New Study Examines Long-Term Benefits of Prostate-Specific Antigen (PSA) Screening for Prostate Cancer
Genitourinary cancer specialists from Seattle Cancer Care Alliance, University of Washington School of Medicine, Fred Hutchinson Cancer Research Center, and Weill Cornell Medicine have published an article, “Reconsidering the Trade-offs of Prostate Cancer Screening,” in the New England Journal of Medicine on the long-term benefits of prostate-specific antigen (PSA) screening for prostate cancer in men. In the article, investigators concluded that the advantages of widespread screening – including reduced mortality and the potential to avoid metastases – are likely greater than estimates cited in current guidelines.
Seattle, Washington (June 17, 2020) – “Currently, much of the medical community considers PSA testing as an example of a screening tool that is ineffective largely based on short-term data from two trials,” said Yaw Nyame, MD, MBA, MS, study co-lead author and investigator and clinical fellow in the Department of Urology at the University of Washington School of Medicine and Seattle Cancer Care Alliance, and a post-doctoral fellow at the Fred Hutchinson Cancer Research Center. “Using data from the more reliable of the two trials and conservative assumptions, our team created a microsimulation model to extrapolate the mortality reduction due to screening from 16 years of follow-up to 25 years of follow-up. Our results show that continued accrual of benefit over time creates a significantly more favorable picture of the value of screening.”
Routine prostate cancer screening relies on measurements of the level of prostate-specific antigen (PSA), produced by the prostate gland, in a man's blood. Men with prostate cancer often have elevated PSA levels. The trade-off with PSA screening is a balance between the potential benefit (i.e., preventing a man from dying of prostate cancer) with possible drawbacks, such as overdiagnosis and overtreatment of prostate cancer. Overdiagnosis is the diagnosis of cancer by screening that would not have been diagnosed without screening in the patient’s remaining lifetime. Overtreatment—the treatment of an overdiagnosed cancer—can cause substantial harms, including urinary incontinence and erectile dysfunction.
“Prostate cancer screening can lead to overdiagnosis, but screening trials did not provide a correct perception of the harms relative to benefits and underestimated the lives that could be saved over the long term. This manuscript leverages a simulation model that was developed by our group to overcome these limitations,” explained Dr. Ruth Etzioni, faculty member of the Public Health Science Division at the Fred Hutchinson Cancer Research Center.
Perceptions of PSA testing as ineffective, combined with overstated harms, have led agencies such as the U.S. Preventive Services Task Force (USPSTF) and organizations including the American Academy of Family Physicians to shy away from recommending routine screening for men. In 2018, the USPSTF provided a grade C recommendation for PSA screening, recommending instead “shared decision making” between patients and their healthcare providers.
These recommendations are rooted on short-term data that suggests that screening prevents one death from prostate cancer per 1,000 men screened at the expense of diagnosing 100 cancers. “Our model, however, shows that we would have to diagnose 11 extra cases of prostate cancer to prevent 1 prostate cancer death at 25-years of follow-up,” states Dr. Nyame. “These recommendations also fail to acknowledge the marked changes occurring in the field that are improving our detection of clinically significant cancer, and changes in our management of low-risk cancers (i.e., active surveillance) that is markedly reducing the harms of overtreatment. The time has come to rethink the use of PSA testing, particularly in high-risk populations, so that we do not miss the opportunity to improve our ability to diagnosis prostate cancer earlier, enhance our ability to treat it effectively, and save more men from serious illness and death.”
Seattle Cancer Care Alliance brings together the leading research teams and cancer specialists from Fred Hutch, Seattle Children’s and UW Medicine — one extraordinary group whose sole purpose is the pursuit of better, longer, richer lives for our patients. Based in Seattle’s South Lake Union neighborhood, Seattle Cancer Care Alliance has nine clinical care sites in the region, including a medical oncology clinic at EvergreenHealth in Kirkland; hematology/medical oncology and infusion services at Overlake Medical Center in Bellevue, medical and radiation oncology clinics at UW Medical Center - Northwest Seattle and medical oncology services at SCCA Issaquah, as well as Network affiliations with hospitals in five states. For more information about SCCA, visit seattlecca.org.
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A protein made by the prostate gland and found in the blood. Prostate-specific antigen blood levels may be higher than normal in men who have prostate cancer, benign prostatic hyperplasia (BPH), or infection or inflammation of the prostate gland.