Experts urge medical societies to reconsider prostate cancer screening guidelines
New model estimates demonstrate the long-term benefits of prostate cancer screening and “suggest that the balance of benefits and harms of screening may be more favorable than is generally appreciated,” experts wrote in The New England Journal of Medicine.
“[Prostate-specific antigen] screening has fallen out of favor in recent years for problematic reasons,” Jonathan E. Shoag, MD, assistant professor of urology at University Hospitals Cleveland Medical Center and Case Western Reserve University and an adjunct assistant professor at Weill Cornell Medical College, told Healio Primary Care. “These include misinterpretation of randomized trial results, using short-term data to estimate the benefits of screening, and not taking into account that many prostate cancers present clinically even without screening.”
Currently, the U.S. Preventive Services Task Force recommends that physicians screen men aged 55 to 69 years for prostate cancer on a patient-to-patient basis and that those older than 70 years should not be screened. The American Academy of Family Physicians does not recommend routine screening in men aged 55 years and older, while the American Cancer Society recommends to start screening at age 40 years based on a man’s life expectancy and risk — and only after he has been advised of the “uncertainties, risks and potential benefits” of screening.
According to Shoag, Yaw A. Nyame, MD, MBA, MHSA, urologic oncologist at the University of Washington Medical Center, Jim C. Hu, MD, MPH, urologist at Weill Cornell Medicine, and other members of the research team, there is a widespread misperception that prostate-specific antigen (PSA) screening has “equivocal or no benefit” based on findings of two large, randomized, controlled trials: the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial and the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial. However, the researchers noted that the PLCO trial was not designed to adequately compare the benefits of screening vs. not screening since 90% of the participants in the control group underwent PSA testing.
Meanwhile, results of the ERSPC trial showed that 570 men aged 55 to 69 years would need to undergo screening to prevent one death from prostate cancer. The findings were based on 16 years of follow-up, which researchers wrote “may not provide a sufficient time horizon to examine the mortality benefit from screening because men often begin screening in their 50s and the median age at death from prostate cancer is 80 years.”
The researchers developed a model to further evaluate the long-term effects of prostate-specific antigen (PSA) screening. The model is based on the long-term survival of patients with prostate cancer and competing mortality in the United States. It projected that 11 more prostate cancer cases would need to be diagnosed to prevent one death from prostate cancer over a 25-year period.
“We used conservative assumptions about the benefits of screening, and how much other changes in prostate cancer treatments would impact mortality,” Nyame said in an interview. “We also did not incorporate more recent improvements in screening or treatment via new technologies. In this sense, our model estimates are very conservative and still demonstrate significant benefit to PSA screening over 25 years.”
The researchers told Healio Primary Care that they hope their model prompts medical societies to examine recently published evidence and new techniques in the diagnosis, management and treatment of prostate cancer.
“The ideal scenario would be for professional societies to recognize the long-term downstream benefits of PSA screening in terms of reducing the risk for prostate cancer metastases and death in men with more than a 10-year life expectancy,” Hu said. “In addition, it would be ideal for guidelines from these societies to recognize that not all men who have the PSA test will be subject to biopsy; some men may receive a prostate MRI which, if normal, avoids biopsies for elevated PSA.
Perspective
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Prostate cancer is one of the most common cancers to affect men; however, the decision about whether to be screened is complex and personal. Screening to detect and treat prostate cancer in men without symptoms may offer benefits, but it is also associated with harms.
Prostate cancer screening has the potential to help find prostate cancer early, when treatment can be more effective, ultimately saving lives, but there are also significant harms of screening that people should be aware of. One of the most mportant harms of screening is frequent false-positive results, which often lead to additional testing and years of follow-up, including repeated blood tests and biopsies. Another important harm is overdiagnosis, which happens when screening leads to the diagnosis of prostate cancer in some men who would not have experienced symptoms from cancer during their lifetime. Thus, treatment of these men provides them with no benefit and can lead to harmful outcomes. Common harms associated with treatment include erectile dysfunction and urinary incontinence. Finally, the benefits of screening are often realized years after treatment, while the harms may occur soon after testing or treatment and may last for some time.
Our current recommendation is that men aged 55 to 69 years should make an individual decision about whether to be screened after a conversation with their doctor about the potential benefits and harms. For men aged 70 years and older, the potential benefits do not outweigh the harms, and these men should not be routinely screened for prostate cancer.
For example, when a man is aged 55 to 69 years is interested in the small potential benefit and more willing to accept the potential harms, screening may be the right choice for him. On the other hand, a man who places more value on avoiding the potential harms may choose not to be screened. We encourage primary care clinicians to be aware of the USPSTF recommendations in regards to prostate cancer screening and encourage these clinicians to continue to have these conversations over the years, as each patient’s values and situation may change.
The Task Force aims to keep all recommendations current, updating each recommendation approximately every 5 years, though the timeline may vary. Given the importance of prostate cancer screening, we anticipate it will likely follow our standard approach.
Editor’s note: The USPSTF last updated its clinical recommendations on prostate cancer screening in May 2018.
Perspective
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This commentary nicely lays out the reasons why it is important that we recognize that the balance of benefits and harms associated with screening and treatment for prostate cancer are evolving. As Shoag and his colleagues stress, early prostate cancer detection is associated with a reduction in prostate cancer deaths and diagnosis of advanced disease. Thus, if harms of diagnostic tests and overtreating indolent prostate cancers can be avoided, then the balance of benefits and harms becomes more favorable, potentially opening the door to considering modifications in guidelines.
Historically, health care professionals have not done a good job at having these discussions with men about screening, or their options if they are diagnosed with prostate cancer. Thus, a recommendation for shared-decision making vs. a direct recommendation for screening has been sensible and prudent.
Shoag and colleagues are experienced, sophisticated modelers, and the model inputs they describe make sense, especially the importance of longer-term follow-up. The number needed to screen to prevent one death is highly dependent on the estimate of screening’s contribution to reducing deaths, and the duration of follow-up, since prostate cancer deaths from advanced disease can occur many years after diagnosis. Compared with the estimates of the number needed to screen that appear in some organization’s shared-decision making, these new estimates are likely to be more reliable.
The American Cancer Society last updated its guideline for prostate cancer screening in 2010. These guidelines endorse the idea that men make a shared decision about prostate cancer screening with their doctor. Like most organizations, the endorsement for shared-decision making was based on the uncertainty about the balance of benefits and harms associated with prostate cancer screening and treatment.
Certainly, some men have averted a premature death from prostate cancer as a result of a PSA test and treatment, but others have been overtreated for a prostate cancer that was not life threatening, and experienced diminished quality of life due to side effects of treatment. The more we can reduce harms that occur in men with non-aggressive disease, the more we are able to advise men how they may benefit from prostate cancer screening and reduce their risks of harms.
The accumulation of new data on prostate cancer has prompted the American Cancer Society to revisit its guideline in 2021.
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