A Number That Should Guide Your Health Choices (It’s Not Your Age)
During her annual visit, the patient’s doctor asks if she plans to continue having regular mammograms to screen for breast cancer, then reminds her that it’s been almost 10 years since her last colonoscopy.
She’s 76. Hmmm.
The age of the patient alone can be an argument against further mammogram appointments. The independent and influential US Preventive Services Task Force, in her latest design guidelinesrecommends screening mammography for women ages 40 to 74, but says “current evidence is insufficient to assess the balance of benefits and harms of screening mammography in women age 75 or older.”
Screening for colorectal cancer, with a colonoscopy or with a less invasive test, also becomes questionable later in life. The task force gives it a C class for those 76 to 85, meaning 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 condition? Were her parents well into their nineties? Does she smoke?
All of these factors affect her life expectancy, which in turn could make future cancer screenings useful, meaningless, or even harmful. The same considerations apply to a range of health decisions in old age, including those regarding drug regimens, surgery, other treatments and screenings.
“There’s no point in drawing these lines by age,” says Dr. Steven Woloshin, an internist and director of the Dartmouth Institute’s Center for Medicine and Media. “It’s age plus other factors that limit your life.”
Slowly but surely, therefore, some medical societies and health organizations have begun to change their approach, basing recommendations on tests and treatments on life expectancy rather than age alone.
“Life expectancy gives us more information than just age,” said Dr. Sei Lee, a geriatrician at the University of California, San Francisco. “It leads to better decision-making more often.”
Some of the task force’s recent recommendations already reflect this broader view testing for lung cancerFor example, the guidelines advise considering factors such as smoking history and “a health problem that significantly limits life expectancy” when deciding when to stop screening.
The task force’s colorectal screening guidelines call for consideration of an older patient’s “health status (e.g., life expectancy, comorbid conditions), prior screening status, and individual preferences.”
The American College of Physicians similarly includes life expectancy in hair guidelines for prostate cancer screening; so does the American Cancer Society, in its guidelines for breast cancer screening for women over age 55.
But how does that 76-year-old woman know how long she will live? How does anyone 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 2019 census data, he found huge variation.
The data shows that the least healthy 75-year-olds, who are in the bottom 10 percent, were likely to die within about three years. Those in the top 10 percent would likely live another 20 years or so.
All of these predictions are based on averages and cannot determine 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 estimates.
This is how Dr. Woloshin and his late wife and research partner, Dr. Lisa Schwartz, the National Cancer Institute in developing the Know your odds calculatorwhich went online in 2015. Initially, it used age, gender and race (but only two, black or white, due to limited data) to predict the probability of dying from specific common diseases and the probability of dying in general over a period of five to 20 years.
The Institute recently revised the calculator to add smoking status, a critical factor in life expectancy and one that, unlike the other criteria, users have some control over.
“Personal choices are driven by priorities and fears, but objective information can help inform those decisions,” says Dr. Barnett Kramer, an oncologist who led the institute’s Cancer Prevention division when it published the calculator.
He called it “an antidote to some of the fear-mongering campaigns patients see on television all the time,” courtesy of drug companies, medical organizations, advocacy groups and alarming media reports. “The more information they can glean from these tables, the more they can guard against health care choices that don’t help them,” said Dr. Kramer. Unnecessary testing, he pointed out, can lead to overdiagnosis and overtreatment.
A number of healthcare facilities 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 risk of breast cancerand Memorial Sloan Kettering Cancer Center offers one for it lung cancer.
However, calculators that look at individual diseases usually do not compare risks with those of mortality from other causes. “They don’t give you the context,” Dr. Woloshin said.
Probably the broadest online tool for estimating life expectancy in older adults eForecast, developed in 2011 by Dr. Widera, dr. Lee and several other geriatricians and researchers. Intended for use by healthcare professionals, but also available to consumers, it offers about two dozen validated geriatric scales that estimate mortality and disability.
The calculators, some for patients living alone and others for patients in nursing homes or hospitals, contain a great deal of information about health history and current functional ability. Handy is that one instrument “time to benefit”. that illustrates which screenings and interventions can continue to be useful at certain life expectancies.
Take a look at our hypothetical 76-year-old. If she’s a healthy, never-smoker who has no problems with daily activities and is able to walk a quarter mile without difficulty, among other things, a mortality scale on ePrognosis shows that her extended life expectancy makes mammography a reasonable choice, regardless of what the age guidelines say.
“The risk of using only age as a boundary means we sometimes undertreat very healthy seniors,” said Dr Widera.
If, on the other hand, she’s a former smoker with lung disease, diabetes, and limited mobility, the calculator indicates that while she should probably continue taking a statin, she could end breast cancer screening.
“Competitive mortality” — the chance that another disease will cause her death before the disease is screened for — means she probably won’t live long enough to see a benefit.
Of course, patients continue to make decisions for themselves. Life expectancy is a guideline, not a limitation on medical care. Some older people never want to stop screenings, even if the data shows they are no longer useful.
And some have no interest at all in discussing their life expectancy; just like some of their doctors. Both parties may overestimate or underestimate risks and benefits.
“Patients will just say, ‘I had a great-uncle who turned 103,'” Dr. Kramer herself. “Or if you say to someone, ‘Your long-term survival chances are one in 1,000,’ a strong psychological mechanism causes people to say, ‘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, the online tools provide valuable context beyond age alone. Given the expected life expectancy, “you know what to focus on, instead of being afraid of what’s in the news that day,” said Dr. Woloshin. “It anchors you.”
However, the developers want patients to discuss these predictions with their medical providers and warn against making decisions without their involvement.
“This is meant to be a starting point” for conversations, said Dr. Woloshin. “It’s possible to make much more informed decisions — but you need some help.”