Effect of obesity on presentation of breast cancer.
BACKGROUND
Obesity has been shown to be associated with reduced survival in patients with invasive breast cancer (IBC), although the mechanisms for this finding are unclear. The objective of this study was to examine the effect of obesity on the presentation and pathologic staging of IBC.


METHODS
From February 15, 2002, to February 15, 2004, all patients undergoing surgery for primary IBC at two institutions were enrolled in a prospective cohort study. National Institutes of Health criteria were used to categorize patients: normal or underweight (NW; body mass index <25 kg/m(2)), overweight (OW; body mass index 25-29.9 kg/m(2)), and obese or severely obese (OB; body mass index > or =30 kg/m(2)). Presentation and pathologic factors were then compared among groups.


RESULTS
The study cohort consisted of 519 patients; 166 (32%) were NW, 177 (34%) were OW, and 176 (34%) were OB. OW (46%) and OB (39%) patients were more likely to be diagnosed with IBC via screening mammography compared with NW (31%) patients (P = .01), although no differences were found between groups with respect to previous use of screening mammography. Aggressive pathologic features, including lymph node metastases, advanced tumor-node-metastasis stage, and grade were found more commonly among OB patients.


CONCLUSIONS
OW and OB patients were more likely to receive a diagnosis via screening mammography, thus suggesting that mammography may play a more important role in OW and OB patients. Despite this, OB patients presented with larger, more advanced tumors; this may help to explain obesity-associated survival differences in IBC patients. This is important information given the prevalence of obesity in North America.
Department of Surgery, Dalhousie University, Queen Elizabeth II Health Sciences Center, 7-007 Victoria Building, 1278 Tower Road, Halifax, Nova Scotia, B3H 2Y9, Canada. geoff.porter@dal.ca
Geoffrey A
GA
Porter
Karen M
KM
Inglis
Lori A
LA
Wood
Paul J
PJ
Veugelers
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis