What’s new?
What was emphatic before is wishy-washy now. The last time the US Preventive Services Task Force weighed in on prostate cancer screening via blood tests, in 2012, it issued unambiguous advice to physicians: discourage men of all ages from getting tested for levels of prostate-specific antigen (PSA). That’s still the advice for men older than 70 or younger than 55.
But for those aged 55 to 69, the task force, a panel of independent experts who advise the federal government, is punting: It recommends “informed, individualized decision making based on a man’s values and preferences.”
Great. How do I do that?
The task force created a useful graphic to help you. We hope you like numbers:
If 1,000 men get PSA screening (cost: roughly $40), 240 will be told their PSA level suggests cancer might be present. Next step: a biopsy, in which a needle, usually inserted through the rectum, samples several spots in the prostate gland.
Of those 240 biopsies, 140 men will be told, oops, the PSA was misleading: You have no signs of cancer. These are called false positives.
Of the other 100 men, in whom biopsy shows definite cancer, up to 50 have malignant cells that will turn out to be so slow-growing — “indolent” — that the cancer would never spread or harm them. These are called overdiagnoses.
Unfortunately, it’s impossible to tell from looking at cancer cells if they’re wimps or killers, so 80 of the 100 men with prostate cancer choose surgery or radiation treatment, either right away or after first trying “active surveillance” (frequent PSA tests, exams, biopsies). At least 60 men suffer urinary incontinence and sexual impotence from the treatment.
Of the 80 treated men, only three benefits. In the other 77, the cancer either wouldn’t have caused harm if left untreated or is so aggressive that treatment doesn’t help.
Of the three men who benefited at all, 1.3 who would have been killed by prostate cancer without PSA screening will not be, over a period of 10 to 15 years.
Bottom line: 1,000 men screened, one prostate-cancer death averted in that time.
Why did the task force back off its 2012 thumbs-down on PSA screening?
By 2012, studies comparing men who undergo PSA testing to men who do not had found that the harms of testing (false positives, overdiagnosis, impotence, incontinence) outweigh the benefits. Specifically, the data available then indicated that just 0.8 of 1,000 men who undergo PSA screening would be spared a prostate-cancer death over the following 10 to 15 years, said Dr. Alex Krist, a task force member and associate professor of family medicine at Virginia Commonwealth University.
By continuing to follow men in the studies, researchers now find that 1.3 prostate cancer deaths are prevented per 1,000 men screened. Just as important, more men are opting for active surveillance instead of treatment. That means the potential harms — impotence, incontinence — of screening are less than the last time the task force calculated all this, “making the balance of potential benefits and harms a little more positive,” Krist said.
Dr. James Eastham, a prostate cancer surgeon at Memorial Sloan Kettering Cancer Center, welcomed that. “This is a reasonable step back from the previous ‘we don’t recommend routine PSA screening,’” he said. “But it’s true that everyone shouldn’t be tested, and that many men with an elevated PSA don’t have cancer at all or, if they do, that cancer doesn’t pose a risk to his life.”
“research has not yet proven that the potential benefits of testing outweigh the harms of testing and treatment,” it says, men should discuss the pros and cons of PSA screening starting at age 50 (but 45 if you’re African-American or have a father or brother who had prostate cancer before age 65).
Even the American Urological Association, which practically accused the task force of killing men with its “not recommended” conclusion of 2012, says routine PSA screening is not advised for men younger than 54 or older than 70. For those 55 to 69, it recommends “shared decision making” — talk to your doctor, understand the risks and benefits and the odds that you’ll be better off — and biannual rather than yearly screening for men who opt in.
Every time there’s a medical controversy, experts seem to duck, telling me to ask my doctor — who has about 13 minutes for me.
“Incorporating shared decision making [into a doctor’s visit] is difficult,” Krist acknowledged. “Physicians are busy, and this is a complicated topic.” He suggests that men learn what they can before a visit — and even print out a cost-benefit analysis. Then they ought to make an appointment to discuss PSA and nothing else, and take their time deciding.
How can I tell the task force what I think?
Until May 8, you can submit comments online. Eventually, the task force will finalize the recommendation.