Newer tests like the prostate-specific membrane antigen (PSMA) PET scan may be more accurate than conventional alternatives for detecting metastatic prostate cancer.

Metastatic prostate cancer is when the cancer has spread beyond the prostate gland to other parts of your body, such as the bones, lymph nodes, and distant organs.

Prostate cancer is easier to treat before it spreads. However, treatments for metastatic disease can help improve survival and quality of life.

Conventional tests for metastatic prostate cancer have limited accuracy, which may contribute to underdiagnosis and under-treatment.

A newer test known as the PSMA PET scan may have several benefits for metastatic prostate cancer.

“With FDA approval [in 2020], this test will be a game-changer for men with high risk disease,” Dr. Louis Potters told Healthline. Potters is the deputy physician-in-chief of Northwell Health Cancer Institute in Lake Success, New York.

“This test… may have a huge impact on the type of therapy that would be most effective [for them].”

Keep reading to learn more about how the PSMA PET scan may improve metastatic prostate cancer diagnosis.

If a doctor suspects you might have prostate cancer, they may order one or more of the following tests:

  • Digital rectal exam (DRE): A doctor inserts a lubricated finger into your rectum to feel for hard areas or bumps on your prostate gland that might be cancer.
  • Prostate-specific antigen (PSA) blood test: This blood test measures your level of PSA, a protein produced in your prostate gland. High PSA levels may indicate prostate cancer.
  • Prostate biopsy: A urologist uses a small needle to collect tissue samples from your prostate. These samples are examined under a microscope for cancer cells.
  • Imaging test: Magnetic resonance imaging (MRI) or a transrectal ultrasound (TRUS) may be performed before, during, or after a biopsy to help locate abnormal tissue in the prostate.

The results of these tests can help a doctor diagnose prostate cancer and assess your risk of metastatic disease.

If a doctor suspects metastasis, they’ll order imaging tests to check for tumors in your lymph nodes, other organs, and bones.

Doctors have conventionally ordered a combination of imaging tests to check for metastatic prostate cancer, including:

  • a CT or MRI scan, to check for metastases in your lymph nodes and other organs
  • a bone scan, to check for metastases in your bones

Although these tests provide more information than a PSA blood test and biopsy alone, they have limited accuracy.

“Phase III, randomized studies have shown that PSMA PET-CT is superior to conventional radiology studies, such as nuclear medicine bone scan, CT, or MRI, in detecting metastatic disease,” said Dr. Michael Feuerstein, Chief of Urology at New York Presbyterian-Westchester.

“This is important in determining your prognosis and the appropriate treatment recommendations.”

The PSMA PET scan is an imaging test that uses a special dye with radioactive tracers to make prostate cancer cells show up more clearly.

In late 2020 and in 2021, the Food and Drug Administration approved two tracers for this test:

  • Gallium 68 PSMA-11 (GA-68 PSMA-11)
  • Pylarify (piflufolastat F 18, 18F–DCFPyL)

These tracers bind to prostate-specific membrane antigen (PSMA), a protein that’s found in high levels on prostate cancer cells. This makes prostate cancer cells appear more clearly on a PET-CT or PET-MRI scan.

A doctor may order a PSMA PET scan if you recently received a diagnosis of prostate cancer and they suspect the cancer may have already spread.

They may also recommend a PSMA PET scan if you’ve already undergone surgery or radiation to treat prostate cancer, but the cancer remains detectable or appears to have returned.

“Patients should ask their doctor if they are suitable candidates for PSMA PET-CT at the time of prostate cancer diagnosis or suspected prostate cancer recurrence,” said Feuerstein.

“The cost may vary by hospital or geographic region. However, the cost should be weighed against the benefit of more accurate cancer staging and treatment recommendations.”

Early testing for prostate cancer can improve the likelihood of diagnosing cancer at an earlier stage. This means you can start treatment earlier, increasing your chances of curing the cancer.

A more accurate diagnosis can also help determine the best treatment approach.

“Improved staging at the time of prostate cancer diagnosis or suspected prostate cancer recurrence will ensure that you receive the proper treatment and are not under- or over-treated,” Feuerstein explained.

For instance, if you have prostate cancer that hasn’t yet spread, a doctor may recommend surgery to remove your prostate gland, radiation therapy to kill cancer cells, or a combination.

If you have metastatic prostate cancer, they may prescribe more invasive treatments, such as hormone therapy, chemotherapy, and medications that target your immune system.

PSMA PET scans can help people with metastatic prostate cancer get earlier and more accurate diagnoses. This may help you avoid unnecessary surgery and begin hormone therapy earlier.

Researchers have been developing new treatments that target PSMA. This is the same protein detected by the PSMA PET scan that is elevated in people with prostate cancer.

“An exciting new development is PSMA-directed therapies for treating men with metastatic disease that no longer responds to androgen-deprivation therapy or chemotherapy,” said Feuerstein.

“A recent phase III, randomized trial demonstrated improved overall survival in men treated with lutetium-labeled PSMA-617, a [radioactive substance] that seeks out PSMA-expressing prostate cancer cells and delivers radiation that destroys the cancer cells,” he explained.

Another 2021 study found that lutetium-labeled PSMA-617 improved progression-free survival and overall survival compared to other metastatic prostate cancer treatments in people whose cancer is resistant to hormone therapy.

Can a person live 10 years with metastatic prostate cancer?

The life expectancy for someone with metastatic prostate cancer will differ for each individual. Research suggests the 5-year relative survival rate is 32% in the United States.

Can you beat metastatic prostate cancer?

There’s no cure for metastatic prostate cancer. However, treatments are available to help stop or slow the progression of the cancer and to increase your life expectancy.

Can you have stage 4 prostate cancer with no symptoms?

In most cases, stage 4 prostate cancer will cause symptoms depending on where the cancer has spread. For instance, if the cancer has spread to your bones, you may feel bone pain. If it affects your bladder, you may experience changes in urinary habits, such as peeing more often.

The PSMA PET scan is a new test for metastatic prostate cancer. It locates the protein PSMA throughout the body, which is found in high levels on prostate cancer cells.

Compared with more conventional tests, it appears to be more accurate at diagnosing prostate cancer that has spread to the lymph nodes, other organs, or bones.

New treatments also seek to target PSMA-expressing prostate cancer cells. The combination of improved diagnosis and new medications may lead to improved treatment of the disease and improved outcomes.