ESTRO 36 Abstract Book

S659 ESTRO 36 2017 _______________________________________________________________________________________________

Out of 74 patients, 38 received BID and 36 received OD CRT with no difference in number of cisplatin-etoposide cycles between groups. In line with the institutional policy, the BID cohort was younger (62 versus 68 years, p=0.017), had smaller tumour volumes at planning CT (79 cc versus 127 cc, p=0.056), and tended to be in a better general WHO performance status (PS) (45% versus 25% at PS 0, p=0.075). At median follow-up of 9.4 months for surviving patients, unadjusted as well as adjusted survival (adjusted for age, WHO PS, stage and GTV) was not significantly better for BID (HR=0.60, 95%CI 0.3–1.4 and HR=0.70, 95%CI 0.3–1.8, respectively). PROMs regarding dysphagia and dyspnea as well as physician-rated toxicities and radiation pneumonitis were not different between groups (figure). Mean esophageal V35 and mean pulmonary V20 were different between BID and OD cohorts (30 Gy versus 41 Gy; p=0.027, and 20 Gy versus 23 Gy; p=0.061, respectively), in line with GTV differences between groups.

using Kaplan-Meier and differences between PFTs prior and post-reRT were analyzed using Student T-Test. Early toxicity was defined when it occurred up to 6 months. Results Median age: 68 (r53-81); 29p (83%) were male The previous treatments SBRT in 17p (49%), 3D-RT 4p (11%) and CT+RT 14p (40%) Mean RT dose 60,4Gy (r34-74). Primary tumors: lung 24 (69%), colorectal 9 (25%), oesophagus 2 (6%). For lung cancer p, the stage distribution was: IA 8 (23%), IB 2 (6%), IIA 2 (5.7%), IIB 1 (3%), IIIA 5 (4%), IIIb 4 (11%), IV 2 (6%). For other primaries, 8p (23%) were non metastatic at diagnosis and developed oligoprogressive disease in thorax which was treated with SBRT and 3 (8.5%) were oligometastatic. The location of reRT site: same lobe 17 (48%), ipsilateral different lobe 7 (20%), contralateral lobes 11 (32%). Median delivered dose of salvage SBRT was 50Gy (50-60) in 10 fractions (r3-10). Median accumulated dose in the lung was 81Gy (r60.10Gy-176Gy). With a median follow-up of 10m local control rate was 74% (IC95%; 0.59-0.9) and 1-year OS was 84% (IC 95%;0.67-1). The metabolic complete response rate was 23%. No differences in the baseline and post re-irradiation PFTs were observed: FEV1, FVC and DLCO difference and CI95% were 2.41 (-1.79-6.62); 65 (-125-257) and 12.5 (-95 - 121). Asthenia GII in 12p (31%) was the most frequent acute toxicity, no long-term toxicities were detected. Conclusion Salvage SBRT for treating isolated intrathoracic relapses achieved an outstanding local control and overall survival in selected p . This treatment did not impair post- reirradiation PFT and long-term toxicities were not observed. EP-1234 Prophylactic Cranial Irradiation (PCI) in Small- Cell Lung Cancer: a single-institution experience. M. Konkol 1 , M. Matecka-Nowak 1 , M. Trojanowski 2 , A. Kubiak 2 , P. Milecki 1 1 Greater Poland Cancer Centre, I Radiotherapy Dept., Poznan, Poland 2 Greater Poland Cancer Centre, Greater Poland Cancer Register, Poznan, Poland Purpose or Objective In 2013 1.963 (ASR 33,6/10 5 ) new lung cancer cases and 1.855 (ASR 31,1/10 5 ) lung cancer deaths were reported in Greater Poland. Compared to 1999 the number of new cases rose by 21% and the number of deaths rose by 16%. In the group of lung cancer patients from the Greater Poland population, diagnosed during 2009-2011, 80% were microscopically verified, among them 79,9% were NSCLC and 20,1% were SCLC. Prophylactic Cranial Irradiation (PCI) in SCLC patients remains an important part of the treatment process associated with a reduction of brain metastases and better survival. This paper is a retrospective review of 146 patients irradiated in Greater Poland Cancer Center, Poznan, Poland. Material and Methods Eighty limited SCLC (LSCLC) and sixty six extensive SCLC (ESCLC) patients irradiated in Greater Poland Cancer Center between 2007-2010 received a standard scheme of 25Gy/10fx with 6MV photons. The qualification based on X-ray post-chemotherapy assessment described as significant partial response or complete response. Mean time from the diagnosis date to the end of treatment was 6 months. The survival data were collected from the national and regional cancer registers. Results Mean observed survival in our patients was 16,8 months (13,6 months for ESCLC and 19,5 months for LSCLC). The 1-, 3- and 5-year observed survival rates were 74,12%, 9,52%, 4,70% for LSCLC and 48,48%, 1,49% 1,49% for ESCLC. For our group as a whole respectively: 65%, 8,6%, 3,3%. After radiotherapy, LSCLC and ESLCL patients survived 7,4 and 12,7 months on average. Grade 3 or 4 toxicity has not been noticed.

Conclusion Treatment selection based on tumour volume and patient condition effectively limited PROMs and physician-rated acute and late dysphagia in BID CRT. This can be explained by the significantly lower esophageal V35 due to smaller GTVs in patients receiving BID treatment. Also, acute and late PROM-dyspnea and radiation pneumonitis did not differ between BID and OD CRT. Treatment allocation could be further improved by dose-volume-fractionation modelling for esophagitis. EP-1233 Early results of SBRT as a salvage treatment after thoracic radiotherapy. A. Navarro-Martin 1 , I. Guix 1 , J. Mases 1 , M. Mutto 2 , E. Nadal 3 , F. Guedea 1 1 Institut Català d'Oncologia, Radiation Oncology, L'Hospitalet de Llobregat, Spain 2 European Oncology Institue, Radiation Oncology, Milano, Italy 3 Institut Català d'Oncologia, Medical Oncology, L'Hospitalet de Llobregat, Spain Purpose or Objective Isolated intrathoracic relapse is common across distinct tumors and especially in lung cancer. Patients who received previous radiotherapy treatment (PRT) are not suitable for salvage surgery and chemotherapy provides poor local control. This study aimed to assess the toxicity and outcome of SBRT re-irradiation (reRT) in patients with solid tumors who developed an intrathoracic relapse. Material and Methods 35p treated with PRT who received salvage SBRT were identified in our database and their medical records were retrospectively reviewed. All patients underwent complete pulmonary function tests (cPFTs) (including DLCO, FEV1 and FVC) and PET-CT scan was performed before and after receiving lung reRT. Treatment planning was based on image fusion with the previous treatment plan and calculating the cumulative total nominal dose. Survival estimations were performed