Colorectal Cancer refers to an autonomous growth in the colon or rectum that can spread (metastasize) to other organs like the liver or lung. This contrasts with a polyp which is also a growth but has not yet to acquire the ability to spread. A polyp is usually referred to as a benign growth.
When diagnosed with cancer, the growth of tumour is no longer under the control of the body and as such, will expand beyond the initial organ. In the case of colorectal cancer, the tumour can grow so large that it causes obstruction or tumour bleeding. The tumour can also grow beyond the confines of the colon and rectum to invade into other organs like the small intestine, bladder, ureter, kidney, and stomach, among others.
Cancers are also fearful because they can spread to distant (far away) organs. In the case of colorectal cancer, it can spread via the bloodstream or within the abdomen to distant organs like the liver, kidney, ovaries, and adrenal gland. This effectively renders the cancer to a Stage IV disease, which is the most advanced stage.
For all potentially curable colorectal cancers, surgery is the mainstay of treatment. Surgery involves removal of the cancerous colon with additional margins to ensure complete removal with no remaining disease. Surgery can be performed either as a keyhole (laparoscopic) or open surgery.
For rectal cancers, there may be a role for radiotherapy treatment before proceeding with surgery. The radiotherapy period is either a 5-day or 6-week treatment regime, depending on the stage of the rectal tumour.
For both colon and rectal cancers, post-operative chemotherapy may be needed. The decision can only be made after the tumour has been removed and examined by a pathologist to determine the exact stage.
For colorectal cancers that have spread, the first-line treatment can be either surgery or chemotherapy. Tumours causing severe pain, bleeding or obstruction will need to be treated with surgery and subsequent chemotherapy.
The surgery can be performed either as an Open approach or a Laparoscopic (keyhole) approach. The Open approach is the traditional approach and is still very often utilised in patients with locally advanced cancers, in emergency situations and in patients with multiple medical problems. The Laparoscopic approach is usually offered as the first option for suitable patients and is currently the most utilised approach. The laparoscopic approach allows for much smaller wounds, faster post-operative recovery, and lesser post-operative pain.
Both surgical approaches require lengths of the colon to be freed up from the surrounding tissue. The segment of the colon containing the tumour is then removed together with the associated lymph nodes and sent for further microscopic examination.
The two ends of the remaining colon will then be joined (anastomosed). The most common method currently employed is to utilise specialised surgical staples. The joining of the colon allows the passage of stools along the usual pathway to the anus.
In a minority of patients, the formation of a stoma may be required. A stoma can be either temporary or permanent. A temporary stoma is usually closed off in 6-12 months’ time through a second surgery. A permanent stoma will be required in circumstances where the anus cannot be preserved or if operative complications occur.
The common symptoms of colorectal cancer include:
• blood in stools
• change in bowel motion habits particularly increased toileting frequency
• watery or loose stools
• further urge to pass motion after just going to the toilet
• unexplained loss of weight
• long-term abdominal pain
For individuals who have no symptoms but are keen to screen for colorectal cancer, a stool test to detect the presence of blood is a good initial test. If blood is detected in the stools, the next step will then be to perform a colonoscopy to fully evaluate the colon. It is important to note that there is a small but significant false-negative rate for the stool test and many individuals have chosen to proceed directly to colonoscopy without doing the stool test. A general guideline is to consider either a stool test or to proceed directly for a screening colonoscopy as an individual approaches 50 years of age.
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