Impact of Fiducial Marker Placement Before Stereotactic Body Radiation Therapy on Clinical Outcomes in Patients With Pancreatic Cancer

Purpose: Localized pancreatic cancer is commonly treated with stereotactic body radiation therapy (SBRT), which often requires the placement of fiducial markers. We compared the clinical outcomes of patients with and without fiducial markers. Methods and Materials: We retrospectively collected data on patients with pancreatic cancer treated with neoadjuvant SBRT at a single institution. Patients were divided into 2 groups based on the placement of a fiducial marker. Local recurrence was the primary outcome. Time to event endpoints were analyzed using COX regression. Results: We included 96 patients with unresectable pancreatic cancer: 46 patients (47.9%) did not have a fiducial marker, and 50 patients (52.1%) had a fiducial placed. Patients in the fiducial group were older and had more locally advanced pancreatic cancer compared with those who did not have a fiducial placed. Most patients in both groups (92.7%) received chemotherapy before SBRT treatment. SBRT was delivered to a median of 36 Gy over 5 fractions in the no-fiducial group, and 38 Gy over 5 fractions in the fiducial group. At a median follow-up of 20 months, local recurrence was similar irrespective of fiducial placement (adjusted hazard ratio [aHR] 0.6, 95% CI 0.3-1.3, P =.59). Furthermore, no difference in overall survival was noted between the 2 groups (aHR 0.8, 95% CI 0.3-1.9, P =.65). In patients who eventually underwent surgery post-SBRT, no difference in surgical margins (P =.40) or lymphovascular invasion (P =.76) was noted between the 2 groups. No patient developed acute pancreatitis after fiducial placement. Conclusions: Our data suggest that the use of fiducial markers does not negatively affect clinical outcomes in patients with localized pancreatic cancer. Prospective confirmation of our results is still needed.