Nevertheless, awareness of some preventive measures may be useful to you and your brother. Taking one aspirin a day Screening for colorectal cancer with fecal occult blood test is worthwhile for you and your brother even before age 50.
Sigmoidoscopy can detect most lesions in younger people and is the recommended procedure.
After 50, with your family history, a colonoscopy is recommended and, if negative, need not be repeated for 3 to 5 years. If negative on two successive studies, it can be repeated less frequently. But a fecal occult blood test should be performed at least annually. If you have any further questions about this, please let us know.