Contrast-enhanced lymphatic US can improve the preoperative diagnostic performance for sentinel lymph nodes in early breast cancer

Abstract

Objectives To evaluate the preoperative diagnostic value of contrast-enhanced lymphatic ultrasound (CEUS) for the sentinel lymph node (SLN) status in early breast cancer. Materials and methods We prospectively recruited 102 consecutive patients with clinically node-negative early breast cancer from July 2021 to October 2021. All patients underwent conventional US and percutaneous CEUS examinations. The CEUS of SLNs were classified into four enhancement patterns: homogeneous (I), featured inhomogeneous (II), focal defect (III), and no enhancement (IV). The diagnostic performance of conventional US and CEUS for SLN metastasis was assessed by receiver operating characteristic (ROC) curves and decision curves. Results A total of 78 women were enrolled in this study, including 55, 18, and 5 patients with negative axilla, 1–2, and ≥ 3 metastastic SLNs pathologically, respectively. The identification rate of SLNs by CEUS was 100%. Patterns I and II can select 91.7% (44/48) of patients with disease-free axilla, while patterns III and IV had higher percentages of metastasis (65.2%, p < 0.001 and 57.1%, p < 0.002, respectively). For the SLN metastatic burden, 100% (48/48) of patients with pattern I/II had ≤ 2 metastatic SLNs. Compared with conventional US, the CEUS enhancement patterns showed significant improvement in diagnosing metastatic SLNs (0.813 vs 0.601, p < 0.001). CEUS had greater clinical benefits and correctly reclassified 48% of metastatic SLNs ( p < 0.001) without sacrificing the classification accuracy of negative SLNs ( p = 0.25), and could improve prediction accuracy by 0.42 ( p < 0.001). Conclusions CEUS demonstrated better diagnostic performance and greater clinical benefits than conventional US for the preoperative diagnosis of SLNs, showing its potential to select candidates for precluding axillary surgery in early breast cancer. Key Points • The homogeneous and featured inhomogeneous enhancement of SLNs are highly suggestive of negative LNs, while focal defect (p < 0.001) and no enhancement (p < 0.002) patterns had higher percentages of metastasis. • The proportion of SLNs with highly suspicious signs on conventional US increases as the type of enhancement pattern increases (no suspicious signs in pattern I/II, 34.8% in pattern III, and 85.7% in pattern IV). • Compared with conventional US, CEUS improved the area under the receiver operating characteristic curve (0.813 vs. 0.601, p < 0.001) and had greater clinical benefits (IDI = 0.42, p < 0.001) for the diagnosis of axillary metastasis.

The Value of Percutaneous Contrast‐Enhanced Ultrasound in Sentinel Lymph Node Identification, Metastatic Status and Burden Diagnosis in Early Breast Cancer

“…Detailed tumor and SLN characteristics of the patients are presented in Table 1. Enhancement Pattern of SLN On the basis of previous studies, 17 we classified the enhancement patterns of SLN into four types including six subtypes. (Figure 3):…”

“…On the basis of previous studies, 17 we classified the enhancement patterns of SLN into four types including six subtypes. (Figure 3):…”

“…However, there is a great overlap between benign and malignant SLN in type II, which results in low diagnostic specificity. 15,23,26 Therefore, on the basis of previous studies, 17 we further subdivided type II into inhomogeneous hypoenhancement (type IIa) and annular or semi-annual (type IIb). Based on this classification, type I, IIa, and IIb were identified as benign SLN enhancement patterns, with an overall pathological agreement rate of 86.3% (44/51), and this result suggests that PCEUS has the potential to safely select majority who do not require axillary surgery.…”

“…A meta‐analysis showed that the identification rate of SLN by CEUS ranged from 70% to 100% 14 . The diagnosis of SLN status and burden is mainly focused on studying its enhancement pattern 15–17 . However, the classification of SLN enhancement patterns and their correlation with final pathological findings are still being explored.…”