Prostate-specific antigen (PSA) blood testing receives high marks as an effective way to monitor disease activity in men diagnosed with prostate cancer. Yet, as a screening tool for prostate cancer, PSA testing is problematic.
PSA naturally tends to increase as men get older, but levels that get too high may suggest prostate cancer. A PSA level of less than 4 nanograms per milliliter (ng/mL) is often reassuring, unless there has been a sudden jump from a much lower number. Many doctors consider a total PSA level higher than 10 ng/mL as the threshold for getting a biopsy to check for cancer.
But what if you have a PSA level between 4 ng/mL and 10 ng/mL?
A man with a PSA reading in this range still can have prostate cancer, but other causes like an enlarged or inflamed prostate are just as likely. Should you get a biopsy or wait?
Nowadays, men with mild to moderately elevated PSA levels can get additional noninvasive tests before going straight to a biopsy. To help decide on next steps, it’s best to consult with a urologist. “Exploring these options with a urologist can help men avoid an unnecessary and uncomfortable procedure that has potential side effects,” says Dr. Marc Garnick, a urologic cancer expert with Harvard-affiliated Beth Israel Deaconess Medical Center.
Here’s a look at these tests and how they can guide you and your doctor in determining your need for a biopsy.
PSA-based blood tests
Variations of PSA tests can help your doctor make a more accurate estimate of your prostate cancer risk.
Free PSA. PSA circulates in the blood in two forms — either bound to other proteins or unbound (also called “free”). A regular PSA test measures both bound and unbound PSA, which together is known as total PSA. In comparison, a free PSA test measures only unbound PSA.
This test, which is often done along with a regular PSA test, calculates free PSA as a percentage of total PSA. A lower percentage 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%.
Prostate Health Index (PHI). The PHI uses the numbers from total PSA, free PSA, and proPSA (a subcategory of free PSA) to calculate prostate cancer risk. 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.
Magnetic resonance imaging
Magnetic resonance imaging (MRI) uses a large magnet and a radio-wave transmitter to create a high-resolution image of your entire prostate gland. Cancerous tissue has different magnetic properties than normal tissue, and an MRI scan can capture these differences. This helps determine the size and location of tumors.
“If your MRI doesn’t suggest the presence of cancer, some doctors recommend that you continue to monitor your PSA levels,” says Dr. Garnick. “If the MRI shows the possibility of cancer, the image can help determine which part of the prostate should be biopsied.”
Even if your MRI scan is normal, your doctor may still suggest a biopsy if other test results are inconclusive, such as a free PSA number between 15% and 25%.
|Keeping tabs on prostate cancerCancer specialists often use MRI and urine biomarker measurements, along with PSA testing, to follow men who have chosen active surveillance — that is, they monitor a low-risk prostate cancer for changes rather than having immediate treatment. “Periodic testing can indicate if the cancer has become more aggressive and whether a biopsy should be done,” says Dr. Marc Garnick, a urologic cancer expert with Harvard-affiliated Beth Israel Deaconess Medical Center.|
The prostate gland can shed biological traces of cancer into urine. Two urine tests may be used to look for and measure these prostate cancer biomarkers. “The tests can be used in conjunction with MRI to help determine the need for a biopsy,” says Dr. Garnick.
PCA3. Normal prostate cells produce low levels of a protein known as PCA3. When prostate cells become cancerous, the PCA3 gene that makes this protein becomes overactive and releases greater amounts of PCA3 in the urine.
HOXC6 and DLX1 mRNA (SelectMDx urine test). Elevated levels of these two urine biomarkers are associated with prostate cancer that is more likely to spread. Very low levels in the urine suggest less aggressive cancer and provide additional comfort in delaying prostate biopsy.
Bible verses for today’s meditation and inspiration: Matthew E. McLaren
“Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable–if anything is excellent or praiseworthy–think about such things.” – Philippians 4:8
“Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours.” – Mark 11:24
“Anxiety weighs down the heart, but a kind word cheers it up.” – Proverbs 12:25
“Who of you by worrying can add a single hour to your life?” – Luke 12:25
“For I know the plans I have for you, declares the Lord, plans for welfare and not for evil, to give you a future and a hope.” – Jeremiah 29:11
“If you, then, though you are evil, know how to give good gifts to your children, how much more will your Father in heaven give good gifts to those who ask him!” – Matthew 7:11
“A cheerful heart is good medicine, but a crushed spirit dries up the bones.” – Proverbs 17:22
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