Digestion & Digestive Health - Colorectal Cancer

Colorectal Cancer - Causes, Symptoms, Diagnosis & Treatment

In the United States, it is the fourth most common cancer in men and women. Caught early, it is often curable. It is more common in people over 50, and the risk increases with age. You are also more likely to get it if you have :

  • Polyps - growths inside the colon and rectum that may become cancerous
  • A diet that is high in fat
  • A family history or personal history of colorectal cancer
  • Ulcerative colitis or Crohn's disease

Although the exact cause for colon and rectal cancers is unknown, there is a great deal of ongoing research being done to find out more information.  Scientists are beginning to understand the link between changes in deoxyribonucleic acid (DNA) and how the changes can cause normal cells to turn into cancer. Some genes contain instructions on how cells grow and divide and go through apoptosis (death).  Genes that result in a speeding up of cellular division are called oncogenes, genes that slow cellular division or cause apoptosis are called tumor suppressor genes.  Changes within several different genes have been linked to the development of cancers.colorectal cancer

A small number of colorectal cancers are caused by inherited gene mutations such as; familial adenomatous polyposis (FAP), hereditary nonpolyposis colon cancer (HNPCC) and Peutz-Jeghers syndrome.

Signs and Symptoms of Colorectal Cancer

Unfortunately, most people with colorectal cancer don't experience any symptoms in the early stage of the disease. That's why screening tests, such as a colonoscopy, are so important. In general, signs and symptoms of colorectal cancer can include the following:

A change in bowel habits

    • Diarrhea, constipation, or feeling that the bowel does not empty completely
    • Blood (either bright red or very dark) in the stool
    • Stools that are narrower than usual
    • General abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps)
    • Weight loss with no known reason
    • Constant tiredness
    • Vomiting

These symptoms may be caused by colorectal cancer or by other conditions such as infections, hemorrhoids, and inflammatory bowel disease. It is important to tell your doctor about any of these symptoms.

Causes of Colorectal Cancer

More than half of all colorectal cancers occur without any known cause. Studies also suggest that genetics may play a role. Some people with colorectal cancer carry specific genetic mutations or have relatives with the condition. Those with a family history of specific genetic syndromes -- such as familial adenomatous polyposis, Lynch syndrome, juvenile polyposis, and Peutz-Jeghers syndrome -- are also at an increased risk for developing colorectal cancer. Smoking and eating a high fat diet also raise the risk of developing cancer. Both genetics and lifestyle factors may play a strong role in determining which "at-risk" individuals develop the disease.

Diagnosis of Colorectal Cancer

You doctor will take a complete medical history, and will perform a physical exam and may order one or more tests to diagnose colorectal cancer. Standard tests used to diagnose colorectal cancer include sigmoidoscopy, colonoscopy, and barium enema. During a sigmoidoscopy or a colonoscopy, a biopsy (sample of tissue) is removed from the colon or rectum and examined under a microscope in order to detect abnormal growths. If the doctor finds cancer, a series of tests (chest x-ray, abdominal CT scan, and blood tests to check liver function) will be done to see if the cancer has spread and to help determine the stage (or extent) of the disease. Stages of colorectal cancer include:

•Stage 0: The earliest stage; cancer is found only in the innermost lining of the colon and/or rectum.
•Stage 1: Cancer has grown through the innermost lining but hasn't spread beyond the colon wall or rectum.
•Stage 2: Cancer has spread to deeper layers of the wall of the colon or rectum, but not the lymph nodes.
•Stage 3: Cancer has spread to nearby lymph nodes but not to other parts of the body.
•Stage 4: Cancer has spread to other parts of the body, such as the liver and lungs.

Preventive Care

Colorectal cancer is highly preventable, even curable, when detected early. Regular screening for colorectal cancer detects polyps before they become cancerous. Current guidelines recommend these screening options, starting at age 50 for people who have an average risk of colon cancer:

•Annual fecal occult blood testing -- tests for blood in the stool
•Stool DNA testing -- tests for DNA markers shed by cancer cells of precancerous polyps
•Flexible sigmoidoscopy, every 5 years -- examination of the rectum and lower colon using a lighted instrument
•Colonoscopy, every 10 years -- examination of the rectum and entire colon using a lighted instrument
•Double-contrast barium enema, every 5 years -- examination using a series of x-rays that reveal outlines of the colon and rectum
•Virtual colonoscopy (CT colonography), every 5 years -- uses a CT scan to take images of the colon
Those with a family history of colorectal cancer should have a colonoscopy every 3 - 5 years, starting at least 10 years before the age of the relative at the time of his or her diagnosis.

Diet and Exercise

Eating plenty of fruits and vegetables as well as foods rich in omega-3 fatty acids (such as salmon and halibut) and calcium (such as sea vegetables and kale) can help reduce the risk of colorectal cancer. Limiting alcohol consumption, quitting smoking, and reducing the intake of high-fat and fried foods, particularly red meats, may also protect developing colorectal cancer.

