You are at Average Risk if you are 50 and older even if you have no other risk factors other than age. You need to have a Colonoscopy once every 10 years. A Colonoscopy is the gold standard for screening and is the best way to determine if you are at risk.
If you have a Single First Degree Relative — a parent, sibling or child — who has been diagnosed with Colorectal Cancer at age 60 or older, you should begin screening at age 40 and have a Colonoscopy no less than once every 10 years.
If you have a First Degree Relative who has had colon polyps (adenoma), begin screening at age 40 or at 5 years younger than the diagnosis of the youngest affected relative, whichever is earlier. Thereafter, you should have a Colonoscopy every 3 to 5 years, depending on the strength of family history and the findings of your previous Colonoscopy.
If you have Multiple First Degree Relatives with colorectal cancer (more than one immediate family member including mother, father, brother, sister), you are at high risk. You should begin screening colonoscopy at age 40 or 10 years younger than the age of onset in the youngest affected relative. You are also considered at high risk if you have Familial Polyposis (an inherited tendency to have multiple colorectal polyps that could become cancerous) or Hereditary Nonpolyposis Colorectal Cancer (an inherited colorectal cancer). For these conditions, screening is individualized and should be discussed with a gastroenterologist. If you are at high risk due to previous polyposis or cancer, follow your Doctor’s advice for surveillance.