Cancer Screening: It Could Be Hard to Get the Facts

Cancer screening guidelines may not adequately explain risks, benefits of screening

/ Author:  / Reviewed by: Beth Bolt, RPh

(RxWiki News) Most people would agree that cancer screening is a good thing. After all, you're either preventing cancer or catching it early. Unfortunately, the majority of cancer screening guidelines may be lacking in important patient information.

At least that's what researchers from the University of Michigan Health System are saying.

In a new study, these researchers found that more than two-thirds of US screening guidelines did not clearly explain both the potential benefits and harms of cancer screening.

"Almost all medical interventions have trade-offs between different types of benefits and harms," said lead study author Tanner J. Caverly, MD, in a press release. Dr. Caverly is a clinical lecturer of internal medicine at the University of Michigan.

He continued, "Patients rely on doctors to base screening recommendations on sound judgment as to whether, in their individual context, the benefits outweigh the harms."

For this study, Dr. Caverly and team looked at 55 professional recommendations for cancer screening and prevention. This included mammography recommendations for breast cancer prevention, colonoscopy recommendations for colon cancer prevention and HPV vaccination recommendations for cervical cancer prevention.

They found that 69 percent of the guidelines did not quantify the potential benefits and harms in similar terms. Fifty-five accentuated the potential benefits, but not the harms.

For instance, some studies used relative risk reduction — often a larger number — to measure a particular screening tool's potential benefits. Absolute risk — often a smaller number — was then used to measure that tool's potential harms.

"By unevenly presenting the statistics, guidelines can unintentionally give a false picture of the benefits and harms," said senior study author Angela Fagerlin, PhD, in a press release. Dr. Fagerlin is the chair of the University of Utah's Department of Population Health Sciences.

She continued, "The relative risk of 'twice as likely' sounds significant, but in terms of absolute risk it might represent a very small difference."

Drs. Caverly and Fagerlin suggest improving these guidelines by quantifying and presenting all potential benefits and harms equally. A well-designed table or graphic could help physicians easily understand the trade-offs of a particular screening tool and make the best decision for their patient, the authors said.

This study was published Feb. 23 in the Journal of the National Cancer Institute.

The VA Advanced Fellowship in Health Services Research & Development, the Michigan Center for Diabetes Translational Research and the National Institutes of Health funded this research. No conflicts of interest were disclosed.

Reviewed by: 
Review Date: 
February 25, 2016
Last Updated:
March 16, 2016