Number (not your age) to guide your choices
At her annual visit, the patient’s doctor asks if she plans to continue having regular mammograms to screen for breast cancer, and then reminds her that it has been almost 10 years since her last colonoscopy. She’s 76. Hmm.
The patient’s age alone may be an argument against further mammogram appointments. The independent and influential U.S. Preventive Services Task Force, in its latest draft guidelines, recommends screening mammograms for women 40 to
74, but says “the current evidence is insufficient to assess the balance of benefits and harms of screening mammography in women age 75 years or older.”
Screening for colorectal cancer, with a colonoscopy or with a less invasive test, becomes similarly questionable at advanced ages. The task force gives it a C grade for those 76 to 85, meaning there’s “at least moderate certainty that the net benefit is small.” It should only be offered selectively, the guidelines say.
But what else is true about this hypothetical woman? Is she playing tennis twice a week? Does she have heart disease? Did her parents live well into their 90s? Does she smoke?
Any or all such factors affect her life expectancy, which in turn could make future cancer screenings either useful, pointless or actually harmful. The same considerations apply to an array of health decisions at older ages, including those involving drug regimens, surgeries, other treatments and screenings.
“It doesn’t make sense to draw these lines by age,” said Dr. Steven Woloshin, an internist and director of the Center for Medicine and Media at the Dartmouth Institute. “It’s age plus other factors that limit your life.”
Slowly, therefore, some medical associations and health advocacy groups have begun to shift their approaches, basing recommendations about tests and treatments on life expectancy rather than simply age.
“Life expectancy gives us more information than age alone,” said Dr. Sei Lee, a geriatrician at the University of California, San Francisco. “It leads to better decision making more often.”
But how does that 76-year-old woman know how long she will live?
How does anybody know?
A 75-year-old has an average life expectancy of 12 years. But when Dr. Eric Widera, a geriatrician at the University of California, San Francisco, analyzed census data from 2019, he found enormous variation.
The data shows that the least healthy 75-year-olds, those in the lowest 10%, were likely to die in about three years. Those in the top 10% would probably live for another 20 or so.
All these predictions are based on averages and can’t pinpoint life expectancy for individuals. But just as doctors constantly use risk calculators to decide, say, whether to prescribe drugs to prevent osteoporosis or heart disease, consumers can use online tools to get ballpark estimates.
For instance, Woloshin and his late wife and research partner, Dr. Lisa Schwartz, helped the National Cancer Institute develop the Know Your
Chances calculator, which went online in 2015.
“Personal choices are driven by priorities and fears, but objective information can help inform those decisions,” said
Dr. Barnett Kramer, an oncologist who directed the institute’s Division of Cancer Prevention when it published the calculator.
He called it “an antidote to some of the fearmongering campaigns that patients see all the time on television,” courtesy of drug manufacturers, medical organizations, advocacy groups and alarmist media reports. “The more information they can glean from these tables, the more they can arm themselves against health care choices that don’t help them,” Kramer said. Unnecessary testing, he pointed out, can lead to overdiagnosis and overtreatment.
A number of health institutions and groups provide disease-specific online calculators. The American College of Cardiology offers a “risk estimator” for cardiovascular disease. A National Cancer Institute calculator assesses breast cancer risk, and Memorial Sloan Kettering Cancer Center provides one for lung cancer.
Probably the broadest online tool for estimating life expectancy in older adults is ePrognosis, developed in 2011 by Widera,
Lee and several other geriatricians and researchers. Intended for use by health care professionals but also available to consumers, it offers about two dozen validated geriatric scales that estimate mortality and disability.
Helpfully, there’s a “time to benefit” instrument that illustrates which screenings and interventions may remain useful at specific life expectancies.
Consider our hypothetical 76-year-old. If she’s a healthy never-smoker who is experiencing no problems with daily activities and is able, among other things, to walk a quarter mile without difficulty, a mortality scale on ePrognosis shows that her extended life expectancy makes mammography a reasonable choice, regardless of what age guidelines say.
“The risk of just using age as a cutoff means we’re sometimes undertreating” very healthy seniors, Widera said.
If she’s a former smoker with lung disease, diabetes and limited mobility, on the other hand, the calculator indicates that while she probably should continue taking a statin, she can end breast cancer screening.
“Competing mortality” — the chance that another illness will cause her death before the one being screened for — means that she will probably not live long enough to see a benefit.
The developers want patients to discuss these predictions with their medical providers, however, and caution against making decisions without their involvement.
“This is meant to be a jumping-off point” for conversations, Woloshin said. “It’s possible to make much more informed decisions — but you need some help.”