We now continue with the diagnosis of colorectal cancer.
Known also as bowel cancer or colon cancer, it is the development of cancer from the colon (the large bowel) or rectum (parts of the large intestine).
Globally more than 1 million people get colon cancer every year. It is more common in developed countries. It is the second highest cause of cancer occurrence and death for men and women in the United States combined. An estimated 141,210 cases were diagnosed in 2011. In the UK about 41,000 people a year get colon cancer making it the fourth most common type.
Australia has one of the highest rates of bowel cancer in the world. Bowel cancer affects men and women, young and old. It is one of the top five causes of premature death among Australians aged 45-74 and is the seventh leading cause of death among those aged 25-44. One in 19 men and one in 28 women will develop colon cancer before the age of 75.
Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and feeling tired all the time.
Cancer occurring in the left side of the colon generally causes constipation alternating with diarrhoea, abdominal pain and obstructive symptoms, such as nausea and vomiting.
Right-sided colon produces vague, abdominal aching, chronic blood loss, weakness, weight loss and/or an abdominal mass.
Patients with the cancer may also present with a rectal fullness, urgency, or bleeding, and cramping rectal pain.
Colon cancer can affect any part of the large bowel (colon) or rectum.During the early stages of bowel cancer, patients may have no symptoms. As a cancerous tumour grows, it can narrow and block the bowel. Minor changes in bowel movements, with or without rectal bleeding are also seen, but they are often ignored or attributed to haemorrhoids. That is why early preventive screening is so important.
Mostly colon cancer is due to old age and lifestyle factors including diet, obesity, smoking, being overweight and lack of physical activity. Dietary factors that increase the risk include red (especially when charred) and processed meat (smoked, cured, salted or preserved) as well as alcohol. Another risk factor is inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis.
If a patient experiences some of the above symptoms for over two weeks, he shall consult a doctor.
Bowel cancer may be diagnosed by obtaining a sample of the colon during a colonoscopy.
A colonoscopy is a detailed examination which looks at the lining of the entire large bowel.
During colonoscopy, small polyps may be removed if found.
Sometimes the first sign of bowel cancer is sudden blockage of the bowel. When this happens, bowel cancer is diagnosed by computed tomography (CT scan) and an emergency operation. Imaging tests such as PET and MRI may also be used in certain cases.
Cancer that is confined within the wall of the colon may be curable with surgery while cancer that has spread widely are usually not curable.
The good news is that, in Australia, bowel problems can be successfully treated in 90% of cases, if detected early.
In diagnosis, we shall differentiate colon cancer with dysentery, which also shows symptoms of diarrhea with blood, urgency, abdominal pain, and an inflammatory disorder of the colon. Dysentery is an infectious disease which comes acutely, starting with fever, vomiting, then diarrhea, urgency, and stool with blood.
Symptoms normally present themselves after one to three days, and are usually no longer present after a week. The frequency of urges to defecate, the large volume of liquid feces passed, and the presence of mucus, pus, and blood depends on the pathogen causing the disease.
Many of the symptoms of colorectal cancer can also be caused by something that isn’t cancer, such as infection, hemorrhoids, irritable bowel syndrome, or inflammatory bowel disease.
The signs and symptoms of hemorrhoids depend on the type present. Internal hemorrhoids often result in painless, bright red rectal bleeding when defecating. External hemorrhoids often result in pain and swelling in the area of the anus. If bleeding occurs it is usually darker. This may include constipation, diarrhea and sitting on the toilet for a long time. Symptoms frequently get better after a few days. Colonoscopy is reasonable to confirm the diagnosis and rule out more serious causes.
In most cases, people who have the above symptoms do not have cancer. Still, if you have any of these problems, it is a sign that you should go to the doctor so the cause can be found and treated, if needed:
- A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days
- A feeling that you need to have a bowel movement that is not relieved by doing so
- Rectal bleeding
- Dark stools, or blood in the stool
- Cramping or abdominal (belly) pain
- Weakness and fatigue
- Unintended weight loss
Current dietary recommendations to prevent these problems include increasing the consumption of whole grains, fruits and vegetables, and reducing the intake of red meat and processed meats. Higher physical activity is also recommended.
As surgery techniques improve, recurrence rates are decreasing; however, there is a chance that the cancer can return.
Following initial treatment, 30-50% of bowel cancer patients in remission develop recurrence, typically within the first 2 – 3 years. If it does, it may or may not cause symptoms.
So increasing surveillance, engaging in physical activity, consuming a diet high in fiber, and reducing smoking and alcohol consumption decrease the risk.
In Australia, The National Bowel Cancer Screening Program is sending out free bowel cancer screening tests to all Australians aged 50–74. The government has suggested the following for prevention: quit smoking, reduce alcohol consumption, maintain a healthy body weight, be active and sit less, and eat a healthy diet.
Experience in Australia shall be shared to people across the world.
Talk to you next time.