Mammographic microcalcifications as a predictor of neoadjuvant efficacy across different breast cancer molecular subtypes

Microcalcifications are significant indicators of breast cancer, particularly for distinguishing the different molecular subtypes. This study aimed to investigate the relationship between microcalcifications detected before treatment and various clinical indicators across different molecular types in breast cancer patients undergoing neoadjuvant chemotherapy (NAC). In this retrospective study, clinical data from 178 breast cancer patients who underwent NAC, and 369 cases total, were analyzed. The patients were categorized into microcalcification and non-microcalcification groups according to mammography results. Statistical methods, including chi-square tests, t-tests, and nonparametric tests, were used to compare clinical variables across different molecular subtypes in the presence and absence of microcalcifications. Additionally, multivariate analyses and regression equations were used to determine the ability of microcalcifications to predict HER2-positive breast cancer. Significant differences were identified between breast cancer subtypes (X 2 = 14.129, p < 0.001) and type of breast surgery (X 2 = 5.073, p = 0.024). Patients with breast microcalcifications demonstrated a higher likelihood of achieving pathologic complete response (pCR) than those without microcalcifications ( p = 0.041), particularly with the HER2-positive subtype, p = 0.004, odd ratio (OR) = 0.115, 95.0 % confidence interval (CI): 0.026–0.498). Conversely, patients with the basal-like subtype exhibited the opposite trend ( p = 0.002, OR = 15.000, 95.0 % CI: 2.782–80.867). The results obtained from residual cancer burden (RCB) analysis were consistent with the pCR findings. Patients with the HER2-positive subtype exhibited the highest likelihood of developing breast microcalcifications (X 2 = 14.129, p < 0.001). We employed a logistic regression equation to predict the probability of achieving pCR in HER2-positive breast cancer and achieved an overall prediction accuracy of 82.72 %. Breast microcalcifications are valuable predictors of NAC effectiveness, particularly with respect to molecular subtypes. Microcalcifications are associated with higher pCR rates and a lower RCB in HER2-positive breast cancer, but may reduce NAC efficacy in basal-like breast cancer. The predictive value of breast microcalcifications for NAC efficacy has crucial clinical implications for the treatment of HER2-positive breast cancer. • Few studies explore the link between microcalcifications and neoadjuvant chemotherapy efficacy in breast cancer. • Microcalcifications predict neoadjuvant efficacy, with varied effects across breast cancer molecular subtypes. • HER2-positive patients with microcalcifications show higher rates of pathologic complete response. • Patients with basal-like breast cancer with microcalcifications may experience reduced neoadjuvant therapy efficacy. • Microcalcifications serve as a predictor for the efficacy of neoadjuvant chemotherapy in patients with HER2-positive tumors.