Colorectal Cancer: Risk Factors, Symptoms, Treatment, Nutritional Considerations

Every cancer starts from the growth of abnormal cells that spread across the entire body and become detrimental and difficult to handle.

Colorectal cancer occurs when the cells that line the colon and rectum become abnormal and grow out of proportion, thereby causing a formation of a mass called a tumor. A tumor can either be cancerous (malignant and can grow and spread) or benign (can grow but will not spread). These changes can be affected by environmental and genetic factors and can take years to develop. Symptoms are most likely not to appear at the early stages of colorectal cancer, so it is important to do a colorectal screening regularly.

What does the Colon/Rectum do in the Body?

The colon and rectum make up the large intestine which is part of the body’s gastrointestinal tract or digestive system. The colon and rectum are part of the body’s system of disposing of waste products. The colon makes up the first 5 to 6 feet of the large intestine, and the rectum makes up the last 6 inches, ending at the anus.

Their functions include:

  • Absorb water and some nutrients from what we eat and drink.
  • Form and store stool.
  • Move waste out of the body.
  • Partly broken down or digested food moves from the small intestine into the colon. Sections of the colon tighten and relax to move the food through the colon and rectum. This movement is called peristalsis.
  • In the colon, bacteria break down food into smaller pieces. The inner layer of the mucosa (called the epithelium) absorbs, or takes up, water and some nutrients. The liquid waste remaining in the colon is formed into the semi-solid stool.

How does Colorectal Cancer develop?

All body cells grow, divide, and then suddenly die to keep the body healthy and functioning in perfect condition. Sometimes, this process of grow-divide-die goes out of control and cells keep growing and dividing without dying. When this happens in the lining of the colon and rectum, colorectal cancer might develop.

Fortunately, the first mass that develops in colorectal cancer is called polyps. Polyps are noncancerous growth that grows on the lining of the rectum and colon. They develop very slowly without any symptoms. If detected during screening, they can be removed.

How is Colorectal Cancer diagnosed?

Colorectal cancer can be diagnosed by using different types of tests depending on your preference and the resources available in your health facility:

  • Endoscopy: ( flexible sigmoidoscopy and colonoscopy): In both tests, a thin, flexible, lighted tube is used to check for polyps or cancer inside the rectum and/or the entire colon. In colonoscopy, the tube is longer and during the process, the doctor can remove most of the polyps and some cancers.
  • Colonography (CT scan, MRI, angiography): also called virtual colonoscopy where x-rays and computers produce images of the whole colon.
  • Stool tests: Fecal samples are examined to check for bloodstains.

Most guidelines recommend that screening starts at 45-75years using stool tests once a year, CT colonography and flexible sigmoidoscopy every 5 years, and colonoscopy every 10years.

What are the Signs to Look Out For?

Sometimes, colorectal cancer come with little or no signs, but when you see the signs mentioned below, you might need to go for screening :

  • Change In bowel habit:  Constipationdiarrhea, narrowing of stools, incomplete disposal, and bowel incontinence might occur even though they are symptoms of other not-too-serious ailments.
  • Blood in or on the stool: this could also be a sign and can be associated with colorectal cancer. Its association with cancer doesn’t necessarily mean it would be cancer, but when you notice this, consult with a doctor for clarity. There are other possible causes of blood in the stool which include anal tears, Crohn’s disease, hemorrhoids, ulcerative colitis.
  • Unexplained anemia: Anemia is a shortage of red blood cells— the cells that carry oxygen throughout the body. If you are anemic, you may experience shortness of breath. You may also feel tired and sluggish, so much so that rest does not make you feel better.
  • Abdominal or pelvic pain or bloating
  • Unexplained weight loss
  • Vomiting

If you experience any of the mentioned symptoms, it is advisable to see your doctor for early detection, diagnosis, and treatment which can be life-saving.

What are the Risk Factors?

Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, cannot be changed. Risk factors linked to colorectal cancer include:

  • Smoking
  • having a family history
  • Lynch syndrome (a most common type of hereditary colon cancer)
  • being older, from 45-50 years
  • personal history of IBD (irritable bowel disease)
  • racial and ethnic background (Africans has higher risk)
  • Diet
  • Being overweight
  • Acromegaly (a hormonal disorder that makes the pituitary gland produce too much growth hormone leading to the development of extremely large bones)

Can Colorectal Cancer be Prevented?

Treatment plans for colorectal cancer totally depend on the stage of cancer. Your doctor would decide what type of treatment would be suitable for each stage.

  • Local treatment: this is the use of surgery and radiation therapy to treat tumors at early stages. This therapy has little or no effect on other parts of the body.
  • Systemic therapy: the use of drugs to treat tumors. The drug is administered through the mouth or directly into the bloodstream. It is either chemotherapy, immunotherapy, or targeted therapy.

Nutritional Considerations

The diet factor is a major contribution to developing cancer. These factors mentioned below are possible ways to reduce risks of colon cancer:

  • Maintaining a healthy weight: Research has it that, for every 5kg gained during adulthood, the risk for colorectal cancer increases by 4%. The type of diet and lifestyle you choose to follow reflect your weight and health status.
  • Avoiding red processed meat: Excess intake of red processed meat increases the risk of developing colorectal cancer. Red processed meat contains some substances that are carcinogenic on contact with high temperature from processing. These compounds are packed in the blood and lead to the development of cancers and also oxidants which could lead to cell destruction. Plant proteins are suggested to be taken in higher amounts to reduce the risk of colorectal cancers.
  • High fiber intake: studies show that diets with high fiber sources have the capacity to reduce colorectal cancer risk by 12%. Fiber-containing foods like fruits, vegetables, and grains should be incorporated into the diet to help reduce the risk of colorectal cancer. Also, foods high in fiber contain magnesium which helps reduce the risks of developing colorectal cancer.
  • Foods rich in B vitamins: leafy vegetables, whole grains, and beans are good sources of folate. Folate helps in proper DNA development and suppression of the development of tumors in the body.
  • Limiting alcohol intake: studies show that limiting alcohol intake to not more than 1 drink per day helped reduce the risk of colorectal disease.


The risk of developing colorectal cancer may be reduced through a healthy plant-based diet and a healthy lifestyle. Even after cancer is diagnosed, your diet choices can help manage and prevent reoccurrence.


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