Maintaining a proper weight and exercising regularly also cut your risk of developing colorectal cancer. Even small amounts of exercise on a regular basis can help. The American Cancer Society recommends at least 30 minutes of physical activity on most days.


Surgery to remove the part of the colon containing tumor is the primary treatment. Depending on the stage of the cancer, surgery is generally followed with chemotherapy. If the tumor is particularly large, you may need radiation before or after surgery.

Some medications or supplements may help prevent the development of polyps or colorectal cancer. Making lifestyle changes, especially eating less red meat, losing weight, quitting smoking, and getting more exercise, may help prevent the disease -- even in people with a family history of the condition.


Even if you have no family history of colorectal cancer, and unhealthy lifestyle can increase your risk of developing the disease. Some experts believe making healthy lifestyle changes may decrease the risk of developing colorectal cancer by as much as 70% for some people.

Many studies support the association between colorectal cancer and lack of exercise and obesity. Research continues to show that exercise and low-calorie diets may help to prevent colorectal cancer.

A large, population-based study of men and women in Hawaii found that the following lifestyle factors were linked with colorectal cancer:

•Heavy alcohol consumption
•History of diabetes
•Frequent constipation
•High-calorie diet
•Physical inactivity
•Low vegetable fiber intake (evidence here is mixed)
•High levels of insulin (hormone that controls blood sugar levels)
•Meat consumption
After surgery, chemotherapy (the use of anticancer drugs to destroy cancer cells) may be given to kill any cancerous cells that remain in the body. Chemotherapy controls the spread of the disease and improves survival rates over time.

Treatment of Colorectal Cancer

Many colon cancer treatment options are available for colorectal cancer, including surgery, chemotherapy, and radiation.Surgery is the most common treatment for colorectal cancer. During surgery, the tumor, a small margin of the surrounding healthy bowel, and adjacent lymph nodes are removed. The surgeon then reconnects the healthy sections of the bowel. In patients with rectal cancer, the rectum is permanently removed. The surgeon then creates an opening (colostomy) on the abdomen wall through which solid waste in the colon is excreted. Specially trained nurses (enterostomal therapists) can help patients adjust to colostomies, and most patients with colostomies return to a normal lifestyle.

The long-term prognosis after surgery depends on whether the cancer has spread to other organs (metastasis). The risk of metastasis is proportional to the depth of penetration of the cancer into the bowel wall. In patients with early colon cancer which is limited to the superficial layer of the bowel wall, surgery is often the only treatment needed. These patients can experience long-term survival in excess of 80%. In patients with advanced colon cancer, wherein the tumor has penetrated beyond the bowel wall and there is evidence of metastasis to distant organs, the five-year survival rate is less than 10%.

In some patients, there is no evidence of distant metastasis at the time of surgery, but the cancer has penetrated deeply into the colon wall or reached adjacent lymph nodes. These patients are at risk of tumor recurrence either locally or in distant organs. Chemotherapy in these patients may delay tumor recurrence and improve survival.

Read Articles about Colorectal Cancer

1. Colon Polyps & Cancer : A polyp is a projection or a "bump" of the bowel wall protruding into the lumen. Polyps may occur anywhere in the gut, but here we will focus only on colon and rectum.

Polyps occur in as many as 40-50% of the population. The number and size of polyps increases with one's age, especially in patients with family history of colon polyps or cancer. High fat, low fiber diet and smoking may play an important role in the causation of these polyps, whereas use of aspirin and similar drugs decrease the risk. Read more here Colon Polyps

2. Colonoscopy or the lower GI scope visualizes the interior of the colon directly. This is in contrast to barium enema or the lower GI x ray, which looks at the colon indirectly.
Indications- Colonoscopy is recommended for evaluation of altered bowel habit, unexplained diarrhea, constipation or abdominal pain, occult or frank blood in stools, colon polyps or cancer or unexplained anemia.

Contraindications- It is generally not performed in cases of perforation or tear in the bowel, severe diverticulitis or colitis and clinically unstable patients. Continue to read about colonoscopy / lower GI scope

3. Colon Screening - March is colon cancer awareness month. Did you know that colon cancer is America's number two cancer killer? Did you know that we can prevent these unnecessary deaths by removing pre-cancerous polyps and by diagnosing cancer at early stages? Did you know that screening for colon cancer is cost-effective and saves lives?
Polyps versus cancer

As many as 95% of colorectal cancers begin as polyps. It takes about 7-10 years for pre-cancerous polyps to transform into cancer. After this initial transformation, the cancer takes about 1-3 years to spread, and this process is known as metastasis. Up to 80% of colon cancer deaths can be prevented by timely removal of the pre-cancerous polyps! Read More about Colon Polyps & Colon Cancer Screening

4. Natural Care & Alternative Medicine