ESTRO 36 Abstract Book

S664 ESTRO 36 _______________________________________________________________________________________________

Purpose or Objective There is no consensus on the application of PORT in patients with completely resected NSCLC and histologically confirmed mediastinal lymph node involvement. In different institutions, the same patients may be advised to recieve PORT or not, e.g. depending on the proportion of involved or resected lymph nodes or on the age and general health of a patient. Therefore our institution takes part in the randomized LUNG ART study (NCT00410683) since 2013. The objective of the presented work was the evaluation of patients consecutively scheduled for PORT in our institution before our participation in LUNG ART. Material and Methods All distant metastases free patients scheduled for PORT after resection of a NSCLC between 2008 and 02/2013 were included in a retrospective analysis. Data on outcome (survival, toxicity) were collected until 07/16. Results 58 patients (28% female, 72% male), median 67 years, with a NSCLC (50% SCC, 45% adenocarcinoma and 5% other) and pretherapeutic UICC-stage IIa (2%), IIb (3%), IIIa (93%) und IIIb (2%) were evaluated. The postoperative nodal status was N2 in 50 (86%) patients and N1 and N0 in 4 patients (7%), respectively. Median 2,5 (0-7) lymph nodes stations were histologically involved. 25 (42%) patients recieved neoadjuvant platinum-based chemotherapy, a downstaging of tumor or lymph nodes could thereby be achieved in 44% and 5% of these patients. 19 (32%) patients recieved adjuvant chemotherapy. Resection mostly was performed by lobectomy (74%), less common were pneumectomy (12%), sleeve resection (7%), others (7%). In 90% of patients resection was complete, 10% had microscopically involved margins.The median duration between resection and start of PORT were 51 (23-212) days. PORT was applied in 95% of patients by means of 3D- conformal planning, in 5% with IMRT. Median duration of PORT were 39,5 (16-51) days with a median total dose of 52,6 (45-60) Gy. 22% of the patients had a locoregional progression median 7 (2-52) months after PORT, of these 54% within the irradiated area which had recieved median 50 (45- 59,4) Gy. 62% of patients developed distant metastases median 15,5 (0-88) months after PORT. 75% of patients died, most due to tumor progression (62%). Median actuarial overall survival was 32 (1-88) months, median progression free survival 11 (1-53) months. The evaluation of risk factors for survival and of toxicity data These preliminary data show that a fifth of patients after PORT will develop a locoregional recurrence, which complys with data in the literature, and imply that doses of around 50 Gy may not be sufficient to prevent locoregional recurrence in these patients. EP-1231 Early Clinical outcome of the first lung SBRT program in a developing country S. Wadi-Ramahi 1 , J. Khader 2 , F. Abu Hijli 2 , H. Ghatasheh 2 , A. Sulaiman 2 1 King Faisal Specialist Hospital and Research Center, Biomedical Physics, RIyadh, Saudi Arabia 2 King Hussein Cancer Center, Radiation Oncology, Amman, Jordan Purpose or Objective The stereotactic body radiation therapy (SBRT) program at our institution was established through cooperation with an internationally renowned institution and it went clinical in 2012. Until the present day, it stands as the only SBRT program in the entire country with patient population that has increased dramatically in the past few years due influx of refugees from regional conflicts. Here, is ongoing. Conclusion

we will present the early clinical outcome of patients treated for lung tumors with SBRT. Material and Methods 10 patients were treated to date in the SBRT service. All patients underwent 10-phase 4DCT and PET-CT scans. The internal target volume (ITV) was constructed from the minimum intensity projection (MIP) dataset and expanded, if needed, following PET findings. 5mm margin was added to create the PTV. All patients received a dose scheme of 48Gy/4 fractions except for 2 who received 60Gy/8 fractions due to toxicity concerns. Lung heterogeneity correction was used during planning on Pinnacle 3 (Philips, Netherlands) and treatment delivery was done on Precise linacs (Elekta, Sweden). Positioning was done by using CBCT imaging on every fraction. After completion of SBRT the patient is seen in 2 weeks for clinical evaluation and follow up (FU) for possible acute side effects. The FU is both clinical and radiological with alternating CT Chest and PET/CT scans every 3-4 months for the first 2 years and 6 months interval afterwards. Results All patients treated were males, with age ranging from 50- 84 years old, mode of 79. All patients were unfit for surgery except for one who refused surgery. Table 1 summarizes the patients’ data showing histology, tumor size, location, and status after last FU. Eight out of ten patients have shown either regression or no evidence of disease (NED) since last FU, while 2/10 have stable disease. One death occurred 15 months from treatment due to unrelated causes, the patient was NED in his last FU. The longest FU period so is 54 months for the first patient treated.

Conclusion The newly established SBRT clinical service in our country serves as the only such treatment for inoperable lung tumor for a population of about 10 million, including 2.7 million refugees. We have started recruiting inoperable lung patients to the service at a slow pace to gain more confidence and experience before admitting larger numbers. One of the major unforeseeable difficulties was the long term follow up, this is partly a result of heterogeneity in patient population. Albeit the short FU, early clinical results are encouraging with most treated patients showing tumor regression or NED. EP-1232 Patient-reported toxicity in twice-daily (BID) versus once-daily (OD) chemoradiotherapy for LS-SCLC J. Lodeweges 1 , A. Niezink 1 , H. Elzinga 1 , E. Haan- Stijntjes 1 , N. Dollekamp 1 , O. Chouvalova 1 , J. Ubbels 1 , M. Woltman-van Iersel 1 , A. Van der Leest 1 , J. Langendijk 1 , J.