Many cancer screenings get phased out as people age. Why these guidelines are controversial.

Screenings are important tools used to detect cancer early on, when it's more likely to be treatable. But many screening guidelines phase out these tests over time based on a patient's life expectancy. Now a new poll finds that's not a popular choice.

The poll, which is part of the ongoing University of Michigan National Poll on Health Aging, involved 2,563 adults aged 50 to 80 who were asked their opinion on cancer screening guidelines. The majority — 62% — said that national guidelines on stopping cancer screenings should not be based on how long that person may have left to live.

For 7 in 10 older adults, they don't believe that it's a "significant problem" that some older adults receive cancer screening tests when guideline recommendations say they should not. The 10-year life expectancy limit on some cancer screening guidelines, such as breast cancer screenings, also raised eyebrows — 27% of those surveyed said it was too short.

"How to help older adults understand when to continue to get cancer screenings and when they should stop is a big topic in cancer prevention these days," Brian J. Zikmund-Fisher, a professor of health behavior and health education at the University of Michigan, who worked on the poll, tells Yahoo Life.

Zikmund-Fisher says that, while it's important to have adults start cancer screenings at the recommended ages, the guidance gets a little more complicated as people age. "There are a lot of older adults for whom continuing to get colonoscopies or mammograms may not be the best idea," he says. "While expert panels can make recommendations, what ultimately matters is what older adults and the health care professionals who care for them are willing to do or not do."

Why is life expectancy used to determine guidelines?

There are a few reasons why life expectancy is used. "Life expectancy takes into account not only age but the health of the person," Electra Paskett, a cancer control researcher with the Ohio State University Comprehensive Cancer Center, tells Yahoo Life. Paskett admits that it's "not an exact measure," but that screening is often done to detect early cancers when they can be treated and lower the risk of death.

If cancer screenings continue when someone is not expected to live more than 10 years, "you don't see the benefit until the time the cancer would have caused death," she says.

Cancer screenings can also come with their own risks, Dr. Christine Sam, assistant member in the Senior Adult Oncology Program at Moffitt Cancer Center in Tampa, tells Yahoo Life. "They can potentially expose a patient to risks such as side effects from anesthesia, unnecessary biopsies as well as unnecessary financial costs," she says.

Using life expectancy for guidelines is tricky, though

While using life expectancy as guidance may work when you look at the population as a whole, it gets trickier when you look at individual situations, Sam says. "Guidelines have merit and are meant to provide recommendations and best practices for the general population but may not speak to every individual situation," she says. "The use of guidelines should never completely replace shared decision-making and honest discussions between the patient and provider."

Sam says life expectancy "should not be the only factor taken into account" when it comes to deciding if someone should be screened for cancer. But, she adds, it's an important factor. "This is a better assessment about the impact a screening test will have on a patient compared to using simple age cutoffs," she says.

Dr. Richard J. Bleicher, clinical director of the Breast Service Line at Fox Chase Cancer Center in Philadelphia, tells Yahoo Life that he understands the concerns about basing screening on life expectancy. "While I do in some cases agree with deescalation of care with advancing age, I am in the camp of individuals who agrees that age alone should not be a justification for limiting care," he says. "I have 80-year-old patients who are in wheelchairs, but I also have 80-year-old patients who are black-diamond skiers — and the entire spectrum in between."

It's also worth noting that guidelines help health care providers decide when to recommend tests to a patient — and they also influence which tests insurance companies will cover, Zikmund-Fisher says. "However, it's important to acknowledge that the reverse is a problem too: Just because insurance does cover a cancer screening test does not necessarily mean that it's a good idea for a particular person to get it," he says. Still, if someone needs a screening test and it's no longer recommended or covered, they may go without it with devastating consequences.

One example: Cervical cancer screenings are generally not recommended past the age of 65. But a University of California, Davis, study published in January found that nearly 1 in 5 new cervical cancer cases are diagnosed in women 65 and up — and more older women had late-stage cancer than younger women, which typically corresponds to lower survival rates.

What should screening guidelines be based on?

As a whole, "screening is extremely important for detecting cancer early," Dr. Richard Reitherman, medical director of breast imaging at MemorialCare Breast Center in Fountain Valley, Calif., tells Yahoo Life. But he admits that determining screening guidelines is complicated. "It shouldn't be based on age necessarily," Reitherman says. "It should be based on multiple factors."

The decision for screenings and treatment should be made with the patient, recognizing that a person's health can vary despite their age, Bleicher says. "People want decisions to be made with them and based upon their vibrancy and their ability to tolerate treatment, rather than just unilaterally and arbitrarily decided for them because of that age number," he says.

Bleicher recommends that doctors consider a person's functional status first — that is, how healthy they are — and their age second, while weighing their family history too. "If I have an 85-year-old who is vibrant and healthy, whose parents lived to nearly 100 years of age, I will still likely recommend screening," he says. "But if I have an 85-year-old who has many medical problems and is nearly at the age where their parents passed away, we may very well discuss foregoing screening studies."

Ultimately, screening "should be a case-by-case decision made by the healthcare provider and patient," Reitherman says.

How to advocate for yourself with cancer screenings

If you want to get a cancer screening test you may have aged out of, Sam recommends speaking with your doctor. "Good conversations with your health care team is paramount," she says. "If a screening test is not recommended, don't hesitate to advocate for yourself and ask, 'Why?'"

Zikmund-Fisher also suggests having an "open and honest" conversation with your medical team about your health. "Ask whether further screenings make sense or not, and be sure to ask why," he says. "Be willing to listen to their recommendations. Honest conversations about life expectancy can help us all get the care we need and avoid the care we don't."