title: 90Y Radioembolization after radiation exposure from peptide receptor radionuclide therapy.
abstract: Previous radiation therapy of the liver is a contraindication for performing (90)Y microsphere radioembolization, and its safety after internal radiation exposure through peptide receptor radionuclide therapy (PRRT) has not yet been investigated.
  
  
  METHODS
  We retrospectively assessed a consecutive cohort of 23 neuroendocrine tumor (NET) patients with liver-dominant metastatic disease undergoing radioembolization with (90)Y microspheres as a salvage therapy after failed PRRT. Toxicity was recorded throughout follow-up and reported according to Common Terminology Criteria for Adverse Events (version 3). Radiologic (response evaluation criteria in solid tumors), biochemical, and symptomatic responses were investigated at 3 mo after treatment, and survival analyses were performed with the Kaplan-Meier method (log-rank test, P < 0.05).
  
  
  RESULTS
  The median follow-up period after radioembolization was 38 mo (95% confidence interval, 18-58 mo). The mean previous cumulative activity of (177)Lu-DOTA-octreotate was 31.8 GBq. The mean cumulative treatment activity of (90)Y microspheres was 3.4 ± 2.1 GBq, administered to the whole liver in a single session (n = 8 patients), in a sequential lobar fashion (n = 10 patients), or to only 1 liver lobe (n = 5 patients). Only transient, mostly minor liver toxicity (no grade 4) was recorded. One patient (4.3%) developed a gastroduodenal ulcer (grade 2). The overall response rates for radiologic, biochemical, and symptomatic responses were 30.4%, 53.8%, and 80%, respectively. The median overall survival was 29 mo (95% confidence interval, 4-54 mo) from the first radioembolization session and 54 mo (95% confidence interval, 47-61 mo) from the first PRRT cycle. A tumor proliferation index Ki-67 greater than 5% predicted shorter survival (P = 0.007).
  
  
  CONCLUSIONS
  Radioembolization is a safe and effective salvage treatment option in advanced NET patients with liver-dominant tumor burden who failed or reprogressed after PRRT. The lack of relevant liver toxicity despite high applied (90)Y activities and considerable previous cumulative activities of (177)Lu-octreotate is noteworthy and disputes internal radiation exposure by PRRT as a toxicity risk factor in subsequent radioembolization.
authors.affiliation: Nuclear Medicine, University Hospital, Bonn, Germany. samer.ezziddin@ukb.uni-bonn.de
authors.forename: Samer
authors.initials: S
authors.lastname: Ezziddin
authors.forename: Carsten
authors.initials: C
authors.lastname: Meyer
authors.forename: Stanislawa
authors.initials: S
authors.lastname: Kahancova
authors.forename: Torjan
authors.initials: T
authors.lastname: Haslerud
authors.forename: Winfried
authors.initials: W
authors.lastname: Willinek
authors.forename: Kai
authors.initials: K
authors.lastname: Wilhelm
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Biersack
authors.forename: Hojjat
authors.initials: H
authors.lastname: Ahmadzadehfar
mesh_terms: D000704:Analysis of Variance; D004621:Embolization, Therapeutic / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000532:radiotherapy / Q000556:secondary / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000473:pathology; D018000:Receptors, Peptide / Q000378:metabolism*; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000009:adverse effects / Q000379:methods*; D015021:Yttrium Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D018000:Receptors, Peptide; D015021:Yttrium Radioisotopes