Colon Cancer Prevention and Screening
Colon cancer is a malignancy arising from the inner lining (mucosa) of the colon and rectum. Colon cancer is the third leading cause of cancer behind breast and lung cancer and is the second leading cause of cancer deaths in the US. African-Americans have a higher incidence of colon cancer. Men have a slightly increased incidence of developing colon cancer than women. The disease is more common in developed countries. Most colon cancers begin as a small precancerous growth called a polyp. The time taken for a polyp to become a cancer is very variable but is in the order of 3-5 years. Remember not all polyps have the potential to grow into cancer.
What Causes Colon Cancer?
The exact cause of colon cancer is not known. Genetic factors play an important role. As the disease is common in the Western World, dietary factors such as consumption of a low fiber, high fat diet may play a key role. A high fiber diet may be protective due to dilution of carcinogens (cancer causing agents). Vitamin C and aspirin may also be important protective agents.
What Are Symptoms of Colon Cancer?
While many patients with colon cancer experience no symptoms, others present with abdominal pain, rectal bleeding or anemia (low blood count). Some may present with bowel obstruction from the tumor.
How to Detect Colon Polyps and Cancer
The most important preventive method is to detect colon polyps and remove them before they turn into colon cancer. Barium enema (X-Ray test), Colonoscopy and CT Colonography (specialized CT Scan) are some of the methods available to detect colon cancer and polyps. Colonoscopy remains the superior test as it allows resection of polyps and obtaining biopsies in the case of cancer to establish a diagnosis.
Screening Guidelines for Colon Cancer
Patients who have no family history of colon cancer need to have Lab studies (Blood counts, Liver and Kidney Blood Tests) and a screening colonoscopy at age 50 and if no polyps found, colonoscopy every 5-10 years thereafter. If a polyp is found at colonoscopy a more frequent surveillance perhaps at 1-3 year interval may be necessary depending on the polyp number, size, histology (Pathology) and appearance (stalk vs flat vs mound like).
Patients with family history of colon cancer need to begin screening 10 years before their relative was diagnosed with colon cancer.
How is Colon Cancer Treated?
Once a cancer is found, surgery, that can often be done through a laparoscope will be needed. Adjuvant chemotherapy or Radiation therapy may be required in a few patients. Detection of premalignant polyps still remains a key goal in the management of colorectal tumors. Patients who have had colon resection for cancer need surveillance colonoscopy at 1-2 year intervals.