Most older women may not have to get breast cancer screening with mammography more than once every three years. But women with dense breasts may need a mammogram at least yearly, new research suggests.
There has been plenty of confusion regarding breast screening and mammogram results, but one thing is clear: mammography helps lower the risk for breast cancer, Reuters reports.
Researchers found that among women 50 to 74 years old, those who did not have a high risk of breast cancer or dense breast tissue were not more likely to die if they went for a mammogram every three years, instead of every two.
But for women with dense breasts, this means a higher risk for cancer tumors, which in turn means yearly mammograms that were linked to fewer breast cancer deaths, compared to screening once every two years.
Amy Trentham-Diaz, lead study author from the University of Wisconsin-Madison, says,
Women with dense breasts and high breast cancer risk may have added benefit from annual compared to biennial mammography.
Doctors have varying opinions on when and how frequently they recommend breast screening mammograms for women who don’t feel discomfort or have no lumps in their breasts. While these routine tests can save lives, they can also put women through painful yet unnecessary treatments.
The American Cancer Society changed its guidelines last year to urge women to start annual screenings at the age of 45 instead of 40, and to go once every two years when they turn 55.
The US Preventive Services Task Force recommends that women ages 50 to 74 get mammograms every other year.
Breast cancer is the most common form of cancer in women worldwide. Around one in nine women will develop it, and the risk increases as one gets older, and if any close female relative has been diagnosed with it.
If mammogram results show suspicious areas, women typically get additional imaging tests to rule out cancer, followed by a biopsy if things remain unclear. When extra tests don’t find cancer, mammograms are called a “false positive.”
For this study, Trentham-Diaz and a team estimated the chances of false positives, biopsies that did not find cancer, and deaths prevented based on age, cancer risk factors and breast density.
They found that compared with screening every two years, mammograms every three years reduced false positives, biopsies, and over-diagnoses. When women had higher risks of breast cancer, however, annual screening was better, regardless of breast density.
Dr. Christine Berg of Johns Hopkins University School of Medicine, who wrote an accompanying piece to the study, says, “Breast cancers are also more difficult to detect in dense breasts. Therefore annual mammograms allow for comparison of subtle changes.”
The only way to find out if a woman’s breasts are dense is through a mammogram, which can then evolve over time.
The end message for women is complex, according to Dr. Kathryn Evers, director of mammography at Fox Chase Cancer Center. “There are numerous risk factors for breast cancer, and women have different levels of comfort with the risks and benefits involved,” she says. Evers, who was not involved in the study, points out that at the end of the day, women should talk to their doctors about what is best for them, taking all these factors into account.
The study was published in the Annals of Internal Medicine.