Multiparametric evaluation of preoperative MRI in early stage breast cancer: prognostic impact of peri-tumoral fat.

ABSTRACT

PURPOSE: Obesity is associated with adverse outcomes in breast cancer patients. Fat-specific cytokines (adipokines) have been proposed as key drivers of breast cancer progression, invasion, and metastasis. We aimed at assessing correlations between peri-tumoral fat, quantified on magnetic resonance imaging (MRI) and pathologic factors potentially impacting therapy recommendations. METHODS: We retrospectively reviewed records of 63 patients with early stage breast cancer who underwent preoperative MRI imaging using appropriately weighted series for breast and tumor contouring. Fat volumes were generated through voxel intensity filtering. The peri-tumoral region was defined as the intersection of a 1-cm spherical extension around the tumor and the breast contour. Peri-tumoral fat was defined as the fraction of a fat content in this volume. Surgical pathology records were used to extract clinical data. Statistical analyses were conducted using Pearson and Spearman correlation coefficients. RESULTS: Among reviewed patients, 45 had T1 tumors (1.22 ± 0.85 cm diameter) and 18 had T2 tumors (2.08 ± 1.06 cm). Axillary lymph nodes were dissected in 31 and positive in 17 patients analyzed. Peri-tumoral fat ratio ranged between 25 and 99 %. Peri-tumoral fat ratio significantly correlated with the nodal-positive ratio of positive axillary lymph nodes (r = 0.532). Peri-tumoral fat ratio demonstrated optimally prominent correlation among obese patients upon body mass index categorical stratification. CONCLUSIONS: In women with early stage breast cancer, peri-tumoral fat correlates positively with the ratio of pathologically involved axillary nodes. This work highlights a novel method for quantitating peri-tumoral fat content. Preoperative breast MRI may be utilized to predict extent of axillary disease.