ESTRO 37 Abstract book

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ESTRO 37

Conclusion Preliminary data shows that this radiotherapy schedule is a clinically viable option for unresectable tumours of the esophagogastric junction or gastric adenocarcinoma to achieve significant palliation of the main presenting symptoms like bleeding and dysphagia. EP-1653 Prognostic factors in stereotactic body radiotherapy to bony oligometastatses from solid tumors. W.H. Mui 1 , S.F. Nyaw 1 , M.Y.P. Wong 1 , R.W.K. Leung 1 , F.C.S. Wong 1 1 Tuen Mun Hospital, Clinical Oncology, New Territories, Hong Kong SAR China Purpose or Objective There is robust data showing promising treatment results in terms of local control, progression free survival and overall survival by the use of Stereotactic Body Radiotherapy(SBRT) as ablative therapy for oligometastatic disease in general. However prognostic factors are less well studied in treating oligometastatic bony disease not only limited to the spine by SBRT. Material and Methods A retrospective review of the treatment outcomes of patients who received SBRT to bony oligometastatic sites in our department since 2005 is conducted. Local, systemic disease control and their survival were assessed against different prognostic factors including age, performance status, synchronous or metachronous metastasis, immediate systemic therapy (including chemotherapy, targeted or hormonal therapy), bone only disease or others, whether all disease sites were treated by ablative therapy, PTV volume and various planning parameters including higher D95(BED10> 51.3Gy = 27Gy/3Frs for non-spinal lesion), achievable V100≥ 90% and D90≥ 99%. Results The treatment outcome of 25 patients and 28 lesions was studied. 23(92%) patients had follow-up imaging with CT, PET, MRI or bone scan. The performance status (ECOG) of 22(88%) patients was 1, 5(20%) patients had other sites of disease apart from bone, 8 (28.6%) lesions were non- spinal lesions. Altogether, 20 (80%) patients received ablative therapy, including SBRT, to all involved disease sites, 21(84%) patients received immediate systemic therapy before or after SBRT, treatment was mostly well tolerated. The median D95 was 24.3Gy (prescribed dose range: 18Gy –50Gy, in 3 -5Frs); V100≥ 90% and D90≥ 99% were achievable in 89.3% of the patients, Fig 1. Over a median follow-up of 16.3 months, the median overall survival and median local progression free survival(PFS) were not yet reached, whereas the median systemic progression free survival was 25.5 months. The local control and systemic control were 89.3% and 52% respectively, Fig 2. Concerning local control after SBRT, bone only disease correlates with improved PFS only in univariate analysis (p=0.014), but not PTV volume, higher D95, planning objectives nor spinal or non-spinal location, Fig 2. In overall survival analysis by cox- regression, ablative treatment to all lesions is the only significant prognostic factor identified; for systemic disease control, bone only disease correlates with improved outcome whereas there is a trend towards positive outcome for ablative treatment to all lesions, Fig 3. Conclusion The study results showed that promising overall survival can be achieved by SBRT to bony oligometastatic disease,

in conjunction with other local ablative treatment. Bone only disease may signify a better overall prognosis. SBRT to bony metastasis resulted in excellent local control along disease course independent of lesion location, PTV volume and D95, though majority of the patients received immediate systemic therapy. EP-1654 Evaluation of tolerability in combined treatment with immune inhibitors and palliative radiotherapy. C. De la Pinta Alonso 1 , E. Fernández-Lizarbe 1 , M. Martín Sánchez 1 , J. Domínguez-Rullán 1 , R. Hernánz De Lucas 1 , C. Vallejo Ocaña 1 , M. Martín Martín 1 , P. Barrionuevo 1 , T. Muñóz Migueláñez 1 , F. López Campos 1 , A. Hervás Morón 1 , S. Sancho García 1 1 Hospital Ramon y Cajal, Radiation Oncology, Madrid, Spain Purpose or Objective Immune checkpoint inhibitors are increasingly used in the treatment of metastatic cancers and associated with immune-related adverse events (ir-AEs) such as endocrine dysfunction or gastrointestinal toxicities. Many patients receiving these agents also receive palliative radiotherapy. We analyzed tolerability of this association treatment in our institution. Material and Methods We analyzed retrospectively 50 patients with metastatic lung cancer (36p), renal cell carcinoma (8p), melanoma (4p), head and neck tumors (1p) and gastrointestinal cancer (1p) who received at least one cycle of CTLA-4, PDL-1 or PD-1 inhibitor and palliative radiation. Ir-AEs, defined using CTCAE v4.0, were tabulated in relation with sequencing, timing and location. Results Median dose of radiotherapy was 26,1Gy (8-30Gy). 19p received radiotherapy in bone lesions and 21p in brain metastases. 4p were treated with anti-CTLA-4 alone, 37p with anti-PD-1 or PDL-1 alone and 9p with both. 28p received concomitant immune checkpoint and palliative radiotherapy. 14/50p patients had ir-AEs. In the concomitant group 6p had mild toxicities and 1p developed severe ir-AEs. There were no associations between the site irradiated and specific ir-AEs. Conclusion Our data suggest the combination of local palliative radiation and CTLA-4 and/or PD1 or PDL1 inhibitors are well tolerated, with manageable ir-AEs that did not appear to be associated with the particular site irradiated. Our conclusions are limited by the heterogeneity of patients and treatments and future confirmatory studies are needed, this information can help guide clinical practice for patients on immune checkpoint therapy who require palliative radiotherapy. EP-1655 Hypofractionated palliative radiotherapy for bladder cancer P. Vargas Arrabal 1 , I. Tovar 1 , P. Galvan 1 , R. Guerrero 1 , S. Rodriguez 1 , A. Ruiz 1 , R. Ching 1 , R. Del Moral 1 , M. Zurita 1 , J. Exposito 1 , J. Bermejo 1 1 Hospital Universitario Virgen de las Nieves, Radiation Oncology, Granada, Spain Purpose or Objective Bladder cancer is a relatively common tumor. It ranks ninth in terms of the number of cancer diagnoses. However, as in many cases can be cured, it is not among the 10 tumors that cause more deaths.