PURPOSE: Objective: The goal of this study was to evaluate the safety and feasibility of placing fiducials in mediastinal and intra-abdominal tumors under EUS guidance. A secondary goal was to determine whether or not fiducials placed under EUS guidance were suitable as markers for CyberKnife.
METHODS: Design: Thirteen patients scheduled to for CyberKnife therapy were evaluated for EUS-guided placement. A linear echoendoscope was used to localize the tumor, insert a 19-gauge FNA needle inseted in tumor and fiducials(3-5 mm) placed. However, when for technical reasons the 5mm fiducials could not be placed, 3mm fiducials were inserted instead. The position of the fiducials was verified by EUS and by fluoroscopy.
RESULTS: Results: EUS-guided fiducial placement was successful in a total of 11/13 patients (84.6%). The locations of the tumors were as follow: retrocrural area at the dome of the diaphragm, porta hepatis, gastroesophageal junction, mediastinum, thoracic paraspinal area and pancreas. Fiducials placement was not attempted in 2 patients because the tumors were not (safely) accessible to the EUS needle. A total of 3 to 6 fiducials were placed in each patient. Fiducials length was 5mm in 9 patients and 3mm in 2 patients. One patient developed an infectious complication that resolved with antibiotics. Of the 11 patients who had fiducials placed, three were not treated because of deterioration of their clinical status. For the other 8 patients, the fiducials were adequate for detection by the CyberKnife system, whether they were of 3mm or 5mm length. No fiducial migrated significantly from its initial position throughout the treatment period.
CONCLUSION: Conclusion: EUS-guided fiducial placement in lesions of the mediastinum and abdomen is a feasible and safe technique that can be used to mark a tumor site and guide CyberKnife radiation therapy.
CLINICAL IMPLICATIONS: A new and less invasive technique that would help to target tumors in areas that were diffucult to reach in conventional ways.
DISCLOSURE: Nadim Haddad, None.