Does change in microcalcifications with neoadjuvant treatment correlate with pathological tumour response?

To determine whether change in microcalcification density and extent after neoadjuvant treatment (NAT) can predict tumour response.

This single-institution, retrospective study included all women with breast cancer who underwent NAT between 1 January 2008 and 31 December 2014, and fulfilled the following criteria: mammography before NAT with pathological microcalcifications, mammography performed after NAT, and tumour resection at Tel-Aviv Sourasky Medical Center. Correlation was made between mammography features and clinicopathological information.

Fifty-four patients met the inclusion criteria. Post-NAT, the number of calcifications remained stable in 30 (55.5%) patients, decreased in 23 (42.6%) patients, and increased in one (1.9%) patient. Patients with a decreased number of malignant calcifications post-NAT had higher rates of pathological complete response compared to patients with no change (59% versus 20%, p=0.009). Patients with triple negative and human epidermal growth factor receptor 2 (HER2) receptor subtypes had higher rates of decreased number of calcifications post-NAT (50% versus 35%) and pathological complete response (57% versus 11%, p=0.007) compared to patients with luminal receptor subtype. In addition, patients who received a combination of chemotherapy and biological treatment had more cases of decreased number of calcifications compared to patients who received chemotherapy alone (56% versus 39%). No significant correlation was observed between calcification change post-NAT and calcification morphology or distribution pattern.

Patients with breast carcinoma and decreased number of pathological calcifications post-NAT had higher rates of pathological complete response compared to patients with no change in calcifications; however, a substantial number of patients with complete pathological response had no change in microcalcification distribution with treatment, questioning the need to completely excise all calcifications post-NAT.