3rd ESTRO Forum 2015 S331 receiver operating characteristic curve (ROC) analysis to define the cut-off points for significant parameters. Results: Median follow-up time was 20.5 months (range 4 -91) and 18 months (14-80) for primary and secondary lung cancer. RP G1-2 has been observed in 23/54 patients (42.59%); no pulmonary toxicity >G2 has occurred, as there has been no toxicity of controlateral lung and other organs at risk. Univariate statistical analysis showed that GTV(p=0.036), PTV

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... 22), MLD (p=0.003) and V5 (p=0.002), V10 (p=0.002), V20 (p=0.012), V30 (p=0.002) were significant variables for the risk of developing RP. Multivariate statistical analysis has found that the predictor variables of RP are V5 (p=0.004), V10 (p=0.009), V20 (p=0.014), V30 (p=0.007) and the MLD (p=0.011). The greatest risk was connected to the variable V30 (HR 1.985 ) . On the ROC curve, the cut-off values of ipsilateral lung V5,V10,V20,V30 and MLD were 29.50%,19.50%,9.55%,4.58% and 4.7%, respectively (Fig.1) . A cutoff of 4.58% for V30 had a sensitivity of 80% and specificity of 82.1%. Conclusions: In our study stereotactic body radiotherapy was well tolerated for primary and secondary lung cancer treatment. V5, V10, V20, V30 and MLD were significantly predictive of RP. Poster: Clinical track: Breast PO-0677 Rotational intensity Modulated Radiation Therapy in complex adjuvant breast and nodes irradiation