ESTRO 38 Abstract book

S697 ESTRO 38

cases. Most lymphomas were located in the conjunctiva (34.6%) and the lower or upper eyelids (34.6%). The majority of patients presented with stage I disease (76.9%). Radiation dose ranged from 21.6-45.0 Gy (median 39.8 Gy) in 1.8-2.0 Gy daily fractions. Median follow-up duration was 83 months. Results All but one patient achieved local complete remission. The 5- year progression-free survival rate was 77.5% (95% CI: 71.2 – 83.8) (Fig. 2). In addition, 5- and 10-year overall survival rates were 84.0% (95% CI: 78.4 - 89.6) and 77.1% (95% CI: 70.2 – 84.0), respectively. Of all patients who died within 5 or 10 years, there was only one documented case of progression. Treatment was in general well tolerated with acute toxicity, e.g. conjunctivitis (42.3%), ophthalmalgia (13.5%) and Keratitis (3.8%) with convalescence in the majority of cases. Late toxicity included all degrees of cataract, 31 patients (59.6%) and of xerophthalmia, 36 patients (69.2%). Conclusion Our retrospective analysis showed that moderate radiotherapy is an effective treatment modality with excellent local control and moderate late complication rates in the management of stage I/II indolent orbital Non- Hodgkin lymphoma. EP-1269 Local review of lung doses in simultaneous integrated boost (SIB) radiotherapy breast plans J.F. Calvo Ortega 1 , J. Fernández-Ibiza 1 , S. Moragues Femenia 1 , C. Laosa-Bello 1 , J. Casals 1 1 Hospital Quirónsalud Barcelona, Radiotherapy, Barcelona, Spain Purpose or Objective To perform a review of the lung radiation doses from breast cancer radiotherapy plans for a specific SIB scheme Lung doses in 185 SIB treatment plans were included in this study. The whole breast ± axillary or supraclavicular lymph nodes and the tumor bed were planned to simultaneously receive 45.57 Gy and 55.86 Gy in 21 fractions, respectively. Supine radiotherapy with no breathing adaption was performed. Plans were computed using the AAA algorithm of the Eclipse TPS v 13.0 and IMRT tecnique, modeled for 6 MV photon beams of a Varian Clinac 2100 CD. All plans fulfilled the organ-at-risk dose constraints used in our department for this 21 fraction radiotherapy scheme. The following metrics were analyzed: V5 ips , V20 ips , and mean lung dose (MLD ips ) for the ipsilateral lung, and mean dose to both lungs (MLD whole ). Vx ips is the percentage volume of the ipsilateral lung receiving ≥ x Gy. The values of these metrics collected in our plans were compared with the multicentric data recently reported by Aznar et al. in Radiother Oncol. 2018 Jan;126(1):148-154, as a way of assessing the quality of our breast plans. Results For breast plus regional lymph nodes (37 cases), comparison of our values vs. Aznar's values was (average ± standard error): 43.8 % ± 2.1 % vs. 46.6 % ± 6.0 % for V5 ips ; 14.3 % ± 0.3 % vs. 22.8 % ± 1.3 % for V20 ips ; 9.1 Gy ± 0.4 Gy vs. 11.2 Gy ± 0.5 Gy for MLD ips ; and 4.8 Gy ± 0.2 Gy vs. 7.3 Gy ± 0.4 Gy for MLD whole . For simple breast (148 cases), comparison of our values vs. Aznar's values was (average ± standard error): 29.8 % ± 0.8 % vs. 40.2 % ± 2.2 % for V5 ips ; 9.9 % ± 0.3 % vs. 13.8 % ± 0.4 % for V20 ips ; 6.2 Gy ± 0.1 Gy vs. 8.6 Gy ± 0.2 Gy for MLD ips ; and 3.2 Gy ± 0.1 Gy vs. 5.7 Gy ± 0.2 Gy for MLD whole . Conclusion used in our department. Material and Methods Electronic Poster: Clinical track: Breast

Inclusion of the regional lymph nodes considerably increased the metric values relative to irradiation of the whole breast only. Lung average doses attained with the 21 fraction SIB scheme used in our department were always smaller than the reported ones by Aznar et al. This can be considered as a quality test for our designed treatment plans. EP-1270 Outcomes and toxicity of stereotactic radiotherapy for metastatic breast cancer –a retrospective study M. AL-Hanaqta 1 , M. Niglas 2 , C. Jiang 3 , P. Cheung 2 , W. Chu 2 , H. Chung 2 , S. Myrehaug 2 , I. Poon 2 , A. Sahgal 2 , H. Soliman 2 1 Royal medical services, Radiation oncology, Amman, Jordan ; 2 Sunnybrook HSC, Radiation oncology, Toronto, Canada ; 3 University of Toronto, School of medicine, Toronto, Canada Purpose or Objective Technological advances in radiotherapy have allowed for the delivery of ablative doses to sites of disease in most parts of the body. In this trial, we describe the outcomes of a group of breast cancer patients treated to sites of metastatic disease with stereotactic radiotherapy (SBRT). Predictors of treatment outcomes are also investigated in this cohort. Material and Methods After institutional research ethics board approval, patients with metastatic breast cancer who received SBRT to metastatic disease from 2011 to 2016 were identified by electronic chart review. Patient demographics, histologic information and clinical data were collected from the electronic patient record and the radiation treatment planning system. Outcomes of interest included local control (LC), overall survival (OS), and progression free survival (PFS). In addition to Kaplan- Meier estimates, univariate analysis using the log-rank test, and multivariate analysis with cox regression was used to assess covariates, which were identified a priori. Results 120 patients between the ages of 25 to 82 (median 54.8 years) with 193 treated lesions were identified. Median follow-up was 9.8 months (range 0.03 to 72.31 months). Patients’ estrogen receptor (ER), progesterone receptor (PR) and Her-2 status were 83.9%, 70.7% and 18.4% respectively (maybe better to describe subtype here, e.g. luminal a). 70.3% had lymph node positive disease at diagnosis. The majority of treated lesions were in the spine (45%), followed by liver (20%), lung (18%) and non- spine bone (14%). There were no recorded grade 4 or 5 toxicities, with only 5.3% of patients reporting side effects (most commonly mild pain). 1-year LC, PFS and OS was 88%, 45% and 84% respectively. On univariate analysis, PFS varied depending on treatment indication (oligometastasis, oligoprogression or salvage) with a median PFS of 24.4 months, 5.6 months and 8.1 months respectively (p<0.001). Similarly, a difference in OS by treatment indication was also seen with 1-year survival of 91%, 82% and 57% respectively (p<0.001). Survival was influenced by molecular subtype, with the worst survival seen in patients with triple negative disease (p=0.001). Conclusion Local control rates remain excellent after SBRT to sites of metastatic disease in this population of breast cancer patients. The most significant risk for these patients remains distant failure, with significantly longer PFS in those being treated for oligometastatic disease in comparison to other indications. Favourable PFS observed in the oligometastases subgroup would support further randomized evaluation of the potential benefit of SBRT in this population, as is currently being performed in other tumour histologies.