Based on the results of a new study, researchers suggest the use of breast magnetic resonance imaging (MRI) with Node-RADS scoring may offer a more standardized assessment of lymph node involvement in women with breast cancer.
For the retrospective study, recently published in European Radiology, researchers assessed the utility of the Node-RADS scoring system in predicting lymph node invasion (LNI) based on a review of contrast-enhanced MRI data from 192 patients (median age of 56) who had invasive breast cancer, microinvasive or high-risk ductal carcinoma in situ. All patients in the cohort had breast surgery and lymphadenectomy procedures, according to the study. Out of 1,134 total lymph nodes assessed, the researchers noted that 32.8 percent were metastatic, according to the study.
The study authors noted that three reviewing radiologists with 15, seven and four years of experience, respectively, utilized the Node-RADS scoring system in their interpretations of the breast MRI images.
The researchers found that at higher cut-off thresholds (Node-RADS >3, Node-RADS >4) for differentiating malignant lymph nodes, researchers noted 100 percent specificity rates and positive predictive values (PPVs) for the two more experienced radiologists but precipitous declines in sensitivity and negative predictive value (NPV) for all reviewing radiologists.
However, when the researchers utilized a Node-RADS > 2 cutoff for determining malignant lymph nodes, they noted average sensitivity, specificity, PPV and NPV of 91.5 percent, 87.4 percent, 87.4 percent and 91.5 percent respectively.
“ … The Node-RADS score showed moderate-to-high overall accuracy in identifying LNI, and the Node-RADS > 2 can be considered the best cut-off for discriminating malignant nodes. This indicates that the scoring system can effectively aid in identifying suspicious lymph nodes, staging the disease, establishing a standardized language for communicating the presence of such nodes, and avoiding unnecessary biopsies,” wrote lead study author Federica Pediconi, M.D., an associate professor of radiology in the Department of Radiological, Oncological and Pathological Sciences at Sapienza University of Rome in Italy, and colleagues.
The researchers also noted inter-reader agreements, ranging between 71 to 83 percent, for the reviewing radiologists. The overall area under the receiver operating characteristic curve (AUC) for use of the Node-RADS scoring system was 97 percent for the senior radiologist and 93 percent for the other two reviewing radiologists, according to the study findings.
“This high level of concordance indicates that the Node-RADS scoring system can be reliably applied by different readers, enhancing its practical utility in clinical settings, including for novice radiologists,” maintained Pediconi and colleagues.
Three Key Takeaways
1. Standardized assessment. The Node-RADS scoring system offers a standardized method for assessing lymph node involvement in breast cancer, potentially improving the accuracy and consistency of staging the disease.
2. Optimal cut-off for accuracy. A Node-RADS score >2 is identified as the best cut-off for distinguishing malignant lymph nodes, providing a balance of high sensitivity (91.5 percent) and specificity (87.4 percent), which aids in accurate diagnosis and avoids unnecessary biopsies.
3. High inter-reader agreement. The Node-RADS system shows high inter-reader agreement (71-83 percent) and a strong area under the ROC curve (AUC) for all radiologists, indicating its reliability and practicality in clinical settings, including use by less experienced radiologists.
The study authors suggested the use of Node-RADS scoring with breast MRI may provide a viable standardized option for detecting metastatic lymph node involvement given the limitations of the eighth edition of the TNM staging system and the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS). Pediconi and colleagues pointed out that current TNM staging lacks definitive imaging-based scoring for lymphadenopathy and the BI-RADS classification doesn’t establish specific size cut-off thresholds nor considers increases in size from previous exams.
“These guidelines, although providing more clarity on the measurement and evaluation of lymph nodes, still rely on subjective and qualitative criteria, lacking a definitive quantitative scoring system for diagnosing lymphadenopathy through imaging,” added Pediconi and colleagues.
(Editor’s note: For related content, see “Preoperative Breast MRI Identifies Additional Cancer in Nearly 25 Percent of Young Women with Breast Cancer,” “Abbreviated Breast MRI and Dense Breasts: What Emerging Research Reveals” and “Leading Breast Radiologists Discuss the USPSTF Breast Cancer Screening Recommendations.”)
Beyond the inherent limitations of a retrospective study, the authors suggested the application of Node-RADS scoring may be more tailored to those who have surgical treatment for breast cancer. Accordingly, they cautioned that extrapolation of the study findings to a broader population may be limited.
