title: Severe intestinal toxicity after stereotactic ablative radiotherapy for abdominopelvic malignancies.
abstract: OBJECTIVE
  The purpose of this study is to identify the predictors for severe intestinal toxicity (IT) in patients with abdominopelvic malignancies treated with three fractions of stereotactic ablative radiotherapy (SABR).
  
  
  METHODS
  From 2001 to 2011, 202 patients with abdominopelvic malignancies were treated with curative-intent SABR. Among these, we retrospectively reviewed the clinical records of 55 patients with the presence of the intestine that received a dose ≥20 % of the prescribed dose. The total dose ranged from 33 to 60 Gy in three fractionations (median dose, 45 Gy). We analyzed the clinical and dosimetric parameters for severe IT ≥ grade 3 according to the National Cancer Institute Common Toxicity Criteria v4.0: V(20-35) (volume of the intestine that received xGy) and D(max) (maximum point dose).
  
  
  RESULTS
  Severe IT was found in six patients (the median time, 3 months). V(25) was the best dosimetric predictor for severe IT (P = 0.004). With V(25) ≤ 20 ml, severe IT decreased from 50 to 4 %. SABR duration was the best clinical predictor. Severe IT decreased in patients who received SABR at 4-8 days than on three consecutive days (0 vs. 18 %, P = 0.037).
  
  
  CONCLUSIONS
  Following three fractions of SABR, V(25) is a valuable predictor of severe IT. And SABR would be conducted with a treatment interval of at least 48 h if possible.
authors.affiliation: Department of Radiation Oncology, Korea Institute of Radiological & Medical Sciences, and Kyung Hee University Hospital at Kangdong, Seoul, Republic of Korea.
authors.forename: Sun Hyun
authors.initials: SH
authors.lastname: Bae
authors.forename: Mi-Sook
authors.initials: MS
authors.lastname: Kim
authors.forename: So Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Won Il
authors.initials: WI
authors.lastname: Jang
authors.forename: Chul Koo
authors.initials: CK
authors.lastname: Cho
authors.forename: Hyung Jun
authors.initials: HJ
authors.lastname: Yoo
authors.forename: Kum Bae
authors.initials: KB
authors.lastname: Kim
authors.forename: Dong Han
authors.initials: DH
authors.lastname: Lee
authors.forename: Chul Ju
authors.initials: CJ
authors.lastname: Han
authors.forename: Ki Young
authors.initials: KY
authors.lastname: Yang
authors.forename: Sang Bum
authors.initials: SB
authors.lastname: Kim
mesh_terms: D000008:Abdominal Neoplasms / Q000473:pathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007422:Intestines / Q000473:pathology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010386:Pelvic Neoplasms / Q000473:pathology / Q000601:surgery*; D011379:Prognosis; D016634:Radiosurgery / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D056910:Republic of Korea; D016896:Treatment Outcome