title: Minimising critical organ irradiation in limited stage Hodgkin lymphoma: a dosimetric study of the benefit of involved node radiotherapy.
abstract: BACKGROUND
  Chemotherapy plus radiotherapy is the standard of care for patients with limited stage Hodgkin lymphoma (HL). Radiotherapy is evolving from involved field radiotherapy (IFRT) to involved node radiotherapy (INRT) to decrease radiotherapy-related morbidity. In the absence of long-term toxicity data, dose-volume metrics of organs at risk (OAR) provide a surrogate measure of toxicity risk.
  
  
  METHODS
  Ten female patients with stage I-IIA supradiaphragmatic HL were randomly selected. All patients had pre-chemotherapy computerised tomography (CT) and CT-positron emission tomography staging. Using CT planning, three radiotherapy plans were produced per patient: (i) IFRT, (ii) INRT using parallel-opposed beams and (iii) INRT using volumetric modulated arc therapy (VMAT). Radiotherapy dose was 30.6 Gy in 1.8 Gy fractions. OAR evaluated were lungs, breasts, thyroid, heart and coronary arteries.
  
  
  RESULTS
  Compared with IFRT, INRT significantly reduced mean doses to lungs (P < 0.01), breasts (P < 0.01), thyroid (P < 0.01) and heart (P < 0.01), on Wilcoxon testing. Compared with conventional INRT, VMAT improved dose conformality but increased low-dose radiation exposure to lungs and breasts. VMAT reduced the heart volume receiving 30 Gy (V30) by 85%.
  
  
  CONCLUSIONS
  Reduction from IFRT to INRT decreased the volumes of lungs, breasts and thyroid receiving high-dose radiation, suggesting the potential to reduce long-term second malignancy risks. VMAT may be useful for patients with pre-existing heart disease by minimising further cardiac toxicity risks.
authors: Department of Radiation Oncology and Cancer Imaging. Electronic address: Belinda.Campbell@petermac.org.
authors: B A
authors: BA
authors: Campbell
authors: Department of Radiotherapy.
authors: C
authors: C
authors: Hornby
authors: Department of Radiotherapy.
authors: J
authors: J
authors: Cunninghame
authors: Department of Radiotherapy.
authors: M
authors: M
authors: Burns
authors: Department of Radiation Oncology and Cancer Imaging.
authors: M
authors: M
authors: MacManus
authors: Department of Radiation Oncology and Cancer Imaging.
authors: G
authors: G
authors: Ryan
authors: Centre for Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne; Department of Radiology, University of Melbourne, Parkville.
authors: E
authors: E
authors: Lau
authors: Department of Haematology, Peter MacCallum Cancer Centre, Melbourne; Department of Medicine, University of Melbourne, Parkville, Australia.
authors: J F
authors: JF
authors: Seymour
authors: Department of Radiation Oncology and Cancer Imaging.
authors: A
authors: A
authors: Wirth
mesh_terms: D000328:Adult; D003964:Diaphragm / Q000473:pathology / Q000528:radiation effects; D005260:Female; D006689:Hodgkin Disease / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects; D015182:Lymphatic Irradiation / Q000009:adverse effects* / Q000379:methods; D008207:Lymphatic Metastasis / Q000532:radiotherapy; D008875:Middle Aged; D059351:Organ Sparing Treatments / Q000379:methods*; D058958:Organs at Risk / Q000528:radiation effects*; D011832:Radiation Injuries / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000009:adverse effects / Q000379:methods*; D018570:Risk Assessment; D055815:Young Adult