How common are cancers of the colon or rectum?
Cancer of the large bowel (colon and rectum) is the third most common type of cancer diagnosed in the UK. In UK, each year, approximately 23,000 people develop colon cancer and approximately 14,000 people develop rectal cancer.
How common are the cancers of the colon and rectum in India?
Colon and rectal cancer is one of the common cancers among men and women from the Indian subcontinent. It ranks sixth or seventh among all other cancers. The incidence (newly diagnosed cases of cancer in a year) of colon and rectal cancers in India is about 4 patients per 1,00,000 population for both sexes together.1
In India, between the years 2001-2003, across five urban centers - Mumbai, Delhi, Chennai, Bhopal and Bangalore, – and one rural center - Barshi, a total of 1,922 cases of colon cancer (2.17% of all cancers) were registered for men and women combined across all age groups, while a total of 1,915 cases of rectal cancer (2.16% of all cancers) were registered for men and women combined across all age groups.
Considering all men, women and children with all types of cancers together, a grand total of 3,837 cases of colon and rectal cancer (4.33% of all cancers) were registered at the six centers mentioned above, between the year 2001-20032.
The TATA Memorial Hospital (T.M.H.) in Mumbai, India registered a grand-total of 19,127 cases of all types of cancer patients in the year 2006 for men, women and children combined. In that same year at T.M.H., 278 people were diagnosed with Colon Cancer, out of which 193 (70%) were males and 85 (30%) were females and 438 people were diagnosed with Rectal Cancer, out of which 302 (70%) were males and 136 (30%) were females3
Like most types of cancer, colon and rectal cancers are more common in older people – more than 80% of these cancers are diagnosed in people over 60.
What causes cancer of the colon or rectum?
In most people, the cause of colon and rectal cancer is still unknown, but research is going on to try to find the cause. We do know that certain risk factors can increase our chances of developing colon or rectal cancer. These risk factors include eating a lot of processed meats, being overweight, getting very little exercise, and smoking.
Some people have a higher risk of developing bowel cancer as they have inherited a faulty gene.
Colon cancer and rectal cancer are not infectious and can‘t be passed on to other people.
Colon cancer and rectal cancer are not infectious and can’t be passed on to other people.
There is evidence that a diet that contains a lot of animal fat and red meat (especially processed meats such as sausages, bacon and pies) can increase the risk of developing bowel cancer.
The greatest increase in risk seems to be for people eating two or more portions of red or processed meat a day. People who eat less than two portions per week seem to have the lowest risk.
No link has been found between eating poultry such as turkey and chicken, and an increased risk of colon or rectal cancer. Eating a diet low in fruit and fresh vegetables may also increase the risk.
Cancer of the colon or rectum may be more common in people who get very little exercise and who are overweight. It‘s also more common in people who have smoked cigarettes for a long time, such as 20 years or more.
People who‘ve had Ulcerative Colitis or Crohn‘s disease (diseases of the lining of the bowel) for a long time also have an increased risk of developing bowel cancer.
Inherited faulty genes
A person who has one or more family members with bowel cancer may have a higher risk of developing it. They are usually only at higher risk, if bowel cancer has been diagnosed in a close family member (such as a parent, sister or brother) under the age of 45, or when there is colon or rectal cancer in several close members on the same side of a family.
People who are worried about bowel cancer because of their family history can be referred to specialist clinics. At the clinic their risk will be carefully assessed. Regular screening, usually with a colonoscope, can be arranged for people who have a high risk of developing the disease. Contact your GP or our cancer support specialists for more information.
Only about 5% (5 in every 100) of colon and rectal cancers are caused by an inherited faulty gene.
Familial conditions – FAP and HNPCC
There are two very rare conditions that can run in families (familial) called familial adenomatous polyposis (FAP) and hereditary non-polyposis colon
cancer (HNPCC). People with either condition have a very high risk of developing colon or rectal cancer.
Familial Adenomatous Polyposis (FAP)
People with FAP have many hundreds of thousands of benign tumours (polyps) in the lining of the colon. They should be regularly screened using colonoscopy or sigmoidoscopy to look for signs of cancer. Usually, people with FAP are recommended to have an operation to remove their colon. Unless the colon is removed, nearly everyone with FAP will develop colon cancer.
FAP causes about 1% (1 in every 100) of bowel cancers.
Hereditary Non-Polyposis Colon Cancer (HNPCC)
People with HNPCC have an increased risk of developing bowel cancers at a young age, sometimes in more than one place in the colon. Unlike FAP, people with HNPCC have very few polyps in the bowel. If you have HNPCC you are likely to be screened every couple of years using colonoscopy. Screening usually starts from the age of 25, or five years before the age at which your youngest relative developed bowel cancer.
HNPCC causes about 3% (3 in every 100) of bowel cancers.