title: Safety of 90Y radioembolization in patients who have undergone previous external beam radiation therapy.
abstract: OBJECTIVE
  Previous external beam radiation therapy (EBRT) is theoretically contraindicated for yttrium-90 ((90)Y) radioembolization (RE) because the liver has a lifetime tolerance to radiation before becoming vulnerable to radiation-induced liver disease. We analyzed the safety of RE as salvage treatment in patients who had previously undergone EBRT.
  
  
  METHODS
  Between June 2004 and December 2010, a total of 31 patients who had previously undergone EBRT were treated with RE. Three-dimensional treatment planning with dose-volume histogram (DVH) analysis of the liver was used to calculate the EBRT liver dose. Liver-related toxicities including RE-induced liver disease (REILD) were reviewed and classified according to Common Terminology Criteria for Adverse Events version 4.02.
  
  
  RESULTS
  The mean EBRT and RE liver doses were 4.40 Gy (range, 0-23.13 Gy) and 57.9 Gy (range, 27.0-125.9 Gy), respectively. Patients who experienced hepatotoxicity (≥grade2; n=12) had higher EBRT mean liver doses (7.96 ± 8.55 Gy vs 1.62 ± 3.39 Gy; P=.037), the only independent predictor in multivariate analysis. DVH analysis showed that the fraction of liver exposed to ≥30 Gy (V30) was the strongest predictor of hepatotoxicity (10.14% ± 12.75% vs 0.84% ± 3.24%; P=.006). All patients with V30 >13% experienced hepatotoxicity. Fatal REILD (n=2) occurred at the 2 highest EBRT mean liver doses (20.9 Gy and 23.1 Gy) but also at the highest cumulative liver doses (91.8 Gy and 149 Gy).
  
  
  CONCLUSIONS
  Prior exposure of the liver to EBRT may lead to increased liver toxicity after RE treatment, depending on fractional liver exposure and dose level. The V30 was the strongest predictor of toxicity. RE appears to be safe for the treatment of hepatic malignancies only in patients who have had limited hepatic exposure to prior EBRT.
authors.affiliation: Division of Interventional Radiology, Stanford University School of Medicine, Stanford, California 94305-5642, USA.
authors.forename: Marnix G E H
authors.initials: MG
authors.lastname: Lam
authors.forename: Mohamed H K
authors.initials: MH
authors.lastname: Abdelmaksoud
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Chang
authors.forename: Neville C
authors.initials: NC
authors.lastname: Eclov
authors.forename: Melody P
authors.initials: MP
authors.lastname: Chung
authors.forename: Albert C
authors.initials: AC
authors.lastname: Koong
authors.forename: John D
authors.initials: JD
authors.lastname: Louie
authors.forename: Daniel Y
authors.initials: DY
authors.lastname: Sze
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D008099:Liver / Q000528:radiation effects*; D008113:Liver Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D011836:Radiation Tolerance; D019233:Retreatment / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000009:adverse effects / Q000379:methods*; D015021:Yttrium Radioisotopes / Q000009:adverse effects*
chemical_list: D015021:Yttrium Radioisotopes