Prostate-specific antigen screening: Values and techniques shape decisions

(Press-News.org) CHAPEL HILL, N.C. - What's most important to a man as he decides whether or not to undergo prostate-specific antigen- PSA- screening for prostate cancer? What does he value most about the screening? And what's the best way to present the information to help him make an appropriate decision for himself?

An international team of scientists led by the University of North Carolina has published a study evaluating different ways of helping men consider their values about PSA screening. They report that the decision-making process was influenced by the format in which information was presented.

Their results were reported in the Feb. 11, 2013 online edition of the journal JAMA Internal Medicine.

Michael Pignone, MD, MPH, study senior author, says, "Whether to undergo PSA screening is a difficult decision for middle-aged men. PSA screening at best seems to produce only a small reduction in prostate cancer deaths and has considerable downsides.

"Effective prostate cancer screening aids should promote understanding of the benefits and risks involved in deciding whether or not to be screened and should incorporate patient values. Our study evaluated different values clarification methods to determine if there is a difference in men's decision-making based on how they are asked to think about what factors matter to them. We found that there is a difference, and our findings pave the way for further studies."

Dr. Pignone is professor of medicine and chief of the division of general internal medicine, senior research fellow and co-director of the program on medical practice and prevention for the Cecil Sheps Center for Health Services Research, and a member of UNC Lineberger Comprehensive Cancer Center.

The team described PSA screening decision options in terms of four key attributes: effect on prostate cancer mortality, risk of biopsy, risk of being diagnosed with prostate cancer and risk of becoming impotent or incontinent as a result of treatment.

These attributes were presented in three different formats. The balance sheet was a table of relevant features of PSA screening, and participants were asked to consider this information as they saw fit; in the second format, participants were asked to rate and rank the four attributes; in the third group, participants considered a series of hypothetical choices made up of different levels of these attributes.

The study involved 911 men ages 50 to 70 from the United States and Australia at average risk of developing prostate cancer. They were asked to complete questionnaires before and after value clarification.

Men who completed the balance sheet option where PSA screening versus no screening options were labeled most often chose the screening option: 43.7 percent. Men who completed the two unlabeled rate and rank and hypothetical choices surveys where the options were not labeled PSA screening or no screening were less likely to choose the screening option: 34.2 percent for the rate and rankings, 20.2 percent for the hypotheticals.

Dr. Pignone says, "What we learned was that how screening information is presented makes a difference in how men view the relative importance of different features of the decision. What this means is that more studies must be completed to determine the best method of value clarification around decision making for PSA screening."

### Other UNC study authors are Trisha Crutchfield, MHA, MSIS; Carmen Lewis, MD, MPH; and Stacey Sheridan, MD, MPH. Additional authors are Kirsten Howard, PhD, MPH from the University of Sydney in New South Wales, Australia; Alison Brenner, MPH from the University of Washington in Seattle; and Sarah Hawley, PhD, MPH, from the University of Michigan.

Funding for the study was provided by an Established Investigator award K05 CA129166 from the National Cancer Institute (Dr. Pignone and Ms. Crutchfield) and from the University Cancer Research Fund of the University of North Carolina at Chapel Hill.