Colorectal cancer: to screen or not to screen?A simple, widely available blood test for colorectal cancer colorectal cancer
Malignant tumour of the large intestine (colon) or rectum. Risk factors include age (after age 50), family history of colorectal cancer, chronic inflammatory bowel diseases, benign polyps, physical inactivity, and a diet high in fat. could save nearly 10,000 lives a year in the United States and thousands more worldwide, two new studies show-but only if more people use it.
Although the test is painless, many people find it repugnant REPUGNANT. That which is contrary to something else; a repugnant condition is one contrary to the contract itself; as, if I grant you a house and lot in fee, upon condition that you shall not aliens, the condition is repugnant and void. Bac. Ab. Conditions, L. because it requires them to supply a fecal sample for lab analysis. Still, doctors say, a little unpleasantness beats risking an untimely, agonizing death.
Colorectal cancer kills 55,000 people in the United States each year. The fecal occult blood test Fecal Occult Blood Test Definition
The fecal occult blood test (FOBT) is performed as part of the routine physical examination during the examination of the rectum. , often ordered by physicians for people over age 50, detects traces of blood shed by malignant bowel tissue. This enables doctors to diagnose and remove some tumors early, boosting a person's odds of sur- vival. Still, because the test detects just one of every four tumors, doctors have questioned whether mass screening would improve overall survival.
Until now, just one controlled trial controlled trial Clinical research A clinical study in which one group of participants receives an experimental drug while the other receives either a placebo or an approved–'gold standard' therapy. See Blinding, Double-blinded. had addressed the effectiveness of large-scale screening. In that study of 46,551 people, Jack S. Mandel and his colleagues at the University of Minnesota (body, education) University of Minnesota - The home of Gopher.
Address: Minneapolis, Minnesota, USA. in Minneapolis reported that screen- ing reduces colorectal cancer mortality by one-third. But the study, published in the May 13, 1993 New England Journal of Medicine The New England Journal of Medicine (New Engl J Med or NEJM) is an English-language peer-reviewed medical journal published by the Massachusetts Medical Society. It is one of the most popular and widely-read peer-reviewed general medical journals in the world. , had a drawback. The researchers used a highly sensitive test that misses fewer cases of colorectal cancer, but yields more false positives, than the one generally available. Doctors then had to perform the more expensive, more invasive colonoscopy to confirm the presence of cancer.
The new studies, done in Nottingham, England, and Funen, Denmark, assessed the blood test now in common use, the researchers report in the Nov. 30 Lancet.
Jack D. Hardcastle and his colleagues at the University Hospital of Queens Medical Centre in Nottingham tested 44,838 symptomfree men and women age 45 to 74 at least once between 1981 and 1991. The researchers compared the per- centage of deaths from colorectal cancer in this group with that in a group of 74,998 untested people. They found that 15 percent more people in the untested group died of the disease-and recommended that the United Kingdom consider routine screening for colorectal cancer.
In Funen, Ole Kronborg and his team at Odense University Hospital studied 30,966 people who had not been tested and 30,967 people who had. The volunteers ranged in age from 45 to 75. The researchers found that 18 percent more unscreened than screened people died of the disease. Kronborg also con- cludes that mass testing could be beneficial.
The American Cancer Society American Cancer Society,
n.pr established in 1913, this national volunteer-based health organization is committed to the elimination of cancer through prevention and treatment and to diminishing cancer suffering through advocacy, scholarship, research, estimates that just one in four U.S. adults has had the test. To expand this pool, the nation should begin mass screening without waiting for "perfect tests," argue David Lieberman of the Oregon Health Sciences University in Portland and Marvin H. Sleisenger of the Univer- sity of California, San Francisco in a Lancet editorial. The cost of such testing, however, would work out to $200,000 for each life saved, they note.
Efforts to develop more accurate tests are under way. Bert Vogelstein of Johns Hopkins Medical Institutions in Baltimore is working on a way to detect an altered version of the ras gene, which is shed in the feces of people with colorectal cancer. "Its mutations are particularly easy to detect," he says.
David Shibata of Harvard Medical School Harvard Medical School (HMS) is one of the graduate schools of Harvard University. It is a prestigious American medical school located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts. in Boston and his colleagues report in the Dec. 5 New England Journal of Medicine that people whose tumors express the DCC (1) (Direct Cable Connection) A Windows 95/98 feature that allows PCs to be cabled together for data transfer. DCC actually sets up a network connection between the two machines. (deleted in colon cancer colon cancer, cancer of any part of the colon (often called the large intestine). Colon cancer is the second most common cancer diagnosed in the United States. ) gene are more likely to survive than those whose tumors do not. Ultimately, they say, patients with better prospects might benefit most from aggressive therapy.