title: A systematic review of contralateral liver lobe hypertrophy after unilobar selective internal radiation therapy with Y90.
abstract: BACKGROUND
  A curative liver resection is the treatment of choice for both primary and secondary liver malignancies. However, an inadequate future liver remnant (FLR) frequently precludes successful surgery. Portal vein embolization is the gold-standard modality for inducing hypertrophy of the FLR. In recent times, unilobar Yttrium-90 selective internal radiation therapy (SIRT) has been reported to induce hypertrophy of the contralateral, untreated liver lobe. The aim of this study was to review the current literature reporting on contralateral liver hypertrophy induced by unilobar SIRT.
  
  
  METHODS
  A systematic review of the English-language literature between 2000 and 2014 was performed using the search terms 'Yttrium 90' OR 'selective internal radiation therapy' OR 'radioembolization' AND 'hypertrophy'.
  
  
  RESULTS
  Seven studies, reporting on 312 patients, were included. Two hundred and eighty-four patients (91.0%) received treatment to the right lobe. Two hundred and fifteen patients had hepatocellular carcinoma (HCC), 12 had intrahepatic cholangiocarcinoma and 85 had liver metastases from mixed primaries. Y90 SIRT resulted in contralateral liver hypertrophy that ranged from 26% to 47% at 44 days to 9 months. All studies were retrospective in nature, and heterogeneous, with substantial variations relative to pathology treated, underlying liver disease, dosage and delivery of Y90, the number of treatment sessions and time to measurement of hypertrophy.
  
  
  CONCLUSIONS
  Unilobar Y90 SIRT results in significant hypertrophy of the contralateral liver lobe. The rate of hypertrophy seems to be slower than that achieved by other methods.
authors.affiliation: Department of Hepatopancreatobiliary and Transplantation Surgery, Singapore General Hospital, Singapore.
authors.forename: Jin-Yao
authors.initials: JY
authors.lastname: Teo
authors.affiliation: Duke-NUS Graduate Medical School Singapore, Singapore.
authors.forename: John C
authors.initials: JC
authors.lastname: Allen
authors.affiliation: Department of Nuclear Medicine, Singapore General Hospital, Singapore.
authors.forename: David C
authors.initials: DC
authors.lastname: Ng
authors.affiliation: Division of Medical Oncology, National Cancer Center Singapore, Singapore.
authors.forename: Su-Pin
authors.initials: SP
authors.lastname: Choo
authors.affiliation: Division of Medical Oncology, National Cancer Center Singapore, Singapore.
authors.forename: David W M
authors.initials: DW
authors.lastname: Tai
authors.affiliation: Department of Gastroenterology and Hepatology, Singapore General Hospital, Singapore.
authors.forename: Jason P E
authors.initials: JP
authors.lastname: Chang
authors.affiliation: Department of Radiology, Singapore General Hospital, Singapore.
authors.forename: Foong-Khoon
authors.initials: FK
authors.lastname: Cheah
authors.affiliation: Department of Hepatopancreatobiliary and Transplantation Surgery, Singapore General Hospital, Singapore.|Duke-NUS Graduate Medical School Singapore, Singapore.
authors.forename: Pierce K H
authors.initials: PK
authors.lastname: Chow
authors.affiliation: Department of Hepatopancreatobiliary and Transplantation Surgery, Singapore General Hospital, Singapore.|Duke-NUS Graduate Medical School Singapore, Singapore.
authors.forename: Brian K P
authors.initials: BK
authors.lastname: Goh