ESTRO 37 Abstract book

S918

ESTRO 37

response. An increase in the percentage of apoptotic cells suggests less effective DNA repair whereas patients with lower percentage of apoptotic CTCs might have higher repair capacity. This correlates with individual DNA repair capacity showing less effective DNA repair in CTCs and poor prognosis. At present sample collection is ongoing to obtain data for a minimum of 100 patients. EP-1709 An effectiveness evaluation of the palmar fascia irradiation of patients with Dupuytren’s disease T. Latusek 1 , L. Miszczyk 1 , G. Gierlach 2 , P. Zając 3 1 Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Radiotherapy, Gliwice, Poland 2 District Hospital of Orthopedics and Trauma Surgery, Hand Surgery, Piekary Śląskie, Poland 3 District Hospital of Orthopedics and Trauma Surgery, Pediatric Orthopedics and Trauma Surgery, Piekary Śląskie, Poland Purpose or Objective Dupuytren's disease is a fibroproliferative disorder of an unknown etiology manifested by a progressive contracture of fingers. The basic method of the treatment is surgery. Among non-surgical treatments, radiotherapy (RT) represents a relevant method. The aim of the study was to evaluate the efficacy of palmar fascia irradiation in patients with Dupuytren's Disease. Material and Methods The research included a group of 117 patients with Dupuytren's disease irradiated in the Department of Radiotherapy in the Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology in Gliwice. Patients’ medical records from the Institute of Oncology in Gliwice and the Provincial Hospital of Orthopedics and Trauma Surgery in Piekary Slaskie have been analysed retrospectively. The following were assessed: smoking history and the subjective evaluation of the effect of the therapy and its side effects before irradiation and check-up visits. All patients were irradiated to a total dose of 21Gy given in 7 fractions. Results After the RT, 35% of patients showed an improvement, in 58% of patients the disease progress stopped, whereas 7% of patients reported a deterioration. During the observation period, 7.5% of patients noted a deterioration of the contracture or the topical condition, in 35% stagnancy was observed, and 57.5% of patients showed a reduction of the contracture and an improvement in the topical condition. After the RT, 87.5% of patients had no side effects, in 7.5% there was a slight skin erythema, 2.5% had superficial epidermis exfoliation, and 2.5% reported dry skin Conclusion The obtained results allow one to conclude that palmar fascia irradiation is an effective method of treatment for patients with Dupuytren's disease and it is characterised by a low proportion of complications. EP-1710 Pre- versus post-operative radiotherapy: complications after combined therapy for spinal metastases. B. Pielkenrood 1 , L. Pogoda 1 , J. Van der Velden 1 , H. Verkooijen 2 , J. Verlaan 3 , N. Kasperts 1 1 UMC Utrecht, Radiotherapy, Utrecht, The Netherlands 2 UMC Utrecht, Epidemiology, Utrecht, The Netherlands 3 UMC Utrecht, Orthopeadics, Utrecht, The Netherlands

Purpose or Objective The majority of cancer patients develop bone metastases with the spine as most common location (30-70%). These metastases can cause pain, spinal instability, and spinal cord compression, thereby decreasing quality of life. To improve quality of life and preserve spinal stability, a combined treatment of surgical stabilization and radiation therapy (RT) is necessary for patients with spinal instability, furthermore mechanical pain will not improve after radiotherapy alone . Currently it is unknown whether pre- or postoperative RT is better. Therefore, we studied the rate of complications in patients who received pre-operative RT compared to patients who received post-operative RT. Material and Methods All patients receiving surgical therapy in combination with RT for spinal metastases between 2009 and 2017 where included in this study. Patients were identified from the PRESENT cohort, a prospective cohort of all patients treated with RT for bone metastases at the UMC Utrecht, and the spinal metastases database of the UMC Utrecht. Complications were defined as complications according to the Clavien-Dindo classification grade 2-4 or neurological damage without therapeutic options within 3 months after completion of treatment. Statistical analysis was done using IBM SPSS 23. Results Of the 142 patients receiving RT and surgery , 91 patients (64%) received pre-operative radiotherapy and 51 patients (36%) received post-operative radiotherapy. The number of days between radiotherapy and operation was 0-280 in the pre-operative RT group and 8-69 days in the post-operative RT group. Of all patients, 71 (50%) had any complication after the combined treatment. Most complications were in the post-operative RT group (53% vs. 45%). The rate of total complications between pre-operative and post-operative RT was not statistically different. (OR=0.74; 95% CI 0.35- 1.55)Most common complications were neurologic complications (n=27), and wound complications (n=10) . In the pre-operative RT group, 3 patients (6%) had wound complications. In the post-operative RT group, 7 patients (8%) experienced wound complications. In the pre- operative RT group, 12 patients(24%) had a neurological complications compared to 13 patients(14%) in the post- operative RT group. Neither the rate of wound complications or neurological complications were statistically different in the pre-operative RT group vs. post-operative RT group(OR=0.75; 95% CI 0.12-3.48 for wound complications) and (OR= 1.56; 95% CI 0.60-3.96 for neurological complications) Conclusion These preliminary results show no significant differences in complication rates between patients who received pre- operative or post-operative RT for spinal metastases. In further research we can focus on the prevalence of complications within certain time frames pre- and postoperatively. EP-1711 Stereotactic body radiotherapy for oligometastatic bone metastases: a two-year follow-up study I. Guix 1 , A. Navarro 1 , A. Lozano 1 , M. Laplana 1 , J. Mases 1 , J. Gonzalez 1 , S. Almendros 1 , N. Garcia 1 , M. Stefanovic 1 , F. Guedea 1 1 Catalan Institute of Oncology, Radiation Oncology, Barcelona, Spain