Effective surgical management of mesothelioma requires the identification of the extent of actual tumor mass, as well as the identification of the malignant status of a patient’s lymph nodes. The former is important so the treating physician understands how much of an area has been affected, while the latter can be indicative of systemic malignancy and a worse prognosis. Researchers have developed many tests to identify these issues, but new methods are regularly being studied to increase the accuracy of the reports. Researchers from the Duke University Medical Center and the University of Alabama at Birmingham have recently released the results of their study on the effectiveness of endoscopic ultrasound-guided fine needle aspiration (EUG-FNA) to determine the nodal status of patients who are being treated for pleural mesothelioma.

Introduction to the Study

Nodal status is an important metric in the analysis of any cancer, but this is especially true for patients with pleural mesothelioma who may be eligible for radical surgery. Previous studies have shown that patients with mesothelioma involvement in the lymph nodes who undergo an extrapleural pneumonectomy (EPP) have a statistically poor outcome, and because of this, some institutions will not perform an EPP for patients with nodal involvement. Thus, developing tests to identify nodal status is an especially important area of current research.

Computed tomography (CT) scans and/or positron emission tomography (PET) scans are currently used for the initial evaluation of a patient’s lymph nodes. If the scan shows any enlarged lymph nodes, then a more invasive procedure will be used to take a tissue sample of the enlarged nodes. The authors of the study were the first group to investigate the effectiveness of endoscopic ultrasound-guided fine needle aspiration (EUG-FNA) in determining nodal status for patients with mesothelioma.

EUG-FNA is a type of surgical biopsy where a thin, hollow needle is inserted into a tissue area and a sample of the cells from that area are removed for analysis. After the cells have been removed, they will be analyzed for the existence of any malignancy. In this case, the cells are removed from selected lymph nodes and those cells are analyzed for the presence of any mesothelioma cells. This procedure allows the doctor to better stage a patient’s disease than if he did not—or was not able to—examine the patient’s actual lymph nodes. EUG-FNA has previously been shown to be useful in the evaluation of lymph node status for patients with small cell lung cancer and with non-small cell lung cancer.

To evaluate EUG-FNA’s efficacy for mesothelioma patients, the authors analyzed its use in six patients with confirmed pleural mesothelioma. On two patients, they biopsied two sites, so a total of eight sites were evaluated.

Conclusion

EUS-FNA detected lymph node involvement in 50% of the cases it was completed on, while mediastinoscopy, which is an alternative technique, didn’t identify any. There were two false negatives in the EUS-FNA test, but they were attributed to sampling errors and not to cytological errors. In those cases, the area that was sampled didn’t show any malignancy, but other nodes were in fact malignant.

The authors feel that a full-scale clinical trial should be commenced to fully study the efficacy of EUS-FNA. They feel it can be very effective in the staging of mesothelioma and suggest its further study may have important implications for the treatment of this difficult disease.

Labels: mesothelioma