Smokers, Drinkers And Men Appear To Develop Colorectal Cancer At Earlier Ages
Alcohol use, tobacco use and male gender are associated with an earlier onset
of colorectal cancer and also with location of tumors, findings that could have
important implications for screening, according to a study in the March issue of
Archives of Internal Medicine, one of the JAMA/Archives journals.
Colorectal cancer is the second leading cause of cancer deaths, according to
background information in the article. Screening asymptomatic patients is an
important strategy for reducing these deaths, because by the time patients
experience symptoms, the cancer may have progressed beyond the point where it
can be cured. Generally, physicians recommend that patients begin screening at
age 50 years, the authors write. However, physicians might recommend that
individuals with certain risk factors, including family history, begin screening
at earlier ages. Screening methods include flexible sigmoidoscopy, which
involves inserting a flexible optical instrument through the rectum into the
lower portion of the large intestine, and colonoscopy, which involves inserting
a longer flexible optical instrument through the rectum and into the entire
colon, is more expensive, has higher complication rates and usually is performed
by a gastroenterologist or surgeon rather than a primary care physician.
Anna L. Zisman, M.D., and colleagues at Evanston-Northwestern Healthcare,
Feinberg School of Medicine, Northwestern University, Evanston, Ill., examined
the records of 161,172 patients with colorectal cancer to assess whether certain
risk factors, alcohol and tobacco use, should also be considered in screening
decisions. They analyzed the relationship between use of these substances and
age of onset of colon cancer as well as location of onset--distal or proximal
colon. Distal tumors, including those in the lower left part of the colon and
the rectum, can generally be detected by flexible sigmoidoscopy, while proximal
tumors in the right side of the colon can be missed by methods other than
colonoscopy.
Patients who were classified as alcohol or tobacco users, defined as those who
had smoked or drank alcohol in the previous year, developed cancer at a younger
age than non-drinkers and non-smokers. Current alcohol and tobacco users
developed cancer an average of 7.8 years earlier (age 63.2 years in women and
62.1 years in men) than those who had never drank or smoked. Those who had never
smoked but drank or who had never drank but smoked were each an average of 5.2
years younger at cancer diagnosis than those who neither smoked nor drank.
Individuals who stopped drinking one year or more prior to the study and had
never smoked developed cancer an average of 2.1 years earlier than those who had
never drank or smoked. The effect of smoking appeared to be particularly large
for women; women who smoke but never drank developed cancer 6.3 years younger
than those who never drank or smoked, compared with 3.7 years in men. In
additional, current alcohol and tobacco consumption was associated with an
increased likelihood of distal colorectal cancer, although women in all
categories were less likely to have distal cancer than men.
These findings suggest that individuals who smoke and drink should undergo
screening for colorectal cancer beginning at a younger age, the authors write.
In addition, women who do not smoke or drink may be more prone to proximal
cancers and might therefore want to consider undergoing colonoscopy instead of
flexible sigmoidoscopy. "In the future, we envision the development of risk
scores with exogenous (e.g., alcohol and tobacco use, age, body mass index, diet
and calcium consumption) and hereditary factors to tailor an individual's
colorectal cancer screening program," they conclude.
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(Arch Intern Med. 2006; 166: 629-634. Available pre-embargo to media at http://www.jamamedia.org/.)
Editor's Note: This study was supported in part by a research grant from the
National Institutes of Health, Bethesda, Md.
Contact: Amy Ferguson
JAMA and Archives Journals