title: Involved-nodal radiation therapy leads to lower doses to critical organs-at-risk compared to involved-field radiation therapy.
abstract: BACKGROUND
  Involved field radiotherapy (IFRT) after cytotoxic chemotherapy has become the standard of care in treating pediatric patients with Hodgkin lymphoma. However, recent interest in shrinking the treatment volume to involved node radiotherapy (INRT) may allow lower doses to critical organ structures. We dosimetrically compared IFRT and INRT treatment approaches.
  
  
  METHODS
  INRT treatment plans were retrospectively constructed from 17 consecutively treated pediatric patients identified with Hodgkin lymphoma who had been previously treated with conventional IFRT. The radiation doses delivered to organs-at-risk (OARs) with virtual INRT treatment plans based on INRT field design were then compared to the original IFRT treatment plans. Metrics for comparison included mean doses to organs and volumes of organ receiving at least 50% of the original prescription dose (V50%). A one-tailed, paired t-test was then performed to verify statistical significance at an alpha level of 0.05.
  
  
  RESULTS
  All organs at risk compared in this investigation (kidneys, heart, thyroid, parotids, and lungs) had significantly lower doses of radiation with INRT when compared to IFRT (p<0.05). Furthermore, the volume of the breast receiving at least 50% of the initial prescription dose was statistically lower in the INRT plans.
  
  
  CONCLUSIONS
  Utilizing the concept of INRT results in a reduction of radiation dose to critical organ structures in pediatric patients with Hodgkin lymphoma when compared to the more traditional method of IFRT.
authors.affiliation: Dept of Radiation Oncology, Rutgers Cancer Institute of NJ, New Brunswick, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Mulvihill
authors.affiliation: Dept of Radiation Oncology, Rutgers Cancer Institute of NJ, New Brunswick, United States.
authors.forename: Kevin
authors.initials: K
authors.lastname: McMichael
authors.affiliation: Dept of Radiation Oncology, Rutgers Cancer Institute of NJ, New Brunswick, United States.
authors.forename: Sharad
authors.initials: S
authors.lastname: Goyal
authors.affiliation: Dept of Pediatric Oncology, Rutgers Cancer Institute of NJ, New Brunswick, United States.
authors.forename: Richard
authors.initials: R
authors.lastname: Drachtman
authors.affiliation: Dept of Pediatric Oncology, Rutgers Cancer Institute of NJ, New Brunswick, United States.
authors.forename: Aaron
authors.initials: A
authors.lastname: Weiss
authors.affiliation: Dept of Radiation Oncology, Rutgers Cancer Institute of NJ, New Brunswick, United States. Electronic address: khanat@cinj.rutgers.edu.
authors.forename: Atif J
authors.initials: AJ
authors.lastname: Khan
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D059248:Chemoradiotherapy; D006689:Hodgkin Disease / Q000188:drug therapy / Q000532:radiotherapy*; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects*; D008207:Lymphatic Metastasis; D058958:Organs at Risk / Q000528:radiation effects; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies
keywords: Hodgkin lymphoma; INRT; Involved nodal radiation therapy