PREVENTING COLON CANCER Screening And Early Detection Save Lives

There are other potential benefits to this new technology. For example, it may reduce the number of conventional colonoscopies performed for diagnostic purposes, and increase the number performed therapeutically for the specific purpose of removing polyps. These procedures also can provide an electronic record that can be stored, transmitted to distant locations, and used for future analysis. As the technology becomes more sophisticated, a cleansing bowel preparation may no longer be necessary, making the test even more acceptable to patients.

FDA's Harvey says that although the agency has cleared this new technology as a general radiological tool, there is not yet a Medicare coverage policy for virtual colonoscopy. In addition, many insurance companies do not currently pay for the procedure because outcome data from large patient groups are not yet available. Currently, virtual colonoscopy is most often performed in clinical trials designed to establish whether this type of testing is an effective method for colorectal cancer screening.

Other technologies may be available within the next several years, such as more accurate stool testing. These tests could be conducted in a manner similar to the current fecal occult blood tests. However, instead of testing for microscopic blood, these tests could detect DNA mutations in the cells that have been sloughed off by polyps and cancers. This approach promises to be more sensitive and specific in detecting abnormalities, and could result in fewer false positive tests.

According to the Mayo Clinic's Ahlquist, the ability to detect polyps accurately through virtual colonoscopy and DNA testing can reduce the frequency of testing, and thereby reduce overall medical costs. "The transition from a flat [normal] colon lining to a polyp to a cancer takes seven to 10 years. That's a large window of opportunity. If a diagnostic tool has the potential to detect the polyps, it probably does not need to be applied more frequently than every five years."

Treating the Disease

The type and duration of colorectal cancer treatment depend upon the extent of the disease and when it is discovered. Treatments can include surgery, chemotherapy, radiation, or a combination of all three.

Surgery is the most commonly performed treatment for colorectal cancer. If the tumor is discovered before it has penetrated the bowel wall, removal of the cancer is usually all that is necessary for a complete cure. Specific surgical procedures may require the removal of a portion of the large bowel, which is reconstructed by sewing or stapling the two ends together. In part due to new surgical techniques and devices, a colostomy, where a portion of the colon is rerouted through the abdominal wall to the outside surface and a bag is worn to collect wastes, may not be necessary.

Small cancers localized to the rectum can be removed surgically, with radiation therapy follow-up. For large cancers that have grown through the rectal wall, a technique called "mesorectal excision" can be performed. The procedure allows removal of all cancerous tissue, but avoids severing of nerves involved in sexual and urinary function. Large rectal tumors are often treated with chemotherapy and radiation before surgery.