Predictive value of dynamic contrast-enhanced breast magnetic resonance imaging and diffusion-weighted imaging findings for sentinel lymph node metastasis in early-stage invasive breast cancer.

Objectives: This retrospective study aimed to evaluate the predictive value of the preoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) findings of mass lesions for predicting sentinel lymph node (SLN) metastasis in early breast cancer.

Methods: A total of 310 patients with suspicious mass lesions detected in preoperative MRI who subsequently underwent surgery and SLN biopsy (SLNB) between September 2015 and September 2022 were analysed. The relationship between DCE-MRI and DWI findings and SLNB positivity was analysed.

Results: SLNB was positive for SLN metastasis in 108 of 310 lesions. Younger age (P = 0.001) and larger lesion size (P < 0.001) were found to be associated with SLNB positivity. Findings associated with SLN metastasis included peritumoural oedema in 53%, adjacent vessel sign (AVS) in 81%, and increased whole-breast vascularity (WBV) in 58% of patients with positive SLNB (P < 0.001). The SLNB positivity rate was higher in mass lesions with DCE-MRI findings of heterogenous enhancement pattern (P = 0.003), medium or rapid initial phase enhancement (P = 0.001), and washout delayed phase kinetic curve (P = 0.001). It was found that lower tumoural apparent diffusion coefficient (ADC) values (P = 0.003) and higher peritumoural/tumoural ADC ratios (P = 0.018) increased the probability of encountering SLN metastasis.

Conclusions: Patient age, presence of peritumoural oedema, presence of AVS, increased WBV, and initial phase kinetic curve of the lesions on MRI were found to be associated with SLN metastasis.

Advances in knowledge: We found that younger age and MR findings obtained from the perilesional area of breast cancer may be helpful in the preoperative prediction of SLN metastasis.