I am 45. My father was diagnosed with colon cancer at about age 45. My sister recently had a colonoscopy, and they removed more than 200 polyps. I didn't realize I should have started having colonoscopies at 35 until after my sister called and gave me all of this information. I have asked my doctor for a referral for a colonoscopy, but am having a difficult time getting one. How can I get my doctor to order this test?

D.I

Most cases of colon cancer are not hereditary and occur after the age of 50. So, for most people, it is recommended to begin screening for colon cancer at age 50.

However, your sister is right that a family history of colon cancer and polyps is very important in determining when to begin colonoscopy screening. People who have a parent or sibling who has had colon cancer face a higher risk of developing colon cancer than the general population. In such cases, it is recommended that you begin screening at an age 10 years younger than the age at which your affected member was diagnosed. Thus, since your father was diagnosed at age 45, you should have been screened starting at age 35.

More important is the discovery of "more than 200 polyps" during your sister's colonoscopy. This finding suggests that your family may have an inherited tendency to develop polyps (colonic polyposis syndrome). In these syndromes, affected family members develop hundreds of polyps in the colon, which will inevitably develop into colon cancer. It is important that members of such families undergo endoscopic examination of the colon starting in the teenage years. Genetic testing may also be considered since we now know the genes responsible for some of the syndromes. Finally, if multiple polyps are found, a recommendation is often made to surgically remove the colon to prevent future development of colon cancer. Your sister should certainly discuss these options with her doctor.

In addition, you should definitely have a colonoscopy to determine if you might also have multiple polyps. You should stress your family history of colon polyps and colon cancer to your doctor, who should refer you right away to a gastroenterologist for a colonoscopy.