Among the most widely known diseases of the digestive system is colon cancer. According to the Centers for Disease Control (CDC), 51,783 Americans died from colon cancer in 2011 (the most recent year for available data). Excluding skin cancers, colon and rectal cancer, or colorectal cancer, is the third most common cancer diagnosed in both men and women in the United States, according to the American Cancer Society.Polyp growth and irregular cells, which may or may not be cancerous, are the most common development paths for colorectal cancers (also referred to as CRC), and can be detected during a routine colonoscopy, according to Dr. John Marks, a gastroenterologist affiliated with the Main Line Health health care system."The best news is that, if caught early enough, they can also be removed during the colonoscopy - eliminating the possibility that they grow further and become cancer," Marks said. For those patients whose cancer has already spread, there are various minimally invasive surgical options that have extremely good prognoses. It is recommended that asymptomatic patients without a family history begin getting tested regularly between the ages 45 and 50, according to Marks. "Symptoms which may suggest that you need a colonoscopy at an earlier age include rectal bleeding and stool/bowel habit changes which last for more than a few days."While CRC gets a great deal of attention, many diseases and conditions of the digestive system - including irritable bowel syndrome, diverticulitis, GERD (acid reflux) and Crohn's disease - can be chronic and are difficult to diagnose and treat, according to Dr. Larry Good, a gastroenterologist affiliated with South Nassau Communities Hospital. "With many of these diseases, blood work and colonoscopies all looks normal, so there is an absence of red flags." Many of the diseases of the digestive system are tied to the foods we eat, and a number of sufferers can reduce their symptoms by restricting their diets, Good said. "Of course no one wants to hear that they can't eat certain foods, but many times, eliminating acidic things from the diet, such as tomatoes, onions, and red wine, can have an impact," Good said. There are a number of tests to detect digestive tract ailments. A colonoscopy is the examination of the inside of the colon using a long, flexible, fiber-optic viewing instrument called a colonoscope, according the American Gastroenterological Association. Other testing procedures include upper GI endoscopy, capsule endoscopy, endoscopic retrograde cholangiopancreatography and endoscopic ultrasound.