title: Novel radiotherapy techniques for involved-field and involved-node treatment of mediastinal Hodgkin lymphoma: when should they be considered and which questions remain open?
abstract: OBJECTIVE
  Hodgkin lymphoma (HL) is a highly curable disease. Reducing late complications and second malignancies has become increasingly important. Radiotherapy target paradigms are currently changing and radiotherapy techniques are evolving rapidly.
  
  
  METHODS
  This overview reports to what extent target volume reduction in involved-node (IN) and advanced radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy-compared with involved-field (IF) and 3D radiotherapy (3D-RT)- can reduce high doses to organs at risk (OAR) and examines the issues that still remain open.
  
  
  RESULTS
  Although no comparison of all available techniques on identical patient datasets exists, clear patterns emerge. Advanced dose-calculation algorithms (e.g., convolution-superposition/Monte Carlo) should be used in mediastinal HL. INRT consistently reduces treated volumes when compared with IFRT with the exact amount depending on the INRT definition. The number of patients that might significantly benefit from highly conformal techniques such as IMRT over 3D-RT regarding high-dose exposure to organs at risk (OAR) is smaller with INRT. The impact of larger volumes treated with low doses in advanced techniques is unclear. The type of IMRT used (static/rotational) is of minor importance. All advanced photon techniques result in similar potential benefits and disadvantages, therefore only the degree-of-modulation should be chosen based on individual treatment goals. Treatment in deep inspiration breath hold is being evaluated. Protons theoretically provide both excellent high-dose conformality and reduced integral dose.
  
  
  CONCLUSIONS
  Further reduction of treated volumes most effectively reduces OAR dose, most likely without disadvantages if the excellent control rates achieved currently are maintained. For both IFRT and INRT, the benefits of advanced radiotherapy techniques depend on the individual patient/target geometry. Their use should therefore be decided case by case with comparative treatment planning.
authors.affiliation: Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany, Frank.Lohr@umm.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Lohr
authors.forename: Dietmar
authors.initials: D
authors.lastname: Georg
authors.forename: Luca
authors.initials: L
authors.lastname: Cozzi
authors.forename: Hans Theodor
authors.initials: HT
authors.lastname: Eich
authors.forename: Damien C
authors.initials: DC
authors.lastname: Weber
authors.forename: Julia
authors.initials: J
authors.lastname: Koeck
authors.forename: Barbara
authors.initials: B
authors.lastname: Knäusl
authors.forename: Karin
authors.initials: K
authors.lastname: Dieckmann
authors.forename: Yasser
authors.initials: Y
authors.lastname: Abo-Madyan
authors.forename: Christian
authors.initials: C
authors.lastname: Fiandra
authors.forename: Rolf-Peter
authors.initials: RP
authors.lastname: Mueller
authors.forename: Andreas
authors.initials: A
authors.lastname: Engert
authors.forename: Umberto
authors.initials: U
authors.lastname: Ricardi
mesh_terms: D019317:Evidence-Based Medicine; D005858:Germany; D006689:Hodgkin Disease / Q000532:radiotherapy*; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects*; D008479:Mediastinal Neoplasms / Q000532:radiotherapy*; D008495:Medical Oncology / Q000592:standards*; D017410:Practice Guidelines as Topic; D020266:Radiotherapy, Conformal / Q000379:methods* / Q000592:standards*; D016896:Treatment Outcome