Histopathologic consideration of fiducial gold markers inserted for real-time tumor-tracking radiotherapy against lung cancer.

ABSTRACT

PURPOSE: Internal fiducial gold markers, safely inserted with bronchoscopy, have been used in real-time tumor-tracking radiotherapy for lung cancer. We investigated the histopathologic findings at several points after the insertion of the gold markers. METHODS AND MATERIALS Sixteen gold markers were inserted for preoperative marking in 7 patients who subsequently underwent partial resection of tumors by video-assisted thoracoscopic surgery within 7 days. RESULTS: Fibrotic changes and hyperplasia of type 2 pneumocytes around the markers were seen 5 or 7 days after insertion, and fibrin exudation without fibrosis was detected 1 or 2 days after insertion. CONCLUSIONS: Because fibroblastic changes start approximately 5 days after gold marker insertion, real-time tumor-tracking radiotherapy should be started >5 days after gold marker insertion.