title: Late rectal complications evaluated by computed tomography-based dose calculations in patients with cervical carcinoma undergoing high-dose-rate brachytherapy.
abstract: OBJECTIVE
  To investigate the efficacy of dose calculations at the computed tomography (CT)-based rectal point (CTRP) as a predictive factor for late rectal complications in patients with cervical carcinoma who were treated with a combination of high-dose-rate intracavitary brachytherapy and external beam radiotherapy.
  
  
  METHODS
  Ninety-two patients with uterine cervical carcinoma undergoing definitive radiotherapy alone were retrospectively analyzed. The median follow-up time for all patients was 32 months (range, 13-60 months). The cumulative biologically effective dose (BED) was calculated at the rectal reference point as defined by the International Commission on Radiation Units and Measurements Report 38 (BED(RP)) and at the CTRP (BED(CTRP)). Late rectal complications were recorded according to the Radiation Therapy Oncology Group grading system.
  
  
  RESULTS
  The late rectal complications were distributed as follows: Grade 0, 68 patients (74%); Grade 1, 20 patients (22%); Grade 2, 4 patients (4%). Univariate analysis showed that BED(RP), BED(CTRP), RP dose/point A dose ratio, and CTRP dose/point A dose ratio were significantly correlated with late rectal complications (p < 0.05). On multivariate analysis, patients with a rectal BED(CTRP) >/=140 Gy(3) presented with significantly greater frequency of rectal complications (p = 0.031).
  
  
  CONCLUSIONS
  The present results suggest that BED(CTRP) is a useful predictive factor for late rectal complications.
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Anagawa, Chiba, Japan.
authors.forename: Shin-Ei
authors.initials: SE
authors.lastname: Noda
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ohno
authors.forename: Shingo
authors.initials: S
authors.lastname: Kato
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ishii
authors.forename: Osami
authors.initials: O
authors.lastname: Saito
authors.forename: Masaru
authors.initials: M
authors.lastname: Wakatsuki
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tamaki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Tsujii
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001918:Brachytherapy / Q000009:adverse effects*; D018196:Carcinoma, Adenosquamous / Q000473:pathology / Q000532:radiotherapy; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D011879:Radiotherapy Dosage; D012007:Rectum / Q000000981:diagnostic imaging / Q000528:radiation effects*; D012062:Relative Biological Effectiveness; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000532:radiotherapy*