Colon Cancer

By William Pegg

What is colon cancer?

  • Colon cancer is cancer of the large intestine and the lower GI Tract, and sometimes the very end of the tract or the rectal cavity. Both together is referred to as colorectal cancer as the colon and rectal cavity are both affected.
  • Most cases begin as benign lumps of tissue that form within the intestinal wall known as polyps, and overtime the cells that compose them can become damaged and cause cancer.
  • Due to the rather benign nature of the polyps and small size, often no symptoms occur and the person will not be aware of them until the cancer itself actually begins to form and cause symptoms.
  • The cancer is likely to metastasize throughout the abdomen cavity primarily into the walls of the abdominal organs known as peritoneum.
  • peritoneum- The tissue that lines the abdominal wall and covers most of the organs
  • Typically, the cancer first metastasizes into the nearby areas and invades the tissue and eventually causes lesions within the intestinal lining, afterwards the cancer can now spread to other nearby organs and also through the lymphatic system to various sites within the body.
  • This cancer has also been known to be able to invade the blood stream and spread to the bones due to the fact that they are a main site of metastasizing, but it typically tends to stay within the lower abdomen region.

Stages of Colon Cancer

  • Stage 1: cancer has spread to the intestinal lining, but hasn't breached the colon and or rectal wall
  • Stage 2: cancer has spread into or all the way through the walls, but hasn't spread into the lymph nodes
  • Stage 3: cancer has spread to the lymph nodes, but hasn't traveled to other parts of the body yet
  • Stage 4: cancer has spread to other organs and or other parts of the body

Symptoms of Colon Cancer

  • A change in your bowel habits, such as diarrhea or change of the consistency of your stool and other stool changes
  • Blood within the stool or blood discharge from the rectum
  • Constant feeling of discomfort or pain within the abdomen
  • Feeling of the bowels not being emptied completely
  • Weakness and fatigue that is prolonged
  • Unexplained weight loss that is prolonged
  • During the early stages of the disease, many people do not experience symptoms, and when they do appear they are based on the location and size of the cancer

Testing/Detection

  • Colonoscopy: a long slender tube with a video camera is inserted into the rectum in order to get a view of both the colon and rectum region. This test is typically conducted on a yearly basis for many patients in order to detect cancer early enough to survive. If some trouble areas are detected, surgical instruments can be inserted into the tube to take biopsies.
  • Virtual Colonoscopy: a special image capture procedure that takes multiple images of the colon and puts them together to give a detailed look at the inside of it. This procedure is typically done to look for visible problem areas in those that are not able to undergo a colonoscopy and can be effective, but not as effective as the actual test itself.
  • Typically, the way colon cancer is detected is by first the patient noticing changes within themselves and requesting an appointment with a certified physician. Then, the physician will typically order the test and or scans based on the nature of the problem and severity of symptoms. Once the tests are conducted, if any signs of cancer as mentioned previously are found the patient is referred to a specialist to confirm the original findings and begin to undergo possible treatment options based on the progress of the cancer itself.

Treatment Options

  • Early stage cancer- if the cancer is caught early and is localized, surgery to remove the polyps by colonoscopy will be recommend. However, if the polyps cannot be removed by this method, laparoscopic surgery may be suggested. This surgery involves several small incisions in the abdominal region that allow the surgeon to remove the pulps externally.
  • Invasive cancer- if the cancer has spread to various parts of the colon or into the walls of the colon, a colectomy may be ordered to remove the cancerous part of the colon and prevent it from spreading to the rest of the body. However, if the cancer has spread to the rectum, colostomy may be needed to prevent the cancer from spreading as well. This procedure involves part of the bowel being removed and a special bag being used to allow waste to be properly excreted from the body. In both cases of the cancer, often surrounding lymph nodes are removed to test for cancer as well as healthy tissue to make sure the cancer hasn't spread to other areas.
  • Advanced cancer- in this case, surgery is done primarily to relieve symptoms caused by the cancer and to make to the patient more comfortable by easing the blockage and bleeding. Often times, chemotherapy is used with radiation therapy to give the patient the greatest life expectancy.
  • Chemotherapy- drugs are used to target the specific cancer cells by destroying their genetic composition, this is usually done if the cancer has spread to the lymph nodes
  • Radiation therapy- powerful radioactive rays are used to destroy remaining cancer cell, shrink possible tumors, and prevent the cancer from spreading to more parts of the body
  • Targeted drug therapy- typically reserved to those with advanced colon cancer, these are often very expensive and the true side effects are not truly known about many of them. These are usually a last ditch effort to try and lengthen the sufferers life span for just a few more months.

Prognosis

  • If detected in the early stages, the survival rate is about 92%
  • If detected in the middle stages, the survival rate is about 87%
  • If detected in the later stages, the survival rate is 69%
  • If detected in the latest stage, the survival rate is 11%
  • Typically, if someone survives one bout with the cancer, it will most likely relapse and the person will have to fight again due of the fact that they are now more likely to develop abnormal cells
  • If one survives their first bout, they can live normal life spans with some follow up treatment to prevent reoccurrence of the cancer
  • As the stage of cancer increases, the percentage of living keeps dropping quite dramatically. If one goes thorough all 4 stages they may live for about 5 years and then die, but it is more likely they'll die much sooner than that due to the severity of stage 4 cancer
  • Many die in the earlier stages and will only live on average 2-3 years after first being diagnosed with cancer. However, in some severe cases, only a year may be expected depending on the overall health of the patient and the severity of the cancer itself. Basically, the earlier it is detected, the more likely you will survive and surpass the typical life expectancy.

Risk Factors

  • Familial adenomatous polyposis (FAP)- a genetic disorder that causes one to develop thousands of polyps in their colon and rectum. This greatly increases your chance of developing colon cancer before the age of 40. Typically, the APC gene is mutated in this genetic abnormality, but the severity of the disease will depend on the location of the abnormality within the gene itself.
  • Hereditary nonpolyposis colorectal cancer (HNPCC)- increases the chance of colon cancer and rectal cancer greatly before age 50. However, like other colon cancer genetic disorders it can be detected doing a generic test to determine if you carry the gene. This particular mutation occurs on about 5 genes, but MLH1 and MSH2 account for a large majority of the cases.
  • Smoking, drinking, obesity, sedentary life style, old age, and being African- American all increase your chance of developing colon cancer
  • Radiation therapy for prior cancer- localized radiation treatment for prior cancer in the abdomen region may also greatly increase your chance for having a relapse of colon/rectal cancer as it creates more abnormal cells to form by scrambling their genetic code

  • Bad diet- those that eat a low fiber and high fat diet have an increased chance for colon cancer due to the fact that they are slowly damaging cells within the intestinal lining. Also, those that eat an increased amount of red meat are also more likely to develop colon cancer because the fat contained within the meat causes your body to function as properly as it should.

Works Cited

1.) "Colon Cancer." Risk Factors. N.p., n.d. Web. 17 Mar. 2015.

2.) "Diseases & Conditions." Cleveland Clinic. N.p., n.d. Web. 18 Mar. 2015

3.) "Division of Medical Genetics." Hereditary Non-Polyposis Colorectal Cancer (HNPCC) Hereditary Cancer Program › › UConn Health. N.p., n.d. Web. 18 Mar. 2015.

4.) Long-Term Smoking Increases Colorectal Cancer Risk, Study Shows." Long-Term Smoking Increases Colorectal Cancer Risk, Study Shows. N.p., n.d. Web. 18 Mar. 2015.