title: Dosimetric planning study for the prevention of anal complications after post-operative whole pelvic radiotherapy in cervical cancer patients with hemorrhoids.
abstract: OBJECTIVE
  Radiation-induced anal toxicity can be induced by low radiation doses in patients with haemorrhoids. The object of this study was to determine the dosimetric benefits of different whole pelvic radiotherapy (WPRT) techniques in terms of dose delivered to the anal canal in post-operative patients with cervical cancer.
  
  
  METHODS
  The planning CT images of 10 patients with cervical cancer undergoing postoperative radiotherapy were used for comparison of three different plans. All patients had been treated using the conventional box technique WPRT (CV-WPRT), and we tried low-margin-modified WPRT (LM-WPRT), three-dimensional conformal techniques WPRT (CF-WPRT) and intensity-modulated WPRT (IM-WPRT) planning for dosimetric comparison of the anal canal, retrospectively.
  
  
  RESULTS
  Mean anal canal doses of the IM-WPRT were significantly lower (p < 0.05) than those of CV-WPRT, LM-WPRT and CF-WPRT, and V10, V20, V30 and V40 to the anal canal were also significantly lower for IM-WPRT (p < 0.05). The proportion of planning target volumes (PTVs) that received ≥98% of the prescribed dose for all plans was >99%, and the proportion that received ≥108% of the prescribed dose for IM-WPRT was <2%. Volumes of bladders and rectums that received ≥30 or ≥40 Gy were significantly lower for IM-WPRT than for three of the four-field WPRT plans (p = 0.000).
  
  
  CONCLUSIONS
  IM-WPRT can significantly reduce radiation dose delivered to the anal canal and does not compromise PTV coverage. In patients with haemorrhoids, IM-WPRT may be of value for the prevention of anal complications.
  
  
  CONCLUSIONS
  Although tolerance of the anal canal tends to be ignored in patients undergoing post-operative WPRT, patients with haemorrhoids may suffer complications at low radiation doses. The present study shows IM-WPRT can be meaningful in these patients.
authors.affiliation: 1 Department of Radiation Oncology, Dongguk University Gyeongju Hospital, Gyeongju, Republic of Korea.|2 Department of Physics, Yeungnam University, Gyeongsan, Republic of Korea.
authors.forename: J G
authors.initials: JG
authors.lastname: Baek
authors.affiliation: 2 Department of Physics, Yeungnam University, Gyeongsan, Republic of Korea.
authors.forename: E C
authors.initials: EC
authors.lastname: Kim
authors.affiliation: 3 Department of Radiation Oncology, Yeungnam University College of Medicine, Daegu, Republic of Korea.
authors.forename: S K
authors.initials: SK
authors.lastname: Kim
authors.affiliation: 1 Department of Radiation Oncology, Dongguk University Gyeongju Hospital, Gyeongju, Republic of Korea.
authors.forename: H
authors.initials: H
authors.lastname: Jang
mesh_terms: D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000528:radiation effects*; D005260:Female; D006484:Hemorrhoids / Q000150:complications*; D006801:Humans; D008875:Middle Aged; D010388:Pelvis / Q000528:radiation effects; D011832:Radiation Injuries / Q000517:prevention & control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D002583:Uterine Cervical Neoplasms / Q000150:complications* / Q000532:radiotherapy*