Colon cancer
Alternative Names
Colon cancer, Colorectal cancer, Cancer-colon, Rectal cancer, Cancer-rectum, Adenocarcinoma-colon, Colon-adenocarcinomaWhat is Colon cancer
Colon cancer is cancer that affects the large intestine (colon) or the rectum (end of the colon).
In rare cases, certain types of cancer can affect the colon, such as lymphoma, carcinoid tumors, melanoma and sarcomas.
Stages of colon cancer are:
- Stage 0: Very early cancer on the innermost layer of the intestine
- Stage I: Cancer is in the inner layers of the colon
- Stage II: Cancer has spread through the muscle wall of the colon
- Stage III: Cancer has spread to the lymph nodes
- Stage IV: Cancer has spread to other organs
Signs and symptoms
As a rule, people with colon cancer have no symptoms, but sometimes the following symptoms can be indicated as colon cancer:
- Abdominal pain and tenderness in the lower abdomen
- Blood in the stool
- Diarrhea, constipation or other change in bowel habits
- Narrow stools
- Weight loss with no known reason
Possible complications
The possible complications of colon cancer include:
- Blockage of the colon
- Cancer returning in the colon
- Cancer spreading to other organs or tissues (metastasis)
- Development of a second primary colorectal cancer
What causes
Scientists found many causes of colon cancer. Almost all colon cancers begin as noncancerous (benign) polyps that slowly change into cancer.
You are at a greater risk for colon cancer if you:
- Are older than 60
- Are African American of eastern European descent
- Eat a diet high in red or processed meats
- Have cancer elsewhere in the body
- Have colorectal polyps
- Have inflammatory bowel disease (Crohn's disease or ulcerative colitis)
- Have a family history of colon cancer
- Have a personal history of breast cancer
Prevention
The death rate of colon cancer has significantly reduced in the last 15 years. It can be associated with increased awareness and screening by colonoscopy.
Colon cancer can almost always be diagnosed by colonoscopy in its earliest and most curable stages. Almost all people at the age of 50 and older should be screened for colon cancer. Colon cancer screening can often find polyps before they become cancerous. You can prevent colon cancer by removing these polyps.
It is very important to change your diet and lifestyle. Some scientists suppose that low-fat and high-fiber diets may decrease your risk of developing colon cancer.
Treatment
Colon cancer treatment depends partly on the stage of the cancer. Typically, treatments include:
Surgery
Stage 0 colon cancer can be treated by removing the cancer cells, often during a colonoscopy. For stages I, II and III cancer, more extensive surgery is needed to remove the part of the colon that is cancerous.
Chemotherapy
Almost all patients with stage III colon cancer should be treated by chemotherapy after surgery for approximately 6 - 8 months. The chemotherapy drug 5-fluorouracil has been shown to increase the chance of a cure in certain patients.
Chemotherapy is also used to improve symptoms and prolong survival in patients with stage IV colon cancer.
- Irinotecan, oxaliplatin, capecitabine and 5-fluorouracil are the three most commonly used drugs.
- Monoclonal antibodies, including cetuximab (Erbitux), panitumumab (Vectibix), bevacizumab (Avastin) and other drugs have been used alone or in combination with chemotherapy.
Radiation
It is usually used in combination with chemotherapy for patients with stage III rectal cancer.
For patients with stage IV disease that has spread to the liver, various treatments directed specifically at the liver can be used. This may include:
- Burning the cancer (ablation)
- Delivering chemotherapy or radiation directly into the liver
- Freezing the cancer (cryotherapy)
- Surgery
