Ultrasound Unable to Rule Out Lymph Node Metastasis in Lung Cancer
FORT LAUDERDALE, Fla. (EGMN) -Ultrasound examination cannot definitively rule out metastatic disease in the mediastinal lymph nodes of patients with non-small cell lung cancer, according to a review of 151 patients from one center.
In high-risk patients with suspected mediastinal (N2) lymph node metastasis, "I'd go on to mediastinoscopy, and would not accept a negative EBUS [endobronchial ultrasound] or EUS [esophageal ultrasound] result," Dr. Robert J. Cerfolio said at the annual meeting of the Society of Thoracic Surgeons.
"EBUS and EUS are excellent initial tests for suspicious N2 lymph nodes, but false negative rates are underestimated, even when the lymph nodes are large, greater than 1.5 cm," said Dr. Cerfolio, professor of medicine and chief of thoracic surgery at the University of Alabama at Birmingham.
The series he reviewed showed a 28% false negative rate for N2 lymph nodes examined by EBUS, and a 22% false negative rate for N2 lymph nodes examined by EUS. Dr. Cerfolio stressed that all 151 patients who underwent these ultrasound examinations had mediastinal lymph nodes suspected to harbor disease based on prior findings by CT, positron emission tomography, or both.
Patients in the study were assessed during June 2007 and June 2009. All were at least 19 years old, and the median age of the 234 patients who met the enrollment criteria was 66 years. In this group, 72 patients underwent EBUS and 79 were evaluated by EUS.
EBUS identified 29 of the 72 patients as positive for N2 disease, and they were removed from the analysis. Among the 43 judged negative by EBUS, 12 (28%) were subsequently found to actually harbor N2 metastases using mediastinoscopy or other modalities. EUS identified 24 patients as positive. Among the 55 patients with negative N2 lymph nodes by EUS, 12 patients (22%) were later found to have N2 disease.
These false negative rates exceed the rates reported for EBUS and EUS in prior studies. Possible explanations for the higher rates in this series include the selection criteria of the new study, the recent introduction of EBUS at the University of Alabama at Birmingham, and the fact that this study was the first reported to mandate thoracotomy and complete lymph node removal in patients with negative EBUS and EUS results, Dr. Cerfolio said.