My brother-in-law was seemingly the healthiest person I knew. He regularly hiked steep hills as part of his job and kayaked intense oceans as part of his weekend play. He never even got a cold, so he rarely saw the doctor. Luckily he finally got a complete checkup when he turned 50, because it turned out that he had aggressive prostate cancer. This standard screening for prostate cancer in people who don’t have symptoms allowed him to be treated in time.
The basic check-up consists of a digital (finger) rectal exam to feel for prostate abnormalities and a simple blood test to measure the amount of prostate-specific antigen (PSA) in the blood. PSA is a protein produced by the prostate gland that's present in small quantities for healthy men, but it's generally evaluated for men with prostate cancer and other prostate disorders. The goal of PSA screening is to detect prostate cancer early, so that it's easier to treat and more likely to be cured.
So why has PSA screening recently become so controversial when it’s just a simple blood test? The main issue is that PSA screening isn’t good at distinguishing between aggressive life-threatening prostate cancer and slow-growing prostate cancer that may never spread. It can lead to unnecessary side effects from overtreatment of slow-growing prostate cancer, including a risk of incontinence and impotence. But it can also help find aggressive prostate cancer.
This controversy escalated in May 2012 when a government panel of health experts called the U.S. Preventive Services Task Force (USPSTF) recommended against PSA-based screening for prostate cancer for men of any age, stating that the benefits of screening don’t outweigh the harms of overtreatment.
The USPSTF based its recommendation primarily on two large published randomized clinical trials that evaluated the effectiveness of PSA screening. The first is the U.S. Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial in which 76,685 men aged 55 to 74 years were randomly assigned to receive either annual PSA screening or “usual care.” The study found that slightly more prostate cancers were found in the PSA screened group, but the number of people that died from prostate cancer were about the same for both groups -- raising the question of whether men were harmed from overtreatment of cancers that weren’t life threatening.