Endoscopic ultrasound-guided fiducial marker placement for neoadjuvant chemoradiation therapy for resectable pancreatic cancer

BACKGROUND Preoperative neoadjuvant chemoradiation therapy(NACRT)is applied for resectable pancreatic cancer(RPC).To maximize the efficacy of NACRT,it is essential to ensure the accurate placement of fiducial markers for image-guided radiation.However,no standard method for delivering fiducial markers has been established to date,and the nature of RPC during NACRT remains unclear.AIM To determine the feasibility,safety and benefits of endoscopic ultrasound-guided(EUS)fiducial marker placement in patients with RPC.METHODS This was a prospective case series of 29 patients(mean age,67.5 years;62.1%male)with RPC referred to our facility for NACRT.Under EUS guidance,a single gold marker was placed into the tumor using either a 19-or 22-gauge fine-needle aspiration needle.The differences in daily marker positioning were measured by comparing simulation computed tomography and treatment computed tomography.RESULTS In all 29 patients(100%)who underwent EUS fiducial marker placement,fiducials were placed successfully with only minor,self-limiting bleeding during puncture observed in 2 patients(6.9%).NACRT was subsequently administered to all patients and completed in 28/29(96.6%)cases,with one patient experiencing repeat cholangitis.Spontaneous migration of gold markers was observed in 1 patient.Twenty-four patients(82.8%)had surgery with 91.7%(22/24)R0 resection,and two patients experienced complete remission.No inflammatory changes around the marker were observed in the surgical specimen.The daily position of gold markers showed large positional changes,particularly in the superior-inferior direction.Moreover,tumor location was affected by food and fluid intake as well as bowel gas,which changes daily.CONCLUSION EUS fiducial marker placement following NACRT for RPC is feasible and safe.The RPC is mobile and is affected by not only aspiration,but also food and fluid intake and bowel condition.