What is Colon Cancer?
Colorectal cancer is the result of cancerous lumps or growths in the colon. It takes the life of approximately 655,000 people yearly and is the fourth most common type of cancer. As long as the cancer stays in the walls of the colon it is surgically curable.
Causes of Colon Cancer
Like most other cancers, colon cancer is the result of a mutation in the cells of the intestine. As a result of the mutation, normal cells in the lower intestines do not stop growing and dividing. As a result polyps develop and these polyps can lead to cancer.
Medications for Colon Cancer
The chemotherapeutic agents used after surgery include 5-FU (5-fluorouracil), Xeloda (capecitabine), Leucovorin, and Oxaliplatin(Eloxatin). For cancer that has metastasized the drug therapy regiment includes 5-FU, UFT, Leucovorin, Camptosar (Irintecan), Eloxatin, Avastin(Bevacizumab), Erbitux(Cetuximab) and Vectibix(Panitumumab).
Prevention of Colorectal Cancer
Colorectal cancer can be prevented by getting regular colonoscopies starting at the age of 50. In addition regular exercise, a healthy diet and a healthy weight are all means of preventing colon cancer. Recently a study by the National Cancer Institute showed vitamin D can assist in preventing colorectal cancer.
Risk factors of Colon Cancer
There are several risk factors for colorectal cancer:
- Age-by age 50 25% of all adults have colon polyps.
- Alcohol -beer drinkers and those who drink more than two liquor based drinks a day are more likely to develop colon cancer.
- Individuals who have insulin dependent diabetes have a 40% greater risk of developing colorectal cancer.
- A diet high in cholesterol and fat or low in fiber is considered causative agents of colon cancer.
- The environment around an individual can increase or decrease the risk of getting colon cancer.
- There are correlations between colon cancer and race, social status and ethnicity.
- Colon cancer does run in families.
- Colitis will increase the risk of colon cancer.
- Lack of exercise leads to a slack colon and this can lead to cancer.
- Obesity increases the risk of colorectal cancer.
- As colon cancer always develops from polyps, individuals with a propensity of these lumps are more likely to have colorectal cancer.
- Smoking can also lead to colon cancer as tobacco is a carcinogen and it increases the size of polyps.
Symptoms of Colorectal Cancer
Symptoms of colon cancer depend on where the tumors are located in the lower intestine. Individuals may experience a change in the bowel movement such as suddenly being constipated or suddenly experiencing diarrhea. There may also be a sensation of still having to defecate even after the bowel is emptied. The size of the stool can also be smaller or its shape may change. Bright red blood or increased mucous in the stool can indicated colorectal cancer in the lower bowel while a black tarry stool can indicated cancer in the upper large intestine. If the tumor is large enough then bowel obstruction can occur and is the patient experiences vomiting, constipation, abdominal bloat, and pain.
Treatment of Colon Cancer
Treatment does depend on how far the colorectal cancer has progressed. In early stages it is easily curable. Surgery is the primary means of treatment. However, radiation and chemotherapy may be used depending on the progression of the cancer and the patient. There are five types of surgery. Curative surgery means removing the localized polyp or a section of the intestine containing the tumor. Palliative surgery comes about when the cancer has metastasized. The main tumor is resected as is any portion of the metastasized liver. Bypassing the tumor occurs when the tumor has moved beyond the colon and into adjacent organs thereby making excision very difficult. The last two types of operations are fecal diversion and open-and-close surgery. Chemotherapy is used to try and prevent metastasis of the colon cancer. Radiation therapy is not regularly used as it can lead to radiation enteritis. Radiation treatments are usually confined to rectal cancer.
Types of Colorectal Cancer
There are 5 different types of colon cancer.
- Adenocarcinomas-this is the most common form of colorectal cancer. There are two types of adenocarcinomas; mucinous and signet ring cell.
- Leiomyosarcomas-this colon cancer is located in the smooth muscle and has a very high chance of metastasizing.
- Lymphomas-this type of colorectal cancer is quite rare and usually is located in the rectum.
- Melanomas-this type of colorectal cancer usually starts elsewhere in the body and migrates to the colon.
- Neuroendocrine Tumors-there are two types of neuroendocrine tumors; aggressive and indolent. Indolent tumors are canceroid, meaning, while they are cancer like, they have not metastasized. Aggressive neuroendocrine tumors are cancerous.