by Bill Sardi
Recently by Bill Sardi: Growing Up Poor Helped Make Me Rich
I frequently receive inquiries about colonoscopies. People want to know whether they are worthwhile. Certainly colonoscopy, the passage of a fiber optic tube into your intestinal tract to examine for pre-cancerous growths (called polyps) or to directly detect observable tumors in the colon or rectum, is a hard sell. Not only is colonoscopy an ordeal for the patient, a weak economy is forcing more patients to forego this diagnostic procedure as it does cost a few hundred dollars out of pocket. So is the recent news that colonoscopy cuts the death risk for colon cancer in half enough to get 50-plus-year-olds to part with their money and endure this uncomfortable procedure?
The bigger problem is not affordability or discomfort during the procedure, the problem is that, regardless of what you are told by doctors or what you read in news reports, colonoscopy offers implausible benefits.
First, patients are supposed to buy into the idea that detection and removal of intestinal polyps is life saving. But colonoscopy does nothing to prevent polyps from recurring. One study reported more than 40% of the time a surgically removed polyp does in fact return.
Second, do polyps equate with cancer? Colon cancer may emanate from flat growths that simply cannot be detected during colonoscopy. Even the best trained physician may not be able to detect the smallest polyps which is the entire reason for the test, to detect precancerous growth at their earliest stage of development. Even then, the best-trained physician can miss small tumors in the colon. The miss rate for the smallest growths (less than 5 millimeters in size) is around 25%. In one study of 2079 patients who underwent colonoscopy, colon cancer was detected in 13 patients, 7 (58%) who undergone prior colonoscopy and whose cancers were missed or were incompletely removed.
Physicians are likely to give the false impression that the removal of a polyp saved your life. But only between 1 in 10 and 1 in 100 polyps (adenomas) are cancerous. In one study, 1235 colonoscopies were examined and yielded a total of 1933 small or diminutive cancerous polyps. A pathologist found cancer in a biopsy tissue slide in 10.1% of small adenomas (5-10 millimeters in size) and 1.7% of diminutive adenomas (less than 4 millimeters). About 99% of surgically removal polyps are benign.
Third, the recent news that colonoscopy cut the death rate for colon cancer in half may not apply to the population at large. The patient population in that study was comprised of patients who were already known to have intestinal polyps. Colonoscopy needs to be performed on over 10,000 higher-risk patients to save just one life.
Fourth, earlier detection of colon cancer may make it appear that patients are living longer, but actually early detection and treatment of colon cancer just informs the patient and doctor that cancer is there at an earlier point in time. Typical 5-year survival rates are estimated to be 45-60% of the patients undergoing surgical removal of a tumor. Sadly, colon cancer patients are still dying on the same calendar day.
If the doctor detects a malignant mass in your intestines during colonoscopy, survival is only about 2 years regardless of what treatment is rendered. There is treatment for colon cancer, but no cure. A fact not discussed with patients is that chemotherapy and radiation treatment cannot penetrate a solid tumor like those found in the colon. Surgical removal of a malignant mass in the colon only slows down tumor growth. It is not a cure. None of these treatments deal with the cause of the problem.
The rectal cancer recurrence rate following surgical removal of a tumor ranges from 4% to 55% and depends upon the aggressiveness of treatment. Cancer surgeons know they can perform more aggressive surgery that improves survival removes nerves and surrounding organs that leave the patient with urinary and sexual dysfunction. Recurrence rate is reduced to 5-10% and 5-year survival is achieved 70-80% of the time with more aggressive treatment. But the patient may feel life is not worth living.
Yes, certainly, the rationale for screening for colon/rectal cancer is that up to 90% can achieve prolonged survival if their cancer is detected in the earliest stage of development. That is the figure that is advertised. But in reality, about 65% are detected with advanced disease (stage IV) that has a dire prognosis (6% survive 5 years).
A more accurate picture of survival rates is provided by a European report. In a review of 1073 patients who had undergone surgery for colon-rectal cancer, only 31 had more than a 5-year survival rate and 7 lived more than 10 years. Rectal cancer had a 5-year survival rate of about 5% compared to 1% for colon cancer. Half of these long-term survivors had no additional treatment.
Fifth, while gastroenterologists lament that only half of the adult population that should be screened for colon cancer actually undergo colonoscopy, surveys show physicians themselves, even gastroenterologists, often don't undergo this exploratory procedure, often saying they are too busy.
Sixth, that there is a benefit to colonoscopy is statistically remote. Since about 25% of patients undergoing colonoscopy have polyps, it would take about 4500 patients to be screened to find these recurrent colon tumors if all polyps found were malignant. However, only about 1-2 percent of polyps are malignant, so it would require over 110,000 patients to be screened to find 1134 malignant polyps and at least 3000 subsequent colonoscopies to find another 5 tumorous polyps over a 7-year follow-up period.
