Study Debates When to Begin Taking Mammograms

Recent trends in breast cancer detection have wavered. To perform breast self-exams, or not? To get mammograms, or not?

The worry about breast self-exams is that they may skew results into too many false-positive tests. Some who recommend fewer mammograms have suggested that over-screening leads to unnecessary invasive tests and undue anxiety.

A 2010 study done in Norway and Sweden and published in the New England Journal of Medicine did not find significant improvement in survival rates for women who had annual mammograms beginning at age 40.  The authors of the study recommended mammograms every two years, beginning at age 50.

“The attitude of the U.S. has been annual mammograms at age 40,” said Dr. Rosanne Newell, director of the Solomon Katz Breast Center at Sound Shore Medical Center in New Rochelle.

The study—performed with a relatively homogenous population—didn’t include certain populations that are more prone to certain kinds of breast cancer, said Newell.  For example, the rate of triple negative breast cancer— breast cancer cells that test negative for estrogen receptors (ER-), progesterone receptors (PR-), and HER2 (HER2-)—is higher in African-American woman as they get older. Another risk factor for breast cancer is being overweight.

However, the 2011 Breast Cancer Symposium of the American Society of Clinical Oncology overwhelmingly supports these preventive measures. The American Cancer Society agrees.

“While there has been ongoing debate about when and how breast cancer screening should occur, this study validates that women who undergo regular mammography screening present at earlier stages and often require less aggressive treatment than those who do not,” said Dr. Jamie Caughran, medical director of the Comprehensive Breast Center at the Lacks Cancer Center in Grand Rapids, MI.

Caughran, who helped lead the research team for a recent study on mammography said women age 40 and up should use both methods for detection. High-risk patients should seek advice from their doctors about the age for and frequency of tests.  Certain potentially high-risk factors include having a first-degree relative with breast cancer, said Newall.

Should women worry about the additional radiation exposure from yearly mammograms?

“The amount of radiation is really very low compared to a CAT (Computerized axial tomography) scan,” said Newall.

The University of Michigan study, completed this year with data from nearly 6,000 women with breast cancer, counters guidelines by the U.S. Preventative Services Task Force, which recommends generally that women get mammograms every two years beginning at age 50. The USPSTF notes that screenings should be determined on an individual basis.

Among other findings in the Michigan study:

• Breast cancer in women younger than 50 was more likely to be detected first by feel than by mammography. Of the women whose tumors were found by feel, 40 percent were younger than 50.
• Overall, 65 percent of the breast cancer cases were detected by mammography, while 30 percent were detected by feel and the other 5 percent by other methods.
• For women diagnosed with breast cancer before age 50, 49 percent of the cases were detected by mammogram. Of those, 18 percent were Stage 2, and 4 percent were Stage 3.
• For women diagnosed with breast cancer before age 50, 46 percent of the cases were detected by feel. Of those, 50 percent were Stage 2, and 17 percent were Stage 3.
• For women over 50, 81 percent of breast cancers are detected through mammography.

The test is not perfect though.  According to Newall, there is an up to 15 percent rate of false negatives with mammograms, particularly with women with dense breasts. 

Still, “many small breast cancers are picked up,” she said, stressing the importance of mammograms for early detection and treatment of cancers.

In 2011, ASCO predicts 230,480 new cases of breast cancer for women, 2,140 for men, and 57,650 non-invasive cases. About one in eight women will develop breast cancer, according to ASCO.

According to the Center for Disease Control (CDC), approximately 124 out of every 100,000 women developed breast cancer in 2007 in New York State and approximately 22 out of every 100,000 woman died from it.  Using the latest U.S. Census data for 2010, that would translate to about 23,932 women who develop breast cancer in New York State, with 4,246 deaths.

“Women of all ages presented with palpable tumors, highlighting the use of self-breast exam as an important public health measure,” Caughran said.

 Please visit the American Cancer Society's website for more information on mammograms.