Now federal guidelines suggest that most people can stop getting colonoscopies after age 75. In general, the risk of cancer among young adults is so low that screening healthy young people (who don’t have unusual risk factors) doesn’t make sense.ow federal guidelines suggest that most people can stop getting colonoscopies after age 75. In general, the risk of cancer among young adults is so low that screening healthy young people (who don’t have unusual risk factors) doesn’t make sense.