Background: Smokers are more likely than non-smokers to die of breast cancer. Metastases to distant organs is the primary reason for death, and the lung is a common site of metastasis. Factors determining patterns of metastasis to different organs are poorly understood. We hypothesized that cigarette smoking might increase the susceptibility of the lung to the development of metastatic foci from breast cancer. Purpose: To compare the smoking status of women with and without pulmonary metastases from breast cancer. Methods: A retrospective, case-control study design was used. Cases, women with radiographic evidence of pulmonary metastatic disease, were identified from hospital discharge records and the Tumor Registry at UCDMC. 2 controls without metastatic disease were matched to each case according to year of diagnosis, age at diagnosis, tumor size, and nodal status. Charts were reviewed to confirm pulmonary metastatic disease and ascertain smoking status. Smoking prevalence in the two groups was compared with preliminary statistical analysts using Chi square tests. Results: 87 cases with pulmonary metastatic disease were identified and compared with 174 controls without pulmonary metastatic disease. The groups were well matched for the selected variables. 33 of 87 cases (38%) of cases were "ever smokers" compared to 50 of 174 controls (29%). 20 cases (23%) were active smokers, compared with 15% of controls. These results were not statistically significant. However, among the subgroup whose metastases were limited to the lung (24), the prevalence of active smoking (33%) was significantly greater than the prevalence of active smoking in the control population. (p<0.05) Conclusion: Among women with metastatic disease limited to the lung, the prevalence of active cigarette smoking at the time of breast cancer diagnosis is higher than in a matched control population without pulmonary metastatic disease. There is a trend toward a higher prevalence of ever-smoking and active smoking among all women with pulmonary metastatic disease, regardless of other organ involvement, but this did not reach statistical significance in our preliminary analysis. The relationship between smoking status and the natural history of breast cancer warrants further investigation.
|Original language||English (US)|
|Journal||Journal of Investigative Medicine|
|State||Published - Feb 1999|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)