Screening is an important part of routine medical care. Screening means checking a seemingly healthy person for signs of hidden disease. It is routinely done for various types of cancer, heart disease, diabetes, and other chronic conditions.
Common cancer screening tests include:
- mammogram for breast cancer
- PSA test for prostate cancer
- colonoscopy for colon cancer
- Pap smear for cervical cancer
Screening makes sense when finding and treating a hidden condition will prevent premature death or burdensome symptoms. But it doesn't make sense when it can't do either. That's why experts recommend stopping screening in older individuals, especially those who aren't likely to live another five or 10 years.
Yet an article published online in JAMA Internal Medicine shows that many doctors still recommend cancer screening tests for their older patients. Many don't benefit, and some are even harmed by the practice.
A team from the University of North Carolina, Chapel Hill, looked at cancer screening tests among 27,000 men and women over age 65 who took part in the National Health Interview Survey. They also ranked the participants by risk of dying in the next nine years based on their health.
Among individuals with the highest risk of dying within nine years, many had undergone cancer screening in the two years before the interview. More than half of the men in this group had a PSA test to check for hidden prostate cancer. The screening rates were 41% for colorectal cancer, 37% for breast cancer, and 31% for cervical cancer.
Smarter screening decisionmaking
These findings are troubling. Asking people who can't benefit from a cancer screening test to have one is a waste of their time and money, not to mention a waste of taxpayer money (since these tests are usually covered by Medicare). Screening tests can also cause physical and mental harm. A colonoscopy can tear the lining of the colon, potentially causing a serious infection.
A high PSA test often sends men to undergo expensive biopsies. These can cause infection and pain. And if prostate cancer is found, many men will opt for treatment with surgery or radiation therapy even though the slow-growing cancer would not have shortened their lives. Mammograms don't usually cause problems, but many lead to biopsies that show no cancer present.
Medical societies and other expert groups recommend the following:
- Stop routine Pap smears to screen for cervical cancer at age 65 if Pap smears have been negative in the past.
- Stop routine screening mammography for women at average risk of breast cancer after age 75.
- Stop screening colonoscopies for adults at average risk of colorectal cancer at age 75.
- Stop routine screening with PSA for men at average risk of prostate cancer, independent of age.
Unfortunately, many doctors ignore these guidelines. Why? Experts realize that cancer screening recommendations based on age alone are too arbitrary. A frail 75-year-old with heart disease and diabetes is different from a robust 75-year-old who exercises every day. So many experts suggest considering a person's life expectancy. If it is less than 10 years, cancer screening is unlikely to improve a person's survival or quality of life, and the risks of screening are greater than the benefits.
But estimating life expectancy is very difficult. So doctors are reluctant to make what amount to a guess for many of their patients.
That's why a decision about cancer screening should be mutually made by an individual and his or her doctor. Equally important, the person should be well informed about the risks of the test and about what will happen if a test suggests there may be cancer that won't shorten the his or her life.
At the same time, all of us should be focusing more on preventing cancer in the first place, rather than trying to detect it later. The best ways to do this include:
- staying physically active and spending at least 150 minutes per week on moderate intensity exercise
- maintaining a healthy weight
- not smoking or using other tobacco products
- avoiding alcohol or drinking moderately (no more than one alcoholic beverage a day for women, no more than two a day for men)
- eating a diet rich in fruits, vegetables, and whole grains.