ESTRO 36 Abstract Book

S666 ESTRO 36 _______________________________________________________________________________________________

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 The Concord-2 study results show, that the 5-year net survival rates among lung cancer patients diagnosed during 2005-2009 in Poland (13,4%) and Greater Poland (13,2%) were on the average European level. Similarly, presented SCLC group meets 5-year survival rates of that time. Comparing to other authors, we have noticed slightly better results in 1- year survival - Schild et al: 56% (PCI arm, LSCLC&ESCLC), Slotman et. al: 27,1% (PCI arm, ESCLC). Nevertheless, in spite of good results shown above, the prospective analysis shoud be done. Contemporary salvage treatments for intracranial relapse may be underestimated especially if provided before patients become symptomatic. EP-1235 Stereotactic body radiotherapy for lung metastases: retrospective analysis of a single-center H. Herrmann 1 , C. Proksch 1 , K. Dieckmann 1 1 Universitätsklinik für Strahlentherapie Medizinische Universität Wien, Wien, Austria Purpose or Objective A significant number of cancer patients with initially localized disease develop distant metastases at follow up. A subset of patients with successful treatment of the primary tumor develop oligometastatic disease months to years after initial treatment. Other patients with metastatic disease present with long-lasting stable disease or remission during systemic treatment and develop progression in single lesions in later course of disease. For these patients with low tumor burden, a semi-curative treatment strategy might be an option. In recent years, stereotactic body radiotherapy (SBRT) of the lung has been shown to provide an alternative to surgical resection of lung metastases. Typically, SBRT in the lung is performed with high single-doses per fraction. High

radiation doses to the lung could result in severe fibrosis, which might especially be relevant for patients with

impaired lung function. Material and Methods

We retrospectively analyzed 95 metastatic patients (male, n=64; female, n=31) who underwent SBRT in the lung at our institution from 2005-2015 with a total of 166 lung metastases. The median age was 65 years (range 38-84 years) at initial SBRT treatment. Primary tumors were colorectal cancer (n=35), renal cell carcinoma (n=15), head and neck cancer (n=12), melanoma (n=8), and other malignancies (n=25). Parameters assessed were: local control, survival, lung function test before start of treatment and during follow up, PTV volume, extent of fibrosis on CT scans. Results The treatment regimen most often used was 12.5 Gy x 3 fractions prescribed to the 65% isodose (n=100; EQD2 for α/β=10 Gy: 70.3 Gy at prescribed isodose, 140.5 Gy at 100% isodose) and 15 Gy x 3 fractions prescribed to the 65% isodose (n=33; EQD2 for α/β=10 Gy: 93.8 Gy at prescribed isodose, 190.8 Gy at 100% isodose). The median PTV volume was 15.9 ccm (range: 3.6 – 404.5 ccm). Median follow up was 20 months (range 1 – 136 months). The overall survival at 1 and 2 years was 85% and 68%, respectively. We achieved high local control after SBRT treatment at 1 and 2 years which was 95% and 88%, respectively. Signs of morphologically dense radiation induced fibrotic changes (hounsfield units > 10 as evaluated on CT scans) 4-6 months after treatment was seen in 40 % of all treated lesions. The median diameter of these fibrotic changes were 6.0 cm (range: 2.0 – 10.4 cm). Before SBRT treatment the median baseline FEV1 value of lung function test was 2.5 L (range: 0.96 – 3.96 L). FEV1 values at 1 years after treatment (expressed as mean percentage of baseline FEV1 ±SD) decreased to 95% (±8%) which was significant ( p <0.05) in a paired t-test. Conclusion SBRT treatment for lung metastases results in high local control rates and can be safely applied. The impact on lung function test at one year after treatment was minimal although high biological doses were delivered. We conclude, that SBRT to the lung can be recommended to oligometastatic patients as an effective alternative treatment to surgical resection. EP-1236 Validation of the clinical diagnostic method for solitary pulmonary nodules before SBRT in Navarra M. Campo 1 , I. Visus 1 , S. Flamarique 1 , M. Barrado 1 , A. Martin 1 , M. Rico 1 , E. Martinez 1 1 Hospital of Navarra, Oncología radioterapia, Pamplona, Spain Purpose or Objective In the general practice of the Hospital of Navarra, solitary pulmonary nodules (SPN) are frequently treated with SBRT without cytological confirmation due to patients´ co- morbidities that heighten the risks associated with transthoracic biopsy. In this analysis we study the reliability of our clinical diagnostic system to better know the accuracy and quality of our protocols. Material and Methods We analyze retrospectively the pathological results of SPN treated surgically under suspicion of being stage I non- small-cell lung cancer (NSCLC) during 2012 and 2013. The suspicion was based on the criteria of an expert board composed by pneumologists, radiation oncologists, medical oncologists, thoracic surgeons, radiologists and pathologists. The decision of treating was taken according to the FDG-PET features, the morphological characteristics on CT and the growing pattern of the SPN.