The impact of quality and quantity of visceral fat on survival outcome of early-stage breast cancer patients with prior chemotherapy.

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584 Background: Obesity not only increases morbidity, but also chemo-resistance of breast cancer (BC). Several studies focusing on body mass index (BMI) of BC patients have been performed; however, a recent report suggested that the quality of visceral adipose tissue (VAT) plays a crucial role in fat cell function. We set out to clarify the effect of quality and quantity of VAT on survival outcome of BC patients who underwent chemotherapy. Methods: From 2,230 patients who underwent treatment for BC at our institution from January 2004 to December 2015, we included 271 patients who received chemotherapy in neo-adjuvant (NAC) or adjuvant setting. Quantification was performed using computed tomography (CT) 3-dimensional volumetric software and quality of VAT was assessed based on the CT Hounsfield Unit of VAT (VAT-HU) using electrically stocked CT images. The correlation between BMI, amount of VAT (aVAT), and VAT-HU were analyzed using Pearson’s correlation test. The effect of these factors on pathologic complete response (pCR) was evaluated using Logistic regression model with the following covariates: menopausal status, size, nodal status, and subtype. Furthermore, survival analysis for distant disease-free survival (DDFS) was performed using Kaplan Meier method and Cox proportional hazard model. Results: aVAT and VAT-HU were significantly correlated with patient BMI (p<0.05). Forty-six patients achieved pCR (24%). Logistic regression model for pCR showed that aVAT and VAT-HU did not affect pCR (p=0.60 and 0.36). After a median follow-up of 112 months, tertile stratification revealed that the third tertile of aVAT had significantly shorter DDFS in the NAC setting (p<0.05). When adjusted by covariates in the Cox proportional regression model, aVAT and VAT-HU demonstrated significant contribution to worse DDFS ([p<0.05, hazard ratio {HR} 1.39; 95% confidence interval {CI} 1.11 to 1.75] and [p<0.05, HR 1.20, 95% CI 1.01 to 1.43], respectively). Conclusions: The quantity and quality of VAT was significantly related to the survival outcome especially in the NAC setting. This new insight would enable prediction of recurrence risk in obese BC patients with prior chemotherapy.