Colon cancer is one of the most commonly diagnosed cancers in the United States and is a leading cause of cancer-related death. In 2000 alone, nearly 50,000 Americans died from the disease, which is highly curable if detected and treated early.

An estimated 95 percent of all colon cancer cases involve the glandular tissue present in the colon wall, which is normally active in the secretion of materials to lubricate waste products before they are excreted. Such cancers typically develop from benign tumors called adenomas and are referred to as adenocarcinomas. Overall, larger adenomas are more likely to develop into malignant growths than smaller adenomas.

Highly developed countries have higher rates of colon cancer than other parts of the world. This is believed to be due in large part to the customary diet in these countries, which generally includes significant amounts of red meat and fat and little fiber. A similar reasoning is often utilized to explain the rise in colon cancer rates in the United States since mid-twentieth century, the diet of the average American coming to include larger amounts of beef and fatty foods since that time.

Frequently colon adenocarcinoma is asymptomatic in its earliest stages. When symptoms do develop, they generally are manifested as disorders of digestion and waste eradication. Among the most common symptoms of the disease are diarrhea, constipation, pain in the abdomen, appearance of blood in the stool, and appetite loss. Fatigue, shortness of breath, jaundice, and accumulation of fluid in the abdominal cavity (ascites) may also occur, but usually not until the disease is well advanced. Due to the generally slow development of symptoms, most adenocarcinomas of the colon have grown several centimeters in diameter by the time they are successfully diagnosed.

Several types of exams are used to diagnose colon adenocarcinomas. A digital rectal exam and an occult fecal blood test are usually the initial techniques utilized, while more advanced examinations involve sigmoidoscopy or colonoscopy, both of which employ a flexible tube-like instrument to inspect one or more parts of the colon. A biopsy is sometimes performed in conjunction with these procedures in order that abnormal tissue can be tested for the presence of cancer cells. A special type of x-ray called a double-contrast barium enema is often used to produce initial images of any growths present, and other advanced imaging techniques (CT scans, MRI, etc.) are generally exploited during staging of the disease.

Colon Adenocarcinoma at 10x Magnification - Surgery is the most commonly employed treatment for localized colon cancers, but may not be appropriate for all patients. In its earliest stages, colonoscopic means of eradicating a tumor may sometimes be sufficient, but surgical resection is necessary most of the time.

Colon Adenocarcinoma at 40x Magnification - In addition to diet, other factors that may play a role in the onset of colon cancer include age (older individuals are more susceptible), physical inactivity, a personal history of chronic inflammatory bowel disease, and a family history of colon cancer, which is sometimes associated with Gardner syndrome or familial adenomatous polyposis.

Colon Adenocarcinoma at 10x Magnification - Colon cancers may be treated with both external and internal radiation therapy, sometimes alone and sometimes before or following surgery. Chemotherapy is most frequently used when tumors have already metastasized to distant areas or as an adjuvant therapy to other forms of treatment.