Objective: To establish and validate a radiomics nomogram based on contrast-enhanced (CE)-MRI for predicting the efficacy of neoadjuvant chemotherapy (NAC) in human epidermal growth factor receptor 2 (HER2)-positive breast cancer with non-mass enhancement (NME).
Methods: A cohort comprising 117 HER2-positive breast cancer patients showing NME on CE-MRI between January 2012 and December 2019 were retrospectively analysed in our study. Patients were classified as pathological complete respone (pCR) according to surgical specimens and axillary lymph nodes without invasive tumour cells. Clinicopathological data were recorded, and images were assessed by two radiologists. A total of 1130 radiomics features were extracted from the primary tumour and six radiomics features were selected by the maximal relevance and minimal redundancy and least absolute shrinkage and selection operator algorithms. Univariate logistic regression was used to screen meaningful clinical and imaging features. The rad-score and independent risk factors were incorporated to build a nomogram model. Calibration and receiver operator characteristic curves were used to confirm the performance of the nomogram in the training and testing cohorts. The clinical usefulness of the nomogram was evaluated by decision curve analysis.
Results: The difference in the rad-score between the pCR and non-pCR groups was significant in the training and testing cohorts (p < 0.01). The nomogram model showed good calibration and discrimination, with AUCs of 0.900 and 0.810 in the training and testing cohorts. Decision curve analysis indicated that the radiomics-based model was superior in terms of patient clinical benefit.
Conclusion: The MRI-based radiomics nomogram model could be used to pre-operatively predict the efficacy of NAC in HER2-positive breast cancer patients showing NME.
Advances in knowledge: HER2-positive breast cancer showing segmental enhancement on CE-MRI was more likely to achieve pCR after NAC than regional enhancement and diffuse enhancement.The MRI-based radiomics nomogram model could be used to pre-operatively predict the efficacy of NAC in HER2-positive breast cancer that showed NME.