I know that October is Breast Cancer Awareness Month, however a patient recently told me her father has colon cancer yet she does not want a colonoscopy. Yesterday a 56-year-old male with blood in his stool refused a colonoscopy. In both instances, they cited fear of the procedure as their excuse however I was quick to point out, “Colon cancer will suck more.”
Colon cancer is the fourth most common cancer in the United States. The most common symptoms to watch out for include: change in bowel habits (diarrhea or constipation without explanation), reduced diameter of stool (pencil thin), red blood in stool (lower GI bleed), black specks or black stools (upper GI bleed). There may also be iron deficient anemia due to the blood loss or bloating if there is a large tumor in the colon.
Risk factors include: age (commonly in the 60’s and 70’s unless there is a family history), history of polyps on a prior exam, smoking, poor dietary habits (high in red meat, low in fiber, fruit, and vegetables), sedentary lifestyle, and maybe alcohol use (studies go back and forth).
There are several different tests your health care provider may do if you present with concerning symptoms or are at the age to begin screening. First there is the digital rectal exam where your health care provider inserts a gloved finger into your rectum to feel for lumps, bumps, or thickening. Then they can perform a quick fecal occult test (is there blood in your stool?) or give you the kits to take home and do yourself. Next, you may need a flexible sigmoidoscopy where a lighted probe is inserted rectally to visualize your rectum and lower colon, or you may need a full colonoscopy where your entire colon is visualized. If there are any concerns, your provider can remove polyps or take biopsies at that time.
A virtual colonoscopy uses a barium swallow and a CT scan of your colon, however if any polyps or concerns are found, the doctor will have to go in like a regular colonoscopy to remove them.
At the moment there is no screening blood test for colon cancer that is reliable. The blood test available is much more useful if monitoring tumor load. Newer technology includes stool DNA testing for colon cancer and so far the sensitivity is between 70-90 percent.
Unless you have a family history or concerning symptoms, screening generally begins at 50 years old.
Do not put off your screening for colon cancer. Assuming all is negative, you may not have to return for 10 years which is different from your yearly Pap and mammogram!