Clinical impact of PSMA PET/CT in primary prostate cancer compared to conventional nodal and distant staging: a retrospective single center study

Abstract

Background: To evaluate the impact of Gallium-68 [ 68 Ga] labeled prostate specific membrane antigen (PSMA) positron emission tomography (PET)/X-ray computed tomography (CT) compared with conventional imaging on staging and clinical management of men evaluated for primary prostate cancer (PCa). Methods: Men with newly diagnosed biopsy-proven PCa who had been staged with a conventional staging protocol including bone scintigraphy (BS) and additionally underwent [ 68 Ga]PSMA PET/CT, were evaluated retrospectively. Imaging findings from BS, magnetic resonance imaging (MRI) and/or CT were categorized regarding locoregional nodal (N) and distant metastasis (M) status as negative, positive or equivocal before and after addition of the information of PET/CT. Also, the imaging-based level of confidence (LoC) in correct assessment of N and M status was scored. Impact of PET/CT on clinical management was evaluated by the percentage of treatment category changes after PET/CT as determined in the multidisciplinary tumour board. Results: Sixty-four men with intermediate and high-risk PCa were evaluated. With additional information of PET/CT, N status was upstaged in 23%, and downstaged in 9%. M status was upstaged in 13%, and downstaged in 23%. A net increase in LoC of 20% was noted, mainly regarding M status. Treatment category changed from palliative to curative in 9%, and from curative to palliative in 3%. An undecided treatment plan changed to curative in 14%, as well as to palliative in another 9%. In total, a 36% treatment category change was noted. High negative predictive value of PET/CT for M status was indicated by 27 patients that underwent robot-assisted radical prostatectomy and reached postoperative biochemical disease-free status or had a likely other site of disease recurrence. Conclusions: PSMA PET/CT can cause considerable changes in N and M staging, as well as in management compared to conventional staging. Findings of this study support the replacement of BS and CT by PSMA PET/CT in staging primary PCa.

Yüksek Ri̇skli̇ Prostat Kanseri̇nde 68ga-Psma Pet/Bt’ni̇n Tedavi̇ Yöneti̇mi̇ne Etki̇si̇

“…A prospective multicenter study involving 108 newly diagnosed PCa patients was published by Roach et al where PSMA PET affected therapy management in 21% of patients by detection of more extensive disease (14). Moreover, Donjwisk et al concluded that N and M status was upstaged in 23% and 13% of patients and was downstaged in 9% and 23% of patients, which resulted in a 36% treatment change (23). Our results were in concordance with the previous studies.…”

Cancer clinical trial vs real‐world outcomes for standard of care first‐line treatment in the advanced disease setting

“…19 Specifically in prostate cancer the addition of PSMA PET scans were reported to upstage patients with otherwise localised disease in over 10% of cases. 20 More intensive surveillance of early-stage CRC patients can bring forward detection of recurrence by 6-7 months. 21,22 Lead-time bias as a result of earlier detection of metastatic disease, may also mean fitter patients with less advanced disease are being treated, who potentially would derive more benefit from the initial first-line treatment.…”

“…Recent changes in practice across many solid tumour types include the increasing adoption of FDG PET, which is widely available in oncology practice, and can upstage a significant number of patients 19 . Specifically in prostate cancer the addition of PSMA PET scans were reported to upstage patients with otherwise localised disease in over 10% of cases 20 . More intensive surveillance of early‐stage CRC patients can bring forward detection of recurrence by 6‐7 months 21,22 .…”

Estimating the Potential of Radiomics Features and Radiomics Signature from Pretherapeutic PSMA-PET-CT Scans and Clinical Data for Prediction of Overall Survival When Treated with 177Lu-PSMA

“…Radiomics features (RFs) extracted from base-line prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PSMA-PET/CT) scans, together with patient-specific clinical parameters, can facilitate diagnosis and treatment of prostate disease [ 1 , 2 ]. As PSMA-PET/CT is gaining importance in the diagnosis and treatment planning of patients with advanced prostate cancer [ 3 ], obtaining additional information using radiomics features is of great interest, especially in the use of therapy planning [ 4 ]. Within the concept of theranostics, using the same ligand to PSMA either labeled with the positron emitter gallium-68 ( 68 Ga) or the therapeutic beta-emitter lutethium-177 ( 177 Lu) [ 5 ], this question is of special interest as one may speculate that the distribution of the 68 Ga-PSMA may predict therapeutic use of 177 Lu-PSMA in a symbiotic way.…”