According to a study published in the British Journal of Cancer, a common medication for breast cancer may have reduced efficacy in patients who smoke vs. non-smokers. 

Helena Jernström, associate professor and principal investigator, and colleagues conducted a study to investigate whether preoperative smoking was correlated with prognosis in various treatment groups. The cohort included 1,065 patients in Lund, Sweden, without preoperative treatment between 2002-2012. Smoking status was compared in relation to the patient and tumor characteristics, and prognosis in different treatment groups. 

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At the preoperative visit, 21% of patients stated that they were either a regular smoker or a “social smoker.” Of the 1,016 patients included in the survival analysis, no significant association between smoking and the risk of breast cancer events were seen (adjusted HR 1.45, 95% CI: 0.95–2.20). 

For patients aged ≥50 years with estrogen receptor-positive tumors who were treated with aromatase inhibitors (AI), smoking was associated with the risk of breast cancer events (adjusted HR 2.97, 95% CI: 1.44–6.13), distant metastasis (adjusted HR 4.19, 95% CI: 1.81–9.72), and death (adjusted HR 3.52, 95% CI: 1.59–7.81). 

“The treatment with aromatase inhibitors worked significantly better in the non-smoking patients. However, we saw little or no difference between smokers and non-smokers among patients treated with the drug tamoxifen, radiotherapy or chemotherapy,” reported Jernström.

Overall, preoperative smoking was only associated with a higher risk of breast cancer events and distant metastasis in AI-treated patients. “If confirmed, smoking status should be taken into consideration when selecting an endocrine therapy.” 

For more information visit nature.com.