Smoking can increase risk of second cancer in breast cancer survivors

May 3 2010

Women who survive early-stage breast cancer and smoke have an increased chance of developing a new second cancer in their other breast or elsewhere. Investigators from The Cancer Institute of New Jersey (CINJ) are releasing these findings at an oral presentation during the 92nd Annual Meeting of the American Radium Society taking place this week in Cancun, Mexico. CINJ is a Center of Excellence of UMDNJ-Robert Wood Johnson Medical School.

It has been shown that women who survive breast cancer have two- to six-times increased risk of developing cancer in their other breast, compared with women who have never had breast cancer. In hopes of making second cancers less likely, researchers have studied risk factors that can be controlled, such as smoking, obesity and alcohol consumption. Conflicting results on this subject recently appeared in studies published in the Journal of Clinical Oncology and the American Journal of Epidemiology.

This latest study focused on female smokers with early-stage breast cancer who had breast conserving therapy to remove their disease. Breast conserving therapy is the standard treatment given to most patients with early-stage disease and consists of a lumpectomy followed by radiation therapy to the breast. Data were analyzed from 796 self-reported smokers who received breast conserving therapy between 1975 and 2007 at Yale University School of Medicine.

The team found that at 15 years post-treatment, the risk of developing a new second cancer was significantly greater in smokers compared to non-smokers (25 percent versus 19 percent). The study also found that smokers had a greater risk of developing cancer in the other breast than those who did not smoke (13 percent versus eight percent) 15 years following treatment. While correlation was made to other prognostic factors, including age, family history, hormone receptor status and HER2/neu status, smoking was found to be independent of these other indicators.

CINJ Associate Director, Bruce G. Haffty, MD, professor and chair of the Department of Radiation Oncology at UMDNJ-Robert Wood Johnson Medical School, is the senior investigator. "We believe this study looks at the largest subgroup of women to date on this topic. These new data are significant in that they show women can exercise some control over a known risk factor for developing a new second cancer," he noted.