Getting to a definite diagnosis of prostate cancer takes a few steps. You might notice a few symptoms, or the idea might not show up on your radar until a routine screening test produces abnormal results. If that’s already happened, it doesn’t always mean you have prostate cancer.
The only way to confirm prostate cancer is with a biopsy. But it’s possible to rule out prostate cancer and eliminate your need for a biopsy through other screening tests, including:
- digital rectal exam (DRE)
- free prostate specific antigen (PSA) test
- transrectal ultrasound (TRUS)
- urine test to determine your Mi-prostate score (MiPS)
Continue reading to learn more about prostate cancer testing and when a biopsy might be necessary.
Isn’t a PSA test enough?
The prostate specific antigen (PSA) test is a common screening test for prostate cancer. PSA is a protein that comes from the prostate gland. The test measures the amount of PSA in your blood. It’s a simple blood test, and for some men, it turns out to be a lifesaver.
On the other hand, its value as a diagnostic tool is fairly limited. High PSA levels may be a sign of prostate cancer, but it’s not enough to diagnose the disease with certainty. That’s because there are other reasons your PSA levels could be high, including urinary tract infection and inflammation of the prostate.
Also, a single abnormally high PSA test result can’t tell you if the high level is temporary or rising over time.
Low PSA levels cannot definitively rule out prostate cancer, either. The fact is that PSA tests can result in both false positives and false negatives.
PSA tests can be useful during and after treatment for prostate cancer. Rising PSA levels may signal that treatment is not effective or there is a recurrence of the cancer. If your PSA levels are decreasing, your current treatment is probably doing its job.
What does a digital rectal exam do?
In a digital rectal exam (DRE), the doctor inserts a gloved finger into your rectum to feel for irregularities of the prostate. It’s a common part of a man’s routine physical examination.
Your doctor might perform a DRE alone or with a PSA test for routine screening. It’s a quick and simple test. Although a DRE can signal a problem, such as an enlarged prostate, it cannot determine if it’s due to prostate cancer.
Prostate cancer is diagnosed 15 to 25 percent of the time when abnormal findings on a DRE lead to biopsy.
What is free PSA?
The routine PSA test measures total PSA in your blood. But there are two types of PSA. Bound PSA is attached to a protein. Free PSA is not. The free PSA test breaks the results down and provides your doctor with a ratio. Men with prostate cancer tend to have lower levels of free PSA than men who don’t have prostate cancer.
It’s a simple blood test, but there’s no consensus among doctors on the ideal ratio of free to bound PSA. The free PSA test is valuable in that it gathers more information, which can help in the biopsy decision.
On its own, the free PSA test can’t confirm or rule out a prostate cancer diagnosis.
What’s the purpose of a transrectal ultrasound (TRUS)?
A transrectal ultrasound (TRUS) is a procedure that produces an image of the prostate. It’s usually ordered after an abnormal PSA and DRE. For the test, a small probe is inserted into the rectum. The probe then uses sound waves to produce a picture on a computer screen.
The test is uncomfortable, but not painful. It can be done in your doctor’s office or on an outpatient basis in about 10 minutes. It can help estimate the size of the prostate and spot abnormalities that may indicate cancer. However, a TRUS can’t confirm the diagnosis of prostate cancer.
A TRUS can also be used to guide a biopsy.
What is a Mi-prostate score (MiPS)?
The MiPS score helps to evaluate your risk of prostate cancer and aggressive prostate cancer. It’s usually performed after you have abnormal results from a PSA test and DRE.
This test involves a DRE, after which you’ll provide a urine sample. The Mi-prostate score (MiPS) combines three markers:
- serum PSA
- TMPRSS2:ERG (T2:ERG)
PCA3 and T2:ERG are genes found in the urine. It’s rare for men without prostate cancer to have high amounts of these markers in their urine. The higher your levels, the more likely it is that you have prostate cancer.
A MiPS provides more information than a PSA test alone. It’s a valuable risk assessment tool and may be helpful in deciding whether or not to go ahead with a biopsy. Like other tests, a MiPS test alone cannot confirm prostate cancer.
About the biopsy
DRE, TRUS, and blood and urine tests are all used to evaluate the likelihood that you have prostate cancer. Along with knowing your family history, symptoms, and personal health history, these tools can help your doctor make a recommendation regarding biopsy. It’s important that you discuss all these factors with your doctor.
The only way to confirm prostate cancer is with a biopsy, but most men who have a prostate biopsy after screening exams do not have cancer.
A biopsy can be done in a doctor’s office or as an outpatient procedure. It doesn’t take long, but it is an invasive procedure. Side effects may include:
- soreness or difficulty urinating for a few days following the procedure
- small amounts of blood in your semen, urine, and bowel movements for a few days to a few weeks
- infection, though you’ll be given antibiotics to reduce your risk
Even though your doctor will take several tissue samples, it’s still possible to miss the area that contains cancerous cells. A biopsy like this would produce a false-negative result. Depending on your other test results, your doctor may want to follow up with repeat PSA tests or another biopsy.
MRI-guided prostate biopsy can help doctors locate suspicious tissue and lower the chance of a false-negative result, however.
If you have prostate cancer, the pathology report will include a Gleason score from 2 to 10. A lower number means the cancer is slow-growing and less likely to spread.
Imaging tests such as MRI and bone scans can help determine if cancer has already spread outside the prostate.
- A biopsy is the only way to confirm prostate cancer.
- Biopsy results can be used to determine how quickly your cancer is likely to spread.
- This invasive procedure can have side effects, though most clear up within a few days to a few weeks.
- False-negatives are possible, so you may need to have additional tests and biopsies.
If you choose not to have a biopsy, or if a biopsy produces a negative result, your doctor can continue to monitor your health using some of these tests.
If the biopsy is positive, your prognosis depends on many factors, such as:
- stage at diagnosis
- tumor grade
- whether or not it’s a recurrence
- your age
- your overall health
- how you respond to various treatments
Most men who have prostate cancer don’t die from it, however, according to the National Cancer Institute.
Risk factors for prostate cancer
When it comes to deciding whether or not to have a biopsy, consider your risk factors, such as age, race, and family history.
Your risk of prostate cancer increases as you age. Almost two-thirds of prostate cancers occur in men who are older than 65. In the United States, prostate cancer is also more common among African-Americans than Caucasians. Your risk doubles if you have a father or brother with prostate cancer, and the risk increases more if you have several relatives who’ve had it. This is especially true if your relative was young at the time of their diagnosis.
Discuss your risk factors and the pros and cons of prostate biopsy with your doctor. There are several ways to screen for cancer. If you had abnormal test results and are concerned about prostate cancer, however, a biopsy is the only way to confirm the diagnosis.