People with advanced colon cancer who have smoked cigarettes or used other tobacco products for many years may have an increased risk that their colon cancer will return, according to research by Dana-Farber Cancer Institute scientists to be presented at the annual meeting of the American Society of Clinical Oncology (ASCO), May 30 – June 3, in Chicago.

Based on data from 965 patients treated for stage III colon cancer, investigators found the chances of recurrence or death up to 22 percent higher in patients with a 20 or more pack year history (calculated by number of years smoking times packs per day) than in those who had never smoked. Smoking history prior to age 30 was particularly harmful for subjects that developed colon cancer years later. Patients who smoked 12 pack years or more before age 30 and developed colon cancer later in life had a statistically significant 37 percent increase in recurrence or death compared to nonsmokers.

The data (abstract 4039) will be presented during a poster session on Monday, June 2, 8 a.m.– 12 p.m. CT, South Building, Hall A1.

"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," said lead author Nadine Jackson, MD, MPH, of Dana-Farber.

Although tobacco use can increase people's initial risk of colon cancer, little is known about the short- or long-term effects of such use on disease recurrence. The current study is part of an effort to explore that issue.

Participants in the study reported their tobacco use on questionnaires filled out during and six months after their treatment. Forty-five percent were identified as past smokers, 9 percent as current smokers, and 46 percent as never smokers.

The study's co-authors are Jeffrey Meyerhardt, MD, MPH, Charles Fuchs, MD, MPH, and Robert Mayer, MD, of Dana-Farber, Boston; Donna Niedzwiecki, PhD, and Donna Hollis, PhD, of the Cancer and Leukemia Group B, Durham, N.C.; and Leonard Saltz, MD, of Memorial Sloan-Kettering Cancer Center, New York.

Dana-Farber Cancer Institute (www.dana-farber.org) is a principal teaching affiliate of the Harvard Medical School and is among the leading cancer research and care centers in the United States. It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC), designated a comprehensive cancer center by the National Cancer Institute.