ESTRO 36 Abstract Book

S755 ESTRO 36 2017 _______________________________________________________________________________________________

setting, chemotherapy in outpatient setting and exclusion criteria: combined radiochemotherapy, hospitalzation, central venous catheter, palliative treatment. 360 patients were selected for the final analysis and were stratified in 3 groups: group I (n=120) 3D-conformal RT for brain tumors or brain metastasis; group II (n=120) RT for body tumors (abdominal, retroabdominal, pelvic, chest, breast); group III (n=120) was control –brain and body tumors on chemotherapy. Mean fraction numbers were 25 (11 - 32), mean total dose – 52 Gy (22 - 66). VTE assessment based on clinical data, venous ultrasound examination (US) and chest CT. Statistical analysis was performed by OpenEpi, Version 3 software pack. Results Deep vein thrombosis (DVT) was detected in 7 cases (5.8%) in group I, 2 cases in group II and 1 case in control group. VTE patients has a different tumors (right parietal area astrocytoma, brain trunk tumor, skull basis cancer, rectal cancer, breast cancer). 3 patients were available for long- term outcomes assessment (12 months after radiation therapy). During 1-year period we haven’t detected thrombosis recurrence. Post thrombotic disease had developed but without severe venous insufficiency. One patient on 11th follow-up month was exposed with repeated course of RT without any complications. The difference between VTE incidence for group I and group III characterized by statistical significance (p=0.018). Risk difference for these groups was 5% (p<0.05). Conclusion Based on study results we suggest that external beam radiation therapy is potentially an independent risk factor for venous thromboembolism development even in outpatient settings. High degree of clinical suspicion and aggressive diagnostic work-up in case of suspicion is necessary. In our opinion VTE prevention with low molecular weight or unfractionated heparin should be considered in selected patients at least during active radiation therapy E. Burchardt 1 , A. Roszak 2 , B. Urbañski 3 , A. Nowak 3 1 Greater Poland Cancer Centre, Department of Oncological Gynecology and Radiotherapy, Poznan, Poland 2 Greater Poland Cancer Centre, oncological gynecology and radiotherapy, Poznań, Poland 3 Greater Poland Cancer Centre, Department of Oncological Gynecology and Radiotherapy, Poznań, Poland Purpose or Objective A series of phase III trials demonstrated the clinical effect of hyperthermia. In January 2016 a new device for deep regional hyperthermia was installed in our cancer centre. The aim of this study was to assess tolerance and acute toxicity of loco-regional hyperthermia given during 101 patients (pts) were evaluated during treatment in the period of time from January till September 2016. 45 pts with cervical cancer (CC) were treated with radical radiochemotherapy. 17 pts with CC were treated palliative with radiotherapy , 10 pts with hepatic lesions (1 HCC and 9 meta ad hepar) treated with chemotherapy, 7 pts with pancreatic ca treated with chemotherapy, 2 breast ca treated with chemotherapy ( 1 with RT and 1 with CT), 11pts with lung ca treated with chemotherapy , 7 pts with rectal ca. treated with radiotherapy, 4 pts with ca. of sigmoid colon treated with chemotherapy, 2 pts with gastric ca. treated with chemotherapy and 1 with radiotherapy. The Celsius TCS hyperthermia system, an electro-hyperthermia, with a maximum output of up to 500 Watts was used. Two different electrode sizes were applied externally by physical means to the region with EP-1431 Acute toxicity in deep loco-regional hyperthermia oncological treatment. Material and Methods

tumour in a targeted and controlled manner. The aim was to increase the temperature to 41 o C - 42 o C, one session lasted 60min. It was combined with either chemotherapy or radiotherapy twice per week. Toxicity of the skin was evaluated at every session with RTOG/EORTC classification system. The tolerance of treatment was ranged as Group 1: very good if there were 1-2 pauses because of discomfort with no other symptoms, Group 2: good- 3-4 pauses because of discomfort and skin toxicity Grade 1, Group 3: poor- > 4 pauses or shortening of hyperthermia course because of itching and skin toxicity>=Gr 2. Results Local deep hyperthermia was easily tolerated. 78 pts didn’t report any problems and were assigned to Group 1. 16 pts were assigned to Group 2 and only 2 pts to the group “poor”. Toxicity was generally mild and never of grade 3. 1/10 pts felt pain in the last few minutes of the session. Acute radiation toxicity was the same with or without hyperthermia. There was a reduced tolerance of hyperthermia in obese persons, with folds of skin on the abdomen. This is primarily due to the fact that between folds of skin sweat is collected what increases negative impression from temperature. All patients with tumours located in pelvis, reported pressure on the coccyx. We haven’t observed any increased vaginal bleeding during radical and palliative treatment of CC. Conclusion Tolerance associated with hyperthermia was very good and most patients felt comfortable during this treatment. Acute toxicity of the skin during the treatment was low. EP-1432 Advantage of butterfly-vmat versus vmat in mediastinal tumors J. Luna 1 , A. Ilundain 1 , S. Gómez-Tejedor 1 , D. Esteban 1 , M. Rincón 1 , J. Olivera 1 , W. Vásquez 1 , I. Prieto 1 , L. Guzmán 1 , J. Vara 1 1 Fundación Jiménez Díaz, Radiation Oncology, Madrid, Spain Purpose or Objective There is a growing concern about the risks of late adverse effects in young people who receive mediastinal radiotherapy. The amazing technical advance has achieved better planned treatments. At present, the new focus of interest is to minimize the low doses in organs at risks (OARs) Material and Methods We present our first results of a new protocol in our Department for mediastinal radiotherapy. This protocol includes the comparison of two treatment plannings for every patient: volumetric modulated arc therapy (VMAT), and Butterfly VMAT (a technique developed by the University of Turin, Radiation Oncology Unit). VMAT was performed with a double arc of 360º. B-VMAT consisted of 2 coplanar arcs of 60º (gantry starting angles 150º and 330º) and 1 no-coplanar arc of 60º (gantry starting angles 330º, couch angle 90º). Until now, five patients have been included: Three mediastinal lymphomas in young women (total dose 36 Gy in two cases and 30 Gy in the other one), one patient diagnosed of hemangiopericytoma located at internal mammary chain (total dose 50 Gy) and the fifth patient diagnosed of thymoma (54 Gy) In the dose- volume histogram, regarding the PTV, the parameters analyzed were V95, V98, V107, Medium dose, Homogeneity index (HI) and conformity index (CI). For OARS- (heart, lung and breast) and body, several dosimetric parameters were registered. Results Our results show similar data in PTV coverage, IH and CI. Regarding the OARs, dosimetric parameters were equivalent in lung, heart and body. However, breast doses were clearly lower with B-VMAT, mainly the lowest doses (V4 and V10). For V4 , the medium value was 45.6% (7.8%