Information about colon cancer tests and screening
Secondary prevention of colon cancer describes the way that doctors identify non-cancerous polyps and early stages of cancer (compare this to primary prevention, such as a good diet that are in the hands of the sufferer). There are two main methods of secondary prevention of colorectal cancer: these are screening and early prevention. By using these strategies the likelihood of developing a fatal cancer can be greatly lowered. Screening is generally recommended to a degree for all people and not just those who are thought to be at risk from cancer. Using these screening methods is very effective as colorectal cancers generally develop very slowly so early detection allows pre-cancerous abnormal tissue to be removed.
The main methods of colon cancer screening and early detection techniques include the following: digital rectal exam (similar to that performed for prostate cancer); Flexible sigmoidoscopy; Colonoscopy; x-ray (double contrast barium enema) and fecal occult blood tests (FOBT).
Recommendations for screening
The American cancer society recommends that people are screened for colorectal cancer from the age of fifty onwards: these screens should include a yearly fecal occult blood test; five to ten yearly double contrast barium enema; and a colonoscopy every ten years.
Digital rectal examination
Although annual digital rectal examination screening is recommended for everybody over 50 as a preventative measure against colon cancer, it is best that men have the exam from the age of 40 as the method is also able to detect prostate cancers. In this procedure the doctor will insert his finger up the rectum and detect any abnormal growths or polyps by touch. Due to the size of the colorectal system additional methods to the digital rectal examination are required to detect cancers that do not first develop in the rectum.
Fecal occult blood tests
As polyps and cancerous tumours may lead to bleeding in the intestine, a tell-tale sign of their presence may be the presence of blood in stools. Often the amount of blood may be small and not easy to detect, therefore a procedure known as fecal occult blood test is performed in order to detect the presence of blood. Following a digital rectal examination a doctor will often perform a fecal occult blood test using faeces present on the examination glove. A piece of diagnostic test paper is smeared and the presence of blood ascertained.
Flexible sigmoidoscopy is an invasive method of colon cancer screening. A viewing instrument is inserted into the anus allowing the doctor to take a detailed look colon tissue. It is estimated that if people were to undergo a sigmoidoscopy screening every five years the incidence of colon cancer could be reduced by as much forty percent.