Objective: This study investigated the correlation of oestrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status with the probability of malignancy (POM) of mammographic calcifications in ductal carcinoma in situ (DCIS).
Methods: A total of 101 women (age range, 27-83 years) with pure DCIS that presented as mammographic calcifications were included. Three radiologists independently reviewed mammograms according to the BI-RADS lexicon and provided 100-point POM scores and a BI-RADS category. ER, HER2 and breast cancer subtypes were determined using immunohistochemistry (IHC) and fluorescence in situ hybridisation. Pairwise correlations between POM and IHC biomarker scores were calculated, and mammographic features were compared between breast cancer subtypes.
Results: HER2 level positively correlated with the POM score (P < 0.0001) and BI-RADS category (P < 0.0001), and ER level inversely correlated with the POM score (P < 0.013) and BI-RADS category (P < 0.010). Fine linear branching (P = 0.004) and segmental (P = 0.014) calcifications were significantly associated with HER2-positive cancers, and clustered calcifications were more frequently observed in ER-positive cancers (P = 0.014).
Conclusion: HER2 status in DCIS correlated positively with the POM of mammographic calcifications, as determined by radiologists on the basis of the BI-RADS lexicon.
Key points: • Prediction of malignancy on mammographic ductal carcinoma in situ is difficult. • HER2 level correlated positively with the probability of malignancy assigned by radiologists. • ER level correlated inversely with the probability of malignancy assigned by radiologists. • HER2-positive DCIS more frequently exhibited fine linear branching or segmental calcifications. • ER-positive DCIS more frequently exhibited clustered calcifications.