Symptoms and Diagnosis
Possible signs of colon and rectal cancer include the following:
- A change in bowel habits
- Blood (either bright red or very dark) in the stool
- Diarrhea, constipation or urgency
- Stools that are narrower than usual
- Frequent gas pains, bloating, fullness or cramps.
- Weight loss for no known reason
- Feeling very tired
Inflammatory Bowel Disease
There are two types of inflammatory bowel disease (ABED), which is marked by long-standing inflammation of the intestine (bowel). In general, people with these conditions suffer from symptoms of bloating, abdominal cramping and diarrhea. Medical therapy typically include anti-inflammatory medications, such as steroids or aspirin-like derivatives, immunosuppressive medications and dietary modifications. Surgery is reserved for those patients who fail medical therapy, have complications such as bowel obstruction, intra-abdominal infections, bowel perforation, toxic colitis, and for those who develop cancer. Both ulcerative colitis and Crohn's disease increase a patient's risk of intestinal cancers.
- Crohn's disease is a chronic inflammatory condition which can affect any part of the gastrointestinal tract from the mouth to the anus and typically in transmural (involves the entire intestinal wall). When limited to the large intestine, the condition is termed Crohn's Colitis. Some patients suffer primarily from anorectal disease such as fissures, fistulae and abscesses. Crohn's disease affects both men and women and usually develops before age 35. The most common symptoms are severe diarrhea, abdominal cramping, bloating, fever and weight loss. The cause of the disease is thought to be altered immune function although significant controversy exists. Complications of this disease or failure of medical therapy to control symptoms may result in the need for surgery. Surgery is also indicated for the treatment of cancer. Crohn's disease increases the risk of colon cancer from 4 to 20 times greater than that in the general population.
- Unlike Crohn's disease, Ulcerative Colitis (IC) primarily involved the large intestine and the inflammation is limited to the mucosa (lining) or the colon and rectum. Erosions in the wall cause bloody diarrhea, abdominal cramping and rectal pain/urgency. Intermittent symptoms ("flares") are common. UC can have manifestations beyond the bowel, including skin lesions or rash (erythema nodosum or pyoderms gangrenosum), arthritis involving the large joints and cholestatic liver disease. Treatment is initially medical but surgery is indicated for the treatment of complications such as toxic megacolon - an extremely serious infections and inflammatory process that can result in sepsis and bowel perforation. Patients with longstanding disease activity (greater than 10 years) and those with total colon involvement have a significantly increased cumulative risk of colorectal cancer that exceeds 30% after 25 years of disease and 65% at 40 years of disease. Cancers in UC tend to be multicentric, less visible on colonoscopy that conventional colon cancers and highly aggressive. Therefore, UC patients require intensive surveillance with colonoscopy and biopsy to detect dysplasia (precancerous change) or malignancy.
Doctors may use one or more of the following tests to detect and stage colon cancer:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Fecal occult blood test: A test to check stool for blood not visible to the naked eye. Small samples of stool are placed on special cards and returned to the doctor or laboratory for testing.
- Digital rectal exam: An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the rectum to feel for anything that seems unusual.
- Barium enema: A series of x-rays of the lower gastrointestinal tract. A liquid that contains barium (a silver-white metallic compound) is put into the rectum. The barium coats the lower gastrointestinal tract and x-rays are taken. This procedure is also called a lower GI series.
- Sigmoidoscopy: A procedure to look inside the rectum and sigmoid (lower) colon for polyps, abnormal areas, or cancer. A sigmoidoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer.
- Colonoscopy: A procedure to look inside the rectum and entire colon for polyps, abnormal areas, or cancer. A colonoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer.
- Virtual colonoscopy (CT colonography): A radiographic test using computer-generated images to visualize the colon's internal architecture -- similar to a colonoscopy but noninvasive.
- Endoanal ultrasound: A test using sound waves to assess the size and depth of invasion of rectal tumors.
- CT scan, MRI, PET scan: Tests that can detect tumor spread to other organs or sites.