Granted, while both studies had their particular limitations, the PSA test has its own limitations. For example, an elevated PSA can be a tip-off to a lethal cancer, but it can also detect less aggressive cancer that may never cause harm. Since we don't yet have a definitive test that can tell the difference, and may not for many years, most prostate cancer experts believe that this cancer is now not only over diagnosed but also over treated.
Does the PSA test save lives -- according to the American Cancer Society, 288,000 men died from prostate cancer in 2008 -- or does it merely subject a large number of men with elevated PSAs to unnecessary surgery or radiation with side effects that can include urinary incontinence, erectile dysfunction, and irritative urinary and bowel symptoms? Doctors and patients alike have always wanted to know the answer for years, and they were hoping that these randomized trials would provide them. Unfortunately, they did not.
According to H. Ballentine Carter, M.D., Director of Adult Urology at the Brady Urological Institute at Johns Hopkins, the studies will not end the controversy surrounding the PSA test, a blood test that millions of men have been taking since it was first introduced in the late 1980s. It's currently estimated that 25 million PSA tests are performed annually in the United States."I am not sure that we learned a tremendous amount from the NEJM studies," admits Dr. Carter. "We already knew that we were over diagnosing and over treating this disease. Now we have numbers to document the extent of over treatment."
The studies published in the NEJM, from large randomized studies performed in North America and Europe, yielded contradictory results. An early analysis of the North American study of 77,000 men aged 55 to 74, which is still ongoing, showed no reduction in death from prostate cancer attributable to prostate cancer after seven to 10 years of follow-up.
However, the European study of 182,000 men aged 55 to 69, which is also ongoing, showed a 20% reduction in death among men who had PSA testing. For every life saved, however, 1,400 men need to be screened and 48 would need treatment following a positive PSA and digital rectal exam to result in one fewer death during a 10-year period.
Another way to look at it: 47 men who had a PSA test followed by surgery or radiation for their cancer may not have needed it, and many might go on to have urinary and erection complaints. In harming their quality of life while ostensibly protecting them from cancer, some men might say that this is too high price to pay for a disease that was not going to cause harm.
However, further follow-up could demonstrate a greater benefit of PSA screening and reduced harm as we learn more about the ability of PSA testing to prevent other outcomes, such as the development of metastatic disease and local progression of cancer that requires treatment. In addition, since prostate cancer takes a long time to progress, the 20% reduction in prostate cancer mortality found after 10 years could be higher with longer follow-up.
"PSA screening is certainly not perfect, but it is clearly saving some lives," says Dr. Carter. "If an individual is thinking about being tested, we now have some numbers to give him and he can make up his mind whether or not to be tested. If a man wants to continue to be tested, that's certainly reasonable. "
Once a man knows the risks and the trade-offs, he may or may not want to have a PSA test. "Americans are not like Europeans," concedes Dr. Carter. "We tend to be aggressive about wanting to know more. In spite of these new reports, I still think most men will still want to have the PSA test."
In light of these new studies, what should a man do? Says Dr. Carter: "I like what Dr. Michael J. Barry, M.D., medical director of the John D. Stoeckle Center for Primary Care, said in his NEJM editorial about the studies. He wrote, "The implications of the trade-offs reflected in these data, like beauty, will be in the eye of the beholder. Some well-informed clinicians and patients will still see these trade-offs as favorable; others will see them as unfavorable. As a result, a shared decision-making approach to PSA screening, as recommended by most guidelines, seems more appropriate than ever."
- Bottom line: What the studies point out is that right now we still don't have a one-size-fits-all type test. While Dr. Carter believes that the value of the PSA test is still debated, until we have a better biomarker test that can differentiate inconsequential from lethal tumors, the PSA test needs to be used more judiciously. "I think a lot of the overtreatment we see has to do with using PSA as an absolute cutoff. I think PSA velocity, how fast the PSA moves over time, may be a better measure of the presence of lethal cancer.
"Doctors can get a lot more information if there is a PSA history, which is why I believe getting a baseline PSA at a younger age is a reasonable thing to do.," says Dr. Carter. "I recommend that all men should have an initial PSA test starting at age 40. A follow-up test should be given at age 45 and then again at age 50. Combining that information with the patient's age, size of the gland, and the free PSA test, should improve the accuracy of the PSA test. This will indicate their risk of developing prostate cancer.
"While not precise, it offers the best indication we have so far about the presence of cancer and what should be done," he says.