ESTRO 36 Abstract Book

S735 ESTRO 36 2017 _______________________________________________________________________________________________

N. Bychkova 1 , E. Khmelevsky 1 1 Gertzen Moscow Research Oncological Institute, Radiotherapy Department, Moscow, Russian Federation Purpose or Objective To study the features of bone metastases according to different primary tumors and their importance for radiotherapy Material and Methods We analyzed 680 cases of symptomatic bone metastases included in the randomized controlled trial and treated with EBRT. The primary breast tumors were diagnosed in 426 (62,6%), prostate in 57 (8,4%), lung in 57 (8,4%), renal in 47 (6,9%), colon in 18 (2,6%), bladder in 11 (1,6%) and other tumors in 64 (9,5%) cases. Patient selection criteria for radiotherapy were pain, risk of pathological fracture/malignant spinal cord compression, increasing neurologic dysfunction. Irradiation of one anatomical area was applied («block concept»). Treatment schedules included 2, 3 and 4 fractions of 6,5Gy and standard treatment schedule with 23 fractions of 2 Gy. Results The average follow-up period was 70 months. Pain intensity before treatment was significantly higher for bone metastases of prostate and lung cancer compared to breast cancer (p<0,01) and for the men in general (p<0,001 for non-prostate cases). Average relative lesion length in irradiation’s areas was significantly lower for renal cancer – 1,8 (for the three-level scale) and significantly higher for prostate cancer – 2,28 (p=0,017). The risk of pathological fracture was the lowest only for prostate cancer metastases – 0,21 compared to 0,46 for breast cancer lesions (p=0,0002). Overall effectiveness of EBRT was 96,1%. Complete response rate (CRR) was observed in 59,1% of cases. CRR correlated with the level of total dose. CRR was significantly higher for bone metastases of breast cancer compared to lung and renal cancer (63,6% as opposed to 40,4% and 28,3%, р<0,02) and for melanoma metastases (75%) compared to renal cancer (p=0,036). It is interesting, that bone metastases of melanoma and soft-tissue sarcomas were one of the most radiosensitive. In the multifactorial analysis MANOVA tumor primary site and pain intensity before radiotherapy were the only independent prognostic factors of the effectiveness of radiotherapy. Conclusion Tumor primary site is a clinical predictor of radiosensitivity of bone metastases, it significantly affect the CRR. Revealed features of bone lesions according to different primary tumors allow to develop individual treatment programs with a view to high efficiency and ease of realization. EP-1389 Superficial hyperthermia with radiotherapy: toxicity and outcome of 62 metastatic lesions G. Cattari 1 , A.G. Di Dia 2 , M. Gatti 1 , E. Delmastro 1 , E. Garibaldi 1 , G. Belli 1 , A. Salatino 1 , P. Gabriele 1 1 FPO-IRCCS Candiolo, Radiotherapy, Candiolo- Turin, Italy 2 FPO-IRCCS Candiolo, Medical Physic, Candiolo- Turin, Italy Purpose or Objective The purpose of this study is to evaluate the safety, feasibility and toxicity of radiotherapy-hyperthermia (RT- HT) in the treatment of superficial recurrent and metastatic tumors in this setting of patients Material and Methods Thirty-nine patients (mean age 69 years; range: 49-93) with histologically confirmed superficial recurrent/metastatic tumours were treated: 19 breast, 10 head & neck, 2 malignant melanoma, 4 sarcomas, 1 uterine, 1 hepatocarcinoma and 2 pancreatic carcinoma. The total number of treated lesions was 62. The mean Karnofsky Index value is 75. Pre-treated patients (70%)

received a previous mean RT dose of 50 Gy. Patients underwent RT treatment using 3D-conformal RT (16/39) or Helical Tomotherapy (23/39). External beam RT was delivered in 5-27 fractions of 1.7-5 Gy to a total dose of 20-57.5 Gy (mean external dose: 39 Gy). Hyperthermia (HT) treatment is performed with a double electromagnetic superficial applicators operating at the frequency of 434 MHz. HT session was delivered once/twice weekly during the period of RT , 1-2 hours after RT [mean value: 5; range: 1-9 sessions]. Average, maximum and minimum temperature parameters were recorded during HT treatment. The treatment goal was to reach 40- 42°C in > 90% (T90) of measured points for a duration of 60 minutes. Acute and late toxicity was evaluated according to the CTCAE criteria. Local control was assessed after the end of the treatment on the basis of the RECIST Criteria Results During HT treatment the median temperature [range] reached was 40.5 °C [39 – 42.9°C]. Five patients interrupted the treatment: 2 pts (5%) for G3 toxicity, 2 (5%) for poor compliance and 1 (2.5%) for clinical progression disease. Two pts (5%) had acute cutaneous toxicity ≥ G3 at 1 month. Four patients had toxicity > G2 at 3 months, three patients had > G2 at 6 months and only one patients at 12 months. No patients showed toxicity ≥ G2 thereafter. The mean follow-up was 12 months (range 1-50 months). The Local control rate was: 87%, 72%, 65% and 53%, 63% and 75% at 1 , 3 , 6 , 12, 24, 36 months respectively. The time to local progression was ranged between 1 and 12 months (mean: 6 months). The detailed results are reported in Table 1. Five patients are dead (4 for disease and one for vascular accident). Univariate analysis showed that Tmean, Tmax, Tmin, T90 parameters were not associated with local control rate

follow-up (months) CR (%) PR (%) SD (%) PD (%) 1 20 48 19 13 3 22 28 22 28 6 26 4 35 35 12 20 6 27 47 24 37.5 - 25 37.5 36 25 - 50 25

TABLE 1: response rate in the time (months) Conclusion

RT-HT is useful combined treatment with a good local control rate and patient compliance. The clinical outcome and the time duration of the follow-up is affected by the advanced stage of diseases. A larger pool and a more detailed patient stratification are needed to evaluate the outcome data in the time Acknowledgments This work was supported by “5 per Mille 2009 Ministero della Salute-FPRC Onlus”. EP-1390 Superior target delineation of renal cell carcinoma bone metastases on MRI vs CT F.M. Prins 1 , J.M. Van der Velden 1 , A.S. Gerlich 1 , A.N.T.J. Kotte 1 , W.S.C. Eppinga 1 , N. Kasperts 1 , L.G.W. Kerkmeijer 1 1 UMC Utrecht, Radiation oncology, Utrecht, The Netherlands Purpose or Objective In metastatic RCC (mRCC) there has been a treatment shift towards targeted therapy, which has resulted in a 50% increase in overall survival. Therefore, there is a need for better local control of the tumor and its metastases. Image-guided SBRT in bone metastases provides improved symptom palliation and local control. After SBRT for mRCC, local control rates have been improved from 50% to 85% when compared to conventional fractionation