Potential of Combination of CE-MRI and Serum Her-2neu Extracellular Domain in Evaluating Effectiveness of Neoadjuvant Chemotherapy in Breast Cancer.

Background and objectives: The incidence and mortality rates of breast cancer continue to pose significant challenges. Neoadjuvant chemotherapy is now established as a standardized treatment for locally advanced breast cancer. Notably, a subset of breast cancer patients may attain pathological complete remission (pCR) through neoadjuvant chemotherapy (NAC). The potential to avoid surgery exists if accurate preoperative recognition of complete pathological remission is achieved. Therefore, our research is dedicated to determine the potential of the combination of contrast-enhanced magnetic resonance imaging (CE-MRI) method with the serum level of extracellular domain of human epidermal growth factor receptor-2 (Her-2neu ECD) in the evaluation of the efficacy of neoadjuvant chemotherapy in breast cancer patients.

Methods: Sixty-six patients with breast cancer who received NAC in our hospital from September 2019 to July 2022 were enrolled retrospectively, and were divided into the pathological complete remission group and non-pathological complete remission (n-pCR) group based on pathological results. All patients underwent 6 to 8 cycles of NAC. Lesions were measured using CE-MRI and apparent diffusion coefficient (ADC) maps before and after NAC. Serum levels of Her-2neu ECD were measured by chemiluminescence before and after NAC. The change in tumor volume, maximum diameter and ADC values before and after NAC were calculated. Two logistic prediction model were established based on the independent predictors, and the performance of the models for predicting pCR of NAC were compared.

Results: The pCR group and n-pCR group were included 30 patients (average age, 48 years) and 36 patients (average age, 48 years), respectively. Hormone receptor status (odds ratio [OR], 4.47 [95% CI: 1.40, 14.32]; p = 0.012), human epidermal growth factor receptor-2 status (OR, 0.15 [95% CI: 0.05, 0.49]; p < 0.01), tumor volume change rate (ΔTV%) during NAC (OR, 1.12 [95% CI: 1.06, 1.26]; p < 0.001), and changes in serum Her-2neu ECD levels during NAC (OR, 1.14 [95% CI: 1.05, 1.24]; p < 0.001) were independently associated with the odds of achieving pCR. The model that combined ΔTV% and ΔHer-2neu ECD showed a relatively higher performance (AUC = 0.914, [95%CI: 0.850, 0.978]) than the model included ΔTV% and Her-2 receptor (AUC = 0.894, [95%CI: 0.819, 0.970]).

Conclusion: The model that combined MRI indicators and serum Her-2neu ECD levels showed a good performance for predicting pCR to NAC in patients with breast cancer.