Smoking Increases Risk of Adverse Events With Aromatase Inhibitor Therapy for Breast Cancer
For many, cigarette smoking is a habit formed in younger years.
Preoperative smoking is associated with increased risk for breast cancer events and distant metastasis in women treated with aromatase inhibitors (AIs). Hampering the utility of AIs, a common treatment for breast cancer, is yet another health risk associated with smoking.1
"Smokers who were treated with aromatase inhibitors had a 3 times higher risk of recurrence of breast cancer compared with the nonsmokers who got the same treatment,” said Helena Jernström, PhD, an associate professor in the Department of Clinical Sciences, Lund University, Lund, Sweden, and senior author of the study.
This study, published in the British Journal of Cancer, examined 1016 patients in southern Sweden whose breast cancer was diagnosed between 2002 and 2012. Approximately 20% of the patients revealed they were regular or social smokers upon scheduling surgery.
Researchers assessed the impact of smoking, taking into account the type of postoperative treatment the patients received. In the 309 patients older than 50 years with estrogen receptor-positive breast cancer treated with aromatase inhibitors, smoking was associated with increased risk of breast cancer events, distant metastasis, and death. Smoking was not correlated with breast cancer events or distant metastasis in other treatment groups.
"The treatment with aromatase inhibitors worked significantly better in the nonsmoking patients. However, we saw little or no difference between smokers and nonsmokers among patients treated with the drug tamoxifen, radiotherapy, or chemotherapy,” said Jernström.
“More studies are needed, but our findings are important as many breast cancer patients receive this type of treatment."
Furthermore, researchers discovered that few patients quit smoking during their treatment, in spite of being counseled on the importance of smoking cessation. Of 206 smokers, only 10% quit smoking in the first year after surgery.
"That was unexpected. Smoking is not health-promoting in any way, after all, so it is always beneficial to stop. But these findings show that patients who smoke need more support and encouragement to quit." stated Jernström.
1. Persson M, Simonsson M, Markkula A, Rose C, Ingvar C, Jernström H. Impacts of smoking on endocrine treatment response in a prospective breast cancer cohort. Br J Cancer. 2016 Jun 9. doi:10.1038/bjc.2016.174 [Epub ahead of print]