Breath-hold technique in conventional APPA or intensity-modulated radiotherapy for Hodgkin's lymphoma. Comparison of ILROG IS-RT and the GHSG IF-RT

The present study addresses the role of intensity-modulated radiotherapy (IMRT) in contrast to standard RT (APPA) for patients with Hodgkin's lymphoma (HL) with a focus on deep inspiration breath-hold (DIBH) technique and a comparison between the International Lymphoma Radiation Oncology Group (ILROG) Involved Site Radiotherapy (IS-RT) versus the German Hodgkin Study Group (GHSG) Involved Field Radiotherapy (IF-RT). APPA treatment and 2 IMRT plans were compared for 11 patients with HL. Furthermore, treatment with DIBH versus free breathing (FB) and two different treatment volumes, i.e. IF-RT versus IS-RT, were compared. IMRT was planned as a sliding-window technique with 5 and 7 beam angles. For each patient 12 different treatment plans were calculated (132 plans). Following organs at risk (OAR) were analysed: lung, heart, spinal cord, oesophagus, female breast and skin. Comparisons of the different values with regard to dose-volume histograms (DVH), conformity and homogeneity indices were made. IS-RT reduces treatment volumes. With respect to the planning target volume (PTV), IMRT achieves better conformity but the same homogeneity. Regarding the D_mean for the lung, IMRT shows increased doses, while RT in DIBH reduces doses. The IMRT shows improved values for D_max concerning the spinal cord, whereas the APPA shows an improved D_mean of the lung and the female breast. IS-RT reduces treatment volumes. Intensity-modulated radiotherapy shows advantages in the conformity. Treatment in DIBH also reduces the dose applied to the lungs and the heart. (orig.)