Multiparametric MRI assessment of primary tumours for predicting axillary tumour burden in women with invasive breast cancer

Abstract Objective To assess the association between multiparametric MRI features of primary tumours and axillary lymph node tumour burden in women with invasive breast cancer. Methods In this retrospective study, women diagnosed with invasive breast cancer who underwent 3T multiparametric MRI, including diffusion-weighted imaging (DWI) from 2019 to 2020, were evaluated. Two radiologists reviewed T2-weighted images (T2WI) for peritumoural oedema and intratumoural necrosis and measured apparent diffusion coefficient (ADC) values by manually placing regions of interest within breast tumours. We also analysed quantitative kinetic features of breast cancer using computer-aided diagnosis (CAD) and clinical-pathologic characteristics. Uni- and multivariable logistic regression analyses were conducted to identify predictors of a high axillary nodal burden (≥3 positive nodes). Results In total, 301 women (mean age, 54.13 years) were evaluated. Forty-three (14.3%) had a high axillary nodal burden by surgical pathology. Multivariate analysis revealed that factors significantly associated with high axillary nodal burden included peritumoural oedema (OR: 7.970; P < .001), lower tumour ADCmax (≤1.098 × 10−3 mm2/s) (OR: 6.978; P < .001), larger tumour size (>2 cm) (OR: 2.986; P = .046), lobular histology (OR: 12.620; P < .001), and the presence of lymphovascular invasion (OR: 3.622; P = .003). CAD-derived kinetic features did not show an association with axillary nodal burden. In subgroup analysis of 238 patients with early clinically node-negative breast cancer, both peritumoural oedema (OR: 7.831; P = .002) and lower tumour ADCmax (≤1.098 × 10−3 mm2/s) (OR: 8.002; P = .002) remained significant predictors. Conclusion Our results suggest that peritumoural oedema as viewed in T2WI and the ADCmax value of breast cancer in DWI are valuable for predicting axillary nodal burden in women with invasive breast cancer. Advances in knowledge Multiparametric MRI features of a primary tumour are useful for predicting axillary nodal burden in patients with invasive breast cancer.