Screening women in their 40s for breast cancer is controversial, especially since an influential organization recommended in 2009 against screening all women of this age group. But now researchers say they have more evidence that yearly mammograms should start at age 40.
The new findings show that women without a family history of breast cancer were just as likely to develop invasive breast cancer, a type of cancer that can be lethal, as women without a family history of the disease. Women in the study were ages 40 to 49.
The findings suggest annual mammograms are beneficial for all women in their 40s, said study researcher Dr. Stamatia Destounis, a radiologist at Elizabeth Wende Breast Care, LLC, in Rochester, N.Y.
"We're identifying a considerable number of breast cancers in that age group," Destounis said, and invasive breast cancers are "not cancers that can wait."
Invasive breast cancers are cancers that have spread beyond their site of origin (often the lining of the milk ducts) and into the breast tissue. These cancers have a worse prognosis and can spread to other parts of the body, Destounis said.
The new study will be presented today (Nov. 29) at the annual meeting of the Radiological Society of North America, in Chicago.
Destounis and colleagues reviewed records from 1,071 women in their 40s who underwent mammograms at Elizabeth Wende Breast Care between 2000 and 2010. A total of 373 were diagnosed with breast cancer as a result of screening.
In the majority of cancer cases (228 patients), the women did not have a family history of the disease, meaning they did not have mothers, grandmothers, sisters or cousins with breast cancer. And of these patients, 64 percent had invasive breast cancer.
Among the patients who did have a family history of breast cancer, 63 percent had invasive cases of the disease.
In addition, about 30 percent of patients in both groups had cancer that had spread to their lymph nodes, Destounis said.
A criticism of mammograms is that they find cancers that ultimately wouldn't be harmful to the patient, Destounis said. But the cancers identified in this study "are cancers that need to be detected," and treated, Destounis said.
Society vs. the individual
In 2009, the U.S. Preventive Services Task Force recommended regular mammograms for women once they reach age 50. The task force said that, for women in their 40s, the benefits of screening did not outweigh the risks, which include unnecessarily biopsies. Indeed, a recent study supported this concern, finding that 61 percent of women who have yearly mammograms will have at least one false positive result over a decade.
Both the American Cancer Society and the National Cancer Institute recommend yearly mammograms starting at age 40.
While we don't have evidence that early mammograms prolong patients' lives, Dr. Stefan Gluck, an oncologist at the University of Miami Sylvester Cancer Center, still recommends mammograms starting at age 40.
"To do screening early is always better than not," Gluck said. A patient's treatment may be less drastic if the disease is caught earlier, Gluck said.
Gluck said screening recommendations are intended for society as a whole and are not necessarily what is best for the individual. "I'm here for my patients, not the population," Gluck said.
Pass it on: Guidelines on breast cancer screening are conflicting, but the decision is ultimately up to the individual.