To explore clinic value of contrast enhanced ultrasound (CEUS) for preoperative sentinel lymph node (SLN) localization and metastasis risk evaluation in patients with breast cancer.

According to the inclusion and exclusion criteria, 21 female breast cancer patients who underwent surgical treatment in the Department of Breast Surgery, People’s Hospital of Jiangsu University from May to September 2019 were enrolled for a prospective study. Before surgery, the position and number of SLN were marked on the skin surface according to the results of percutaneous CEUS and the risk of SLN metastasis was evaluated based on the enhancement mode. The location and number of SLNs was confirmed by intraoperative methylene blue staining. The pathological results after methylene blue staining were used as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of percutaneous CEUS in predicting SLN status were calculated. The Kappa consistency test was used to analyze the consistency between CEUS and pathological examination and the consistency of the interpretation of SLN enhancement mode on CEUS by two sonographers. Fisher’s exact test was used to analyze the differences in CEUS assessment of SLN in patients with different clinicopathological characteristics.

Among the 21 patients, 32 SLNs were detected by percutaneous CEUS and 71 SLNs were detected by methylene blue staining. All SLNs detected by percutaneous CEUS were confirmed by methylene blue staining during the operation. The number of detected SLNs was 1.6±0.9 by CEUS, significantly lower than 3.4±1.4 by methylene blue staining (t=5.017, P<0.001). Nine patients were diagnosed with SLN metastasis by CEUS (7 with SLN metastasis confirmed by pathology and 2 without). CEUS demonstrated 12 patients with no metastasis, in which 11 cases confirmed by pathology, but one had metastasis. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of percutaneous CEUS in the diagnosis of SLN were 7/8, 11/13, 7/9, 11/12 and 85.7 % (18/21), respectively. The results of CEUS and pathology showed a high consistency (Kappa=0.704, P=0.001). The interpretation of 32 SLNs on CEUS showed a high consistency between two sonographers (Kappa=0.829, P<0.001). There was a significant difference in the results of CEUS among patients with different histological grades (P=0.046).

Percutaneous CEUS is feasible for preoperative SLN localization and metastasis risk evaluation in patients with breast cancer.