EUS-guided fiducial placement before targeted radiation therapy for prostate cancer

Background: Image-guided radiation therapy allows the delivery of precisely aimed radiation beams to tumors while minimizing radiation to adjacent normal tissue. This is particularly important in the prostate, a moving target whose positioning depends on the dynamics of its neighboring bladder and rectum. Targeted radiation therapy can be achieved by using implantable radiographic markers, or fiducials, which serve as reference points to accurately delineate tumors. Objective: To determine the feasibility and safety of placing fiducials in the prostate under linear array EUS guidance to facilitate targeted radiation therapy. Design: Retrospective analysis of a prospective database. Setting: University of Miami Hospital and Clinics, a tertiary cancer referral center. Patients: Localized prostate cancer patients scheduled to undergo intensity-modulated radiation therapy. Interventions: A total of 16 patients underwent EUS-guided fiducial placement to delineate the prostate before planned radiation therapy. Results: Fiducial placement was successful in all patients (100%). A total of 71 gold markers were deployed in a 4-quadrant manner outlining the prostate. Seven of 16 patients had an additional fiducial placed to ensure adequate prostate delineation. Patients tolerated the procedure well with minimal discomfort. No complications developed from the procedure. Limitations: Single-center experience, small sample size. Conclusions: EUS-guided placement of fiducials to facilitate image-guided radiation therapy for prostate cancer is a feasible alternative to transperineal or transrectal US approaches, thereby adding to the expanding list of indications for linear EUS. This procedure can be safely performed by endosonographers familiar with perirectal anatomy and transrectal FNA technique.