Finding advanced prostate cancers
These screening tools help diagnose intermediate and high-risk cancers.
- Reviewed by Howard E. LeWine, MD, Chief Medical Editor, 天博体育 Publishing; Editorial Advisory Board Member, 天博体育 Publishing
About four in 10 prostate cancer cases are categorized as low-risk, meaning they’re slow-growing and confined to the prostate gland. In most cases, low-risk patients follow active surveillance, a wait-and-see approach during which the cancer is monitored for changes, and treatment options are explored if it becomes more active.
In comparison, intermediate and high-risk cancers usually require immediate treatments like hormone therapy, radiation, or surgery. (Active surveillance initially may be followed for some intermediate cancers.)
For men who choose prostate cancer screening, it begins with measuring prostate-specific antigen (PSA) in the blood. A PSA level of less than 4 nanograms per milliliter (ng/mL) means a man is unlikely to have cancer. A level of 10 ng/mL or higher usually triggers additional testing. Levels in the middle (between 4 ng/mL and 10 ng/mL) often can be monitored with repeat PSA tests or other diagnostic procedures.
However, a man with a low PSA can still have prostate cancer. And many men with abnormal levels either don’t have cancer or have low-risk cancer that won’t affect their quality of life or longevity.
That’s why scientists continue to explore additional diagnostic strategies beyond PSA testing to identify men who might not immediately need a biopsy versus men who should have biopsies because they are more likely to have intermediate or high-risk cancer. Here are the tests doctors currently use.
Free PSA
PSA circulates in the blood in two forms — bound to other proteins or unbound (also called “free”). A regular PSA test measures both bound and unbound PSA, known as total PSA. In comparison, a free PSA test measures only unbound PSA. This test, often done along with a regular PSA test, calculates free PSA as a percentage of total PSA.
Many urologists measure free PSA in patients with a total PSA level between 4 ng/ml and 10 ng/ml. A lower percentage of free PSA suggests a higher risk of cancer. Most doctors recommend biopsies if free PSA levels are 15% or lower. Prostate cancer is less likely if the free PSA level is higher than 25%.
Artificial intelligence and prostate cancer diagnosisArtificial intelligence (A.I.) is making prostate cancer diagnosis more precise and efficient. Here are two ways it does that. Working with MRI. Here’s how the integration of A.I. and MRI works: After a completed MRI scan, the resulting images are run through A.I. software that measures the volume of the prostate gland and identifies suspicious areas. The software assesses visible features, such as brightness and shadows, as well as those invisible to the human eye. When finished, the software creates a “map” on the image showing where cancer might lie. It provides a Prostate Imaging Reporting and Data System (PI-RADS) score to indicate how likely a suspicious area represents a significant cancer. PI-RADS scores range from 1 (most likely not cancer) to 5 (very suspicious). This use of A.I. aids the radiologist in identifying areas of possible cancer more accurately and quickly and helps determine potential treatment options. Examining biopsies. Paige Prostate is an FDA-approved A.I.-based software program to help increase the accuracy and speed of examining biopsies. Typically, tissue samples from a biopsy are taken from many locations in the prostate and then examined under a microscope by a pathologist. The pathologist determines whether the sample contains cancer cells and, if so, assigns a score to indicate the aggressiveness of the cancer cells. However, this process can be challenging, particularly when there is only a small amount of cancer. The Paige Prostate software helps by analyzing a digital copy of the prostate biopsy samples and identifying areas with the highest likelihood of harboring cancer. This can assist pathologists by flagging areas they should examine in more detail and saving them time finding those areas during their initial review. |
Prostate Health Index (PHI)
The PHI calculates prostate cancer risk using total PSA, free PSA, and proPSA (a subcategory of free PSA) results. Research suggests that men who have a high total PSA and proPSA — but low free PSA — are more likely to have more aggressive prostate cancer.
Urine tests
The prostate gland can shed biological traces of cancer into urine, which urine tests can identify and measure. The tests can be used with an MRI to help determine the need for a biopsy. A new urine test, called MyProstateScore 2.0, takes a different approach and looks for activity of 18 specific genes linked with high-risk tumors. In a study published online April 18, 2024, by JAMA Oncology, researchers applied the 18-gene test to urine samples of more than 800 men with elevated PSA levels who had biopsies and compared the results. The test correctly identified 95% of intermediate cancers and 99% of high-risk cancers.
Imaging technology
MRI produces a high-resolution image of the prostate gland. Cancerous tissue has magnetic properties that differ from normal tissue, and an MRI scan can capture these disparities.
If the scan reveals the possibility of cancer, the detailed image can help the doctor determine the tumor’s size and which part of the prostate should be biopsied, ensuring a more accurate diagnosis.
Two new FDA-approved imaging technologies may help identify cancer that MRI can’t always detect.
With the first, you receive an injection of a radioactive agent called fluciclovine F18 (Axumin). You then undergo a scan with positron emission tomography (PET) and CT. Prostate cancer cells absorb the agent more rapidly than healthy cells, so it concentrates in these specific cells, which are highlighted under a PET and CT scan.
The other test uses an injectable radioactive agent called gallium-68 PSMA-11 (Illuccix, Locametz) with a PET scan. Once injected, the agent binds to prostate-specific membrane antigen (PSMA), which occurs in high levels in prostate cancer cells. The agent makes PSMA-positive lesions in the prostate easier to see on the PET scan.
Image: © Md Saiful Islam Khan/Getty Images
About the Author
Matthew Solan, Executive Editor, Harvard Men's Health Watch
About the Reviewer
Howard E. LeWine, MD, Chief Medical Editor, 天博体育 Publishing; Editorial Advisory Board Member, 天博体育 Publishing
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