Smoking Can Reduce Survival of Breast Cancer Patients

A study published in the Journal of Clinical Oncology has found that smoking before and after diagnosis of breast cancer is associated with increased mortality from breast cancer as well as other conditions, including respiratory and cardiovascular disease.

For this Collaborative Breast Cancer and Women’s Longevity Study, women were recruited from across the states of Wisconsin, New Hampshire, and Massachusetts for a prospective evaluation of the association between smoking status before and after breast cancer diagnosis and mortality. Nearly 20,700 women between the ages of 20 and 79 years, who were diagnosed with incident localized or regional invasive breast cancer between 1988 and 2008, participated in the study. Participants were asked to report on their smoking habits and the age when they started smoking. The women were followed for a median duration of 12 years following diagnosis.

During the 12-year follow-up period of the study, 6778 women dies, 2894 of whom died of breast cancer. The study found that women who smoked a year before their breast cancer diagnosis were more likely to die of breast cancer than never smokers (hazard ratio [HR], 1.25; 95% CI, 1.13-1.37). Other likely causes of death in this population were respiratory cancer (HR, 14.48; 95% CI, 9.89-21.21), other respiratory disease (HR, 6.02; 95% CI, 4.55-7.97), and cardiovascular disease (HR, 2.08; 95% CI, 1.80-2.41). Mortality due to breast cancer was highest among long-term smokers, heavy smokers, or former smokers who quit less than 5 years before being diagnosed, the authors report.

Further, the authors report that 1 in 10 study participants who did not quit following their diagnosis were more likely to die of breast cancer than the never smokers (HR, 1.72; 95% CI, 1.13 to 2.60), or those who quit smoking following their cancer diagnosis. Women who quit had lower mortality from breast cancer (HR, 0.67; 95% CI, 0.38 to 1.19) and respiratory cancer (HR, 0.39; 95% CI, 0.16 to 0.95), the study found.

According to lead author Michael Passarelli, PhD, these results should motivate women who have been diagnosed with breast cancer to quit smoking if they do. “Our study shows the consequences facing both active and former smokers with a history of breast cancer,” he said in an associated press release, adding, “Smoking cessation programs should be considered part of cancer therapy. Recent policy statements from leading research and clinical organizations are now urging oncologists to be as aggressive in getting their patients to stop smoking as they are in treating the cancer.”

Physician organizations like the National Comprehensive Cancer Network (NCCN) have taken the lead in urging oncologists to speak to their patients about quitting. “Once patients have been diagnosed with cancer, they think quitting smoking is not worth it, but there are health benefits of smoking cessation that apply to patients in any stage of cancer,” said Peter G. Shields, MD, deputy director of The Ohio State University Comprehensive Cancer Center, when introducing the Guidelines at the NCCN meeting last year.