March is Colorectal Cancer Awareness Month, which gives me an excellent opportunity to remind you about the importance of prevention, as well as of colonoscopy — a test that can literally save your life.
Colorectal cancer (also called colon cancer or large bowel cancer) is the growth of cancerous cells in the colon, rectum, and the appendix. Colorectal cancer is the second leading cause of cancer death, after lung cancer, in the United States. Each year 142,000 new cases are diagnosed each year and 51,000 Americans die of this disease.
It is the most common cancer of the digestive organs, accounting for 60 percent of all cancer in the digestive tract and 25 percent of cancer fatalities in the United States. There is a 5-6% lifetime risk of cancer — age-adjusted mortality is higher in men. The highest incidence of colorectal cancer is in the USA, Canada, United Kingdom, New Zeland, Australia and increasingly in East Europe, SE Asia, and South America.
Who is at risk for colorectal cancer? The following factors play a role:
- Age. Colorectal cancer affects both men and women of all races and ethnicities. The risk of colorectal cancer begins to increase at age 40, but the disease is typically found in people age 50 or older. In fact, 93 percent of those who develop colorectal cancer are over the age of 50.
- Race. African Americans have a greater risk of colorectal cancer than do people of other races. The American College of Gastroenterology recommends that screening begins at the age of 45 for African Americans.
- Personal or family history of colorectal cancer and adenomatous polyposis of the colon. Approximately 30 to 40 percent of all colorectal cancers have a genetic component, while 50 to 60 percent are sporadic, or non-inherited.
- Personal history of inflammatory bowel disease. Both Crohn’s disease of the colon and ulcerative colitis increase the risk of developing colorectal cancer.
- Genetic colorectal cancer >syndromes. These syndromes include familial adenomatous polyposis (1 to 2 percent of cases) and hereditary non-polyposis colorectal cancer (3 to 5 percent), which is also known as Lynch syndrome. People who have an inheritable syndrome develop colorectal cancer at a much younger age than the general population.
- Radiation therapy for cancer. Radiation therapy directed at the abdomen to treat previous cancers may increase the risk of colorectal cancer.
While colorectal cancer is the second most common cancer in Europe and the United States, it is considered rare in both Africa and Asia (barring Westernized Japan). Why is it more common in the West? Diet and lifestyle differences play an important role. There are seven behavioral risk factors that have been consistently correlated with an increase in colorectal cancer. These are:
- Low physical activity
- Low fruit and vegetable intake
- High caloric intake from fat
- Obesity (50% of colorectal cancer has been attributed to obesity/inactivity)
- High alcohol intake (synergy with low folate status)
- High intake of red (in particular charred ) and processed meat.
Fortunately, there’s much you can do to prevent colorectal cancer.
Prevention is Key
Good nutrition and physical activity play an important role in preventing colorectal cancer. Exercise!!! Prolonged sitting greatly increase the risk of colorectal cancer and portends to a worse prognosis. Physical activity helps prevent the development of colorectal cancer and improves outcomes. High levels of physical activity reduces the risk of developing precancerous polyps by 30%.(2) Aim for at least 30 to 45 minutes of moderate-to-vigorous activity on most days of the week.
The following nutritional factors have also been shown to help prevent colorectal cancer:
- Increase your fruit and vegetable intake. Favor cruciferous vegetables such as broccoli rabe. Cruciferous vegetables are high in fiber and contain chemicals such as indoles and crambene that rev up our detoxification system while protecting our cells against the damaging effects of oxygen free radicals. Meta-alanysis shows that cruciferous vegetables prevent colorectal cancer. Fruits and vegetables also contain cancer-fighting phytochemicals and vitamins.
- Lower your intake of red and processed meats, and consider increasing your intake of fish. Women who eat at least 3 servings of fish per week have been found to be at lower risk for developing precancerous adenomatous polyps of the colon. Overall, diets that simulate a Western-based eating pattern (processed meats, red meats, potatoes, high saturated fats, sweets) have a higher risk of developing colorectal cancer while a Mediterranean style diet (high in fruits, vegetables, whole grains, fish) have a lower risk.
- Consider using soy as a protein source. Soy isoflavones have many biological properties that appear to protect against colorectal cancer.
- Supplement with calcium or dairy products. Researchers have found that increased consumption of calcium is related to a lower risk of recurrent colorectal adenomas. Be cautious with calcium supplementation since recent studies show that more than 1,400 mg of supplemental (not dietary) calcium increases mortality.(8, 9) Consumption of dairy products has been shown to protect against the development of colorectal cancer.
- Maintain adequate levels of vitamin D. Studies have shown that inadequate levels (25 hydroxyvitamin D< 25 ng/mL) of vitamin D places you at a higher risk for developing colorectal cancer, while adequate levels are protective. An increase of vitamin D levels (25 hydroxyvitamin D) of 20 ng/mL decreases the risk of colorectal cancer by 16%. Have your doctor check your vitamin D levels. Exposure to sunlight, milk products, salmon, and vitamin supplements can all help boost vitamin D.
- Consider a multivitamin/multi-mineral supplement. Vitamins such as A, B6, C, E, and folic acid (no more than 400 micrograms), as well as the mineral selenium, have been shown to protect against colorectal cancer.
- Fiber up! Multiple studies show that a diet abundant in fiber protects against colorectal cancer. Eating 3 servings of whole grains per day has found to reduce the risk of colorectal cancer. Meta-analysis shows that for every increase of 10 grams of fiber in the diet per day the risk of colorectal cancer decrease by 10%. Aim for the minimum US Dietary Reference Intake of 25 grams of fiber a day as the average US intake is less than half of this amount
- Spice up your food. Curcumin is a cancer-fighting nutrient derived from the spice turmeric, which is often used in curry. Research has shown that curcumin may help prevent colorectal cancer.
- Ask your doctor about taking aspirin. Meta-analyses have shown that those who take a baby aspirin a day have significant protection against colorectal cancer.
Screening for average risk individuals begins at age 50, though studies suggest that African Americans should begin at age 45. The advice varies for those in higher risk groups:
- People with a sibling, parent, or child with colorectal cancer or an adenomatous polyp diagnosed at younger than age 60 or with two first-degree relatives diagnosed with colorectal cancer at any age should have a colonoscopy starting at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first.
- If you have a history of adenomas with advanced tissue histology or if your doctor has diagnosed you with more than 3 polyps during an exam, you should have your first follow-up colonoscopy in 3 years. Patients with 1 or 2 small adenomas should have their follow-up colonoscopy in 5 years.
- If you have a strong family history of colorectal cancer—especially if the cancers occurred before age 40—you should consider genetic testing for hereditary non-polyposis colorectal cancer and undergo a colonoscopy starting at age 20, or 25, or 10 years earlier than the youngest age of colorectal cancer in the family, whichever comes first.
- Individuals with inflammatory bowel disease should undergo a colonoscopy beginning 8 to 10 years from the time of diagnosis or at age 50, whichever occurs first.
Please take control of your health and talk with your doctor about scheduling a colonoscopy . For more information, discuss this issue with your healthcare professional.
To your good health.
Dr. Gerry Mullin