FORT LAUDERDALE, Fla--Because colon cancer develops in a stepwise progression that occurs over 10 to 15 years, physicians have a "tremendous window of opportunity for prevention," Sidney Winawer, MD, of Memorial Sloan-Kettering Cancer Center, said in a presentation at the second annual Industries' Coalition Against Cancer (ICAC) conference. He believes that colorectal cancer screening is "no longer controversial," based on available data.
FORT LAUDERDALE, Fla--Because colon cancer develops in a stepwiseprogression that occurs over 10 to 15 years, physicians have a"tremendous window of opportunity for prevention," SidneyWinawer, MD, of Memorial Sloan-Kettering Cancer Center, said ina presentation at the second annual Industries' Coalition AgainstCancer (ICAC) conference. He believes that colorectal cancer screeningis "no longer controversial," based on available data.
For companies watching the bottom line, such screening programs,if carefully planned, should also be cost effective, a representativeof Eli Lilly & Co. said at a session on screening programscurrently under development.
The goal of colorectal cancer screening is to prevent cancer byremoving polyps, rather than to detect cancer in the early stages,Dr. Winawer said. He and his colleagues recently published theresults of the National Polyp Study, which has more than 8,000person-years of follow-up in a cohort of 1,400 individuals.
"We expected to see a large number of colon cancers in thiscohort after their polyps were removed, but we observed only five,and none of these were symptomatic. They were all discovered ona follow-up examination as a malignant polyp in the very earlystage." he said.
For asymptomatic individuals at average risk, the American CancerSociety and the WHO Colon Cancer Prevention Program at MemorialSloan-Kettering, which Dr. Winawer heads, recommend, startingat age 50, a flexible sigmoidoscopy every 3 to 5 years, and annualfecal occult blood testing such as Hemoccult.
"The two tests work well together," he said. "TheHemoccult test examines the upper bowel, and the flexible sigmoidoscopeexamines the lower bowel."
For high-risk individuals, including those with a known geneticfactor or family history, the screening strategy changes to oneinvolving colonoscopy and beginning at an earlier age, he said.
To determine an individual's risk of colon cancer, the MemorialSloan-Kettering researchers use two questionnaires to scrutinizehealth habits and family history, although Dr. Winawer said thatunderreporting of fat and calorie intake can be a problem.
Because of the hereditary aspects of the disease, the WHO programfocuses not just on individuals but on families. "Every personwalking into Memorial Sloan-Kettering is waving a flag saying,'I represent my family,'" Dr. Winawer said.
A pilot program for colorectal cancer prevention under developmentat Eli Lilly & Co. is based on a community-based colon cancerscreening program started in 1989 by an Indianapolis gastroenterologygroup.
"Our idea was to change the whole thought process from screeningfor colon cancer to screening for colon polyps and preventingcolon cancer," said James Rogge, MD, of Indianapolis Gastroenterologyand Hepatology. "Our hope is to never find a cancer in thepeople who follow our program."
Dr. Rogge's group chose to base their program on flexible colonoscopyrather than flexible sigmoidoscopy because sigmoidoscopy doesnot examine the entire colon. He noted that colon cancer seemsto be making a "rightward shift," with more cancersand polyps being found higher up in the colon.
The program calls for colonoscopy screening every 5 years startingat age 40 for average-risk individuals. When to stop screeningis still an open question. Dr. Rogge noted that he sees patientsin their 80s and 90s with colon cancer. "So we have to thinkabout these people and try to keep them from getting cancer."
About 1,050 people have gone through the program to date, and32% were found to have either polyps or cancer. The program hasfound 282 adenomatous polyps in 191 patients, 40% above the sigmoidcolon, "above the reach, in my opinion, of the average physiciandoing fiberoptic sigmoidoscopy." Dr. Rogge said. Of the 11cancers found in nine patients, four were in the right colon andwould not have been found with fiberoptic sigmoidoscopy, he noted.
When Indianapolis-based Eli Lilly decided to start a colorectalcancer screening program, they sought to make the program costeffective by using colonoscopy rather than sigmoidoscopy and byforming a partnership with qualified community gastroenterologists.
Gregory Larkin, MD, director of Corporate Health Services at Lilly,noted that the cost of treating an advanced case of colon canceris about $125,000, including lost productivity. By working withDr. Rogge's group and other gastroenterologists in major communitiesin Indiana, the company hopes to provide colonoscopy screeningfor its workers and their spouses at a cost of only about $300,paid for by the company.
"When you charge $2,000 for a colonoscopy, that will neverbe cost effective," Dr. Larkin said. Lilly is also workingwith pathology groups to fix a price for polyp evaluation.
"We plan to be aggressive with our colon cancer awareness,"Dr. Larkin said, to avoid low participation rates that could lowerthe program's cost effectiveness. "We're going to absolutelyswamp our workers with education and questionnaires . . . as withour mammography program, so that the only excuse they'll havefor not being screened is that they don't believe the facts."