ESTRO 37 Abstract book

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ESTRO 37

classified as grade 1 in 85 cases, grade 2 in 18 cases and grade 3 in 7 patients. No toxicity in 111 patients. The patients with 28.5-Gy Gy showed a slightly better cosmetic result, which was the main motivation for the option of this dose reduction midway through our study.Local and distant failure was scored in 32 cases (13,6%). At a median follow-up of 50 months, 169 patients (72%), was alive and disease free, 29 (12,3%) patients die and disease free. Conclusion According to the findings from this retrospective study, the HF-RT schedule is an acceptable alternative for elderly patients, allows a good local control, with acceptable toxicity. EP-1355 The prognostic impact of solid component diameter of tumor in Stage I NSCLC undergoing SBRT T. Itonaga 1 , T. Saitou 1 , M. Okubo 1 , R. Mikami 1 , S. Nogi 1 , T. Koichi 1 1 Tokyo Medical University, Radiology, Shinjuku, Japan Purpose or Objective To evaluate the local control rate impact of the size of the solid component in the tumor for patients with stage I non-small cell lung cancer (NSCLC) who underwent intensity-modulated stereotactic body radiotherapy (SBRT) using compensated filters. Material and Methods This study was approved by the ethical board at the Tokyo Medical University Hospital, and started in 2011. All patients provided written informed consents. Eligible criteria included the following: 1. pathologically proven or clinically diagnosed NSCLC; 2. clinical stage of T1- 2N0M0 according to the 7 th UICC TNM classification; 3. patients who were considered to be unsuitable for surgery due to underlying lung diseases, poor performance status, old age or patient’s refusal. A total number of 48 patients with 50 tumors were enrolled in this study. The median age of patients was 79 years (range, 49-90), the male/female ratio was 30/18, and the stage T1 to T2 ratio was 31 to 19. 95% of the prescribed dose of 75 Gy in 30 fractions was given to 95% of the PTV. In this presentation, we re-measured the maximum tumor diameter (MTD) and the solid component diameter (SCD) according to the 8 th UICC TNM classification. After these tumors were reclassified, local control, overall survival (OS) and local progression-free survival (LFS) rates were recalculated based on the new classification. Prognostic factors were analyzed with uni-variate and multiple variate methods using the Cox proportional hazards regression models among possible prognostic factors of MTD, SCD, Age(>75y), Sex. Results The median MTD and SCD were 21 mm and 19 mm, respectively. 50 tumors were classified into Tis (SCD=0mm, MTD≤30 mm) 2 cases, T1a (SCD≤10 mm) 6 cases, T1b (SCD>10 mm, SCD≤ 20 mm) 24cases, T1c (SCD>20 mm, SCD≤30 mm) 11cases, T2 (Invades visceral pleura, SCD≤30 mm) 2cases, T2a (SCD>30 mm, MTD≤40 mm) 3cases, and T3 (SCD>50 mm, SCD≤40 mm) 2cases according to TNM 8 th edition. During the median follow-up time of 35.9 months (range, 3.8–64.7), the 3-year LFS and OS rates were 82.6% and 87.1%, respectively. In patients with SCD>20 mm, the 3- year LFS rate was significantly lower compared with patients with a 20 mm or less (52.7 vs. 96.0%; p = 0.0008). No significant differences were found in MTD or SCD/MTD ratio. By multivariate analysis, the SCD larger than 20 mm (hazard ratio [HR] = 12.2, p = 0.026) was the only statistically significant indicator of poor LFS rates Electronic Poster: Clinical track: Lung

among the possible prognostic factors. Conclusion

The solid component diameter was the only prognostic factor for patients with stage I NSCLC when intensity- modulated SBRT was performed. This finding appears important to select patients for dose escalation. EP-1356 Radical Accelerated Hypofractionated 3d-CRT In NSCLC Patients on behalf of GOECP-SEOR. N. Rodriguez De Dios 1 , E. Sanchez 2 , A. Otero 3 , J. Lopez 4 , J. Luna 5 , R. Delgado 6 , M. López 7 , E. Cenizo 8 , J. Monroy 9 1 Hospital del Mar, Radiation Oncology, Barcelona, Spain 2 COMPLEJO HOSPITALARIO LEÓN, RADATION ONCOLOGY, LEÓN, Spain 3 HOSPITAL CLÍNICO UNIVERSITARIO VIRGEN DE LA VICTORIA, MALAGA, Spain 4 hospital Universitario Virgen Del Rocío, Sevilla, Spain 5 hospital Universitario Fundación Jiménez Díaz, Madrid, Spain 6 complejo Hospitalario Carlos Haya, Málaga, Spain 7 hospital Clínico Lozano Blesa, Radiation Oncology, Zaragoza, Spain 8 complejo Hospitalario León, León, Spain 9 hospital Universitario De La Ribera, Alcira, Spain Purpose or Objective Increasing the radiotherapy dose can result in improved local control for non-small-cell lung cancer (NSCLC) and can thereby improve survival. This can be compromised by accelerated repopulation of tumour cells during radiotherapy. Accelerated hypofractionated radiotherapy (AHRT) can expose tumors to a high dose of radiation in a short period of time. To describe the outcome of treating early-stage (T1-3N0) non–small-cell lung cancer (NSCLC) with AHRT Material and Methods We identified 103 patients. Mean age was 78.8 ± 7.9 years. Most patients were male (85.4%) and had performance status (PS) ≥ 2 in 45.6% of cases. The AHRT mean dose/fraction, total dose, and number of fractions were 2.87 Gy, 61 Gy, and 19, respectively. Three groups of doses were defined according to BED 10 : ≥ 75 Gy, 61-74 Gy and ≤ 60 Gy. Results After a median follow-up of 30 months, the 1 and 3 years overall survival (OS) was 82.0 and 40.4%. Cause specific survival (CSS) was 89.6 and 63.0%. On multivariate Cox regression analysis, tumor size was an independent risk factor for OS (p=0.01) and CSS (p=0.02). PS ≥ 2 was an independent risk factor for OS (p =0.02). The major acute adverse reactions were grade 2 dermitis (9.7%), grade 2 esophagitis (3.8%) and grade 3 pneumonitis (1%). There were 2 patients with grade 2 late pneumonitis. Conclusion AHRT is a reasonable alternative to conventional fractionated radiotherapy in stage I-II NSCLC without access to SBRT. Tumor size and PS ≥ 2 were independent risk factors for survival. EP-1357 Changes of lung density after radiotherapy for thoracic carcinomas–an analysis of follow up CT scans C. Schröder 1 , R. Engenhart-Cabillic 2 , H. Vorwerk 2 , S. Kirschner 3 , E. Blank 3 , D. Sidow 3 , A. Buchali 3 1 Universitätsspital Zürich, Klinik für Radio-Onkologie, Zürich, Switzerland 2 University Clinic Giessen and Marburg, Clinic for Radiotherapy and Radiation Oncology, Marburg, Germany 3 Ruppiner Kliniken GmbH, Clinic for Radiotherapy and Radiation Oncology, Neuruppin, Germany Purpose or Objective An objective way to qualify the effect of radiotherapy (RT) on lung tissue is the analysis of CT scans after RT. In