If you are at low risk for colorectal cancer, how long should you wait between colonoscopy screenings? Johns Hopkins looked into this question and provides advice.

Most of us grudgingly accept the need for regular colonoscopy screenings but may wonder: Is it really safe to wait a decade before your next colonoscopy? Some researchers have wondered as well.

The 10-year interval, the gold-standard period between screening colonoscopies for people at low risk, is based in part on the amount of time it usually takes a benign polyp to become cancerous. Until recently, there was little evidence to support this practice in people whose previous colonoscopies showed no evidence of cancer or polyps.

But new research suggests that the 10-year standard is more than adequate. In fact, it may be safe -- although not recommended -- to wait up to 20 years between colonoscopy screenings. For example, a Canadian study that reviewed colonoscopy records of 35,975 people confirms that those with a negative (cancer-free) test result had a 72% lower risk of developing cancer over 10 years than the general population.

A German study that spanned more than a decade confirmed this finding and went even further: For people with a prior negative colonoscopy, the low-risk period can extend to 20 years. We're not suggesting that you allow 20 years to pass between your colonoscopy screenings. But if you have a normal colonoscopy result, you can most likely wait at least a decade before undergoing the procedure again.

Important: If a screening colonoscopy catches even one polyp, your risk of colon cancer goes up and so does the recommended frequency of screenings. The same is true if you have a family history of colorectal cancer or other risk factors for colorectal cancer.