171 Background: Oncotype DX Score is a 21-gene expression analysis that has been validated clinically as a reliable predictor of breast cancer recurrence for ER-positive, node-negative breast cancers. Obesity is recognized as a risk factor for many cancers, including breast cancer. Additionally obesity has been shown to be an independent prognostic factor in breast cancer. The primary objective of this study is to determine the correlation between obesity and Oncotype DX score, hence the relationship between obesity and breast cancer recurrence in ER-positive breast cancer. The secondary objective is to investigate the association between weight gain after diagnosis and breast cancer recurrence. Methods: An IRB-exempted retrospective chart review of female patients at Wellspan Group with ER-positive breast cancer who had Oncotype DX analysis in 2008 and 2009. Data collected included Oncotype DX score and BMI (at diagnosis, 6 months and 12 months). Data were analyzed to determine the correlation between Oncotype DX score and BMI at diagnosis, at 6 months and at 12 months. The correlation between Oncotype DX score and BMI changes at 12 months also was determined. Results: A total of 125 patients were identified; 103 had BMI recorded at diagnosis, 88 had BMI recorded at 6 months and 87 had BMI recorded at 12 months. Of these, we were able to determine the BMI changes at 12 months for 82 patients. The Pearson correlation scores were 0.091 (p = 0.361), 0.074 (p = 0.492), and 0.047 (p = 0.669) for BMI at diagnosis, at 6 months and at 12 months respectively. The Pearson correlation score was 0.007 (p = 0.948) for BMI changes at 12 months. Conclusions: Obesity and weight gain are not independent predictors of recurrence in patients with ER-positive breast cancer. The reported adverse prognostic associations may be more prominent in ER-negative breast cancers. This is consistent with the reports suggesting a higher rate of ER-negative, high-grade cancers in obese women as well as a greater magnitude of benefit from dietary and weight reduction interventions seen in women with ER-negative cancers.
Correction: Incorporating Breast Cancer Recurrence Events Into Population-Based Cancer Registries Using Medical Claims: Cohort Study (Preprint)
