Pregnancy associated breast cancer: correlation between parity and ultrasonic characteristics of tumors & background echotexture.

OBJECTIVE: To investigate the characteristics of pregnancy associated breast cancer (PABC) and correlation of parity with ultrasonic tumor and background echotexture, based on the analysis of diagnostic efficiency. METHODS: The ultrasonic images of 184 female patients with PABC and 47 female patients with benign lesions, all of whom were pregnant or within one year postpartum at diagnosis and underwent surgery for their breast conditions in our center from January 2016 to December 2023, were retrospectively analyzed. Ultrasound diagnostic performance was assessed by the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUROC). Breast ultrasound background echotexture was classified according to two criteria: the first classification was homogeneous-fat, homogeneous-fibroglandular, and heterogeneous, the other classification was hypoechoic dominated and hyperechoic dominated. The correlation between parity and ultrasonic characteristics (tumor and background echotexture) was analyzed. RESULTS: The AUROC of ultrasound diagnosis for PABC was 0.939 (95%CI: 0.910-0.969). PABC tumors were predominantly irregular in shape, uncircumscribed, hypoechoic, heterogeneous, and solid. Compared with primiparous women, the PABC tumors were larger in multiparous women (4.00± 3.30cm vs. 3.09 ± 2.01cm, P = 0.037), with a higher rate of lymphatic metastasis (57.27% vs. 41.89%, P = 0.041). In terms of background echotexture, heterogeneous echotexture and hypoechoic dominated were more frequently observed in multiparas than in primiparas (52.73% vs. 37.84%, P= 0.047; 49.09% vs. 32.43%, P = 0.025). Multivariate analysis further indicated multiparous women were more likely to have heterogeneous (OR = 2.241, 95% CI:1.032-4.867, P= 0.041) and hypoechoic dominated (OR = 2.064, 95% CI:1.045-4.077, P = 0.037) breast ultrasound backgrounds than primiparous women, adjusted for confounders. CONCLUSIONS: Ultrasound is effective for diagnosing PABC. Multiparas may show a more heterogeneous and predominantly hypoechoic background echotexture, an increased risk of lymphatic metastasis, and larger tumors.