Abstract
Obesity is associated with adverse biologic features and poor outcome in patients with invasive breast cancer, yet this relationship has not been evaluated in patients with ductal carcinoma in situ (DCIS). From 1996 to 2009, body mass index (BMI) was recorded at initial diagnosis for 1,885 patients with DCIS treated at our institution. Patients were categorized as obese (BMI ≥ 30 kg/m(2)), overweight (BMI 25 to <30 kg/m(2)), or of normal weight or underweight (BMI < 25 kg/m(2)). Logistic regression was used to examine associations between BMI and patient, clinical, and pathologic features and treatment. Local-regional recurrence was calculated using the Kaplan-Meier method. All statistical tests were two-sided. Of the 1,885 patients, 514 (27.7%) were obese, 510 (27.5%) were overweight, and 831 (44.8%) were normal/underweight. In multivariate analysis, overweight and obese patients were significantly more likely to be African American (odds ratio [OR], 3.93; 95% confidence interval [CI], 2.66-5.80) or Hispanic (OR, 1.44; CI, 1.02-2.04), be postmenopausal (OR, 1.63; CI, 1.28-2.07), have diabetes (OR, 4.60; CI, 2.60-8.12), have estrogen-receptor-positive DCIS (OR, 1.39; CI, 1.00-192), and present with a radiologic abnormality rather than clinical symptoms (OR, 1.35; CI, 1.01-1.80). At a median follow-up time of 4.96 years (range, 1.0-14.34 years), no significant differences in local recurrence rates were detected based on patients' initial BMI category. Furthermore, there was no significant difference in risk of recurrence between diabetic patients receiving metformin or not. In conclusion, higher BMI is not associated with adverse biologic features or prognosis in patients with DCIS.