ESTRO 36 Abstract Book

S19 ESTRO 36 _______________________________________________________________________________________________

chemotherapy and INRT were reviewed. Eligibility was restricted to those with Ann-Arbor stage I-II diseases, who had a PET-CT in treatment position prior to chemotherapy. Supra diaphragmatic recurrences were sorted according to radiotherapy fields as in or out-field and their belonging to a treated lymph nodes area was examined, with the aim to state if the target would have been included in an involved-field radiation therapy (IFRT). Distance relapse was defined as a recurrence located beyond the diaphragm. Results Seventy-four consecutive patients were included. Histologic subtypes were nodular sclerosis in 91%, mixed cellularity in 7%, and lymphocyte depleted in 2%. Patients’ mean age at diagnosis was 37.6±13.1 years; median follow-up, 40.6 months. Initially 88% of the patients had stage II diseases and the remaining 12%, stage I. According to the EORTC (European Organization for Research and Treatment of Cancer) criteria 70% had early unfavorable diseases and 30%, early favorable diseases. All patients received ABVD, administrated in 95% of the patients for 3- 4 cycles, followed by BEACOPP after 2 cycles in 2%, or combined with brentuximab in 5%. The mean RT dose was 30.9±2.0 Gy delivered in 1.8±0.05 Gy fractions. IMRT was used in 42 %, and 3D conformal radiotherapy in 18%. Deep inspiration bread hold technique (DIBH) was used in 40%, with 3D conformal radiotherapy in all but one patient (IMRT). A total of 4 patients experienced relapses (crude incidence: 5.4%), which resulted in 3- and 5-year disease free survival rates of 96.9% and 93.8%. Three- and 5-year overall survival rates were 100% and 97.4% respectively. All four patients had supra diaphragmatic recurrences. In two patients, they consisted in a mix of in- and out-field relapses. In-field relapses occurred in regions receiving 30.6 Gy and 32.4 Gy, respectively. In the remaining two patients, relapses were out-field on both side of the diaphragm. In 2 patients out of 4, relapses were located in lymph nodes regions partially irradiated with INRT (1 and 2 areas respectively). Conclusion Although the 4 reported relapses comprised out-field areas, recurrences in partially irradiated lymph node areas, which would have been potentially covered by IFRT fields, occurred in 2 patients (2.7%). On the overall, INRT, implemented in routine, yielded satisfactory outcomes in regard to published series. PV-0045 Estimation of internal risk volume for coronary arteries after motion evaluation with ECG- gated CT M. Levis 1 , C. Fiandra 1 , A.R. Filippi 2 , F. Cadoni 1 , V. De Luca 1 , A. Cannizzaro 3 , D. Garabello 4 , S. Veglia 4 , R. Ragona 1 , U. Ricardi 1 1 University of Torino, Radiation Oncology, Torino, Italy 2 San Luigi Hospital, Radiation Oncology, Orbassano Torino, Italy 3 University of Messina, Radiation Oncology, Messina, Italy 4 A.O.U. Città della Salute e della Scienza, Radiology, Torino, Italy Purpose or Objective Retrospective studies in patients affected with Hodgkin lymphoma and breast cancer demonstrated a linear relationship between heart dose and the risk of coronary artery disease (CAD). In order to spare small structures such as coronary arteries (CA), a highly precise contouring is needed; however, heart motion represents an obstacle for a correct delineation. To date, the entity of motion- induced CA displacement and margins for internal risk volume (IRV) are poorly described. Aim of this study was to quantify CA displacement and then estimate IRV through the use of ECG-gated CT.

Conclusion Taking into account conformality and OAR dose reduction, ARC-A performed as well as B-VMAT. ARC-A does not require couch rotation, therefore reducing set-up error and making it easier to combine with DIBH apparatus compared to B-VMAT. It should be considered as a practical alternative to B-VMAT. We found it useful to have a list of "aspirational" DCs for this planning comparison. In practice, however, each patient’s OARs should be set based on their clinical characteristics and disease location and the best plan should be chosen after comparison of at least two techniques. PV-0044 Is involved-node radiotherapy for Hodgkin lymphoma safe in routine? A. Boros 1 , R. Sun 1 , J. Arfi Rouche 2 , J. Lazarovici 3 , D. Ghez 3 , J.M. Michot 3 , A. Beaudré 4 , A. Danu 3 , J. Bosq 5 , V. Ribrag 3 , R. Mazeron 1 1 Institut de Cancérologie Gustave Roussy, Radiation Oncology Department, Villejuif, France 2 Institut de Cancérologie Gustave Roussy, Radiology Department, Villejuif, France 3 Institut de Cancérologie Gustave Roussy, Oncology Department, Villejuif, France 4 Institut de Cancérologie Gustave Roussy, Radiation Physicist, Villejuif, France 5 Institut de Cancérologie Gustave Roussy, Pathology Department, Villejuif, France Purpose or Objective Involved-node radiotherapy (INRT) answers the need for reducing the irradiated volumes in Hodgkin lymphoma patients, in promising to reduce the risk of late morbidity. However, this concept, combined with modern radiotherapy techniques, exposes to risks of geographic misses. The purpose was to evaluate the efficiency of INRT in daily routine. Material and Methods The data from patients with limited Hodgkin diseases treated with a combined modality associating