Peritumoral edema as a biomarker of the aggressiveness of breast cancer: results of a retrospective study on a 3 T scanner.

PURPOSE: To determine whether there is a correlation between the presence of peritumoral edema detected on T2-weighted sequences and pathological prognostic factors and specific biological subtypes of breast cancer. METHODS: A retrospective study on 120 women with invasive breast cancer, who underwent breast MRI on a 3 T scanner over a period of 12 months, was performed. Peritumoral edema was assessed visually by two breast radiologist in consensus and patients were consequently divided into two groups. For each lesion dimensions, histology and molecular profiling were evaluated. The comparison between the two groups was performed using the χ2 test, subsequently carrying out a univariate and a multivariate logistic regression analysis. RESULTS: 41 (34.2%) invasive breast cancers with perilesional edema and 79 (65.8%) without edema were identified. A significant association between the presence of perilesional edema and a larger lesion size (p = 0.0001), grade 3 (p < 0.001) and a higher Ki-67 index (p < 0.001) was found. The multivariate analysis confirmed that a larger tumor size is independently associated with peritumoral edema. A total of 101 (84.2%) luminal-like, 8 (6.7%) HER2-positive, and 11 (9.2%) triple-negative tumors were included in the study. Peritumoral edema turned out to be less frequently associated with luminal-like lesions (p < 0.001), while the luminal A status was found to have a significant association with the absence of peritumoral edema in the univariate analysis. CONCLUSION: The detection of peritumoral edema on T2-weighted sequences should be considered as a valid additional prognostic tool in the evaluation of breast cancer, since it is associated with biologically aggressive non-luminal breast cancers, characterized by large dimension, high tumor grade, and high Ki-67 values.