Colorectal Cancer Conditions, Diagnostics & Treatments
The Colorectal Cancer Center at Cedars-Sinai gives colorectal cancer patients access to leading specialists in the field. The program also draws on the resources and expertise of the Samuel Oschin Comprehensive Cancer Institute, the S. Mark Taper Foundation Imaging Center and the Pain Center to provide the full range of treatments and services for colorectal cancer patients.
Colon and rectal cancers are among the few preventable cancers. In fact, with early detection, colon and rectal cancers have a high survival rate. They generally begin with the formation of a single polyp. Since polyps come in different varieties, some may be precursors to cancer. However, polyps can be easily detected and removed during a screening called a colonoscopy.
A colonoscopy is an outpatient procedure that either a gastroenterologist or colorectal surgeon performs to evaluate the colon for polyps or cancer. Colonoscopies can also be used to evaluate blood in the stool, anemia, abdominal pain, diarrhea or other changes in bowel habits. A colonoscopy begins with sedating the patient and making him or her as comfortable as possible. A long, flexible tube with a fiberoptic camera at its tip is inserted into the rectum so the entire colon can be viewed. The scope bends as it is gently pushed through the colon to the point where it meets the small intestine. The camera transmits an image to a computer screen allowing the doctor to closely examine the intestinal lining. If polyps are found, they are removed through the scope and sent to the laboratory for diagnosis. The doctor may also remove tissue for a biopsy if any other abnormalities are discovered. The procedure usually lasts 30 minutes and is rarely painful.
In order for the doctor to view the colon without obstruction, the colon needs to be emptied. A patient prepares for the screening by drinking a special liquid preparation and only clear liquids the day before. Pre-colonoscopy preparations may vary but your doctor will give you full instructions before the procedure. It is important to follow all instructions carefully.
Most doctors who treat colorectal cancer recommend that patients who are at average risk for colon cancer should have a screening colonoscopy beginning around age 50. Some people may need screenings earlier if they have risk factors such as family history of colorectal cancer or inflammatory bowel disease. The screening colonoscopy should be repeated every five to 10 years. It may need to be repeated sooner if polyps or cancer are found.
Patients who undergo a colonoscopy need to take the day off from work and will need a ride home since they are sedated for the procedure. Before discharge, your physician or nurse will give you the necessary post-test instructions.
The screening colonoscopy is usually covered by insurance.
Virtual colonoscopy is a relatively new procedure that may be very useful in the future. It requires the same bowel preparaton the day before as a traditional colonoscopy, but no sedation is used during the procedure. Air is blown into the colon through a small tube placed in the rectum. CT scan-like pictures are then taken. Polyps can be seen but cannot be removed during virtual colonoscopy. A traditional colonoscopy is still required for polyp removal. Another drawback of virtual colonoscopy is that it's diffult to determine if the polyps can be safely watched or need to be removed.
The virtual colonoscopy readily available today is two-dimensional and not as sensitive as traditional colonoscopy. The new three-dimensional scans are not yet widely available. At present, two-dimensional virtual colonoscopy is not covered by insurance, and traditional colonoscopy is still recommended.
In the future, virtual colonoscopy that employs three-dimensional imaging and other advanced features may be comparable to traditional colonoscopy.
The Colorectal Cancer Center uses the expertise of its physicians and a variety of procedures to diagnose colorectal cancer and identify the stage of the disease. Most colon and rectal cancers are discovered through either a colonoscopy or barium enema. In the future, virtual colonoscopy may be useful in the diagnosis of colon cancer. Once the diagnosis has been made, it is important to determine the stage of the disease. The stage will have an impact on the cancer's treatment. Tests are conducted to learn if cancer cells have spread through the colon or rectal wall to tissues around it or other parts of the body. These tests could include CT scan, transrectal ultrasound or PET scan.
In this procedure, a technologist inserts a lubricated enema tip into the patient's rectum and allows liquid barium to flow through the enema tip a little at a time. The technologist then takes a series of X-ray pictures of the colon. The exam takes approximately 45 minutes. A patient prepares for the test by drinking a special prep and only clear liquids the day before.
CT scans are special X-rays that are analyzed by a computer, giving cross-sectional images of the body. The abdomen and pelvis are usually checked by these computerized scans when colon or rectal cancer has been diagnosed. These are used to evaluate the extent of other organ involvement, especially the liver, which helps stage the cancer and guide therapy.
Transrectal ultrasound is a diagnostic, painless exam that is performed after a rectal tumor is diagnosed. It is a 15-minute outpatient procedure. A slender, lubricated probe is placed into the rectum. High-frequency soundwaves echo off the suspected rectal tumor and give a picture of the rectum and anything present in it. It helps stage the rectal cancer and guide therapy. To prepare, patients need two enemas a few hours prior to the procedure. No other preparation is required. Patients are free to go back to normal activities after the test is complete.
PET scans are very sensitive detectors of metabolic activity in cancer cells. A PET scan is a test that uses small doses of chemicals called radionuclides attached to a sugar. After this is injected into the patient, the PET scanner detects positron emissions given off by the radionuclide. Malignant tumors grow at a faster rate than normal tissue and use more sugar, so they appears as a higher number on the scan. These are quick and painless and can assess the whole body for tumor spread or recurrence, or can monitor the success of therapy.