The PSMA PET Scan is changing the way doctors decide what treatments to recommend for prostate cancer.
Accurate assessment of a cancer spread is essential.
Until now, physicians estimated the likelihood of prostate cancer metastasis using the Gleason Score and PSA number. Standard body and bone scans were also used to locate metastasis (mets), unfortunately these scans were suboptimal, often overlooking spread or failing to distinguish prostate cancer from other lesions. A new technology, the PSMA PET scan allows doctors to specifically detect prostate cancer metastases much earlier and more accurately than older scans. The PSMA PET scan can detect metastatic areas of prostate cancer in patients with PSA levels as low as 0.2! This means that doctors can be more confident in their treatment recommendations and patients can be treated at the earliest sign of metastasis. This new technology will revolutionize how prostate cancer is treated.
What is the PSMA PET Scan?
PSMA (prostate specific membrane antigen) is present on the surface of prostate cancer cells and new molecular substances called ligands can be synthesized that “stick to” PSMA. When the radioactive ligands are injected into the bloodstream they float around until they attach to a prostate cancer cell. These PSMA “hot spots” light up on the scan, revealing the specific location of the prostate cancer.
At Least Three Types of Patients Can Benefit from PSMA PET Scans:
Newly Diagnosed (TEAL and AZURE): Men with TEAL (Intermediate-Risk) or AZURE (High-Risk) prostate cancer are at risk for metastatic diseases. A PSMA PET scan is the best way to determine if mets are present. When mets are absent, doctors might be able to consider using less TIP or forgoing TIP altogether.
PSA Relapse (INDIGO): When there is a rising PSA after surgery or radiation the question is: “Where is the recurrent cancer located?” The PSMA PET scan can accurately show where the new mets are. Depending on the location and extent of spread, salvage treatment with radiation, TIP, or in certain cases, even active surveillance can be considered. Typically, PSMA PET is an option if the post prostatectomy PSA is ≥ 0.2 and rising and if the post radiation PSA is ≥ 1.0.
Metastatic Disease (ROYAL): Periodic, sequential scanning enables doctors to accurately judge the extent of disease and whether treatment with systemic therapy (TIP, Chemo or Immunotherapy) is working. If the disease is progressing, it is advantageous to detect this as quickly as possible (using the PSMA PET scan) so treatment can be changed to a more successful approach.
Keep in mind that men with confirmed Gleason 6 (SKY) prostate cancer are not likely to benefit from a PSMA PET scan. We know SKY does not spread so for a patient with confirmed Low-Risk prostate cancer the cost, time, money, and exposure to radiation are unjustified.
How to Get a PSMA PET Scan
Though FDA approval is pending, many men are accessing this technology through ongoing clinical trials. The clinical trial will outline the inclusion and exclusion criteria. Visit clinicaltrials.gov for availability. Alternatively, for those with the sufficient financial resources to travel, the PSMA PET scans can be obtained in Australia or Germany.
What is it like to get a psma scan?
A PSMA PET scan, like other types of scans, is an outpatient procedure that takes about two hours. At the imaging center the patient is injected with a radiotracer that takes about an hour to be absorbed. Once the radiotracer has been absorbed the patient is ready to begin imaging. The patient will be placed in a CT scan for about 20 to 30 minutes. Results are typically ready within a couple days.
What are the Drawbacks of PSMA?
While this new technology is an incredible advancement over older scans, there are some drawbacks of note.
- Ten percent of men with prostate cancer don’t express PSMA. These patients will need to use scans other than the PSMA PET scan to determine their cancer’s spread.
- This technology is so new that we don’t yet know the optimal frequency of getting PSMA PET scans. Annual follow-up is common for scanning, so until shown otherwise, PSMA PET scans will be a yearly occurrence. The frequency of the scan is matter of convenience as well as something to take into account financially.
- PSMA PET scans expose patients to radiation. Radiation exposure is something to consider while receiving any type of periodic scan, that being said, PSMA PET scan has less radiation exposure than older scans.
- Like many other scans, the PSMA PET scan also requires contrast. Inform your radiologist of your medical history and any potential allergies that may be an issue.
- The PSMA PET scan is pending FDA approval. This means accessing the scan can be difficult financially and logistically.
The Promise of PSMA PET Scans
Knowing the exact location of the cancer is a huge leap forward. This technology is so valuable that some men may want to consider obtaining the scan through a clinical trial or by traveling outside the country. The new knowledge PSMA PET scans allows for treatment recommendations to be personalized based on each individual’s circumstances.
If you can afford it, and are not concerned with radiation, wouldn’t a PSMA PET Scan be the better choice for an initial scan than an mpMRI (assuming the presence of a prostate nodule, PSA over 4) and prior to first biopsy?
In certain cases the PSMA PET scan might be a reasonable alternative to MRI.