ESTRO 2022 - Abstract Book

S634

Abstract book

ESTRO 2022

Conclusion Our results suggest that all patients with unifocal disease, and those with multifocal disease who have undergone a partial or complete resection, are candidates for radiation dose-escalation.

MO-0723 Outcomes and patterns of recurrence following stereotactic radiosurgery for brain metastases

S. Møller 1 , H. Roed 1 , P. Geertsen 2 , G. Persson 2

1 Rigshospitalet, University of Copenhagen, Dept. of Oncology, Copenhagen, Denmark; 2 Herlev Hospital, University of Copenhagen, Dept. of Oncology, Copenhagen, Denmark Purpose or Objective To determine the efficacy and real-world outcomes of stereotactic radiosurgery (SRS) for brain metastases (BM) in a retrospective study of approx. 1600 patients treated at two neighboring institutions. Study points include demographics and outcomes for various diagnoses, efficacy of SRS in achieving intracranial disease control, patterns of recurrence, patterns of care and outcomes. Materials and Methods A retrospective database containing consecutive patients treated with SRS for BM between 2013-2019 at Rigshospitalet and Herlev Hospital is being built. The two centres participate in common, weekly multidisciplinary team conferences with representation from neurosurgery, radiology, radiotherapy technicians and oncology depts., respectively. Thus, a wholly common treatment strategy is employed. Characteristics of patients, brain metastases (including number, size, location, previous surgery) and radiotherapy (dose, fractionation) are registered as well as survival times, patterns of recurrence and salvage radiotherapy. Relevant disease specific mutations such as EGFR and ALK for non-small cell lung cancer (NSCLC) and ER- and HER-2 status for breast cancer were registered. Collaboration with disease specific teams (e.g. those treating metastatic melanoma or breast cancer) is ongoing and planned, allowing for in-depth analysis of outcomes including mutational subgroups (e.g. EGFR status in NSCLC). Results Currently, 1313 patient cases (of a total of approx. 1600) have been entered into the database. Non-small cell lung cancer (51%), breast cancer (13%) metastatic melanoma (7%) colorectal cancer (6%) and renal cell carcinoma (6%) were the most prevalent diagnoses. Ninety percent of patients had died at the time of data collection. Survival times from first course of SRS were generally poor but varied significantly depending on diagnosis. For example, the median OS for patients with breast cancer was 406 days (95% CI 304-508 days) whereas for patients with colorectal cancer the median OS was 139 days (95% CI 100-178 days). Following the first course of SRS, a follow-up scan was carried out at any time in 65% of patients. Recurrence in the brain was seen in 45% of these cases which corresponds to a radiological relapse rate of 29%. Recurrences were local (42%), remote in brain (new lesion) (36%) or both (22%). Twenty percent of patients received more than one course of SRS (2 courses = 15%, 3 courses = 4%, 4-6 courses =1%). In both courses 2 and 3, one or more suspected relapsed metastases received SRS re- treatment in approximately 44% of cases. Conclusion These real-world data confirm the universally poor prognosis associated with brain metastases, even in this recent patient population treated at two collaborating institutions. Intracranial recurrence rates are in line with published data. Updated analyses including time to intracranial progression, outcomes in eloquently located lesions and outcomes following surgery + SRS will be presented.

MO-0724 Impact of irradiation of the neurogenic niches on survival in patients with brain metastases

F. Cialdella 1 , S. David 1 , D.E. Bruil 1 , S.H. Nagtegaal 2 , A.T. van der Boog 1 , S. de Sonnaville 3 , F. de Vos 4 , J.J. Verhoeff 1

1 University Medical Center Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands; 2 Erasmus Medical Center, Department of Radiation Oncology, Rotterdam, The Netherlands; 3 University Medical Center Utrecht, Department of Neurosurgery, Utrecht, The Netherlands; 4 University Medical Center Utrecht, Department of Medical Oncology, Utrecht, The Netherlands