Colorectal Cancer

What is Colon Cancer

Colorectal cancer is the third most commonly diagnosed cancer in both men and women in the US. Colorectal cancer includes cancer of the colon, rectum and appendix and is caused by uncontrolled cell growth (also know as neoplasia) in the colon, rectum, or vermiform appendix.

The colon and rectum are responsible for the storage and elimination of the body’s solid waste. They are lined with a covering, which, with aging, tends to develop growths, called polyps. Over time, it is these polyps that may become cancerous. Colorectal cancers begin in the lining of the bowel. If left untreated, the cancer can grow into the layers of muscle underneath the bowel and best replica watch mens eventually through the bowel wall. Most cancers start as a small polyp or adenoma growing on the bowel wall. These growths, which resemble mushrooms, are usually harmless, but some will develop into cancer over time. This type of localized bowel cancer is usually found through the use of colonoscopy.

Colorectal cancer is the 3rd most common type of cancer in the world but it is much more common in developed countries, with around 60% of cases being diagnosed in countries in the developed world. In 2008, 1.4 million new cases of colorectal cancer were diagnosed, and there were over 600,000 deaths worldwide from colorectal cancer.

Types of Colorectal Cancer

A type of cancer called adenocarcinoma accounts for more than 95 percent of colorectal cancers.

  • Adenocarcinomas are tumors that start in the lining of internal organs. These tumors start in cells with glandular properties, or cells that secrete. They can form in many different organs, such as the lung or the breast. In colorectal cancer, early tumors start as small adenomatous polyps that continue to grow and can then turn into malignant tumors.

These are other types of cancer that can be found in the colon and rectum, but they are rare.

  • Gastrointestinal stromal tumors (GIST) start in the muscle tissue of the colon. They can be benign at first, but may turn into cancer. When this happens, they are called sarcomas.
  • Lymphoma is a cancer that typically starts in a lymph node, which is part of the immune system. It can also start in the colon or rectum. Lymphomas fall into two categories – Hodgkin disease and non-Hodgkin lymphoma.
  • Carcinoids are tumors caused by hormones. They start in special hormone-producing cells in the intestine. Often they cause no symptoms.

What are the Symptoms of Colorectal Cancer?

The most common symptoms of colorectal cancer:
  • a change in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
  • rectal bleeding or blood in the stool
  • cramping or gnawing stomach pain
  • decreased appetite
  • vomiting
  • weakness and fatigue
  • jaundice – yellowing of the skin and eyes

If you have any of these symptoms, check with your physician, especially if you are over 50 or have a personal or family history of the disease.
 

Each individual may experience symptoms differently.
  • The symptoms of colorectal cancer may resemble other conditions, such as infections, hemorrhoids, and inflammatory bowel disease.
  • It is possible to have colon cancer and not have any symptoms.
  • Always consult your physician for a diagnosis.

Stages of Colorectal Cancer

When colorectal cancer is diagnosed, tests will be performed to determine how much cancer is present. Diagnostics will also check to find out if the cancer has spread to other parts of the body. This is called staging.

Staging is an important step in planning a treatment program. The National Cancer Institute defines the following stages for colorectal cancer:

  • Stage 0 (Cancer in Situ): The cancer is found in the innermost lining of the colon.
  • Stage I (also called Dukes’ A colon cancer): The cancer has spread beyond the innermost lining of the colon to the second and third layers and the inside wall of the colon. The cancer has not spread to the outer wall of the colon or outside of the colon.
  • Stage II (also called Dukes’ B colon cancer): The cancer has spread deeper into the wall or outside the colon to nearby tissue. However, the lymph nodes are not involved.
  • Stage III (also called Dukes’ C colon cancer): The cancer has spread to nearby lymph nodes, but has not spread to other organs in the body.
  • Stage IV (also called Dukes’ D colon cancer): The cancer has spread to other parts of the body, such as the lungs.

Colorectal Cancer

Risk factors may include:

  • Age — Most people who have colorectal cancer are over 50, but it can occur at any age.
  • Race — African Americans have the highest risk for colorectal cancer.
  • Diet — Colorectal cancer is often associated with a diet high in red and processed meats.
  • Polyps — Benign growths on the wall of the colon or rectum—which are common in people over 50—are believed to lead to colorectal cancer.
  • Personal history — A history of colorectal cancer or adenomatous polyps increases risk for colorectal cancer.
  • Family history — People with a strong family history of colorectal cancer or polyps have an increased risk for colorectal cancer.
  • Ulcerative colitis or Crohn’s disease — Inflammation in the lining of the colon common in these two conditions increases risk for colorectal cancer.
  • Inherited syndromes – such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colon cancer (HNPCC)

Other risk factors include obesity, physical inactivity, heavy alcohol consumption, Type 2 diabetes and smoking.

What causes Colorectal Cancer

The exact cause of colorectal cancer—malignant cells found in the colon or rectum—is unknown.

  • In most colorectal cancer, early tumors start as small polyps that continue to grow and can then turn into malignant tumors.
  • A small percentage of colorectal cancers are caused by inherited gene mutations. People with a family history of colorectal cancer may wish to consider genetic testing.
  • The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of these test results.

Prevention of Colorectal Cancer

Although the exact cause of colorectal cancer is not known, it is possible to prevent many colon cancers. Here are some steps to consider:

  • Diet and exercise – Eat more fruits, vegetables and whole grain foods. Avoiding high-fat, low-fiber foods. Get some exercise on a regular basis—even small amounts are helpful.
  • Drug therapy – Some studies have shown that low doses of nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, and estrogen replacement therapy for post-menopausal women may reduce the risk of colorectal cancer. Discuss this with your physician.
  • Screenings – Since some colorectal cancers cannot be prevented, finding them early is the best way to improve the chance of successful treatment. Be sure to have screening tests done at appropriate ages.