A California study has concluded that women between the ages of 66 and 74 only need mammograms every two years. The researchers call the results comparable to having the test annually.
Study results appeared in the Journal of the National Cancer Institute. University of California, San Francisco researcher Dejana Braithwaite concluded that older women screened every other year have no greater risk of detection of breast cancer at a later stage than if they were screened each year, according to HealthMonitor. Braithwaite also found that annual screening was more likely to result in false-positive results than testing every two years.
The study examined data collected between 1999 and 2006 from 140,000 women between 66 and 89. All underwent mammograms at facilities with a data link between Medicare claims and the Breast Cancer Surveillance Consortium. Almost 3,000 had a breast cancer diagnosis.
The Centers for Disease Control and Prevention reports that breast cancer is the second most common cancer is U.S. women, behind non-melanoma skin cancer. Nearly 212,000 women received a breast cancer diagnosis in 2009. That same year, more than 40,000 U.S. women died from the illness.
Doctors use screening mammograms for women with no signs of breast cancer. The National Cancer Institute (NCI) says that potential harm associated with screening mammography includes false-negative results, false-positive results, overtreatment, overdiagnosis, and exposure to radiation.
The recommended frequency of screening women has been controversial over the years. NCI recommends screening mammograms every one to two years for women at least 40 years old and in good health -- coupled with a breast exam by a health care provider on a regular basis -- for the best chance of detecting early breast cancer.
Doctors order a diagnostic mammogram when a patient has a lump or other symptom of the disease. This type of mammogram can also evaluate changes noted during a screening mammogram and image breast tissue in special circumstances, such as the presence of breast implants.
The California scientists estimated the probability of false-positive results over a 10-year period for subjects in the 66 to 74 age group. Nearly half -- 48 percent -- of those who had undergone annual screening had at least one false-positive report. The figure for those screened every other year was only 29 percent. The researchers noted similar data in subjects aged 75 to 89. One potential reason is that breast cancer tends to grow more slowly in older women than in younger patients.
I had a baseline mammogram at 39. As one of the older baby boomers, I've watched screening guidelines vacillate for many years. However, I've continued to have annual mammograms.
Last year -- the "off" year if older women really only need mammograms every two years -- I had to undergo a diagnostic mammogram based on findings from a screening. Fortunately, it was overlapping tissue. I feel safer with yearly screening.
Vonda J. Sines has published thousands of print and online health and medical articles. She specializes in diseases and other conditions that affect the quality of life.