Sept. 6, 2011 -- Once again, researchers are questioning the wisdom of guidelines that do not recommend annual mammograms for women aged 40-49 who are at average risk of breast cancer.
In November 2009, the U.S. Preventive Services Task Force (USPSTF) issued revised guidelines suggesting women 40-49 discuss the risks and benefits of having a mammogram with their doctor and decide what to do on an individual basis.
"But our data show that women who undergo regular mammography screening present at earlier stages and often require less aggressive treatment than those who do not,” says Jamie Caughran, MD, medical director of the Comprehensive Breast Center at the Lacks Cancer Center in Grand Rapids, Mich.
"This is true for women older than 50 years, as well as women aged 40 to 49 years for whom routine mammography is questioned by the USPSTF.”
The American Cancer Society and the American College of Radiology continue to advise women to begin routine screening annually at age 40.
In 2011, more than 290,000 cases of breast cancer are expected to occur in the U.S. Women under 50 account for at least one-fourth of breast cancer diagnoses.
Mammography Associated With Less Advanced Breast Cancer
Caughran presented the findings at a news briefing held in advance of the Breast Cancer Symposium in San Francisco.
Using a statewide breast cancer registry, the researchers examined data on 5,903 women diagnosed and treated for breast cancer between 2006 and 2009.
Among the findings:
- Overall, 3,869 (65.5%) breast cancers were detected by mammography; 1,759 (29.8%) were detected by touch, and 4.7% by other methods. The vast majority (90%) of tumors found by touch were detected during self-exam; only 10% were found during doctor examination.
- In women under 50, about 48% of cancers were detected by mammography, while 46% were found by touch.
- Women with tumors found by touch had more advanced cancers; 50% and 17% were diagnosed at stage II and III, respectively, compared with 18% and 4% found through mammography.
- Forty-six percent of patients whose tumors were detected through touch underwent mastectomy vs. 27% of those whose cancers were found by mammography.
- Twenty-three percent of women whose tumors were found by touch had chemotherapy, compared with 16% of women whose tumors were found by mammography.
Caughran says that although the cost of a mammogram is obviously more than that of self-exam, that needs to be weighed against that fact that finding by touch is associated with more aggressive treatment.
Risks, Benefits of Annual Mammograms in Younger Women
Daniel B. Kopans, MD, professor of radiology at Harvard Medical School, says, "This paper reinforces what many of us have been saying ever since the USPSTF guidelines were issued. Mammography screening saves lives and women should be encouraged to participate from age 40."
A study that used computer models showed that as many as 100,000 lives would be lost unnecessarily among women who are now in their 30s if the USPSTF, rather than the American Cancer Society, guidelines were followed, he tells WebMD.
But George F. Sawaya, MD, says that the researchers fail to mention potential harms -- including anxiety, unnecessary biopsies, and unnecessary treatment of cancers that would never become life threatening -- against which one might weigh benefits. Sawaya was a member of the Task Force but stresses that he is not speaking on its behalf.
"Women aged 40 to 49 years are not omitted from the USPSTF guidelines. The recommendation for women under 50 years is to make individualized decisions based on benefits and harms," says Sawaya, professor of obstetrics, gynecology and reproductive sciences and epidemiology and biostatistics at the University of California, San Francisco.
Caughran counters, "Ask a woman if she'd rather go through the anxiety of an unnecessary biopsy or miss a cancer, and I think she'd pick the former."
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.