title: Acceptable toxicity after stereotactic body radiation therapy for liver tumors adjacent to the central biliary system.
abstract: OBJECTIVE
  To evaluate biliary toxicity after stereotactic body radiation therapy (SBRT) for liver tumors.
  
  
  METHODS
  Among 297 consecutive patients with liver tumors treated with SBRT of 35 to 50 Gy in 5 fractions, patients who were irradiated with >20 Gy to the central biliary system (CBS), including the gallbladder, and had follow-up times >6 months were retrospectively analyzed. Toxicity profiles, such as clinical symptoms and laboratory and radiologic data especially for obstructive jaundice and biliary infection, were investigated in relation to the dose volume and length relationship for each biliary organ.
  
  
  RESULTS
  Fifty patients with 55 tumors were irradiated with >20 Gy to the CBS. The median follow-up period was 18.2 months (range, 6.0-80.5 months). In the dose length analysis, 39, 34, 14, and 2 patients were irradiated with >20 Gy, >30 Gy, >40 Gy, and >50 Gy, respectively, to >1 cm of the biliary tract. Seven patients were irradiated with >20 Gy to >20% of the gallbladder. Only 2 patients experienced asymptomatic bile duct stenosis. One patient, metachronously treated twice with SBRT for tumors adjacent to each other, had a transient increase in hepatic and biliary enzymes 12 months after the second treatment. The high-dose area >80 Gy corresponded to the biliary stenosis region. The other patient experienced biliary stenosis 5 months after SBRT and had no laboratory changes. The biliary tract irradiated with >20 Gy was 7 mm and did not correspond to the bile duct stenosis region. No obstructive jaundice or biliary infection was found in any patient.
  
  
  CONCLUSIONS
  SBRT for liver tumors adjacent to the CBS was feasible with minimal biliary toxicity. Only 1 patient had exceptional radiation-induced bile duct stenosis. For liver tumors adjacent to the CBS without other effective treatment options, SBRT at a dose of 40 Gy in 5 fractions is a safe treatment with regard to biliary toxicity.
authors.affiliation: Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Eriguchi
authors.forename: Atsuya
authors.initials: A
authors.lastname: Takeda
authors.forename: Naoko
authors.initials: N
authors.lastname: Sanuki
authors.forename: Yohei
authors.initials: Y
authors.lastname: Oku
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Aoki
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Shigematsu
authors.forename: Etsuo
authors.initials: E
authors.lastname: Kunieda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001659:Biliary Tract / Q000528:radiation effects*; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000601:surgery*; D003251:Constriction, Pathologic / Q000209:etiology; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D005260:Female; D005704:Gallbladder / Q000528:radiation effects; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D011832:Radiation Injuries / Q000150:complications*; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies