MONDAY, June 2 (HealthDay News) -- Long-term smokers treated for advanced colon cancer are at increased risk for cancer recurrence, a Dana-Farber Cancer Institute study shows.

Researchers analyzed data from 965 people treated for stage III colon cancer, and found that those with a 20 or more pack year history (calculated by number of years smoking times packs per day) were up to 22 percent more likely to have their cancer return or to die than patients who'd never smoked.

The earlier in life a patient started smoking, the greater the risk. Patients who smoked 12 pack years or more before age 30 and developed colon cancer later in life were 37 percent more likely to suffer cancer recurrence or death than nonsmokers.

"After controlling for other factors that may influence the risk of colon cancer recurrence or death, this study highlights further risk of cancer recurrence in individuals who have a higher lifetime total use of cigarettes than never smokers," lead author Dr. Nadine Jackson said in a prepared statement.

The study was expected to be presented Monday at the American Society of Clinical Oncology annual meeting, in Chicago.

It's known that tobacco use increases the risk of colon cancer, but little is known about the short- or long-term effects of tobacco use on cancer recurrence. This study is part of the effort to learn more about those effects.

The patients in the study filled out tobacco-use questionnaires during and six months after their treatment for colon cancer. Forty-five percent were past smokers, 9 percent were current smokers, and 46 percent were never smokers.

More information

The National Cancer Institute has more about colorectal cancer prevention.

-- Robert Preidt

SOURCE: American Society of Clinical Oncology, news release, May 29, 2008

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