Correlation between Imaging Markers Derived from PET/MRI and Invasive Acquired Biomarkers in Newly Diagnosed Breast Cancer

SIMPLE SUMMARY: Histological and molecular breast cancer (BC) characteristics are highly important for individualized therapeutical strategies and personalized risk assessment. Despite the improvement of existing image-based staging examinations over the last years, especially the implementation of PET/MRI examinations at leading tumor centers, the invasive part of BC staging is unavoidable. However, the diagnostic potential of PET/MRI has not yet been fully explored. Thus, this study aimed to analyze possible correlations between PET/MRI imaging markers and invasive acquired biomarkers in newly diagnosed early BC to possibly spare invasive procedures for BC patients in the future. At a population of 169 women a correlation between glucose metabolism and estrogen-receptor and progesterone-receptor expression, Ki67, and tumor grading was shown, whereas no correlation regarding disseminated tumor cells (DTCs) could be found. Thus, [(18)F]FDG-PET/MRI may give a first impression of BC-receptor status and BC-tumor biology during initial staging by measuring glucose metabolism but cannot distinguish between DTC-positive/-negative patients and replace biopsy. ABSTRACT: Purpose: Evaluate the diagnostic potential of [(18)F]FDG-PET/MRI data compared with invasive acquired biomarkers in newly diagnosed early breast cancer (BC). Methods: Altogether 169 women with newly diagnosed BC were included. All underwent a breast- and whole-body [(18)F]FDG-PET/MRI for initial staging. A tumor-adapted volume of interest was placed in the primaries and defined bone regions on each standard uptake value (SUV)/apparent diffusion coefficient (ADC) dataset. Immunohistochemical markers, molecular subtype, tumor grading, and disseminated tumor cells (DTCs) of each patient were assessed after ultrasound-guided biopsy of the primaries and bone marrow (BM) aspiration. Correlation analysis and group comparisons were assessed. Results: A significant inverse correlation of estrogen-receptor (ER) expression and progesterone-receptor (PR) expression towards SUV(max) was found (ER: r = 0.27, p < 0.01; PR: r = 0.19, p < 0.05). HER2-receptor expression showed no significant correlation towards SUV and ADC values. A significant positive correlation between Ki67 and SUVmax and SUV(mean) (r = 0.42 p < 0.01; r = 0.19 p < 0.05) was shown. Tumor grading significantly correlated with SUV(max) and SUV(mean) (ρ = 0.36 and ρ = 0.39, both p’s < 0.01). There were no group differences between SUV/ADC values of DTC-positive/-negative patients. Conclusions: [(18)F]FDG-PET/MRI may give a first impression of BC-receptor status and BC-tumor biology during initial staging by measuring glucose metabolism but cannot distinguish between DTC-positive/-negative patients and replace biopsy.