Scientist can explain effects of false-positive medical testing

The psychology of medical decision making is the primary area of research for Noel Brewer, Ph.D., a member of the cancer prevention and control program at University of North Carolina at Chapel Hill's Lineberger Comprehensive Cancer Centre.

Examples of his research include risk perception and risk communication as well as the effects of false positive medical testing.

Brewer and others from the UNC School of Public Health - where Brewer is an associate professor in the heath behaviour and health education department - published results last year in the Annals of Internal Medicine about the long-term negative consequences of false-positive mammograms.

About half of American women receive a false-positive mammogram at some point in their lives. A false-positive mammogram happens when a women is told her initial mammogram is abnormal, but she later learns her breasts are healthy.

They found that women who received false positives were more anxious, worried and upset than women with normal results. The research also revealed that false-positive mammograms may increase some breast health behaviours. For instance, women who received false-positive mammograms were more likely to conduct breast self examinations.

Brewer also published study results last year in the Journal of Clinical Oncology showing that most breast cancer patients would be receptive to a new genomic test that can determine the chance of breast cancer recurrence and help plan treatment.

They found most patients would have been interested in a genomic test that showed their risk for recurrence at the time they were treated, had it been available. The majority said they would 'definitely' want to be tested (76 percent), receive their results (87 percent), and discuss these results with their physicians.

'Medical testing is getting more sophisticated and more accessible,' Brewer said. 'People regularly deal with genetic and genomic tests. You can even get a full body scan. All of these tests are subject to having false positives. As we increase the number of tests that people are exposed to, we run the risk of making them more and more anxious about their health.'

Brewer is also an adjunct professor in the psychology department in the UNC College of Arts and Sciences. In addition, he is an affiliated scholar in the Interdisciplinary Health Communication program and a faculty associate at the Centre for Genomics and Society.