Overview Of Colorectal Cancer
Colorectal cancer is a cancer of the tissues of the large intestine and colon. A common type of colorectal cancer is caused by abnormal proliferation and growth of the epithelial lining of the intestine that becomes a small lump, called a polyp. Over time some of these polyps may turn into cancer. The resection of polyps can prevent from becoming cancerous. Untreated colorectal cancer can spread through the intestinal wall or metastasize to the liver, lungs, peritoneal lining, brain, or bone. Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer.
Cause Of Colorectal Cancer
Early diagnosis can often lead to a complete cure.
Almost all colon cancers start in the lining of the colon and rectum. When doctors talk about colorectal cancer, this is usually what they are talking about.
There is no single cause of colon cancer. Nearly all colon cancers begin as noncancerous (benign) polyps, which slowly develop into cancer.
You have a higher risk for colon cancer if you:
• Are older than 50
• Are African American or of eastern European descent
• Eat a lot of red or processed meats
• Have colorectal polyps
• Have inflammatory bowel disease (Crohn disease or ulcerative colitis)
• Have a family history of colon cancer
Some inherited diseases also increase the risk of developing colon cancer. One of the most common is called Lynch syndrome.
What you eat may play a role in getting colon cancer. Colon cancer may be linked to a high-fat, low-fiber diet and to a high intake of red meat. Some studies have found that the risk does not drop if you switch to a high-fiber diet, so this link is not yet clear.
Smoking cigarettes and drinking alcohol are other risk factors for colorectal cancer.
Symptoms Of Colorectal Cancer
Colorectal cancer might not cause symptoms right away, but if it does, it may cause one or more of these symptoms:
•A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days
•A feeling that you need to have a bowel movement that’s not relieved by having one
•Rectal bleeding with bright red blood
•Blood in the stool, which may make the stool look dark
•Cramping or abdominal (belly) pain
•Weakness and fatigue
•Unintended weight loss
Colorectal cancers can often bleed into the digestive tract. Sometimes the blood can be seen in the stool or make it look darker, but often the stool looks normal. But over time, the blood loss can build up and can lead to low red blood cell counts (anemia). Sometimes the first sign of colorectal cancer is a blood test showing a low red blood cell count.
Treatment Of Colorectal Cancer
When caught early, colorectal cancer may be treated with a colonoscopy to remove polyps or cancerous cells from the lining of the colon. Advanced diseases may require surgery to remove some of or, in rare cases, the entire colon. Other treatment options include immunotherapy, targeted therapy, chemotherapy, and radiation therapy. The multidisciplinary team of colorectal cancer experts will answer questions and recommend treatment options based on the patient’s unique diagnosis and needs.
- Surgery is the most common treatment for this cancer type and may involve removing tumors, the affected section, or sections of the colon and nearby lymph nodes.
- Radiation therapy is often delivered before or after surgery, to shrink tumors or kill cancer cells that may remain behind.
- Chemotherapy is often given before or after surgery to shrink tumors or kill cancer cells, especially or if cancer has spread to other parts of the body.
- Immunotherapy may be an option for patients whose cancer has specific genomic features.
- Targeted therapy uses bio-engineered drugs that target specific proteins found on cancer cells. These drugs may be used alone or in combination with other treatments.
Exams and Tests
Through screening tests, colon cancer can be detected before symptoms develop. This is when the cancer is most curable.
Your doctor will perform a physical exam and press on your belly area. The physical exam rarely shows any problems, although the doctor may feel a lump (mass) in the abdomen. A rectal exam may reveal a mass in people with rectal cancer, but not colon cancer.
A fecal occult blood test (FOBT) may detect small amounts of blood in the stool. This may suggest colon cancer. A sigmoidoscopy, or more likely, a colonoscopy, will be done to evaluate the cause of blood in your stool.
Only a full colonoscopy can see the entire colon. This is the best screening test for colon cancer.
Blood tests may be done for those diagnosed with colorectal cancer, including:
• Complete blood count (CBC) to check for anemia
• Liver function tests
If you are diagnosed with colorectal cancer, more tests will be done to see if cancer has spread. This is called staging. CT or MRI scans of the abdomen, pelvic area, or chest may be used to stage cancer. Sometimes, PET scans are also used.
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 outside the colon
Blood tests to detect tumor markers, such as carcinoembryonic antigen (CEA) may help the doctor follow you during and after treatment.