Q & A: Prostate cancer screening

Cancer screenings save lives by catching cancer early, when it’s easiest to treat. But when it comes to prostate cancer screening, finding a clear answer on when – or even if – men should get screened can be difficult.

We asked John Davis, M.D., associate professor and director of the Urosurgical Prostate Cancer Program in MD Anderson’s Department of Urology, to answer some common questions about prostate screening.

When should I begin regular prostate screening exams?

Cancer screening exams are tests you take if you don’t have any symptoms. They are often based on factors like age.

With prostate cancer screening, benefit and harm is a mixed picture, Davis says. So, current guidelines vary on the specific age men should begin screening. MD Anderson recommends men begin talking to their doctor at age 45 about the risks and benefits of screening.

African-American men and men with a family history of prostate cancer – especially their father, brother or paternal uncle – should start the conversation earlier.

“What’s being promoted is this concept of shared decision-making. So when you see the advice to talk to your doctor, that’s what it means,” Davis says.

“If a man is healthy and has more than 10 years of life expectancy, that would be the starting point,” he says.

What can I expect during a prostate screening exam?

Prostate screening exams generally include two procedures:

• A blood test that measures the level of prostate-specific antigen (PSA) in the blood. PSA is a protein produced by the prostate gland.
• A digital rectal exam. During this a doctor inserts a finger into the rectum to detect abnormalities in the prostate gland.

Why both tests? It’s possible to have prostate cancer that doesn’t raise the PSA level. The digital exam provides another way to detect tumors.

Davis urges men to track their PSA score over time. This will help your doctor monitor spikes, dips or a steady increase in PSA levels.

A prostate biopsy should not be based on a single PSA score.

If a PSA test can detect cancer early, why shouldn’t every man get regular screening?

It comes down to accuracy.

“The PSA test is looking at a certain level of protein in the bloodstream,” Davis says. “It’s not specific to prostate cancer, but it is specific to the prostate gland. So both cancer and non-cancer sources can affect it.”

Cancer can cause your PSA levels to rise. But so can inflammation, infection and an enlarged prostate.

The test can be tripped up by factors that reduce PSA levels too. These include obesity and certain medications.

PSA testing can lead to treatment or more tests that may be unnecessary. So, it’s important to weigh the risks and benefits.

“Some men are harmed by the process if they have a false-positive PSA, or if a screening work-up leads to diagnosis of low-grade tumor, which are rarely harmful,” said Davis. “One of the ways we do our best to reduce this harm is to encourage men with low-grade tumors to monitor the cancer rather than treat it.”

How can I reduce my risk for prostate cancer?

There is little research showing that lifestyle choices like eating a healthy diet or getting regular exercise have a direct effect on prostate cancer risk.

But taking these steps – along with maintaining a healthy weight – does reduce overall cancer risk.

“When you look at countries that have low-fat diets, a lot of fish, especially Asian diets, they tend to have lower incidence of prostate cancer, compared to a typical Western setting,” Davis says. “Diet and exercise are an important part of prevention.”

Davis advises following a diet that also will reduce your risk for heart disease.

“It’s basically lower red meat intake, lower fat, unlimited fruits and vegetables.”

Davis advices against using supplements like vitamin E or selenium to ward off prostate cancer. It’s always better to get your vitamins and nutrients from food, he says.

What about recent advances in prostate imaging and improved blood tests?

Prostate imaging with MRI (magnetic resonance imaging) has improved significantly in the past five years. In addition, three new prostate biomarkers are now available that are more accurate than PSA. 

These tests mostly are used to evaluate men who have already had a prostate biopsy that did not show cancer, but still have a suspicion of cancer.  

Request an appointment at MD Anderson's Lyda Hill Cancer Prevention Center online or call 877-632-6789.