EUS Guided Interstitial Brachytherapy Of Pancreatic Cancer: A Pilot Study

PART 1Basic Feasibility Study EUS - guided interstitial brachytherapy of the pancreasBackgroundIntraoperative interstitial brachytherapy has been effective when utilized at laparotomy to improve local control in locally advanced pancreatic cancer. Our aim in this study was to investigate the feasibility and safety of EUS - guided brachytherapy of the pancreas in a porcine model.MethodsA modified 18 - gauge needle with radioactive seeds was inserted into the pancreas under EUS guidance. The radioactive seeds were implanted into the tissue by the needle. After 14 days of clinical observation, the animals were killed and the tissue response to brachytherapy was examined.Results All the seeds were implanted successfully and no migration occurred. Localized tissue necrosis and fibrosis was achieved in pancreas, without significant complication. One pig had mild hyperlipasemia. Biochemical parameters were normal in the remaining pigs.ConclusionsEUS - guided implantation of radioactive seed is a safe, simple and minimally invasive technique for interstitial brachytherapy.PART 2Clinical Pilot Study:Endoscopic Ultrasound - Guided Interstitial Brachytherapy of Unresectable Pancreatic CancerBackground and Study AimsIntraoperative interstitial brachytherapy has been found to be effective when used during laparotomy to improve local control in patients with locally advanced pancreatic cancer. In this study, we report the results of using endoscopic ultrasound - ( EUS - ) guided interstitial brachytherapy in patients with advanced pancreatic cancer, with respect to tumor response, clinical response, safety, and complications.Patients and MethodsFifteen patients (eight men, seven women;median age 61 years) with unresectable pancreatic adenocarcinoma were enrolled into the study, eight patients with stage III disease and seven patients with stage IV disease. A mean number of 22 radioactive seeds per patient were implanted into the tumors by EUS -guided needle puncture. The mean total implanted activity was 19. 6 mCi, the minimum peripheral dose was 14 000 cGy, and the mean volume of implants was 52 cm3. Patients were followed - up by examination and by imaging tests every 2 3 months;clinical end points included the Karnofsky performance status and pain responses, tumor response ( assessed by computed tomography and/or EUS) , and survival.ResultsDuring a median follow - up period of 10.6 months, the objective tumor re-sponse was classified as " partial" in 27 % of patients ( with a mean duration of partial response of 4.5 months) , " minimal" in 20 % patients, and indicative of " stable disease" in 33 % of patients. Clinical benefit was shown in 30 % of patients , mostly due to reduction in pain, but this lasted for a limited time. Local complications ( pancreatitis and pseudocyst formation) occurred in three patients;grade III hematologic toxicity occurred in five patients without serious clinical sequelae.ConclusionsEUS - guided intraoperative interstitial brachytherapy had a moderate local tumor effect and showed some clinical benefit in 30 % of the patients in this study. Combination of this form of treatment with external radiation and/or chemotherapy should be tested in future trials.