[Preoperative evaluation of sentinel lymph node biopsy using contrast-enhanced ultrasonography in early breast cancer patients and the involved disturbing factors].

Objective To explore the preoperative evaluation of sentinel lymph node (SLN) biopsy using contrast-enhanced ultrasonography (CEUS) in early breast cancer patients and the involved disturbing factors. Methods Eighty-three female early breast cancer patients who underwent concurrent surgery in the Affiliated Cancer Hospital of Zhengzhou University between January 2017 and May 2018 were enrolled. CEUS was used to seek SLN and determine lymph node metastasis after signature of preoperative informed consent. Rapid pathological examination was used to determine whether metastasis existed in SLN. The sensitivity, specificity, accuracy, the differences between CEUS and pathological results, and the involved disturbing factors were evaluated. Results A total of 212 SLNs were detected by CEUS and SLN biopsy with an average of 2.6 SLNs detected per patient, including 39 SLNs with cancer metastasis (18.4%) and 173 SLNs without cancer metastasis (81.6%). Among the 83 patients, 29 patients were predicted SLN-positive preoperatively utilizing CEUS (including 21 cases with SLN pathological metastasis and 8 cases with non-metastasis), 54 patients were predicted SLN-negative (including 5 cases with SLN pathological metastasis and 49 cases with non-metastasis). The preoperative evaluation of SLN utilizing CEUS were performed with a sensitivity of 80.8% (21/26), specificity of 86.0% (49/57), positive predictive value of 72.4% (21/29), and negative predictive value of 90.7% (49/54), positive likelihood ratio of 5.75, negative likelihood ratio of 0.22, and the accuracy of 84.3% (70/83), respectively. The area under the ROC curve (AUC) was 0.834 (95% CI: 0.736-0.906). The primary tumor mean size of SLN-negative group predicted preoperatively utilizing CEUS was (1.78±0.14) cm, and that of the SLN positive group was (2.64±0.19) cm. The difference between the two groups was (0.86±0.24) cm with statistical significance (P=0.000 6). The SLN mean size of SLN-negative group (141 SLNs) was (1.41±0.05) cm and that of SLN-positive group (71 SLNs) was (1.69±0.07) cm. The difference between the two groups was (0.28±0.09) cm with statistical significance (P=0.002 8). Conclusions Preoperative CEUS possesses the predictive value for SLN metastasis in early breast cancer. The predicted results may be influenced by the primary tumor size and the SLN size. Key words: Contrast-enhanced ultrasonography; Breast cancer; Sentinel lymph node