EUS-Guided Fiducial Gold Marker Placement in Metastatic Colon Cancer to the Spleen, Primary Author Ameya Deshmukh. Co-authors include Dr. Ahmed Mohamed El-Malagui, Dr. Javier Tejedor Tejada, Dr. Nassim Parsa, and Senior Author Dr. Jose Nieto. These are our disclosures. This patient has a past history of colon cancer in remission. However, a recent CT scan revealed an abnormal isodense splenic mass. EUS-Guided Fine Needle Biopsy and Fiducial Marker Placement was determined to be the optimal next step in evaluation of the splenic mass and to prepare for future image-guided radiation therapy. Fiducial markers are radiographically visible markers that are inserted into the target lesion and are used in image-guided radiation therapy. These markers allow for more accurate and precise targeting of tumors. This allows for elevated doses of radiation to the target lesion with minimizing risk of injury to the surrounding organs and tissue. A 22-gauge needle was used for both biopsy and fiducial marker placement due to its versatility in challenging and post-surgical anatomy. The gold fiducial marker placement utilized the back-loading technique. First, the stylet is retracted to approximately 3 centimeters and the fiducial marker is then loaded on the needle carrier and inserted on the FNA needle tip. Then the fiducial marker is released into the needle tip as the needle carrier is removed. Sterile bone wax is used to seal the tip of the FNA needle, holding the fiducial marker in place. Deployment of the fiducial marker into the target lesion occurs as the needle is pulled back and the stylet is advanced. The isodense splenic mass is located in the white circle below. First, a linear echoendoscope was advanced into the stomach where the splenic tumor was visualized on EUS. The mass appeared to be hypoechoic and measured to be approximately 2.73 centimeters by 1.88 centimeters. A 22-gauge Francine needle was used to biopsy the mass using one pass with three actuations via a transgastric approach. A comprehensive EUS assessment of tumor size, location, and nearby vasculature occurred before both marker placement and fine needle biopsy to minimize any local bleeding. Additionally, a 22-gauge needle was used due to its versatility in challenging anatomical locations. After the biopsy was completed, the gold fiducial placement occurred. First, two gold fiducial markers were placed on the margins of the tumor. A third marker was placed in the center of the mass. A minimum of three markers were placed. All fiducial markers were placed using the back-loaded technique. Here is gross examination of biopsy samples. A CT scan post-procedure confirmed the correct placement of the fiducial markers seen here. 3D image reconstruction helps visualize the correct placement of the fiducial markers more clearly and models the approach for subsequent radiation therapy. The pathology results revealed malignant glands with background necrosis, which were consistent with metastatic colon carcinoma. The EOS-guided approach streamlines the process, allowing for the biopsy and marker placement to occur within the same operative session and allows for greater spatial visualization, tumor assessment, and avoidance of the surrounding vasculature, aiding in the accurate placement of the fiducial markers. The use of preloaded fiducial markers has been shown to decrease procedure time by approximately 44% when compared to the backloaded method used in this case. Combining the EOS-guided approach and preloaded fiducial needles may further decrease the procedure time over more traditional methods of fiducial marker insertion. Recent meta-analysis found the pooled rate of technical success was 98%. EOS-guided insertion of gold fiducial markers and biopsy has been shown to be a safe procedure with the potential for quicker diagnosis and marker placement to facilitate image-guided radiation therapy in patients with metastatic gastrointestinal malignancies. Additional studies are needed to assess long-term outcomes of EOS placement of fiducial markers. These were the references used.

endoscopic ultrasound

EUS-guided

fiducial gold marker placement

metastatic colon cancer

spleen