Colorectal cancer is the term that combines the cancer of the colon and the rectum. Colon is the large intestine that is found in the lower part of the digestive system. Rectum is the posterior region that exists for last 5-7 inches of the colon. Colon cancer begins as small clumps or polyps that are harmless. Over time, these polyps get converted into cancerous tumors. Regular screening of the colon is necessary to prevent colorectal cancer.
Colorectal cancer does not produce any signs or symptoms in the early stages. Some of the symptoms that are found in patients with this type of cancer are given below:-
- Sudden changes in bowel movements and its consistency.
- It can cause constipation problem or diarrhea. There will be abdominal discomfort and feeling of not emptying the bowel fully in these patients.
- Bloated sensation or fullness
- Bloody discharge in your stool will be there. Sometimes you will pass long and thin pencil like stools.
- Sudden weight loss without any apparent reason
- Loss of appetite and extreme tiredness
- Unbearable pelvic pain in the last stage of cancer
Any person with one or more symptoms mentioned above should see his doctor without any delay.
Exact cause of colorectal cancer is unclear. Doctors believe that cancer develops in the colon when the healthy cells of the colon are attacked and altered. The way in which healthy cells grow gets changed or becomes uncontrolled. This leads to the formation of more volumes of healthy cells than required. Excess of growth of cells can cause cancerous tumors in the intestine. In due course, these abnormal cells will become cancerous.
- Polyps :
Clumps or polyps begin to appear on the colon more particularly in the lining of the intestine. Polyps are cluster of tissue bags having the shape of mushroom. Once your doctor finds growth of polyps inside the colon it has to be removed.
- Gene Mutations :
Colorectal cancer can be caused due to hereditary factor. It is passed to the offspring from the parents. Gene mutations occur during the formation of zygote in which defective genes are sent to the fetus which increases the risk of cancer. Family adenomatous polyposis shortly called FAP is a rare disease in which the affected person develops hundreds of polyps in the colon. Lynch syndrome also makes one prone to colon and rectal cancer.
Read more on Anal Cancer
Stages of Cancer :
Colon as well as rectal cancer is distinguished according to the stage of development. By knowing the correct stage your doctor will be in a better position to provide treatment.
Colon Cancer Stages :
- Stage 0 is the early or first stage of cancer. At this stage cancer causing cells are found only in the lining of the colon.
- Stage 1 is the second stage in which the cancerous cells will spread quickly crossing the lining barrier to the 2nd and 3rd layers of the colon. At this stage the complete inner wall is affected leaving the outer wall.
- Stage 2 : Now the tumor will extend through the muscles of the colon attacking outer wall of the colon but lymph nodes still remain unaffected.
- Stage 3 : At this time the cancer would have spread entirely on the outer wall of the colon and also on some of the lymph nodes.
- Stage 4 : Apart from colon, now the cancer cells will start spreading to other body parts like liver or lungs. The tumor will grow in size and it is the final stage of colon cancer.
Rectal Cancer Stages :
Rectum is located in the posterior end of the colon and hence there are many treatment options to prevent cancer cells from spreading.
Stage 0 : The cancer cells are found only on the inner lining of the rectum. In this stage the tumor can be removed easily by surgery after removing the infected portion of the rectum.
Stage 1 : Even at this stage the tumor cells will not advance to the outer wall but the tumor will multiply to attain full growth.
Stage 2 : Now the cancer cells have made progress to protrude through the muscular wall to attack other organs like uterus or bladder. It becomes difficult to treat at this stage but treatments are available.
Stage 3 : At this stage the tumor will spread till the lymph nodes gaining more strength attacking other organs vigorously.
Stage 4 : This is the final stage of rectal cancer. Now the tumor causing cells would have reached various parts of the body that includes liver and lungs.
Who are at risk?
Old age, belonging to African/American race, family history of colorectal cancer, having chronic inflammatory disease in the colon, family history of polyps, resorting to low fiber diet, obesity, leading sedentary life, smoking and heavy use of alcohol makes one prone to colon/rectal cancer.
If you are having the signs and symptoms of colorectal cancer your doctor may order for blood test, colonoscopy test, and multiple radiation images like X-ray and CT scan for getting correct picture of your colon.
There are several options of treatment for colorectal cancer. Treatment is given based on the severity of the symptoms and intensity of polyps that has affected the colon/rectum. Your doctor will decide on the course of treatment based on the stage of cancer. Surgery, radiation and chemotherapy are the best methods of treatment given for colorectal cancer.
Surgical Methods :
Colonoscopy method is effective for removing small sized localized polyps. Polyps in the early stage of cancer can be efficiently removed on this procedure. Laparoscopic method is used for removing large sized polyps. The surgeon will make small incisions in many places of the abdominal wall. He will then insert devices that carry cameras that will display the polyps on the screen. Then these polyps are removed using surgical instruments attached to the device.
Invasive Colon Cancer :
Colectomy (removal of colon) is done for treating full grown cancer on the colon. This treatment is used for treating cancer on stage 3 and 4 in which the cancer cells have penetrated the outer wall of the colon affecting lymph nodes also. The colon is removed either in part or in full during this surgery. After removing the cancerous portions of the colon, the surgeon will connect the remaining portion of the colon with the rectum. Depending on the intensity of growth of cancerous cells the colon will be removed permanently or temporarily.
Advanced Stages :
If the cancer is on the final stage then your surgeon will perform an operation for removing the blockage on the colon so that you can get some relief from the symptoms. However cancer cannot be cured at this stage but the quality of life can be improved. Often chemotherapy is to be done after the surgery and sometimes before the operation. For some patients, the cancer would have spread to the liver for which the surgeon will remove the part of the liver affected by cancer causing lesions.
This is the widely used method for destroying cancer causing cells on the colon. Drugs are used for attacking the cancerous cells and tumors. It is done either before the surgery or after the process. Often chemotherapy is combined with one or more surgical methods.
Radiation Therapy :
This is an effective method for killing cancer cells using powerful energy. It can be used for shrinking tumor causing lesions or bumps inside the colon. Both chemotherapy and radiation therapy is used for treating cancer in the advanced stage.
Drug Therapy :
Specific drugs are used to treat advanced stage of colorectal cancer. Avastin, Erbitux and Vectibix are largely used in combination with chemotherapy or surgical methods for treating cancer.
Biological Approach :
In this method, the body’s immune system will be triggered to fight against cancer cells. Cytokines like interferons and interleukins are used for stimulating the cells to attack and destroy cancer causing lesions. Colony stimulating factors are also used for stimulating the immune system for fighting against cancer.
People with high rate of risk factors and those who have crossed 50 years should screen themselves for detecting any cancer. It is easy to prevent the disease in early stages by testing it through colonoscopy rather than waiting for the symptoms to appear in final stages. Include plenty of fiber rich diet in your diet. Quit smoking and avoid taking alcohol. Maintain healthy weight and do exercises at least for half-an-hour daily.