I am back from vacation this week and as I scanned the medical journals, I found an article in the New England Medical Journal that I felt was important and wanted to share it with my readers in this newsletter.
My patients know that I routinely ask if they are up-to-date on colonoscopy or other forms of screenings for colorectal cancer. Most women who see me are concerned about their mammograms and pap smears, but colorectal screening is potentially just as important a screening procedure as the “usual gyne tests” for women over 50! According to the article (which was a review of colorectal adenomas, the precursors to colon and rectal cancer), in 2016, 134,000 persons in the US will be found to have colorectal cancer, and 49,000 will die from it. Adults in the US have a lifetime risk of 5% for developing this cancer.
I won’t go into the pages of details in the article that cover the pathological features of the adenomas (polyps) that lead to malignancy, but put succinctly, size matters; polyps that are 1 cm or larger are most likely to become cancerous. And there are known risk factors: Age is critical and risk increases with age and risk begins to accelerate at 50. Ethnicity is also a factor; black individuals have a higher risk of polyps becoming cancerous than white individuals from 50 to 65 years of age and Hispanics have a lower risk than non-Hispanics from 50 to 80 years of age. Other important factors that increase risk include a medical history of a first degree relative with colorectal cancer, a personal history of smoking and alcohol consumption, obesity, and red meat in the diet. (When I saw this latter risk factor 30 years ago from the statistically relevant data in the Nurses Study, I stopped eating red meat. I also lost 8 pounds!)
There is also a protective effect from the consumption of fruits and vegetables, regular physical exercise, and current or past regular use of NSAIDs, (Ibuprofen, aspirin etc. at least two times per week for more than one year). A prior negative colonoscopy also decreases the chance that in the future an individual will develop cancerous polyps. Oh and one more thing… hormone replacement therapy also decreases the development of the type of adenomas that lead to colon cancer.
There has been a decline in mortality from colorectal cancer since 1975, and this is due to the several factors: screening (responsible for over 50% of the decline), better diet and exercise, use of hormone replacement therapy, NSAIDs, as well as a decrease in smoking and alcohol consumption. And advances in therapies for colorectal cancer have, thank goodness, also improved mortality rates.
When it comes to screening, colonoscopy is the gold standard and should be done initially in low risk individuals at age 50. If no polyps are found and there is no significant family history or risk factors this can be repeated every 10 years. As many of you know, it does require a bowel prep, which is unpleasant, but the procedure itself should be painless since it is done with sedation. Virtual colonoscopy is less likely to cause surgical complications, is only slightly uncomfortable for a few minutes, has a 90% sensitivity for polyps and is now considered basically equivalent to optical colonoscopy. The preparation may be a little onerous, but is still necessary in order to clean the colon so the walls can be seen on CT scan. If a suspicious polyp is noted then a full colonoscopy with biopsy is necessary. The recommendation is that it be done every five years. Sigmoidoscopy shows only the lower third of the colon but can be done as an office procedure and requires even less prep. If this is chosen it should be combined with an annual test for blood in the stool. There are two stool tests that may also be effective; they require no preparation but are less accurate than colonoscopy. The first is a fecal immunochemical test (FIT) which detects blood in the stool and has a 72% sensitivity for detecting colorectal cancer and a 24% sensitivity for detecting pre-cancerous adenomas. It is considered more effective when combined with a sigmoidoscopy. The second and newest test is Cologuard, which can detect DNA mutations associated with colorectal cancer and has a 92% sensitivity but only a 42% for detecting pre-cancerous adenomas. It is more expensive than FIT and requires that the stool be put in a special container with fluid and be sent by UPS to the testing site. (I know that sounds awkward and weird but the company gives you a complete kit and instructions.) Not all insurances will pay for Cologuard but Medicare does…
Despite the fact that we have all these procedures to screen for colorectal cancer, only 59% of persons 50 years of age or older in the US are current with recommended screening. And since we know what decreases risk: diets that are low in fat, regular physical exercise, maintenance of appropriate weight, avoidance of smoking and less or no red meat, it would be wonderful if the majority of the population did all the right things. These lifestyle choices would reduce just about every disease…