Posted by Brigham and Women's Hospital May 7, 2012
Should you get a prostate cancer screening? It depends on who you ask or what you read.
While one research study shows that the benefit of prostate cancer screening is significant, another study finds little, if any, benefit. And while one expert defends the prostate-specific antigen (PSA) screening test – which measures levels of the PSA protein in the blood – another just as passionately dismisses it. With studies, experts, and news stories disseminating such widely varying viewpoints, it’s easy to understand why men and their loved ones would feel confused – and wonder how to arrive at an informed decision.
Start by asking an expert.
Dr. Anthony D’Amico, Professor and Chief of Genitourinary Radiation Oncology at Brigham and Women’s Hospital and Chief of the Prostate Cancer Radiation Oncology Service at Dana-Farber/Brigham and Women’s Cancer Center, has been treating prostate cancer for more than 20 years and continues to be a firm advocate of prostate cancer screening, particularly for younger men. “PSA screening is effective in decreasing cancer death,” says D’Amico. “It’s a critical tool for having an informed conversation with a man about whether he needs treatment or not.”
Dr. D’Amico is concerned that men aren’t getting the whole picture, and he points to the U.S. Preventive Services Task Force’s (USPSTF) recent recommendation against routine PSA tests for healthy men as an example of how public opinion can be swayed according to who’s telling the story. He, along with several other physicians, expressed their concern with the USPSTF recommendation in a recently published rebuttal, “What the U.S. Preventive Services Task Force Missed in Its Prostate Cancer Screening Recommendation.”
D’Amico, supported by the American Cancer Society, believes that the task force recommendation fails to adequately address why three recent major prostate cancer screening studies present vastly different findings and neglects the PSA’s noteworthy benefit for younger men.
A Swedish study, which had the youngest (median age of 56) and presumably healthiest men, found that there was a 44% reduction in prostate cancer deaths among men who were routinely screened, as compared to those who were not. A European study, with a slightly older group (median of 60), found a 20% reduction in deaths among screened men, and a U.S. study, with the oldest group (median of 63), found virtually no benefit from screening.
D’Amico believes that there are several reasons to place more weight on the results of the Swedish and European studies over the U.S. study.
One is that because the PSA was widely available in the U.S. but not in Europe during the study periods, the U.S. study suffered from a considerable amount of contamination – meaning that 50% of the men who were supposed to be part of the unscreened control group had undergone PSA screening before the study – thereby diminishing the reliability of the study’s results. The European and Swedish studies, however, had far less contamination.
Another key characteristic of the Swedish study is the comparative youth of its participants, as it’s commonly accepted that younger men are likely to benefit more from early diagnosis than older men. One advantage to diagnosing a man with prostate cancer at a younger age is that he’s less likely than an older man to die of another disease, and, thus, proceeding with prostate cancer treatment holds greater promise. Another distinct advantage is that it is much easier to detect prostate cancer in a younger man by using the PSA test, as his PSA level is less likely to be falsely elevated by the benign prostate enlargement that often occurs in older men.
D’Amico also cited the length of the Swedish study as another strong point – 14 years, versus 11 for the European study and 9 for the U.S. – as the number of men needed to be treated in order to save a life declines as the study goes longer. As it stands, the Swedish study found that it was only necessary to treat 12 men in order to save one life, whereas 48 men needed to be treated in order to save one life in the European study.
Despite the strength of the Swedish numbers, some experts are still concerned that routine PSA tests can lead to unnecessary treatment. D’Amico, however, believes that the benefits of PSA screening greatly outweigh the risks, particularly for young and/or healthy men at high risk, and that oncologists and urologists have the necessary tools to effectively limit unnecessary treatment. “We have the information that can help individualize whether a man with certain type of prostate cancer needs treatment or not,” explains D’Amico. And when treatment is recommended, he added, patients further benefit from therapies that are more effective and have less harmful side effects than what was available just a decade ago.
D’Amico is not only concerned that the USPSTF recommendation will dissuade men from getting the test, but will also limit access to the test for men who want it. “The USPSTF recommendation likely means that Medicare and other insurance plans will no longer cover the cost of PSA screening,” says D’Amico. “Therefore, only men who can afford to pay for the test will have the opportunity to benefit from it, which creates a health care disparity.”
“No one should be at increased risk for dying of prostate cancer,” asserts D’Amico. “To deny a man the opportunity to know whether he has prostate cancer and whether he needs treatment is just not in anybody’s best interests.”– Chris P.