Elastography in the assessment of sentinel lymph nodes prior to dissection.
OBJECTIVE
Breast cancer starts as a local tumor but can become metastatic and spread via the lymph nodes. When the pre-operative assessment of the axillary lymph nodes is negative patients generally undergo sentinel node biopsy (SNB), followed by a secondary surgical axillary lymph node dissection (ALND) if the SNB is positive. The extemporaneous anatomo-pathological analysis of the sentinel lymph node enables metastases to be detected and an ALND at the same time of the SNB. The goal of this study was to evaluate the added value of ShearWave Elastography (SWE), compared with the conventional pre-operative assessment, in the screening of sentinel lymph nodes with a high metastatic risk, which could then benefit from an extemporaneous anatomo-pathological analysis.


METHODS
Women undergoing breast surgery with SNB were prospectively enrolled. Before surgery, they underwent ultrasound and elastography imaging of axillary lymph nodes using the SuperSonic Imagine device and its ShearWave™ elastography mode (SWE™). The results obtained were compared to the immunohistochemical results for the removed lymph nodes.


RESULTS
65 patients were enrolled. From the 103 lymph nodes examined by elastography and the 185 lymph nodes removed we were able to pair 81; 70 were healthy and 11 were malignant. The stiffness measurements (mean and maximal values) were significantly different between the healthy and metastatic lymph nodes, (p<0.05). The areas under the ROC curves were 0.76 (95% confidence interval (CI): 0.58-0.94) and 0.75 (95%CI: 0.55-0.95) for the mean and the maximal stiffness, respectively.


CONCLUSIONS
These encouraging results show a correlation between the metastatic risk of lymph nodes and their increased mean stiffness. Elasticity variables and potential thresholds that seem to predict the metastatic status of axillary lymph nodes were identified. If confirmed by further larger studies, these results could be useful in clinical practice for the identification of lymph nodes at high metastatic risk that could benefit from a intra-operative analysis to reduce the number of secondary surgical procedures.
Radiology Department, Hôpital Privé Jean Mermoz, 55 avenue Jean Mermoz, 69008 Lyon, France. christophe.tourasse@radiologie-lyon.com
Christophe
C
Tourasse
Jean François
JF
Dénier
Azzam
A
Awada
Anne-Christel
AC
Gratadour
Karima
K
Nessah-Bousquet
Joël
J
Gay
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000556:secondary* / Q000601:surgery; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods; D016217:Ultrasonography, Mammary / Q000379:methods*; D055815:Young Adult