prospective clinical studies [8][9][10][11], 2 reviews (clinical [6] and preclinical [7]), 2 retrospective clinical studies [12,13], 1 pilot clinical study [14] and 1 clinical case [15]. Additionally, we found 5 registered clinical trials (NCT03313726 [22], NCT03876912, NCT03860987, EudraCT 2018-004853-26 and EudraCT 2017-002345-29).…”

Initial evaluation of PET/CT with 18F‐FSU‐880 targeting prostate‐specific membrane antigen in prostate cancer patients

“…The effect of treatment on the uptake of PSMA‐targeted probe is not fully elucidated yet. Short‐term androgen deprivation therapy has been reported to increase PSMA expression in castration‐sensitive PC cells, and long‐term androgen deprivation therapy is reported to reduce the visibility of the lesions . In the present patient cohort, cases 1 and 2 received PET/CT with no treatment.…”

“…Short-term androgen deprivation therapy has been reported to increase PSMA expression in castrationsensitive PC cells, 29 and long-term androgen deprivation therapy is reported to reduce the visibility of the lesions. 30 In the present patient cohort, cases 1 and 2 received PET/CT with no treatment. With the increasing number of patients examined with PSMAtargeted probes, many pitfalls are emerging.…”