Latest Colorectal Cancer Research

Latest Colorectal Cancer Research
In science news, a new study shows 40 percent of all colorectal cancers might be prevented if
everyone had colonoscopy screening as recommended. The large, long-term study from the
Harvard School of Public Health, or HSPH, supports existing guidelines that suggest individuals
with an average risk for colorectal cancer have a colonoscopy every ten years.
The Centers for Disease Control and Prevention, or CDC, calls regular screening beginning at
age 50 “the key to preventing colorectal cancer,” which is the second leading cause of cancerrelated
deaths in men and women in the United States. Colorectal cancer is the uncontrolled
growth of abnormal cells in the lower part of the large intestine known as the colon and in the
rectum. The National Cancer Institute expects U.S. doctors to diagnose 142,820 cases of
colorectal cancer in 2013 and believes 50,830 will die from the disease that year.
Colonoscopy and Other Screening Tools for Colorectal Cancer
Doctors use screening tools like colonoscopy, fecal occult blood tests, and sigmoidoscopy as
part of regular screenings. Fecal occult blood tests test for the presence of blood hidden in
stool. During a sigmoidoscopy, a doctor uses a camera mounted onto a long, flexible tube
inserted into the patient’s rectum to view the lowest part, or the distal end, of his colon. A doctor
uses the tube and mounted camera technology during a colonoscopy to see further into the
higher part, or proximal end, of a patient’s colon. Cancer can occur in either the distal or
proximal regions of the large intestine.
The study, which appeared in the New England Journal of Medicine, underscores the
importance of regular screenings. Support for the study came from the National Institutes of
Health. Co-author of the study and associate professor in the Department of Epidemiology at
HSPH Shuji Ogino said the study “provides strong evidence that colonoscopy is an effective
technique for preventing cancers of both distal and proximal regions of the colorectum, while
sigmoidoscopy alone is insufficient for preventing proximal cancer."
The researchers analyzed data gathered from 88,902 people participating in the two long-term
studies, the Nurses’ Health Study and the Health Professionals Follow-up Study. The Harvard
scientists based their study on responses to questionnaires issued to participants every two

years between 1998 and 2008. Among the participants, researchers identified 1,815 cases of
colorectal cancer and 474 deaths from the disease.
The Harvard scientists found that both sigmoidoscopy and colonoscopy lowered the risk for
developing or dying from colorectal cancer in the distal, or lower part of the colon but that only
colonoscopy reduced the risk for cancer in the proximal, or higher part of the large intestine.
Sigmoidoscopy alone is unlikely to reduce the risk for developing or dying from cancer that
starts in the upper portion of the colon.
Additionally, the researchers found that widespread compliance with recommended
colonoscopy screenings every ten years could reduce the overall prevalence of colorectal
cancer by 40 percent. These findings could help improve and strengthen the current guidelines
for colorectal cancer screening.
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