If the PSA level rises again after treatment of prostate cancer, this may be a possible indication of a relapse (recurrence). PSMA imaging with a modern low-level radioactive marker for PET (positron emission tomography),detects tumor sites and metastases even more precisely than previous methods. Since 2014, the West German Prostate Center has been using this modern and highly sensitive method in cooperation with the Clinic and Polyclinic for Nuclear Medicine at the University Hospital Cologne.
"With the PSMA marker, we can achieve an even better contrast between tumor and healthy tissue," explains Dr. Neubauer from the West German Prostate Center. This is because while conventional imaging with CT,MRI or bone scintigraphy reaches certain limits, the PSMA marker can also detect recurrent tumors with PSA values below 1.0. The sensitivity in the case of very small bone metastases is also significantly better. This benefits not only patients with a recurrence, but also men who are still suspected of having prostate cancer, even though the tissue sample has so far failed to detect a tumor.
The use of a PSMA PET/CT is useful in:
- Patients with an increase in PSA after prostate cancer therapy.
- PSA increase with negative biopsy
- Patients with castration-resistant metastatic prostate cancer.
- Patients with high-risk prostate cancer at initial diagnosis.
The weakly radioactive substance binds exclusively to the protein PSMA (prostate-specific membrane antigen), which is produced in prostate carcinomas and their metastases in concentrations up to ten times higher than in normal prostate cells. In contrast, the protein is only present in very small quantities in men with a healthy prostate. If the radioactively labeled PSMA marker (known as a tracer) is injected into the patient's bloodstream, it accumulates in the tumor tissue and can be visualized using positron emission tomography (PET). The PET examination is performed in the Department of Nuclear Medicine at the University Hospital of Cologne on a modern PET/CT scanner, which is particularly sensitive and requires less radiation exposure than conventional devices.
The examination by means of PSMA PET/CT improves the diagnosis, but also the further therapy planning. This makes it possible to better assess whether a patient with a prostate cancer recurrence should again undergo local treatment such as brachytherapy (internal radiation), external radiation, or systemic treatment such as chemotherapy or hormone therapy. "If we are able to treat local recurrences and metastases even more specifically, this in turn increases the cure or survival rate," Dr. Neubauer emphasizes.
Since November 2014, in cooperation with the Department of Nuclear Medicine at the University Hospital of Cologne, there is also the option to perform lutetium-177-PSMA therapy in patients with castration-resistant, metastatic prostate cancer, in whom all other therapy options (chemotherapy, hormone therapy) have been exhausted.
Current scientific studies:
1 Fanti S, Goffin K, Hadaschik BA et al. Consensus statements on PSMA PET/CT response assessment criteria in prostate cancer. Eur J Nucl Med Mol Imaging. 2021 Feb;48(2):469-476.doi: 10.1007/s00259-020-04934-4. epub 2020 Jul 2. PMID: 32617640;PMCID: PMC7835167.
2 Hofman MS, Lawrentschuk N, FrancisRJ et al: proPSMA Study Group Collaborators. Prostate-specific membrane antigenPET-CT in patients with high-risk prostate cancer beforecurative-intentsurgery or radiotherapy (proPSMA): a prospective, randomised,multicentrestudy. Lancet. 2020 Apr 11;395(10231):1208-1216.doi:10.1016/S0140-6736(20)30314-7. epub 2020 Mar 22. PMID: 32209449.
3 Li R, Ravizzini GC, Gorin MA, Maurer T et al: The use of PET/CT in prostate cancer. Prostate Cancer Prostatic Dis. 2018 Apr;21(1):4-21. doi:10.1038/s41391-017-0007-8.Epub 2017 Dec 11. PMID: 29230009.
4 Dietlein F, Kobe C, Neubauer S, Schmidt M et al: PSA-stratified performance of 18F- and 68Ga-lab eled tracers in PSMA-PET imaging of patients with biochemical recurrence of prostate cancer. J NuclMed. 2017; 58