New Prostate Cancer Screening Method With Lifesaving
Using a selective screening strategy for prostate
cancer may reduce the harms associated with prostate-specific antigen (PSA) testing while preserving the number of
lives saved, according to a study by Hutchinson Center researchers.
Lead author Dr. Ruth Etzioni and Roman Gulati of the Public Health Sciences Division, along with University of
Washington urologist Dr. John Gore, found that compared with a standard screening strategy, using higher thresholds
for biopsy referral for older men and screening men with initially low PSA levels less frequently may be a way to
improve the tradeoff between screening benefits and overdiagnosis. Their findings were published Feb. 5 in
Annals of Internal Medicine.
The researchers used a computer model to compare 35 screening strategies that varied in terms of age of first
and last screening, screening intervals, and PSA thresholds for biopsy referral. They looked at false-positive
results, cancer detected, overdiagnoses (cancers detected that would otherwise never become clinically
significant), deaths from prostate cancer, lives saved, and months of life saved.
Measuring PSA levels can help doctors determine which patients may be at risk for prostate cancer. Patients with
an elevated PSA level may require a biopsy to determine if cancer is present. However, biopsies are associated with
many troublesome side effects and still cannot tell a doctor with certainty which cases of prostate cancer are
life-threatening and require treatment.
Controversial current guidelines
Current prostate cancer screening guidelines have been the source of controversy. Last spring, the U.S.
Preventive Services Task Force concluded that the harms of existing PSA screening strategies outweigh the benefits.
Other advisory groups are less clear, recommending informed decision-making on an individual level. This can be
difficult because there is sparse data available to help doctors have nuanced conversations with their patients
about whether and how often to have prostate cancer screening.
The researchers found that doing PSA tests less often in men at low risk of prostate cancer would substantially
reduce the harm of overtreatment, while increasing the risk of death only slightly. Specifically, their evaluation
showed screening men ages 50 to 74 with low PSA levels every other year instead of annually would increase the
lifetime death risk by 0.1 percent, from 2.15 percent to 2.23 percent. At the same time, it would reduce number of
PSA tests by 59 percent, and false positives, which often lead to painful biopsies, by almost half.
Setting a higher threshold for PSA levels for older men would accomplish the same thing. In older men, screening
up to age 74, but recommending biopsies only in men with PSA levels in the top 5 percent for their age, increased
the probability of lives saved more than it increased overdiagnoses.
The National Cancer Institute and Centers for Disease Control and Prevention funded the study.
News Author and Sources: Ruth Etzioni, Roman Gulati of Fred Hutchinson Cancer
Research Center Public Health Sciences Division model advantages of more tailored PSA testing approach matched to
age, cancer risk - http://www.fhcrc.org/en/news/center-news.html