Integration of DCE-MRI primary lesion kinetics significantly improves the Katz pathologic nomogram accuracy to predict the presence of occult axillary lymph node metastases in breast cancer patients with a positive sentinel lymph node biopsy, according to a study published in the January 2014 issue of Academic Radiology.
Breast cancer patients are more readily foregoing completion axillary dissection after a positive sentinel lymph node biopsy, but lack of complete pathologic staging information from axillary dissection makes identification of patients who would benefit from high axilla/supraclavivular lymph node identification difficult. The Katz nomogram and other clinicopathologic models are used to assess risk for occult disease in the high axilla. “The Katz nomogram incorporates tumor histology, primary tumor size, lymphovascular space invasion, extranodal extension, the number of involved sentinel nodes, the number of uninvolved sentinel nodes, and the size of the largest sentinel node metastasis,” wrote the study’s lead author, Christopher Loiselle, MD, of the University of Washington Medical Center in Seattle, and colleagues.
The authors’ retrospective study investigated the approach of combining DCE-MRI tumor kinetics features with the Katz nomogram to improve prediction of axillary node involvement by analyzing patients who underwent DCE-MRI, positive sentinel lymph node biopsy, and completion axillary lymph node dissection.
Clinically node-negative invasive breast cancer patients who underwent preoperative DCE-MRI, had a sentinel node biopsy with positive findings, and had complete axillary dissection were identified for the study. Clinical records and prospective databases provided clinical/pathologic factors, primary lesion size, and quantitative DCE-MRI kinetics. Four or more positive axillary nodes were predicted by the DCE-MRI parameters, modeled with stepwise regression, and then compared to the Katz nomogram both individually and with a combined MRI-Katz nomogram model.
The study criteria determined 99 positive sentinel lymph node biopsy cases in 98 patients to be acceptable. Findings indicated that DCE-MRI total persistent enhancement and volume adjusted peak enhancement were significant predictors of four or more metastatic nodes, as identified by stepwise regression. Receiver operating characteristic curves revealed that the Katz nomogram had an area under the curve of 0.78, 0.79 for the DCE-MRI multivariate model, and 0.87 for the combined MRI-Katz model. The researchers found that the combined model was significantly more predictive than the Katz nomogram.
“The capability of primary lesion DCE-MRI kinetics to predict additional axillary lymph node status is highly relevant for care of sentinel lymph node–positive patients and a promising area for future study and validation in a prospective trial,” wrote Loiselle and colleagues.