In France, prostate cancer is the most common cancer in men over 50 years of age (nearly 50,000 new cases per year) and is the third leading cause of cancer-related death in men (approximately 9,000 deaths per year).~Among patients who have undergone a curative treatment strategy for localized prostate cancer, between 27% and 53% of them will have a biochemical recurrence within 10 years.~Biochemical recurrence is defined as :~After total prostatectomy by the persistence of a detectable PSA or the reappearance of a detectable PSA above 0.2 ng/ml after a more or less long period of undetectability.~After conservative treatment (radiotherapy or brachytherapy) by an increase in PSA above a threshold set at nadir +2 ng/ml Biological recurrence precedes the occurrence of symptomatic metastases by an average of 7-8 years.~Currently, after prostatectomy, when the PSA is < 1 ng/mL, no imaging test is recommended for the assessment of recurrence (grade A recommendation).~The sensitivity of currently available tests does not provide sufficiently discriminating information for this PSA value.~Multiparametric MRI performs well in detecting local recurrence, particularly in the case of PSA > 1 ng/mL (sensitivity of 98%, specificity of 94% for the detection of 5 mm lesions).~18F-choline positron emission tomography (PET-choline) is of interest in the detection of distant lymph node and/or visceral recurrences; indeed, PET-choline has proven its superiority in detection compared with conventional examinations, particularly for PSA values above 2ng/ml with a detection rate of up to 90%.~However, the performance of this examination remains dependent on the PSA level and is low when the PSA level is below 1 ng/ml (sensitivity around 5-24% for a PSA below 1 ng/ml).~The performance of PET-choline is optimised for low PSA by taking into account the PSA doubling time and velocity.~Recently, prostate specific membrane antigen ligand positron emission tomography (PET-PSMA) has emerged as the most promising new molecular imaging modality for the management of prostate cancer.~Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein selectively overexpressed in 90-100% of prostate cancer lesions, as well as in metastatic lymph nodes and bone metastases, making it an ideal target for molecular imaging of prostate cancer.~This tracer appears to perform better than other imaging modalities, particularly for low PSA values, with a detection rate of 50% for a PSA level below 0.5 ng/ml compared to 5-20% with PET-choline. Indeed, a 2019 meta-analysis evaluating the value of PSMA-PET in patients with biologic recurrence of prostate adenocarcinoma reported detection rates of 45%, 59%, 75% and 95% for PSA levels < 0.5 ng/mL, between 0.5 and 0.9 ng/mL, between 1 and 1.9 ng/mL and 2 ng/mL respectively.~The aim of this study is to evaluate PSMA ligand PET for the detection of occult biological recurrence in patients with prostatic neoplasia referred to the Brest University Hospital .
The aim of this study is to evaluate PSMA-PET for the detection of occult biological recurrence in patients with prostatic cancer referred to the Brest University Hospital.