The colon and rectum are continuous and cancers affecting them are referred to as colorectal cancers. Rectal cancer causes nearly 50,000 deaths a year in the U.S alone. Nearly 2/3 of colorectal cancers occur in the colon while about 1/2 occur in the rectum. In fact, colorectal cancers are the third-leading cause for cancer deaths in the U.S. after lung cancer and breast cancer. Typically colon cancer starts as small adenomatous polyps that later turn cancerous. Incidence of colorectal cancer is higher in Western nations as compared to Asian and African countries. More men tend to get affected by this form of cancer than women. Often hereditary syndromes cause multiple polyps in the digestive tract. Environmental and genetic factors play a large role in the occurrence of colorectal cancers. Those suffering from inflammatory bowel disease or ulcerative colitis have an increased risk of developing colorectal cancers.
Rectal cancers do not produce symptoms in the initial stages. They can be detected only by digital or proctoscopic screening tests. If you notice blood in your stools or change in the shape of the stools or cramping pain in the lower abdomen, visit a doctor to check for signs of colorectal cancer. Patients may notice change in bowel habits and urinary symptoms. Stools may be narrower and often black and tarry. A feeling of bloating or colic pain may be experienced on account of obstruction due to tumor. Sometimes there is bowel perforation accompanied by fever and pain. Weight loss, fatigue and anemia may result.
A digital rectal examination helps in detecting abnormal lesions. Any tumor can be assessed for size and ulceration. Laboratory tests and screening procedures such as x-rays and Endoscopy aid in visualizing the lining of the colon. Since the risk of colorectal cancer increases with age, the American Cancer Society recommends yearly digital examination of the rectum for those above 50 years. Any abnormal lesions in the rectum are examined and a biopsy is performed. If a diagnosis of rectal cancer is established, staging has to be established to determine the depth of tumor penetration. Staging aids the physician in determining the treatment options. Rectal cancers are divided into 4 stages. In the first 2 stages and suspected stage 3 state, surgery is used to remove the affected part of the rectum along with its vascular and lymph. Radiation and chemotherapy are also resorted to. Radiation therapy helps in shrinking the tumor prior to surgery. Rectal cancer is often linked to diets rich in fat and calories and low in fiber. Colon cancers can be prevented with the right diet and lifestyle. Diets rich in unsaturated animal fats and highly saturated vegetable oils are known to cause colorectal cancers. High-fiber food helps in the formation of soft and bulky stools, diluting carcinogens and decreasing colonic transit time. This allows lesser chance for polyps to develop. Other dietary elements such as calcium, selenium, carotenoids and vitamins A, C and E help in destroying dangerous free radicals in the colon.
Physicians who specialize in the diagnosis and treatment of the digestive system or gastrointestinal tract are gastroenterologists. When they specialize to treat children in the same area, they are termed as pediatric gastroenterologist. They treat conditions such hepatitis, colon or rectal cancer, ulcerative colitis and Crohn's disease. A gastroenterologist must complete four years of degree, four years of medical school, three years residency in internal medicines and later specialize in gastroenterology for a period of two to three years. Certification from a recognized board is necessary.
Role of gastroenterologist
- Diagnose and offer medical treatment for any kind of disorder in the gastrointestinal tract.
- Order for blood tests, x-rays, endoscope checks of the stomach called gastroscopy or for the large intestine called colonoscopy depending on the patient's illness.
- Assist a surgeon in exactly locating the area of problem that needs treatment in the gastrointestinal section.
- They follow up digestive system disorders that include esophagus, small and large intestine, stomach, pancreas and the liver. They also follow up on symptoms of heartburn, indigestion, ulcers etc following an operation.
Modern techniques and gastroenterologist
- Use of ultra high frequency in endosonography gives better understanding of any lesions formed.
- Measuring of myoelectric and contractile activity in the gastrointestinal tract, esophageal and anal manometry to understand constipation, nausea, abdominal pain etc better in any patient.
- Electrogastrography and few other modern techniques have made it easier to understand the esophageal transit in patients easier.