Objective To explore the diagnostic value of ultrasound, MRI, and mammography in different molecular subtypes of breast cancer.

Methods A cohort of 212 female patients, aged (47.6±9.3) years old and with confirmed breast cancer, from Huizhou Municipal Central Hospital from January 2018, to April 2022, was retrospectively analyzed. In accordance with the results of pathology and immunohistochemistry, the patients were grouped into four groups: 31 cases of Luminal A, aged (49.2±10.8) years; 104 cases of Luminal B, aged (46.1±8.9) years; 45 cases of human epidermal growth factor receptor-2 (HER-2) overexpression, aged (49.6±10.1) years; and 32 cases of triple-negative breast cancer (TNBC), aged (48.5±8.5) years. The clinical characteristics of the patients and the imaging features of ultrasound, MRI, and mammography were analyzed. Intergroup comparisons of metric data conforming to normal distribution were performed using independent sample t-test (equal variance). Intergroup comparisons of count data were performed using chi-square test or Fisher’s exact probability method. Statistically significant features were evaluated for accuracy of the diagnostic efficacy by using ordered logistic regression analysis and area under the curve (AUC).

Results Among the clinical features, the differences in menopausal status and lymph node metastasis among patients with breast cancer of different molecular subtypes were statistically significant (χ²=10.345, 10.026; P=0.016, 0.018). The results of ultrasonography showed that the margins of Luminal A breast cancer tumor were mostly blurred, the margins of Luminal B and HER-2 overexpression breast cancer tumors were mostly angular or hairy, and the margins of TNBC tumor were mostly lobulated. Moreover, the internal echoes in the tumors of the four subtypes were mostly heterogeneous echogenicity, which was more commonly seen in Luminal B. The blood flow Alder grade was mostly grade 0 or Ⅰ within Luminal A and TNBC, whereas the blood flow Alder grade within Luminal B and HER-2 overexpression breast cancer was mostly grade Ⅱ or Ⅲ. The differences were statistically significant (χ²=33.542, 12.283, 10.699; all P<0.05). The results of MRI showed that the tumor enhancement characteristics of Luminal A, Luminal B, and HER-2 overexpression breast cancer were mainly inhomogeneous enhancement, and the proportion of ring enhancement in TNBC tumors was higher than those in the other three, with a statistically significant difference (χ²=30.142, P<0.001). The results of mammography showed that calcification was mostly present in Luminal B and HER-2 overexpression breast cancer tumors, whereas no calcification was found in Luminal A and TNBC tumors. The calcification pattern in Luminal A and Luminal B breast cancer tumors was mainly punctate calcification, whereas that in HER-2 overexpression and TNBC tumors was mainly polypoidal or linear. The differences were all statistically significant (χ²=9.627, 11.792; both P<0.05). The patients' menopausal status and the tumor margins of breast cancer could be used as independent predictors of the molecular subtypes of breast cancer (B=0.729, 0.775; OR=7.053, 23.696; 95%CI: 0.193~1.267, 0.463~1.087; both P<0.05), with an AUC of 0.635 (95%CI: 0.528~0.742).

Conclusion Differences were observed in the characteristics of ultrasound, MRI, and mammography in different molecular subtypes of breast cancer, indicating their certain diagnostic value.