At her annual visit, the patient’s doctor asks if she plans to continue getting regular mammograms to screen for breast cancer, then reminds her that it’s been almost 10 years since her last colonoscopy.
She’s 76. Hmm.
The patient’s age alone can argue against more appointments for mammograms. The independent and influential US Preventive Services Task Force, in its latest draft guidelinesrecommends screening mammograms for women ages 40 to 74, but says “current evidence is insufficient to assess the balance between benefits and harms of screening mammography in women ages 75 and older.”
Detection of colorectal cancer, with a colonoscopy or with a less invasive test, becomes equally questionable in advanced ages. The working group gives a C grade for those 76 to 85, which means that there is “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? Does she play tennis twice a week? Does she have a heart disease? Did her parents of hers live well into their 90’s? She smokes?
Any or all of these factors affect your life expectancy, which in turn could make future cancer screening tests helpful, useless, or downright harmful. The same considerations apply to a variety of health decisions at later ages, including those involving drug regimens, surgeries, other treatments, and screening tests.
“It doesn’t make sense to draw these lines by age,” said Dr. Steven Woloshin, an internist and director of the Dartmouth Institute’s Center for Medicine and Media. “It is age plus other factors that limit your life.”
Slowly, therefore, some medical associations and health advocacy groups have begun to change their approaches, basing testing and treatment recommendations on life expectancy rather than simply age.
“Life expectancy tells us more than age alone,” said Dr. Sei Lee, a geriatrician at the University of California, San Francisco. “It leads to better decision making more often.”
Some recent recommendations from the task force already reflect this broader vision. For older people undergoing lung cancer testsFor example, the guidelines advise considering factors such as smoking history and “a health problem that substantially limits life expectancy” when deciding when to stop screening.
The task force’s colorectal screening guidelines call for consideration of the “health status (eg, life expectancy, comorbid conditions), prior screening status, and individual preferences” of an older patient.
The American College of Physicians also incorporates life expectancy into its Prostate Cancer Screening Guidelines; so does the American Cancer Society, in its guidelines for breast cancer screening for women age 55 and older.
But how does that 76-year-old woman know how long she will live? How does anyone know?
A 75-year-old person has an average life expectancy of 12 years. But when Dr. Eric Widera, a geriatrician at the University of California, San Francisco, analyzed the 2019 census data, he found huge variation.
The data shows that the least healthy 75-year-olds, those in the bottom 10 percent, were likely to die in about three years. Those in the top 10 percent would probably live for another 20 or so.
All these predictions are based on averages and cannot determine people’s life expectancy. But just as doctors constantly use risk calculators to decide, for example, whether to prescribe drugs to prevent osteoporosis or heart disease, consumers can use online tools to get rough estimates.
For example, Dr. Woloshin and his late wife and research associate, Dr. Lisa Schwartz, helped the National Cancer Institute develop the Know Your Possibilities Calculatorwhich went online in 2015. Initially, it used age, sex, and race (but only two, black or white, due to sparse data) to predict the odds of dying from specific common diseases and the overall odds of mortality within five to 20 years.
The Institute recently reviewed the calculator to add smoking status, a critical factor in life expectancy and one over which, unlike the other criteria, users have some control.
“Personal choices are driven by priorities and fears, but factual information can help inform those decisions,” said Dr. Barnett Kramer, an oncologist who headed the institute’s Division of Cancer Prevention when he published the calculator.
He called it “an antidote to some of the scare campaigns patients see all the time on TV,” courtesy of drugmakers, medical organizations, advocacy groups and alarming media reports. “The more information they can get from these charts, the more they can arm themselves against healthcare options that don’t help them,” Dr. Kramer said. Unnecessary testing, he pointed out, can lead to overdiagnosis and overtreatment.
Various health institutions and groups offer disease-specific online calculators. The American College of Cardiology offers a “risk estimator” for cardiovascular disease. A calculator from the National Cancer Institute assesses breast cancer riskand Memorial Sloan Kettering Cancer Center provides one for lung cancer.
However, calculators that analyze individual diseases do not usually compare the risks with those of mortality from other causes. “They don’t give you the context,” Dr. Woloshin said.
Probably the most extensive online tool to estimate life expectancy in older adults is electronic forecast, developed in 2011 by Dr. Widera, Dr. Lee, and several other geriatricians and researchers. Designed for use by healthcare professionals but also available to consumers, it offers around two dozen validated geriatric scales that estimate mortality and disability.
The calculators, some for patients living alone and others for those in nursing homes or hospitals, incorporate considerable information about health history and current functional capacity. Fortunately, there is a “time to benefit” instrument illustrating which tests and interventions may continue to be useful at specific life expectancies.
Consider our hypothetical 76-year-old man. If she is a healthy woman who has never smoked, has no problems with daily activities, and can, among other things, walk a quarter mile without difficulty, a mortality scale on ePrognosis shows that her extended life expectancy makes mammography a reasonable option, regardless of what the age guidelines say.
“The risk of using age as a cutoff means that sometimes we are not treating well” very healthy older adults, Dr. Widera said.
If you’re a former smoker with lung disease, diabetes, and limited mobility, on the other hand, the calculator says that while you should probably continue taking a statin, you can stop getting screened for breast cancer.
“Competing mortality” (the chance that another disease will kill you before the one being tested for) means that you probably won’t live long enough to see a benefit.
Of course, patients will continue to make their own decisions. Life expectancy is a guide, not a limit in medical care. Some older people never want to stop getting screened, even when the data shows they are no longer useful.
And some have exactly zero interest in discussing their life expectancy; so do some of your doctors. Either party may overestimate or underestimate the risks and benefits.
“Patients will just say, ‘I had a great-uncle who lived to be 103,’” Dr. Kramer recalled. “Or if you say to someone, ‘Your chances of long-term survival are one in 1,000,’ a strong psychological mechanism leads people to say, ‘Oh, thank God, I thought it was hopeless.’ I saw it all the time.”
But for those looking to make health decisions based on evidence-based calculations, online tools provide valuable context beyond age. Given the projected life expectancy, “you’ll know what to focus on, rather than being scared by what’s on the news that day,” Dr. Woloshin said. “It anchors you.”
However, the developers want patients to discuss these predictions with their medical providers and warn against making decisions without their input.
“This is meant to be a starting point” for the talks, Dr. Woloshin said. “It’s possible to make much more informed decisions, but you need help.”