Colon cancer is also known as colorectal cancer. This type of cancer begins in the lining of the colon or the large intestine and ends in the rectum or the end of the colon.
The incidence of colon cancer in India (for both sexes together) is around 4 cases for every 100,000 people.
People suffering from colon may show no symptoms at all. Certain symptoms that are indicative of colon cancer are:
- Unexplained weight loss
- Change in bowel habits
- Diarrhea or constipation
- Narrow-shaped stools
- Abdominal pain
- Lower abdomen tenderness
- Blood in stool
- Fatigue and weakness
There is no specific identified cause of colon cancer. Inherited as well as acquired gene mutations may cause colon cancer to arise. Usually, colon cancer manifests as non-cancerous or benign polyps in the colon and then gradually turns into cancer.
Risk Factors And Complications
Factors that put people at risk of developing colon cancer are:
- Age above 50 years
- Medical history of colorectal polyps or colorectal cancer
- Previously suffering from inflammatory bowel disease
- Relatives suffering from colorectal cancer or adenomatous polyps
- Being African American
- Suffering from Type II diabetes
- Excessive alcohol intake
- Long-term smoker
- Being obese
- Sedentary lifestyle
- More intake of red meat and processed meat
Tests And Diagnosis
With regular screening, colon cancer can be captured in its infancy and the growths can be removed. Some screening tests are as follows:
- Guaiac-Based Fecal Occult Blood Test (gFOBT): Stool samples are checked for traces of blood, which could indicate colon cancer.
- Fecal Immunochemical Test (FIT): Fecal samples are tested for hidden blood. The blood vessels of large polyps are fragile, so they are torn when stool passes. A very minute amount of blood leaks out, which this test intends to find.
- Stool DNA Test: Stool samples are checked for mutated DNA sequences.
- Sigmoidoscopy: It involves a flexible tube with a light, which is placed inside the lower colon and rectum to identify polyps.
- Colonoscopy: The entire colon and rectum are checked using a long and flexible tube.
- Double Contrast Barium Enema: An X-ray is taken of the colon and rectum.
- CT Colonography (Virtual Colonoscopy): A CT scan is done of the colon and rectum.
If diagnosed with colon cancer, blood tests such as complete blood test, tumor marker tests, and liver function tests are done.
Procedures done for diagnosis are colonoscopy, biopsy, and imaging tests such as MRI, CT scan, angiography, ultrasound, and chest X-ray.
Once colon cancer is diagnosed, treatment is commenced depending on the stage of the cancer.
- Surgery – Colonoscopy is done to remove cancer cells for Stage 0 cancer. For Stages I – III, colon resection is done.
- Chemotherapy – For patients with Stage III cancer, chemotherapy is usually done after surgery. This technique is called adjuvant chemotherapy. Frequently used drugs are 5-fluorouracil, irinotecan, capecitabine, and oxaliplatin. Patients with Stage IV cancer are given chemotherapy to improve their quality of life and prolong their lifespan.
- Radiation therapy – If the cancer has spread to an internal organ or the lining of the abdomen, radiation therapy is used. This is to ensure that all cancer cells are destroyed, even ones that could not be removed by surgery.
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