title: The different volume effects of small-bowel toxicity during pelvic irradiation between gynecologic patients with and without abdominal surgery: a prospective study with computed tomography-based dosimetry.
abstract: OBJECTIVE
  To evaluate the effect of abdominal surgery on the volume effects of small-bowel toxicity during whole-pelvic irradiation in patients with gynecologic malignancies.
  
  
  METHODS
  From May 2003 through November 2006, 80 gynecologic patients without (Group I) or with (Group II) prior abdominal surgery were analyzed. We used a computed tomography (CT) planning system to measure the small-bowel volume and dosimetry. We acquired the range of small-bowel volume in 10% (V10) to 100% (V100) of dose, at 10% intervals. The onset and grade of diarrhea during whole-pelvic irradiation were recorded as small-bowel toxicity up to 39.6 Gy in 22 fractions.
  
  
  RESULTS
  The volume effect of Grade 2-3 diarrhea existed from V10 to V100 in Group I patients and from V60 to V100 in Group II patients on univariate analyses. The V40 of Group I and the V100 of Group II achieved most statistical significance. The mean V40 was 281 +/- 27 cm(3) and 489 +/- 34 cm(3) (p < 0.001) in Group I patients with Grade 0-1 and Grade 2-3 diarrhea, respectively. The corresponding mean V100 of Group II patients was 56 +/- 14 cm(3) and 132 +/- 19 cm(3) (p = 0.003). Multivariate analyses revealed that V40 (p = 0.001) and V100 (p = 0.027) were independent factors for the development of Grade 2-3 diarrhea in Groups I and II, respectively.
  
  
  CONCLUSIONS
  Gynecologic patients without and with abdominal surgery have different volume effects on small-bowel toxicity during whole-pelvic irradiation. Low-dose volume can be used as a predictive index of Grade 2 or greater diarrhea in patients without abdominal surgery. Full-dose volume is more important than low-dose volume for Grade 2 or greater diarrhea in patients with abdominal surgery.
authors.affiliation: Department of Radiation Oncology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan.
authors.forename: Eng-Yen
authors.initials: EY
authors.lastname: Huang
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Sung
authors.forename: Sheung-Fat
authors.initials: SF
authors.lastname: Ko
authors.forename: Chong-Jong
authors.initials: CJ
authors.lastname: Wang
authors.forename: Kuender D
authors.initials: KD
authors.lastname: Yang
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000368:Aged; D000704:Analysis of Variance; D003967:Diarrhea / Q000145:classification / Q000209:etiology*; D019583:Dose Fractionation, Radiation; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D007421:Intestine, Small / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects*; D008875:Middle Aged; D010388:Pelvis; D011446:Prospective Studies; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy