Passive Smoking and Breast Cancer - a Suspicious Link


Background: Breast cancer is the most common malignancy of women in the world. The disease is causedby infectious and non-infectious, environmental and lifestyle factors. Tobacco smoke has been one of the mostwidely studied environmental factors wiith possible relevance to breast cancer. The purpose of this study wasto assess the impact of tobacco smoking in breast cancer patients in a hospital based cohort and to establishprognostic implications if any. Materials and
Methods: A retrospective audit of 100 women with pathologicaldiagnosis of invasive breast cancer was included in this study. The verbal questionnaire elicited information oncurrent and previous history of exposure to smoking in addition to active smoking. All analyses were adjustedfor potential confounders, including stage at presentation, alcohol intake, hormonal replacement therapy, oralcontraceptive intake, obesity and menopausal status.
Results: The mean age at presentation of breast cancer was51.4 ± 10.86 years. Mean age of presentation was 53.1±11.5 and 45.7±11.9 years in never smokers and passivesmokers, respectively. Age at presentation varied widely in patients exposed to tobacco smoke for >10 years inchildhood from 40.3± 12.0 years to 47.7± 13.9 in patients exposed for > 20years as adults. Among passive smokers,60.9% were premenopausal and 39.1% of patients were postmenopausal. In never smokers, 71.4% were postmenopausal. Expression of receptors in non-smokers vs passive smokers was comparable with no significantdifferences. Metastatic potential in lung parenchyma was slightlyelevated in passive smokers as compared tonever smokers although statistically non-significant.
Conclusions: An inverse relationship exists between theintensity and duration of smoking and the age at presentation and poor prognostic factors. The results stronglysuggest efforts should be taken to prevent smoking, encourage quitting and restrict exposure to second handsmoke in India.