Written by Dr. Ady Oster
People do not talk about colon cancer very much. Perhaps this is because it’s embarrassing to discuss, perhaps because they do not know much about it. That is a shame, because colon cancer is common and it is one of the most preventable cancers.
Colon cancer is the fourth most common cancer among Asian Americans, for both men and women (after breast, prostate, and lung) and (because it is more deadly than prostate cancer) colon cancer is the third most common cause of cancer deaths. While a few people with colon cancer have family members who also had colon cancer, most colon cancer occurs in people who do not have a family history of this cancer.
Cancers occur when a group cells grow out of control. Initially, they remain in one organ forming a lump. In time they can spread to other organs. Most cancers are much more easily treated when they are still in one organ. Colon cancers start as a polyp. These are small, warty-looking bulges in the inside lining of the colon. Over time, some of these polyps can become cancers (10% in ten years), invade the lining of the colon, and eventually spreading to other organs. Because polyps are small, they do not cause pain, diarrhea or constipation. It is impossible to feel polyps. The only way to know if you have a polyp is by having a doctor look at the inside of the colon. If polyps are removed, they can no longer become cancer. Therefore, the best way to prevent colon cancer is to have a colonoscopy to look for and remove polyps.
Most polyps and cancers cause bleeding (not visible) into the stool. Usually it is too small to be visible, but it may be detectable with special stool tests. Another way to look for polyps or colon cancer is to have stool tested for microscopic blood. Older tests required eating a special diet for several days and collecting several stool samples. Newer tests do not require any special diet and only one stool sample. If any blood is found, a colonoscopy will be required to find the source of the blood and remove any polyps that are found. If no blood is found, stool tests will need to be repeated every year in order to provide adequate reassurance that no polyps or cancers are in the colon.
During a colonoscopy, a doctor uses a long, flexible fiberoptic scope to examine the entire colon. If any polyps are found, they are usually removed at that same time. Since polyps take several years to develop and will take even longer to become a cancer. People without any polyps can safely wait ten years between each colonoscopy. People who do have polyps will need to have colonoscopies more often, depending on how many and how big these polyps were. People are usually sedated for a colonoscopy, so most people do not remember having the procedure. Unfortunately, in order for doctors to clearly see the lining of the colon, it must be cleaned of any stool. Therefore, people are asked to drink only clear liquid on the day or two prior to the test. On the evening before the test, they need to drink medicine that cleans the stool in the colon by causing diarrhea. This can be uncomfortable for a few hours.
The risk of cancer increases with age. Most people should begin testing for polyps or colon cancer at age 50. People who have family members with colon cancer should talk to their healthcare provider about the right age to start.
Despite the embarrassment or discomfort, it is important to talk about colon cancer. Talk to your primary care doctor about whether colon cancer testing is appropriate for you. Talk to your loved ones to make sure they have talked to their doctor about colon cancer. You can make an appointment to meet with a primary care provider here at Charles B. Wang Community Health Center by calling (212) 379-6998 for Manhattan, and (718) 362-3006 (37th Ave) or (929) 362-3006 (45th Ave) for Queens. For more information, visit the internal medicine webpage.
Written by Dr. Ady Oster. Dr. Oster is the section chief of internal medicine at the Charles B. Wang Community Health Center. He received his medical degree from the Albert Einstein College of Medicine, and completed his residency training at Yale-New Haven Hospital and University of California at San Francisco. Dr. Oster is board-certified in internal medicine.