Objective  To investigate causes and factors affecting microcalcification (MC) changes after neoadjuvant chemotherapy (NAC) in patients with breast cancer and to assess the correlation between MC reduction and complete remission rate pathological complete response (pCR) of tumors.

  Methods  Clinical data of 215 patients with breast cancer who visited Tianjin Medical University Cancer Hospital from January 1, 2015 to December 31, 2018 were collected. The patients were grouped according to MC range and number of changes, and factors that affected MC changes were evaluated. According to whether MC decreased or not, the patient group was divided into the MC range and MC number reduction groups, and the correlation between the decrease in MC and pCR, assessed using different molecular typing methods, was analyzed. The sensitivity and specificity of the receiver operating characteristic curve analysis (ROC) were used to evaluate the accuracy of MC reduction in predicting pCR.

  Results  The patients with a distribution of diffuse, initial MC range of >2 cm and MC quantity of >20 were more likely to have an MC reduction. The pCR rate was higher in the group with reduced and non-reduced MC. No significant difference was found between the group with decreased MC and the control group. The decreases in MC according to the different molecular typing methods were independent of factors affecting pCR. Reduction in MC range predicts pCR with a sensitivity of 77.78 and specificity of 57.45 (P=0.0001).

  Conclusions  The change factors of MC in patients with breast cancer after neoadjuvant chemotherapy were the range, number, and distribution of calcification. The pCR rate of the patients with reduced MC was high, but the accuracy of pCR prediction based on reduced MG was low. Thus, mammography was not recommended for evaluating pCR after neoadjuvant chemotherapy.