The Medical Minute: Screening mammography saves lives

May 09, 2007

By Susann E. Schetter

Breast cancer is the most frequently occurring cancer in women. This year, approximately 180,000 women in the United States will be diagnosed with this disease. The good news is that death related to breast cancer has decreased significantly due to early diagnosis and improved treatments. For many patients, physicians talk in terms of cure.

Since 1990 in the United States alone, the mortality rate of breast cancer has decreased 25 percent due to early diagnosis.

Early diagnosis is achieved through annual screening mammography. This screening examination takes 10 to 15 minutes once a year and can literally save lives. Annual screening is advocated for all women older than age 40 and should continue annually for as long as the person is in good health.

Mammography is the only screening examination proven to reduce mortality from breast cancer. Concerns are often voiced regarding the radiation received during annual screening. The conventional mammogram offers the same amount of radiation as a plane ride on a commercial jet from New York to Los Angeles. Radiation doses are decreased further with certain types of digital mammography.

Annual screening in women ages 40 to 49 has recently been challenged in the national media. An article published in the American College of Physicians in the Annals of Internal Medicine proposed that there are no proven benefits of annual screening in this age group. However, there are no valid trials that prove this hypothesis. The data to which they refer was extracted from prior trials that have serious flaws, poor quality mammograms or published information that has been repudiated by the very authors in years following publication. This information is misleading to physicians and dangerous for women.

In fact, current studies look at this subgroup and prove a 26 to 29 percent reduction in mortality in the 40 to 49 age group. This is at least as good and maybe better than the benefit after 50.

Statistics show that the incidence of breast cancer increases with age, and nearly 80 percent of breast cancer occurs in women over 50.

False positive screening mammograms do occur. Across the nation, approximately 10.6 percent of all women getting a mammogram receive a phone call to return for additional images. These additional images are invaluable in determining the need for additional studies. Most women that receive a call back have findings on their mammogram related to the abnormal appearance of normal breast tissue.

Breast imagers understand the anxiety and uncertainty related to this recall experience, and if additional images are needed, work to accommodate women at their convenience to complete the problem solving. Women should remember that a recall does not mean that they have breast cancer. The recall rate at Penn State Hershey Breast Program's imaging area is below the national average, only 6 to 7 percent.

Women with known risk factors should know that screening mammography should begin before age 40 in certain cases. Women with a first-degree relative (mother, sister) with the history of breast cancer should begin screening at an age 10 years prior to the age of diagnosis in their relative. Women with a history of radiation to the chest, such as in Hodgkin's lymphoma, should begin eight years following cessation of therapy, but not before age 25.

Only about 5 percent of cancers occur due to mutations in the BrCa I and BrCa II genes, and about 20 percent of women with cancer will have a family history. This means that most women with breast cancer, 70 to 80 percent, have no known risk factors.

A detailed list of risk factors can be found on the American Cancer Society Web site at online.

Women of high risk, greater than 20 percent lifetime risk, have been shown to benefit from annual MRI added to the screening mammogram, sometimes recommended in an alternating fashion at six month intervals. Women who believe they fit into this group of patients should consult with their health-care provider.

In honor of Mother's Day, Penn State Hershey Breast Program will host an employee mammogram screening day for all Penn State campus employees from 8 a.m. to 2 p.m., Saturday, May 12. Call the 24-hour CareLine at (800) 243-1455 to schedule an appointment at one of the following Penn State University Physician Group locations: 670 Cherry Drive, Hershey, suite 201, or 121 Nyes Road, suite B.

Susann E. Schetter is chief of the Division of Breast Imaging, Department of Radiology, at Penn State Milton S. Hershey Medical Center and Penn State College of Medicine.

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Last Updated March 19, 2009