Breast Cancer Screenings Controversy Continues

Breast cancer screening benefits and harms for women 40 to 49

(RxWiki News) Cancer screening guidelines and recommendations are utterly confusing. For example, if you're a woman in your 40s, do you have mammography or not?

A review of a massive amount of data may help you have a more informed discussion with your doctor about what's best for you.

In looking at the benefits and harms of breast cancer screenings in women aged 40-49, a group of researchers has determined that two risk factors are most important to consider - the type of breast tissue a woman has and her family history.

For women who have these risks, every-other-year screening may be a good choice, as the benefits outweigh the harms, according to two articles published in the May 1, 2012 issue of Annals of Internal Medicine

"Talk to your doctor about when and how often to have breast cancer screenings."

Group Health Research Institute Senior Investigators Diana Miglioretti, PhD described the objective of this international research effort: "Mainly, we wanted to find out the tipping point: what level of increased risk women in their 40s needed to have to reach the same benefit-to-harm ratio for screening mammography as women aged 50 to 74," she said.

The benefits of breast cancer screening, according to the researchers, include years of life gained and breast cancer deaths averted.

The harms of screening include false-positives (what appears to be positive for disease that turns out to be false) mammography examinations which can result in overdiagnosis, more procedures, pain and anxiety.

Researchers also found that digital mammograms tend to result in more false-positives than single-film mammograms.

A harm that wasn't included but is very real is the cost of additional unnecessary procedures. 

"Our research suggests the benefit-harm balance is tipped in favor of every-other-year screening for women in their 40s who are at about twice the average risk of developing breast cancer," says the study's senior author Jeanne Mandelblatt, MD, MPH., associate director for population sciences at Georgetown Lombardi Comprehensive Cancer Center. 

This two-fold increase in risk of developing breast cancer occurs in women who have:

  • Extremely dense breasts as seen on a mammogram. About 13 percent of the women aged 40 to 49 have dense breasts
  • A first-degree relative with breast cancer; this accounts for about nine percent of women in this age group. 
  • If the relative was under the age of 50, the risk increases to more than two-fold.

Researchers acknowledge that designing and implementing  "risk-based" screening policies and guidelines will be tricky.

"For example, the need to have a mammogram to determine breast density is an important point to consider in regards to implementing risk-based guidelines based on breast density." Dr. Mandelblatt points out.

This analysis was based on  the collaboration of data through the records of three national research groups: the Breast Cancer Surveillance Consortium (BCSC), which contains information on over 9.5 million mammograms, 114,000 breast cancer cases, and more than 2.3 million women; Cancer Intervention and Surveillance Modeling Network (CISNET) which provided the model for the analysis  and the Oregon Evidence-based Practice Center. 

dailyRx Contributing Expert, Daniel R. Kopans, MD, PhD, disagrees whole-heartedly with these findings. " There are NO DATA - NONE, that show that any of the parameters of screening change abruptly at the age of 50, or any other age.

"To equate a recall from screening, which is generally resolved with a few extra pictures, as if it is as bad as dying from breast cancer is either insensitive, or worse," said Dr. Kopans who is professor of radiology at Harvard Medical School and senior radiologist - the Breast Imaging Division - Massachusetts General Hospital.

A vocal advocate for breast cancer screening starting at age 40, Dr. Kopans said, "All women should be informed of the 'risks and benefits'. Those who suggest that there is biological or scientific support for having different guidelines for women 40-49 and those 50 and over are either uniformed, or consciously choosing to mislead women and their physicians."

"These results are not intended to guide clinical care, but to provide evidence to groups striving to individualize screening guidelines based on risk factors," Mandelblatt said. 

"Ultimately, though, the decision of when to start screening and how often, and whether to have digital or film mammography should be left to women and their health care providers," she concluded.

This research was supported by grants from the National Cancer Institute.

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Review Date: 
April 30, 2012