ESTRO 2020 Abstract book

S609 ESTRO 2020

Proper patient selection is warranted if better outcomes are to be achieved with SBRT of liver metastases. However it might be difficult to point a precise definition of disease stage beyond which such intervention is unuseful because some patients may still benefit from treatment and the treatment itself is very well tolerated with minimal impact on daily activity PO-1061 Stereotactic body radiotherapy for adrenal metastases of oligometastatic or oligoprogressive tumors L. König 1 , M.F. Häfner 2 , S. Katayama 1 , S.A. Koerber 1 , E. Tonndorf-Martini 1 , D. Bernhardt 1 , B. Von Nettelbladt 1 , F. Weykamp 1 , P. Hoegen 1 , S. Klüter 1 , M.S. Susko 3 , J. Debus 1 , J. Hörner-Rieber 1 1 University Hospital Heidelberg, Department of Radiation Oncology, Heidelberg, Germany ; 2 University of Heidelberg, Department of Radiation Oncology-, Heidelberg, Germany ; 3 University of California, Radiation Oncology, San Francisco, USA Purpose or Objective Local ablative treatment strategies are frequently offered to patients diagnosed with oligometastatic disease. Stereotactic body radiotherapy (SBRT), as ablative treatment option, is well established for lung and liver metastases, whereas for isolated adrenal gland metastases the level of evidence is scarce. Material and Methods This single-institution analysis of oligometastatic or oligoprogressive disease was limited to patients who received SBRT to adrenal metastasis between 2012 and 2019. Patient, tumor, treatment characteristics, and dosimetric parameters were analyzed for evaluation of their effect on survival outcomes. Results During the period of review 28 patients received ablative SBRT to their adrenal gland metastases. Most common primary tumors were non-small cell lung cancers (46%) with most patients diagnosed with a single adrenal gland metastasis (61%), which occurred after a median time of 14 months. SBRT was delivered to a median biological effective dose at a/b of 10 (BED 10 ) of 75 Gy (range: 58-151 Gy). Median gross tumor volume (GTV) and median planning target volume (PTV) were 42 and 111 mL, respectively. The homogeneity and conformity indices were 1.17 (range: 1.04-1.64) and 0.5 (range: 0.4.0.99), respectively, with the conformity index being effected by dose restrictions to organs at risk (OARs) in 50% of the patients. Overall response rate based on RECIST criteria was 86% (CR=29%, PR=57%) with 2-year local control (LC) of 84.8%, 2-year progression-free survival (PFS) of 26.3%, and 1-and 2-year overall survival (OS) of 46.6 and 32.0%, respectively. A trend for superior PFS was seen if BED 10 was >75Gy (p=0.101) or if the PTV was <100ml (p=0.072). SBRT was tolerated well with only mild toxicity. Conclusion SBRT for adrenal metastases resulted in promising LC with low toxicity. However, modern motion management strategies and MR-guided radiotherapy may increase the possibility of dose escalation and hence LC while simultaneous allowing superior sparing of adjacent OARs. PO-1062 Stereotactic body radiotherapy can delay polymetastatic conversion in liver oligometastatic patients L. Nicosia 1 , F. Cuccia 1 , V. Figlia 1 , N. Giaj-Levra 1 , R. Mazzola 1 , F. Ricchetti 1 , M. Rigo 1 , M. Bonù 2 , F. Alongi 1 1 Ospedale Sacro Cuore "Don Calabria", Radiation Oncology, Negrar, Italy ; 2 ASST Spedali Civili di Brescia, Brescia University, Brescia, Italy Purpose or Objective SBRT demonstrated to increase survival in oligometastatic patients. Nevertheless little is known regarding the natural

Conclusion Definite CRT with dose-escalation to 60 Gy is a feasible treatment option with good 5 year survival rates for patients with inoperable, unresectable or recurrent esophageal cancer. PO-1060 Cyberknife SBRT for liver metastases in heavily pre-treated patients P. Martenka 1 , A. Skrobała 2 1 Greater Poland Cancer Centre, Radiation Oncology Department, Poznan, Poland ; 2 Greater Poland Cancer Center, Physics Department, Poznań, Poland Purpose or Objective To retrospectively analyze the early results of Cyberknife SBRT for liver metastases of first 11 consecutively treated patients at our institution in terms of treatment setup and planning, acute toxicity , and patterns of failure. Material and Methods Eleven consecutive patients were treated with SBRT for liver metastases at our institution since August 2013.Overall 17 lesions in 11 patients ( 4 males ,7 females) were eligible for analysis. Most patients were heavily pre- treated and referred to radiation oncology as a last call palliative consultation. As for previous systemic therapy - 3 or more lines of chemotherapy were already incorporated in treatment in 7 out of 11 patients. As for local operative and or ablative ( radiofrequency, etanol injection) treatment as much as 6 patients had such interventions prior to SBRT(including two patients with hemihepatectomy ).Also extrahepatic extension of disese was present in 8 patients( of which all were deemed stable or in partial remission ).For treatment planning contrast CT,4D CT and MR imaging were performed. The patient population was very heterogeneous both in terms of histology of primary tumor as well as localization of metastases within liver and dimension of GTV (10-80mm). However all but one were uniformly treated with respect to normal tissues constraints to 45Gy/3 fractions every second day. Results We analyzed retrospectively the stability of gold marker position defined as the relation in position between the day of implantation and the day of acquiring images for treatment planning(typically 10 days later) . In first six patients there were three major dislocations of fiducials. Seemingly in first 4 patients the inter-fiducial distance was suboptimal - less than 20mm . As for acute toxicity - the overall treatment tolerance was excellent. Only some patients reported grade 1 somnolence or nausea. However, most patients found the fiducial implementation as the most traumatic experience throughout the whole treatment process. Interestingly, two patients reported acute severe right lateral abdominal pain after first fraction without any further relevant sequelae .Patients were treated with one dose of opioid (tramadol) - pain quickly resolved and patients were free of pain until the end of treatment completion and during the follow – up and similar incidents never occurred again. During follow- up period (range 1-14 months) we observed hepatic in - field,hepatic out- of- field, and extrahepatic disease progression in 4 ,6 and 8 patients respectively during that very short follow-up period.We did not observed any Grade 2 or higher liver toxicity. Conclusion