If you’re in the habit of getting annual mammograms, the thought of stopping, even when you’ve reached an age when the risks might outweigh the benefits, may seem alarming.
Because the dominant public health approach has traditionally supported screening, mammogram benefits may be overestimated—and its harms underestimated—particularly for women ages 75 and older. While continuing a screening regimen may simply seem like a given instead of a choice, it’s important to fully understand mammography’s potential benefits and risks in the context of your overall health to make an informed decision.
The current guidelines
Even though advancing age is the major risk factor for breast cancer, current guidelines give little advice to doctors treating women ages 75 and older. This absence of advice stems from the lack of older women included in screening mammography clinical trials. The extent of screening benefits remains unknown given the dearth of data. In fact, most medical societies—including the American Cancer Society, the American College of Obstetricians and Gynecologists, and the American College of Radiology—decline to suggest an upper age limit for annual screening mammograms, instead leaving the decision to women and their doctors.
The groups suggest weighing the potential benefits and risks as well as the individual’s overall health and expected longevity. The U.S. Preventive Services Task Force (USPSTF)—a federal advisory panel of medical experts—recommends mammograms every other year for women up to and including age 74 and concludes that current evidence is insufficient to assess screening mammography in women older than 74.
For younger women, the advice has changed a bit. Though once a staunch supporter of earlier and more regular mammograms, the American Cancer Society modified its recommendations in October 2015, now recommending that annual mammograms be optional for women 40 to 44. Women age 45 should start getting annual mammograms and continue with yearly screening till age 54, according to the guidelines. Women 55 and up can transition to getting a mammogram every other year, though they may choose to continue annual screenings, as long as they are in good health with a life expectancy of at least 10 years.
The other medical societies continue to recommend that women at average risk should begin getting annual mammograms at age 40. However, the USPSTF recommends that women start mammography screening later, at age 50, and continue to do so every two years.
In a review published in the April 2014 issue of the Journal of the American Medical Association (JAMA), researchers aimed to provide an individualized decision-making approach to breast cancer screening for women ages 75 and older. The study authors suggested that 10-year life expectancy be the guide for the decision to continue or stop screening. They based their conclusion on the limited data available from 1990 to the present examining risk factors for women over 65 and the harms and benefits of mammograms for women over 75.
The pros of screening
The main benefit of mammograms is their ability to identify cancer at an early and typically treatable stage, which lowers the chances of dying of breast cancer. Mammograms also enable doctors to identify small cancers that haven’t yet caused detectable symptoms and that may require only minor surgery—important for older women who can’t tolerate major surgery.
In the JAMA review, the authors noted that no controlled, randomized clinical trials—considered the gold standard in study design—were conducted on women older than 74. However, they pointed to three past studies using hypothetical models that estimated the benefits of performing screening mammograms in women ages 70 to 79 vs. stopping screening at age 69. All three models arrived at the same conclusion: Women continue to benefit from screening after 69 years of age.
Mentally, getting a mammogram may be reassuring for some older women, too, and make them feel good about their health.
The cons of screening
The harms of screening mammograms are important to consider. Overdiagnosis is the most serious harm: Mammograms may identify a slow-growing cancer that would have otherwise never caused symptoms or needed treatment. But since screening can’t distinguish between slow-growing and more aggressive cancers, doctors must treat the cancer as if it’s harmful. As a result, treatment such as chemotherapy, radiation, and surgery can lead to needless pain, anxiety, potential complications, and healthcare costs. The overdiagnosis risk increases with age, as more slow-growing cancers develop in older patients.
What’s more, the benefits of breast cancer treatments in women ages 75 and older remain largely unknown because, again, few studies have included women in this age group. And while some treatments may be effective among older women in good health, the risks of complications increase with age, especially among women with limited life expectancy.
Treatment-related complications include short-term cognitive decline, increased toxicity, and mortality from chemotherapy; fatigue, breast pain, swelling, and increased risk of heart disease from radiotherapy; and increased risks of endometrial cancer, blood clots, joint and muscle pain, heart disease, and fractures from hormonal therapies. Twenty percent of women ages 65 and older who undergo breast cancer surgery have complications.
Finally, women ages 75 and older who undergo screening every other year have a 14 to 27 percent likelihood of a false-positive mammogram result (when a screening indicates an abnormality but no malignancy actually exists). The probability increases with age and is doubled if screening is done yearly. False-positives can lead to repeat tests that may cause psychological distress, as well as potential complications from follow-up procedures, such as breast biopsies.
Late-life risk factors
The order of importance of a woman’s risk factors may shift over time, another factor to take into account when reconsidering routine mammograms. A woman’s risk of developing breast cancer increases with advancing age, peaking between ages 75 and 79. However, reduced life expectancy associated with aging makes her more likely to die of another condition, such as heart disease, than from breast cancer.
Whereas a family history of breast cancer has always been considered a major risk factor, doctors are unsure whether it plays such a large role in late-life breast cancer. Likewise, risk factors associated with hormonal factors—a woman’s age at the time of her first period and first birth—may become less important as women get older. Instead, other conditions affected by hormones become more important, such as lifelong obesity, dense breasts, and high bone mass that may indicate high levels of estrogen in the body.
Questions to ask your doctor
You can make an informed decision about continuing routine mammograms by weighing the pros and cons of screening mammograms based on your overall health, life expectancy and preferences. Consider asking your doctor:
• What are my personal breast cancer risk factors?
• What are the harms of mammograms at my age?
• Am I in good enough health to get a mammogram?
• What do you suggest to your patients in similar health?
• Are treatments available for me if cancer is found?
• What are the risks of treatment?
Screening may not be practical for everyone and can even be harmful to some—namely, older women with a limited life expectancy who may not reap the same benefits from a mammogram as younger women may.
The JAMA study serves as a reminder that the practice of getting mammograms after age 74 should not be performed year after year without giving the routine further thought. Doctors and patients need to discuss carefully the risks associated with mammograms, along with the screening’s protective effects.
Despite a mammogram’s potential risks, observational studies suggest that women ages 75 and older in good health with a life expectancy of more than 10 years should still be given the opportunity to consider screening.