Abstract 80: Hodgkin‘s lymphoma advanced radiation treatment techniques: balance between late effects and secondary malignant neoplasms risk.
Authors: Cella Laura , Conson Manuel , Pressello Maria Cristina , Molinelli Silvia , Donato Vittorio , Orecchia Roberto , Schnaider Uwe , Salvatore Marco , Pacelli Roberto 
Published: August 2014

Abstract
Purpose
In the past decades, treatment improvements have made Hodgkin's lymphoma (HL) one of the most curable malignancies. However, due to the low patients mean age, the combined use of potentially harmful therapeutic agents, and the efficiency of the therapy that allows a high cure rate with a long life span expectation, late effects of HL treatment represent an important and considerable threat for this specific patient population. Technological advances, such as intensity modulated radiotherapy (IMRT) or Tomotherapy, in Hodgkin's lymphoma (HL) radiation therapy by high conformal treatments considerably increased normal tissue sparing and control over organs-at-risk (OAR) dose distribution. However concern raised about the increased volume of tissues exposed to low radiation doses. Different radiotherapy (RT) techniques for Hodgkin's lymphoma (HL) were analyzed to clarify the trade-offs between radio-induced toxicities and second cancer induction risk.
Methods and Materials
Three different size planning target volume (PTVi) scenarios from a planning CT scan of a representative female patient with supradiaphragmatic HL were generated. Five plans were simulated for each PTVi: a conventional parallel-opposed (AP-PA) plan, a forward intensity modulated plan (FIMRT), an inverse intensity modulated plan (IMRT), a Tomotherapy plan (TOMO), a proton plan (PRO). A radiation dose of 30 Gy or cobalt gray equivalent (CGE) was prescribed. Dose-volume histograms of PTVs and organs at risk (OARs) were calculated and related to available dose-volume constraints (DVCs). Second malignant neoplasm (SMN) risk for breasts, thyroid, and lungs was estimated through the Organ Equivalent Dose (OED) model.
Results
With similar level of PTVi coverage, for PTV1 and PTV2 scenarios, the DVCs were respected by all plans except for whole-heart-V25 for which only TOMO and PRO plans were able to reduce it under 10%. In PTV3 scenario AP-PA, only TOMO and PRO plans were compliant with all constraints.
In all scenarios, the IMRT and TOMO increased the risk of development of breast, thyroid, and lung SMN compared with AP-PA technique. Only PRO plans succeeded in reducing the risk of predicted SMN compared with AP-PA technique.
Conclusions
Advanced RT techniques can be successfully used in HL patients to better spare OARs. However, the estimated increased SMN risk inherent to TOMO and IMRT techniques must be carefully considered.
Citation Format: Laura Cella, Manuel Conson, Maria Cristina Pressello, Silvia Molinelli, Vittorio Donato, Roberto Orecchia, Uwe Schnaider, Marco Salvatore, Roberto Pacelli. Hodgkin‘s lymphoma advanced radiation treatment techniques: balance between late effects and secondary malignant neoplasms risk. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 80. doi:10.1158/1538-7445.AM2013-80