The colon is the leading 122 cm of the large intestine. Colon and rectal cancer, or colorectal cancer, is cancer that starts in the large intestine (colon) or the rectum (end of the colon).

Most cases of colon cancer begin as small, non-cancerous (benign) polyps, which grow in the colon’s inner lining. Polyps may be small and have few, if any, symptoms. Polyps vary in type, but many are pre-cancerous tumors that grow slowly over the years and do not spread until cancer invasion beyond the mucosal lining.

As polyps grow, additional genetic mutations further destabilise the cells. When these pre-cancerous tumors change direction (growing into the wall of the tube rather than into the space in the middle of it) and invade other layers of the large intestine (such as the submucosa or muscular layer), the pre-cancerous polyp has become cancerous.

In most cases this process is slow, taking at least eight to 10 years to develop from into cancer.

It is preventable and highly curable if detected in early stages.

Symptoms of colorectal cancer are numerous and nonspecific. They include:

• unexplained fatigue and weakness as a result of anaemia and occult (not visible) blood loss.
• shortness of breath,
• unexplained weight loss,
• bloating,
• narrow (skinny) stools,
• diarrhoea or constipation,
• red or dark blood in stool or in the rectum,
• unexplained weight loss,
• persisitent abdominal discomfort such as cramps, gas or pain,
• a feeling that your bowel doesn’t empty completely,
• change in your bowel habits, including diarrhoea or constipation or a change in the consistency of your stool, that lasts longer than four weeks

Colorectal cancer can be present for several years before symptoms develop. Symptoms vary according to where in the large intestine the tumor is located. The right colon is wider and more flexible. It can even be called relatively spacious as compared to the rest of the colon.

Many people with colon cancer experience no symptoms in the early stages of the disease. When symptoms appear, they’ll likely vary, depending on the cancer’s size and location in your large intestine.

The specific cause of colorectal cancer is unknown. The understanding of certain genetic causes continues to grow, nonetheless. Doctors know that colon cancer occurs when healthy cells in the colon develop errors in their genetic blueprint, the DNA. However, the following factors can increase one’s risk of colorectal cancer.

• Age: More than 90% of people are diagnosed with colorectal cancer after age 50. Colon cancer can occur in younger people, but it occurs much less frequently.
• Inherited syndromes that increase colon cancer risk. Genetic syndromes passed through generations of your family can increase your risk of colon cancer. These syndromes include familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, which is also known as Lynch syndrome
• Family history of colorectal cancer (especially parents or siblings). If more than one family member has colon cancer or rectal cancer, your risk is even greater.
• Personal history of Crohn’s disease or ulcerative colitis for eight years or longer.
• Colorectal polyps
• Personal history of breast, uterine or ovarian cancer.

There are, however, many modifiable risk factors; favourably modifying these risk factors reduces the chance of suffering from colorectal cancer.

Such modification includes proper control (if present) of:

• Low-fibre, high-fat diet: Colon cancer and rectal cancer may be associated with a low-fibre diet with processed food and trans fat.
• A sedentary lifestyle
• Diabetes
• Obesity
• Smoking
• Heavy and regular consumption of alcohol
• Radiation therapy directed at the abdomen to treat previous cancers increases the risk of colon and rectal cancer.

When a colorectal cancer is diagnosed, additional tests are performed to determine the extent of the disease, called staging.

The staging for colorectal cancer ranges from stage I, the least advanced cancer, to stage IV, more advanced cancer.

Stage 1

It involves only the innermost layers of the colon or rectum. The probability of cure (excellent prognosis) for stage 1 colorectal cancer is over 90%.

Stage 2

It show bigger growth and extension of tumor through the wall of the colon or rectum into adjacent structures.

Stage 3

It manifests the spread of the cancer to the lymph nodes around but isn’t affecting other parts of your body yet.

Stage 4 (metastatic)

It has spread, or metastasised, to distant organs or lymph nodes far from the original tumour.

With each subsequent stage of colon cancer, the risk for recurrent cancer and death due to spread of the cancer (metastasis) rises. As noted, earlier cancers have lower risks of recurrence and death. By the time a person has stage 4 colorectal cancer, the prognosis is poor. However, even in stage 4 colorectal cancer (depending on where the cancer has spread) the opportunity for treatment exists.

1. Get screened for colon cancer

Several screening options exist — each with its own benefits and drawbacks. Talk about your options with your doctor, and together you can decide which tests are appropriate for you.

One common examination of the colon is done through a colonoscopy. Colonoscopy is a procedure that enables a gastroenterologist to examine the inside of the colon with a colonoscope, a 122-cm long, flexible and thin tube with a camera and a source of light at its tip, connected to a monitor. When the patient is sedated, the tip of the colonoscope is inserted into the anus and then is advanced slowly, under visual control, into the rectum and through the colon usually as far as the cecum, which is the leading part of the colon.

One widely accepted recommendation is healthy people at normal risk for colon cancer should undergo colonoscopy at age 50 and every 10 years thereafter, if completely normal. For those with polyps found in the colonoscopy, the patient needs to come back earlier for a repeat of the colonoscopy to detect new polyps.

However, those with an increased risk, such as those with a family history of colon cancer, should consider screening earlier.

2. Make lifestyle changes to reduce your risk

You can take steps to reduce your risk of colon cancer by making changes in your everyday life.

Eat a variety of vegetables. Vegetables contain vitamins, phytonutrients, minerals, fiber and antioxidants, which may play a role in cancer prevention. Choose a variety of vegetables so that you get an array of vitamins and nutrients.

Drink alcohol in moderation, if at all. If you choose to drink alcohol, limit the amount of alcohol you drink to no more than one drink a day for women and two for men.

Stop smoking. Talk to your doctor or therapist about ways to quit.

Exercise most days of the week. Try to get at least 30 minutes of exercise on at least 4 times a week. If you’ve been inactive, start slowly and build up gradually to 30 minutes. Talk to your doctor before starting any exercise programme.

Maintain a healthy weight. If you are at a healthy weight, work to maintain your weight by combining a healthy diet with daily exercise. If you need to lose weight, ask your doctor about healthy ways to achieve your goal. Aim to lose weight slowly by increasing the amount of exercise you get and reducing the number of calories you eat.