Sonographic features of triple-negative and non-triple-negative breast cancer

Triple-negative breast cancer (TNBC) is known to have unique molecular, clinical, and pathologic characteristics. The growth pattern of this cancer may also affect its appearance on sonography. Our study evaluated the sonographic features of TNBC according to the American College of Radiology Breast Imaging Reporting and Data System sonographic classification system and compared these features with those of non-TNBC.

Data from 315 consecutive breast cancer cases were collected. The images were reevaluated by an examiner blinded to the patients' characteristics and histologic results according to the Breast Imaging Reporting and Data System. The sonographic features of TNBC (n = 33) and non-TNBC (n = 282) were compared.

Triple-negative breast cancer was significantly correlated with a younger patient age (P = .002) and was associated with higher tumor grades (P < .001), more lymph node involvement (P = .014), and a trend toward a larger tumor size. With regard to sonographic features, the margin of TNBC was more frequently described as lobulated or microlobulated (75.8% versus 49.5% in non-TNBC; P = .005). The echoic halo was observed significantly less often in TNBC than in non-TNBC(39.4% versus 62.8%; P = .014). Cooper ligaments were displaced rather than disrupted in TNBC compared to non-TNBC (P = .003). Regarding the posterior acoustic features, enhancement was observed significantly more often in TNBC (36.4% versus 13.0% in non-TNBC; P = .031).

Triple-negative breast cancer and non-TNBC have different sonographic features. This finding can be explained by the pathologic profile of this breast cancer subtype. Some of the distinct sonographic criteria for TNBC are more likely to be associated with benign masses. Knowledge of the distinct sonographic features of TNBC would help the examiner avoid false-negative classification of this tumor type.