Breast cancer screening saves lives. Cancer specialists and researchers agree with this statement and encourage women to be screened. But experts’ opinions vary about exactly how often screening should be done and at what age screening should begin. These differences of opinion among experts lead to varying guidelines from multiple sources and cause confusion for patients and even doctors.
Benefits of annual mammography
For women at average risk of breast cancer, The University of Texas MD Anderson Cancer Center recommends annual clinical breast examination and screening mammography (x-rays of the breast) beginning at age 40 years. Women at high risk of breast cancer may need to begin screening at an earlier age or undergo screening at more frequent intervals.
“We know that annual screening results in fewer women dying from breast cancer,” said Therese Bevers, M.D., a professor in the Department of Clinical Cancer Prevention. “And that’s what MD Anderson is about. We want fewer women to die from breast cancer, and that’s why we recommend annual mammograms beginning at age 40.”
Dr. Bevers added that these guidelines are in accordance with those of the National Comprehensive Cancer Network, an alliance of 26 leading cancer centers, including MD Anderson.
Avoiding false-positive findings
Last fall, the American Cancer Society (ACS) made headlines when it changed its breast cancer screening guidelines. The ACS had previously recommended annual screening mammography beginning at age 40 years for women at average risk of breast cancer, but the organization’s new guidelines for women at average risk call for screening mammography every year between ages 45 and 54 years and every other year at age 55 years and older. However, the new ACS guidelines also recommend that annual screening be available to women between 40 and 44 years old and those 55 years and older. This last suggestion was ignored or only briefly mentioned in some news reports about the new ACS guidelines.
“If people just see a headline that says the ACS recommends that screening start later and occur less often, they miss the nuances of what the guidelines actually say,” Dr. Bevers said. “If you consider those additional statements, that a woman can begin screening at age 40 and can continue annual screening after age 55, the ACS endorses what MD Anderson is doing.”
Dr. Bevers said that the ACS suggests beginning screening at 45 years because women 45 years and older have a greater incidence of breast cancer and a slightly lower rate of false-positive findings (masses that look like cancer but are not) on mammography than women 40–44 years old.
False-positive findings can lead to additional screening tests, including needle biopsy, and can cause anxiety for the patient. However, Dr. Bevers said, studies have shown that this anxiety is short-lived.
Benefits of clinical breast examinations
Another key difference between the MD Anderson and ACS guidelines is that MD Anderson recommends clinical breast examinations while the ACS does not. “The ACS felt that there were no data to support the clinical breast exam,” Dr. Bevers said. “We acknowledge that the data are limited, but some data show benefit from the clinical breast exam. And we think the value of the clinical encounter extends beyond the clinical breast exam. A woman should see her clinician every year—whether a clinical breast exam is done or not—because the doctor can help determine the patient’s risk of breast cancer.”
Like the MD Anderson guidelines, the ACS guidelines call for starting screening mammography earlier for women at higher risk of breast cancer. But several factors influence cancer risk, and doctors can help their patients weigh these factors to decide on appropriate screening.
“The doctor also can give women advice about reducing their risk of breast cancer by losing weight or avoiding weight gain, following a healthy diet, and exercising,” Dr. Bevers said. “Ultimately, we’d like to not only detect cancers early but also prevent cancers from occurring in the first place.”
Dr. Bevers is concerned that the confusion from conflicting guidelines might discourage women from breast cancer screening. She advises women to discuss their risk factors for breast cancer and the benefits of screening mammography with their doctors. “For women at average risk,” Dr. Bevers said, “annual mammography and clinical breast exams starting at age 40 is the highest level of care, so that’s what we’ll continue to recommend.”
For more information, ask your physician, call askMDAnderson at 877-632-6789, or read MD Anderson’s breast cancer screening guidelines.
OncoLog, January 2016, Volume 61, Issue 1