Balancing the Benefits and Risks of Mammograms

Breast cancer screening by mammogram is effective in preventing some deaths but risks are a consideration

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) High public awareness of breast cancer has driven charity walks and fundraising from large organizations that stress the importance of regular screening mammograms.

But a new medical editorial reminds women to carefully balance the benefits and risks of mammograms as they seek early prevention of the potentially deadly disease.

As evidence of the small benefit, the editorial writers cited recent large-scale research that found for every 10,000 women screened about 27 deaths would be avoided.

Risks linked to mammograms include the potential that repeated X-ray radiation might actually cause cancer.

"Ask an oncologist about recommendations for mammograms."

Harald Weedon-Fekjaer, from the Department of Public Health at the Norwegian University of Science and Technology, Department of Biostatistics at the University of Oslo and Center for Biostatistics and Epidemiology at Oslo University Hospital, led this recent research.

The research team set out to determine the effectiveness of modern mammogram breast cancer screenings.

A mammogram is essentially an X-ray of the breast and is a frontline tool in early detection of breast cancer.

The United States Preventive Services Task Force recommends a mammogram screening every other year for women aged 50 to 74 years. However, the issue of mammogram screening is the source of some debate.

Weedon-Fekjaer and team used data from all Norwegian women aged 50 to 79 years over a study period from 1986 to 2009.

Included in that time period, 1995 to 2005, the government of Norway established a national screening program that sent out invitations for screening every other year to women between 50 years old and 69 years old.

In total, 638,238 study participants were observed for more than 15 million person-years of evaluation.

The researchers found that, over the course of study, 1,175 women invited to the mammography screenings died of breast cancer. In the group that was not invited to screenings, 8,996 women died from breast cancer.

Women who were invited to the study had a 28 percent lower risk of death from breast cancer than the women not invited to screenings.

More specifically, the study found that about 76 percent of the women invited to screenings actually attended. Receiving the screening was associated with a 37 percent decreased risk of death from breast cancer.

The research team also estimated how many women in the 50-69 year age group would need to be invited to a once-every-other-year screening to prevent one death. Based on the study results, 368 women would need to be invited to prevent one death.

In a recent editorial article in BMJ, medical professors Joann Elmore, MD, MPH, of University of Washington School of Medicine in Seattle, and Russell Harris, MD, of the University of North Carolina-Chapel Hill, wrote that the Norwegian study "adds important information to a growing body of observational evidence estimating the benefits and harms of screening."

The editorial authors praised the Norwegian team’s work for covering a two decade time period and for confirming “what is already known: the benefits of screening mammography are modest at best.”

The editorial authors went on to weigh the benefits of mammography against the harms of screening like overdiagnosis, mental stress and high medical costs. They called for balanced information for women around the world instead of the prevalent trend of emphasis on the benefits of screening mammography.

“Beyond it’s relevance to women’s decision making today, the Norwegian study should make us reflect on how to monitor the changing benefits and harms of breast cancer screening," Drs. Elmore and Harris wrote.

This study and editorial were published in June in BMJ.

The Norwegian Research Council provided financial support for the study.

The authors did not report any conflicts of interest, financial or otherwise.

Review Date: 
June 17, 2014
Last Updated:
June 25, 2014