ESTRO 36 Abstract Book

S278 ESTRO 36 _______________________________________________________________________________________________

outcomes of SBRT for unresectable liver metastases and to analyze prognostic factors affecting OS of these selected oligometastatic patients. Material and Methods Patients with 1 to 3 unresectable liver metastases, with maximum individual tumor diameters less than 6 cm and a Karnofsky Performance Status of at least 70, were enrolled and treated by SBRT on a phase 2 clinical trial. Dose prescription was 75 Gy on 3 consecutive fractions. SBRT was delivered using the volumetric modulated arc therapy by RapidArc (Varian, Palo Alto, CA) technique. Primary end point was in field local control (LC), secondary end points were overall survival (OS), progression free survival (PFS) and toxicity. Results Between February 2010 and September 2011, a total of 61 patients with 76 lesions were enrolled in this phase II trial, with a median follow-up time of 1.9 years. One-, three- and five- years LC rates were 94%, 78% and 78 %, respectively, with a median LC of 1.7 years. Median OS was 2.3 years and the survival rates were 83%, 30% and 21% at 1, 3 and 5 years, respectively. Univariate analysis showed two independent positive prognostic factors affecting survival: female sex (p = 0.012) and primary tumour (p = 0.001). Toxicity was moderate. One patient experienced G3 late chest wall pain, which resolved within 1 year from SBRT. No cases of RILD were detected. Conclusion Long-term results of this Phase II study suggest the efficacy and safety of SBRT for unresectable liver metastases at 5 years of follow-up. Selection of cases with positive prognostic factors may improve long-term survival of these oligometastastic patients and may confirm the role of SBRT as an effective alternative local therapy for liver metastases. OC-0525 Factors affecting local control for pulmonary oligometastasis treated with SBRT A. Sharma 1 , M. Duijm 1 , E. Oomen-de Hoop 2 , J. Aerts 3 , C. Verhoef 4 , M. Hoogeman 1 , J. Nuyttens 1 1 Erasmus MC-Daniel den Hoed Cancer Center- Rotterdam- The Netherlands, Department of Radiation Oncology, Rotterdam, The Netherlands 2 Erasmus MC-Daniel den Hoed Cancer Center- Rotterdam- The Netherlands, Department of Medical Oncology, Rotterdam, The Netherlands 3 Erasmus MC-Daniel den Hoed Cancer Center- Rotterdam- The Netherlands, Department of Pulmonology, Rotterdam, The Netherlands 4 Erasmus MC-Daniel den Hoed Cancer Center- Rotterdam- The Netherlands, Department of Surgical Oncology, Rotterdam, The Netherlands Purpose or Objective To evaluate local control (LC) and identify factors associated with LC for inoperable pulmonary oligometastases treated with stereotactic body In 206 patients, 326 pulmonary oligometastasis were treated with SBRT. Oligometastatic tumors were defined as ≤ 5 metastases in no more than two organs at time of treatment. Metastases were categorized as synchronous if metastases developed within 5 months of diagnosis of primary tumor, else were assigned to metachronous group. SBRT schedule depended on location of metastasis, its size and dose calculation algorithm. Dose to PTV was prescribed at 70-90% isodose line (median 78%), covering at least 95% of the PTV. LC was calculated from first session of SBRT to date of local recurrence. Patients without any local recurrence at date of last follow up were censored. Variables assessed as prognostic factors for LC included: metachronous versus synchronous metastasis, pre SBRT chemotherapy, primary radiotherapy (SBRT). Material and Methods

site, location in lower lobes versus other, central and peripheral lung metastasis, tumor size, single versus fractionated SBRT, BED, algorithm used, delay in SBRT. Toxicity was recorded as per NCI CTCAE, version 3.0. Ninety per cent of pulmonary oligometastasis were treated with BED>100 and with fractionated SBRT. Two hundred and thirty nine oligometastases were peripheral in location and majority (258) were <3 cm in diameter. Primary tumor site included 117 colorectal tumors, 36 lung cancers, 11 melanoma,10 sarcoma, 7 breast carcinoma, and 25 metastases were from other sites. Median follow up was 22 months (range 1-100). Results LC at 2 and 5 years was 83% and 73%, respectively. On univariate analysis BED <100 (HR=3.08), single fraction radiotherapy (HR=2.81), synchronous metastasis (HR=2.13), pre SBRT chemotherapy (HR=2.83), and SBRT delay > 4 months (HR=2.49) were significantly associated with inferior LC. At BED >100 synchronous metastasis (2 year LC 76% vs 88%), pre SBRT chemotherapy (2 year LC 78% vs 91%), and SBRT delay >4months (2 year LC 79% vs 90%) were significantly associated with lower LC rate. On multivariate analysis BED <100 (HR 4.36), single fraction radiotherapy (HR 4.02), pre SBRT chemotherapy (HR 2.32), synchronous metastasis (HR 2.16), and SBRT delay >4 months (HR 2.17) remained independently associated with lower LC. Median OS in entire cohort was 32 months. The 2, 3, and 5 year OS rates were 63%, 47% and 30%, respectively. Less than 2% of patients experienced grade 3 acute or late toxicities. There were no grade 4 and 5 events. Conclusion The study identified 5 factors independently associated with inferior LC. Despite BED >100 synchronous metastasis, pre SBRT chemotherapy and SBRT delays were significantly associated with inferior LC rate. These findings will help to refine SBRT practice for pulmonary oligometastasis.

OC-0526 Quality of life after SBRT in bone metastases: analysis from the prospective PRESENT cohort G. Fanetti 1 , A.S. Gerlich 2 , E. Seravalli 2 , H.M. Verkooijen 3 , M. Van Vulpen 2 , R. Orecchia 4 , B.A. Jereczek-Fossa 1 , J. Van der Velden 2 1 European Institute of Oncology - University of Milan, Department of Radiation Oncology, Milan, Italy 2 University Medical Center, Department of Radiation Oncology, Utrecht, The Netherlands 3 University Medical Center, Julius Center for Health Sciences and Primary Care, Utrecht, The Netherlands 4 European Institute of Oncology - University of Milan, Scientific Directorate, Milan, Italy Purpose or Objective Stereotactic body radiotherapy (SBRT) is an emerging treatment in patients with bone metastases (BM). Local control is achieved in up to 95% of lesions and up to 80% of patients experience pain relief after SBRT. However, in patients with a limited life expectancy, quality of life