Colon cancer is cancer in any part of the large bowel (colon or rectum). It is sometimes known as colorectal cancer or rectal cancer, depending on where it starts.
It develops in the inner lining of the bowel (mucosa) from growths on the bowel wall called polyps. Most polyps are harmless (benign), but some become cancerous (malignant) over time.
Cancer can narrow and block the bowel or cause bleeding and if untreated, can grow into the deeper layers of the bowel wall and spread from there to the lymph nodes (glands). These small, bean-shaped masses are part of the body’s lymphatic system. If the cancer advances further, it can spread to other organs, such as the liver or lungs (metastasis).
In most cases, the cancer develops slowly and stays in the bowel for months or years before spreading.
Bowel cancer is the second most common cancer in Australia. It is estimated that about 17,000 people are diagnosed with bowel cancer every year. About one in 19 men and one in 28 women will develop bowel cancer before the age of 75.
Signs and Symptoms
In its early stages, bowel cancer often has no symptoms. However, some people with bowel cancer may experience persistent symptoms.
- Changes in previously normal bowel habits such as
- Diarrhoea, constipation, smaller more frequent bowel movements
- Appearance of the stool may change (narrower stools or presence of mucous)
- Feeling of fullness or heaviness in the rectum or bowel
- A feeling that the bowel has not emptied completely after a bowel movement
- Blood in the stools or on the toilet paper
- Unexplained weight loss or loss of appetite
- Weakness or fatigue related to anaemia through chronic blood loss.
- Rectal or anal pain
Please note: Not everyone who has these symptoms has bowel cancer. Other conditions such as Haemorrhoids, Diverticular disease (inflammation of pouches in the bowel wall) tears in the anal canal or some foods or medications can also cause these symptoms
Short-term changes in bowel function are very common and usually do not indicate a serious problem. However, if you have any of the above symptoms for more than four weeks, see your doctor promptly for a check-up.
- Age – most commonly affects people over the age of 50 but can occur at any age. The average age at diagnosed is 69 years, however, about 7% of bowel cancers are in people younger than 50.
- Polyps – the presence of polyps in the bowel.
- Bowel diseases – people who have an inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis, have a significantly increased risk, particularly if they have had it for more than eight years.
- Lifestyle factors – being overweight, having a diet high in red meat (particularly processed meats such as salami or ham), drinking alcohol and smoking increase the risk.
- Other diseases – people who have had bowel cancer once are more likely to develop a second bowel cancer as are people who have had other cancers such as ovarian or endometrial cancer.
- Strong family history – bowel cancer may run in families especially if a parent or sibling has been diagnosed before they turned 55.
- Rare genetic disorders – Familial adenomatous polyposis (FAP) and Lynch Syndrome. These are rare and account for about 5-6% of bowel cancer cases.
Being physically active, maintaining a healthy weight and eating a high-fibre diet may help protect against bowel cancer.
An open colectomy uses a single large incision approximately 15 – 25 cms down the center of the abdomen through the abdominal wall. The diseased section of bowel is then removed through the incision. The two cut ends of bowel are sewn together. Some soft tubes may be left in the abdomen to drain any accumulating fluids. Stitches or staples are used to close the wound. A dressing is placed over the incisions.
A colostomy or ileostomy may be needed in the post-operative period. In this procedure, an artificial opening is created in your abdomen, called a stoma. One or both ends of the intestine are then attached to the stoma. This allows waste to exit your bowel through the stoma. The waste material is collected in a pouch called an “ostomy” bag. A colostomy may be temporary or permanent.
A temporary colostomy allows the intestine to rest and heal. When your intestine has healed properly, you may be able to undergo another operation to rejoin the ends of the intestine.
With open colectomy a hospital stay of 7-10 days is usual.
This was the standard operation in the past and although laparoscopic (minimally invasive) surgical techniques have largely superseded the open procedure it may still be advised and performed in some cases.