How should the elderly be screened for different types of cancer? At what age do these various screening tests do more harm than good, revealing minuscule or slow-growing cancers that might never have caused significant problems during the patient’s remaining years, potentially leading to unnecessary invasive procedures, side effects and needless worry?

That’s one of the biggest debates among cancer experts today, and there is no one-size-fits-all answer to the question — something that’s become even more apparent over the last year.

In early August, the U.S. Preventive Services Task Force made a surprising announcement recommending that doctors discontinue routine prostate cancer screening in men over 75, based on evidence it says indicates that the benefits of treatment as a result of screening in these men are “small to none.” On the flip side, the federal task force said such treatment can often lead to unnecessary anxiety and surgery, as well as side effects such as erectile dysfunction and bladder control and bowel problems.

“While it’s clear there is benefit to a significant number of men, it’s equally clear that many men end up being diagnosed and treated for cancers that would likely not have caused them any significant harm,” Dr. Durado Brooks, a prostate cancer specialist for the American Cancer Society, told the Associated Press.

But back in April, a study published in the Journal of Clinical Oncology suggested just the opposite when it comes to elderly women and breast cancer. Although doctors frequently advise women over 80 to skip annual mammograms and instead be screened every two to three years, the new study found that among those who had a mammogram every year or two before their diagnosis, 68 percent found the cancer at an early stage, compared with 56 percent of those who got mammograms irregularly and 33 percent who skipped mammograms altogether.

Those screened frequently were also more likely to still be alive five years after their diagnosis, although experts point out this could be due to the “healthy patient bias.” In other words, women who were getting more frequent mammograms may have been doing so because they were healthy enough to get out to a mammography facility and withstand the rigors of treatment, so they were also more likely to survive longer.

And in 2007, two new studies presented at the American College of Gastroenterology’s annual meeting suggested benefits from continued colorectal cancer screening among healthy people age 80 and over. As with mammography and breast cancer, the screening appeared to lead to earlier diagnoses and improved survival for these elderly patients.

Why the difference? Why might it be beneficial to keep screening the elderly for breast cancer and colorectal cancer, but not prostate cancer? First, says Dr. Columbus Giles, a member of the leadership council of the American Cancer Society, it’s important to understand that this book is still being written. “The studies are still being done, and this is a question that’s been controversial over the years and will continue to be,” he said.

Several major studies on prostate cancer screening and treatment, for example, are expected within the next couple of years, and may provide more insight.

That said, one reason why there might be more benefits to screening the elderly for certain types of cancer and not others relates to the process of the cancer itself. “Prostate cancer tends to be a much slower-growing type of tumor than breast cancer,” explained Giles. “On the other hand, breast cancer generally is faster growing and more aggressive.”

Indeed, men with very small prostate tumors sometimes choose “watchful waiting” over any treatment at all, something that isn’t seen as often with breast cancer.

“If I’m 90 years old and in very good health, my life expectancy might be another five or 10 years,” said Giles. “If I get prostate cancer at that age, it might take another 10 years to kill me, so why go through the side effects of treatment?”

On the other hand, he pointed out that an equally healthy 90-year-old woman, with a similar life expectancy, might have it substantially shortened by untreated breast cancer.

Ultimately, Giles advises that each patient be treated as an individual, not as “an 80-year-old” or “a 60-year-old.”

“I’ve been in clinical practice for a number of years, and had people much younger than the standard age cutoffs who would not benefit from certain types of screening given their medical conditions,” he said.

Conversely, there are very healthy elderly people who might want screening well after the usual cutoff date. If you’re 85 and in good health, and your parents both lived to nearly 100, you might choose screening in an effort to protect as much of those remaining potentially healthy years as possible.

“Whenever we offer any of these tests, we have to explain that the studies around them are not conclusive, and different groups may have different outcomes,” said Giles. “These are decisions that need to be made by each individual in consultation with their doctor.”

About the Author

Gina Shaw is the medical writer for The Washington Diplomat.