title: Dose to organs at risk in the upper abdomen in patients treated with extended fields by helical tomotherapy: a dosimetric and clinical preliminary study.
abstract: BACKGROUND
  The aim of this work was to determine the technical feasibility and safety of extended-field radiotherapy (EF), performed by Helical TomoTherapy, in patients with positive pelvic and/or para-aortic nodes. Dosimetric data were collected and acute and sub-acute toxicities of the upper abdominal organs at risk (OAR) were evaluated.
  
  
  METHODS
  Twenty-nine patients suitable for EF irradiation for local disease and/or nodal disease in the pelvic or para-aortic area were treated. The prescription dose was 50.4/54 Gy (1.7-1.8 Gy/fraction) for prophylactic lymph nodes (N-) and 60-70.5 Gy (2-2.35 Gy/fraction) for clinically evident gross disease (N+). Modulation factor (MF), pitch and field width (FW) were chosen to optimize dose distribution and treatment duration. Dose values of PTVs and OAR were analysed. The length of the treatment field, the N + and N- volumes, and treatment duration were reported. To evaluate the safety of treatment, haematological, hepatic, renal and pancreatic functions were assessed before, during and after treatment. The median follow-up time was 17.6 months (range: 6-22 months).
  
  
  RESULTS
  The treatment was well tolerated and all patients but one completed treatment without interruption. Four of the 29 patients experienced G3 haematological acute toxicity (13.8%), but no patient experienced sub-acute grade G3 toxicity. Ten patients experienced G1 and three G2 acute gastrointestinal toxicity (nausea). No sub-acute gastrointestinal or renal toxicity was observed. Only one (3.7%) patient had a persistent slight increase of pancreatic enzymes and two (7.4%) patients a slight increase of hepatic enzymes six months after radiotherapy (G1 toxicity).
  
  
  CONCLUSIONS
  With our treatment design and dose regimen, we found that EF treatment by TomoTherapy could be safely and effectively delivered with minimal acute and sub-acute toxicities in the upper abdomen area.
authors.affiliation: Department of Medical Physics, Institute for Cancer Research and Treatment (IRCCS) at Candiolo, Turin, Italy. sara.bresciani@ircc.it.
authors.forename: Sara
authors.initials: S
authors.lastname: Bresciani
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Garibaldi
authors.forename: Gabriella
authors.initials: G
authors.lastname: Cattari
authors.forename: Angelo
authors.initials: A
authors.lastname: Maggio
authors.forename: Amalia
authors.initials: A
authors.lastname: Di Dia
authors.forename: Elena
authors.initials: E
authors.lastname: Delmastro
authors.forename: Domenico
authors.initials: D
authors.lastname: Gabriele
authors.forename: Michele
authors.initials: M
authors.lastname: Stasi
authors.forename: Pietro
authors.initials: P
authors.lastname: Gabriele
mesh_terms: D000005:Abdomen / Q000528:radiation effects*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016889:Endometrial Neoplasms / Q000532:radiotherapy; D005260:Female; D005500:Follow-Up Studies; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D008099:Liver / Q000201:enzymology; D008198:Lymph Nodes / Q000528:radiation effects; D008207:Lymphatic Metastasis / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk; D010179:Pancreas / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D013997:Time Factors; D016896:Treatment Outcome