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.
For companies watching the bottom line, such screening programs,
if carefully planned, should also be cost effective, a representative
of Eli Lilly & Co. said at a session on screening programs
currently under development.
The goal of colorectal cancer screening is to prevent cancer by
removing polyps, rather than to detect cancer in the early stages,
Dr. Winawer said. He and his colleagues recently published the
results of the National Polyp Study, which has more than 8,000
person-years of follow-up in a cohort of 1,400 individuals.
"We expected to see a large number of colon cancers in this
cohort after their polyps were removed, but we observed only five,
and none of these were symptomatic. They were all discovered on
a follow-up examination as a malignant polyp in the very early
stage." he said.
For asymptomatic individuals at average risk, the American Cancer
Society and the WHO Colon Cancer Prevention Program at Memorial
Sloan-Kettering, which Dr. Winawer heads, recommend, starting
at age 50, a flexible sigmoidoscopy every 3 to 5 years, and annual
fecal occult blood testing such as Hemoccult.
"The two tests work well together," he said. "The
Hemoccult test examines the upper bowel, and the flexible sigmoidoscope
examines the lower bowel."
For high-risk individuals, including those with a known genetic
factor or family history, the screening strategy changes to one
involving colonoscopy and beginning at an earlier age, he said.