It is estimated 50% of people over age 60 will develop at least one polyp, and discovery and removal of polyps may give patients the false impression their life has been saved. Colonoscopy maybe saves 1 in 100 of these patients.
The American Cancer Society (ACS) set a nationwide goal to increase to 75% by 2015 the proportion of people aged 50 and older who have colorectal cancer (CRC) screening, but doctors seem to know better. A survey of physicians in Wisconsin found only 38.2% of doctors would screen a moderate-risk patient.
If there is some advantage to undergoing colonoscopy, I haven't been able to find it.
Part II: Thinking About Prevention of Colon/Rectal Cancer
In my previous blog I wrote about the implausibility of any benefit from colonoscopy. So people ask: "what are we to do?" Family members of loved ones who have succumbed to colon/rectal cancer are particularly concerned about prevention.
The good news is that colon cancer varies by 20 times among countries. The diet plays a much stronger role than heredity. North American and European Countries have the highest rates, India the lowest. The obvious factors involved (smoking, sunlight/vitamin D, meat/iron intake) are mostly ignored by modern medicine. Inherited predisposition for colon cancer accounts for only 5% of all cases. But this less frequent genetic form of colon cancer receives great attention.
Almost half of all patients thought “cured” of colon cancer develop recurrence within 5 years usually due to undetected spread of their cancer. This begs for prevention. Preemptive measures to ward off the occurrence of cancer appear to be a more productive course than undergoing repeated colonoscopies which most of the time detect inconsequential polyps or large invasive Stage IV tumors that have a dire prognosis. The most promising treatments never address the cause of the disease.
Space is limited here so I must briefly present bullet points.
- Smoking increases colon cancer risk by 3-fold compared to never-smokers. [International Journal Cancer 91: 585-87, 2001]
- Smoking and drinking alcohol further increases the risk for colon cancer. Data shows that alcohol and tobacco users developed cancer an average of 7.8 years earlier than those who had never drank or smoked.
- A high-saturated fat diet increases the risk for colon cancer by 4-fold compared to a high-fat diet that includes fish oil.
- Omega-6 oil, such as provided in corn and safflower oil, is known to enhance the growth of tumor cells, whereas omega-3 oils, such as from fish or flaxseed oil, have the opposite effect. This has also been found specifically for colon cancer.
- Mice that are genetically prone to develop intestinal polyps, a precursor of colon cancer, hardly develop them at all when given omega-3 oil.
- Studies have demonstrated a reduced risk of colon cancer when populations with diets high in total fat switched to a diet high in total fiber and certain whole-grain foods. Researchers indicate the source of fiber needs to be considered. Bran appears to inhibit colon cancer more consistently than other sources of fiber.
- Refined grain intake actually increases the risk for colon cancer.
- Olive oil also appears to cut the risk for colon cancer in half.
- The combination of iron and fat in the diet increases the risk for rectal cancer by 330%! The combination of fat plus high-dose iron from red meat or iron pills may be problematic.
- In a study conducted in Japan, it was found that red meat increases the risk for colon cancer in men and in women, while daily coffee drinking reduces the risk for colon cancer.
- Decades ago supplemental vitamin C was shown to reduce polyps among patients who are genetically prone to colon cancer (familial polyposis). When 3000 milligrams of vitamin C was given to five patients who had rectal adenoma polyps following surgery. Rectal polyps disappeared in two patients, regressed partially in two and increased in only one.
- A 50% reduction in colon cancer risk can be achieved by adults who maintain adequate vitamin D blood levels, but for most adults in North America and Europe this means vitamin supplementation will be required.
- Drinking water reduces the risk of colon cancer in men. Men who consume the most water have a 92% lower risk of rectal cancer compared to men who drink less water.
- Long-term exposure to chlorinated drinking water (30-40 years) increases the risk of colon cancer.
- Foods with refined sugars confer almost 3-times increased risk for colon cancer.
- It has long been known that blood clots are common among cancer patients. Researchers now suggest patients admitted to the hospital for blood clots in their legs be screened as they exhibit a 3 times greater risk for colon cancer.
- Chronic constipation may increase the risk for colon cancer.
- Genetically susceptible mice, infection of the colon increased the number of adenomas by 4 times by 6 months of age. Helicobacter pylori infection has been shown to increase the number of polyps in the digestive tract. Crohn's disease, which increases the risk for colon cancer, is associated with para-tuberculosis infection.
Summary and recommendations