December 30, 2013 | by Denise Heady
Preventive mammogram guidelines have long been a hot topic for debate.
Medical professionals and health care organizations are divided on how often a woman should be screened and at what age a woman should start preventive screening.
Health care organizations such as the American Cancer Society recommend annual mammograms for women beginning at age 40. The U.S. Preventive Services Task Force recommends that women be screened every two years starting at age 50.
A new study, however, found that women who had mammograms every 12 to 18 months lowered the risk that cancer would spread to the lymph nodes.
“[The new study] adds more power behind the fact that we do need screening mammograms starting at age 40 and every year,” said Laura Kruper, M.D., director of the Rita Cooper Finkel and J. William Finkel Women’s Health Center at City of Hope, in an interview with HealthDay.
The study was led by Lilian Wang, M.D., assistant professor of radiology at Northwestern University/Feinberg School of Medicine in Chicago, and the findings were presented this month at the annual meeting of the Radiological Society of North America.
Wang conducted the study to explore what would happened if women followed the revised guidelines the U.S. Preventive Services Task Force issued in 2009 and were screened every two years instead of one.
Researchers studied 332 women who were diagnosed with breast cancer found during a routine mammogram from 2007 to 2010. The women were divided into three groups based on the length of time between their screening mammograms: less than 18 months, 18 months to three years and more than three years.
Wang evaluated the women to see how many of them had cancer that had spread to their lymph nodes. She found that the women in the less than 18-month interval group had the lowest rate of spread to the lymph nodes at 8.7 percent. The other two groups came in with significantly higher rates: 20.5 percent for the 18-month to three-year interval group and 15.4 percent for the over three-year interval group.
Although the study was able to link frequent mammograms to less lymph node involvement, researchers were not able to determine a cause-and-effect relationship.
“Our study shows that screening mammography performed at an interval of less than one and a half years reduces the rate of lymph node positivity, thereby improving patient prognosis,” Wang said in a press release.
Kruper agreed with Wang and told HealthDay that the study’s focus on cancer spreading to the lymph nodes is valid. In its earliest stages, breast cancer is often confined to the breast, and cancer cells can be removed surgically. But as the disease progresses, cancer cells can spread to the lymph nodes and then on to other parts of the body.
"If you catch someone with early-stage cancer, they are going to need less-extensive surgery, and maybe no chemo," Kruper said in the HealthDay interview.
“We should be following the guidelines of the American Cancer Society and other organizations, recommending that women undergo annual screening mammography beginning at age 40,” Wang said.