The PSA Test: 7 Reasons It Still Matters

Value of test in detecting prostate cancer is under attack—but that's wrongheaded.

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The U.S. Preventive Services Task Force asked doctors last year to stop checking PSA levels in elderly men—the very men who are most likely to have prostate cancer. By age 75, the officials reasoned, doctors are more likely to keep tinkering with their patients until they die of treatment side effects or something other than prostate cancer altogether. This spring, the New England Journal of Medicine published two long-term studies that questioned whether knowing a man's PSA level actually helps men survive. Healthcare commentators say that PSAs set off a cascade of overtreatment, endangering patients and tolerating wasteful medicine, and that patients should be wary.

You might expect that the surgical specialists at the center of prostate cancer treatment would have reined in their PSA testing, but they haven't. The American Urological Association actually lowered its recommendation for the age at which doctors should start offering patients the PSA test from 50 to 40. It was the first revision of the guidelines in nearly a decade. The next one, says Kirsten Greene, a urologist who worked on the committee, should take just a year, in light of the accelerating data and heightened public debate.

"The key change is how we react to abnormal tests and to a cancer diagnosis, which is generally less aggressively for some men than in the past," says Gerald Andriole, chief of urologic surgery at Barnes-Jewish Hospital/Washington University School of Medicine in St. Louis. Andriole says that men shouldn't be afraid to get diagnosed; good urologists avoid overtreating less-dangerous cancers. Active surveillance or targeted attacks on very small tumors that spare healthy prostate tissue are both popular options.

From the latest research, here are seven reasons why urologists are encouraging men of any age who expect to live at least another 10 years to think hard about getting a PSA test, even if they have to pay out of pocket:

1. Keeping tabs on PSA saves lives. Many urologists flat out reject a large study published in the New England Journal of Medicine earlier this year that found men who got the PSA test did worse than men who didn't. The dissenters say the results weren't trustworthy—many of the men who weren't supposed to get tested actually did, thanks to their proactive primary-care docs. Another recent large NEJM study found that nine years after entering the study, men who got regular PSA screening were 20 percent less likely to die of prostate cancer. One model suggests the PSA test has contributed to much of the 30 percent decline in prostate cancer deaths seen in recent decades.

2. There's no magic PSA number. In the urologists' latest recommendations, it is clear that there's no one-size-fits-all age at which to be tested or bad PSA number. For many years, a particular reading of 4 or above was a battle cry that called for a biopsy or aggressive treatment. In reality, any reading is suspect. Without knowing much more about him, studies give a middle-aged man a 10 percent chance of having visible cancer on biopsy even if his PSA level is zero. Today, doctors consider a single PSA number in the context of your specific health background, race, and family history (it may also help diagnose benign enlargement or an infection), and then suggest when to be tested next. If you do get a biopsy, the criteria for serious concern are stricter, and there are more conservative treatment options.

3. Velocity matters. Your first PSA test is neither your last nor your most important. Depending on your age and your current PSA number, the question is how much, and how fast, subsequent test numbers increase. Researchers are busy determining just how much velocity is normal. (Some researchers say a speed bump of more than 0.25 in one year for a 40-year-old man should prompt concern.) Every man generates a history of data points his doctors can interpret in light of the research.

4. There's more than one kind of PSA to measure. Enlarged but noncancerous prostates usually release "free" PSA that circulates through the body, while PSA produced by cancer cells tends to attach itself to proteins in your blood. By considering the ratio of the types of PSA, as is done by looking at the ratio of bad to good cholesterol for heart disease, doctors can offer you better advice about your risk and what you should do next.

5. The younger you are, the more meaningful the PSA test. Older prostates tend to get bigger and put out more PSA, complicating interpretation. Higher PSA levels at a younger age are an indicator of elevated risk and call for closer monitoring of factors like your PSA velocity. At the same time, prostate cancer therapies are most effective and sparing of function when the cancer is at an early stage.

6. PSA numbers reveal your prognosis and are critical in follow-up. If you do develop a serious form of prostate cancer that requires aggressive treatment, your PSA levels prior to treatment will help your medical team determine the risk of recurrence. It's one factor among many others, such as how the tumor looked under the microscope after surgery, but the latest studies show it's of real value. After surgery to remove the prostate, the PSA test is even more critical: Detection of extremely minute levels can signal cancer recurrence. The earlier doctors know the cancer is back, the earlier patients can decide about secondary treatments like radiation and hormonal therapy.

7. For now, PSA is the best we've got. Scientists are looking hard for a better "biomarker" than the PSA, ideally one that doesn't require so much deliberation. Candidates are surfacing, but they require more proof. Physical measures like the prostate's size can be misleading, as Mayo Clinic researchers reminded us this week. Studies show that a digital rectal exam plus a PSA test is the surest way to pick up prostate cancer. But if you've got to pick only one test, PSA is still the best.