Associations between obesity, smoking and lymph node status at breast cancer diagnosis in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.

Authors

Smith A, Mullooly M, Murphy L, Barron TI, Bennett K

Affiliations

• Dept. Pharmacology and Therapeutics, Trinity Centre for Health Sciences, St. James' Hospital, Dublin, Ireland.
• Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, United States of America.
• Division of Population Health Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland.

Abstract

INTRODUCTION: There is evidence suggesting that smoking and obesity prior to a breast cancer diagnosis is associated with poorer outcomes. In this study, we investigate the associations between smoking and obesity prior to a breast cancer diagnosis and the presence of lymph node metastases at diagnosis.

METHODS: Women with stage I-III breast cancer (n = 3,304) were identified from the National Cancer Institute's Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Univariable and multivariable log-binomial models were used to estimate relative risks (RR) and 95% confidence intervals (CIs) for associations between lymph node positive breast cancer and; i) smoking, and ii) obesity prior to diagnosis.

RESULTS: Pre-diagnostic smoking/obesity was not associated with lymph node metastasis at diagnosis in multivariable analyses; (RR 0.82, 95%CI 0.61, 1.10) and (RR 0.95, 95% CI 0.81, 1.12), respectively.

CONCLUSION: Obesity and smoking information was recorded a number of years prior to breast cancer diagnosis, therefore these findings should to be replicated in a larger cohort of women, with more detailed smoking and obesity information.