If there is any silver lining to growing older, it's that the risk of certain diseases diminishes. For example, if you don't have colorectal cancer by age 75, the feeling has been that you no longer need to be screened for it.

Unfortunately, a new Dutch study takes a different view.

Researchers at Erasmus University in The Netherlands suggest that colonoscopy should be considered for persons age 75 or older who have not previously been screened for colon cancer. This represents a sea change in clinicians’ thinking, the authors of a related editorial say.

For those older than age 75, colorectal cancer screening may be a medical ‘green banana’ that takes years to ripen, in terms of preventing death at a time when life expectancy is dwindling.

The U.S. Preventive Services Task Force (USPSTF) recommends those between the ages of 50 and 75 undergo fecal occult blood testing (FOBT), sigmoidoscopy, or colonoscopy, and advises against screening persons over 75 who have been screened regularly. However, the USPSTF does not make any recommendations about those over age 75 who have never been screened, and many clinicians believe that means screening is not necessary after 75.

By indicating that screening is necessary in older persons, the study findings could have important clinical implications, according to C. Seth Landefeld and Amanda Clark of the University of Alabama at Birmingham, who wrote the editorial accompanying the study. The sedation and procedures are far more risky for people at 75 than they are at 50.

The Dutch researchers wanted to determine the maximum age up to which older people without previous CRC screening should be tested and which test is most appropriate at which age. They used a computer simulation to compare a group of 10 million patients between the ages of 76 and 90 who had not been previously screened and who also had no, moderate, or severe medical conditions, to a group of previously screened older persons.

For older persons with no other medical conditions who had not been screened previously, CRC screening was effective in terms of CRC cases detected, CRC deaths prevented, and effect on quality of life up to age 86 years. It was also cost effective.

Screening effectiveness and cost effectiveness decreased as the number and severity of patients’ additional medical conditions increased. Among the screening options, colonoscopy was most effective and still cost effective up to 83 years, sigmoidoscopy was indicated until age 84 years, and FOBT was indicated until age 86.

Older persons and their physicians take a pragmatic approach to screening, Landefeld and Clark write in their editorial. For those older than age 75, CRC screening may be a medical "green banana" that takes years to ripen, in terms of preventing death at a time when life expectancy is dwindling.

The findings of the Dutch study should encourage people to go for that so-called green banana and look into CRC screening, according Landefeld and Clark. People who are age 75 and older may want to talk to their doctor about getting CRC screening.

The study and related editorial are published in Annals of Internal Medicine.