Body mass index at the time of diagnosis and the risk of advanced stages and poorly differentiated cancers of the breast: findings from a case-series study.
BACKGROUND
Obesity is a risk factor for postmenopausal breast cancer and is independently associated with shorter disease-free and overall survival. Currently, in clinical settings, the combination of stage and grade of cancer at the initial presentation of the disease is the best prognostic indicator.


OBJECTIVE
To evaluate the association between body mass index (BMI) and risk of advanced stages and poorly differentiated grade of breast cancer.


METHODS
A case-series study of women diagnosed with their first primary invasive breast cancer. Patients include a total of 831 women aged >or=40 years with a mean BMI of 29.6(± 6.6)  kg m(-2). Pathological, clinical and demographic data were retrieved from electronic medical records. Multinomial logistic regression analysis was preformed to estimate the risk of more advanced stages and poorly differentiated grade of cancer, adjusting for covariates.


RESULTS
Obese compared with normal weight women had an 80% increased risk of cancer with more advanced stages (III/IV) and poorly differentiated grade (odds ratio = 1.80, 95% confidence interval 1.13-2.86, P = 0.014). No significant increase in risk was observed for overweight women.


CONCLUSIONS
Obesity at the time of diagnosis of breast cancer is associated with more advanced stages and poorly differentiated grade of cancers.
Stark
A
A
Henry Hood Center for Health Research, Geisinger Health System, Danville, PA 17822, USA. astark1@geisinger.edu
Stahl
M S
MS
Kirchner
H L
HL
Krum
S
S
Prichard
J
J
Evans
J
J
D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D016017:Odds Ratio; D012307:Risk Factors