ESTRO 2022 - Abstract Book

S1052

Abstract book

ESTRO 2022

Twenty-eight patients with prior pneumonectomy, treated with SBRT on 32 metastatic lesions, were identified. Median age was 62.3 years (range: 48-85). Twenty-four patients (86%) had a previous pneumonectomy for non-small cell lung cancer (NSCLC), 1 for a kidney cancer, 1 for a thymoma, 1 for a sarcoma and 1 for a colon cancer. The median time between pneumonectomy and SBRT was 70.34 months (SD: 143.16). Four patients had previous thoracic adjuvant radiotherapy, with doses ranging from 45 to 66 Gy in 20 to 33 fractions. Only one lesion was confirmed by biopsy. Median GTV was 4.06 mL (range: 0.39-110.65), median PTV was 16.32 mL (range: 3.6-231.35). Median MLD was 3 Gy (range: 0.27-13.27). The median follow-up time was 28.9 months (SD: 11). No grade >3 toxicity was observed. Twenty-one lesions (36.6%) were treated with static coplanar fields, 8 lesions (25%) were treated with VMAT and 2 lesions (6%) with static non-coplanar fields with a Cyberknife. Motion management was obtained in 18 lesions (56%) with a 4D-CT scan, in 12 lesions (37.5%) with DIBH and in 2 lesions with a tracking system (Cyberknife). One local failure was registered. There were 2 regional failures and 10 distant failures. The median OS was 33.6 months (range: 3-73 months). The median OS was 33.6 months [CI 95% : 2-73] and 1-, 2- and 5-years OS rates were respectively of 85%, 72% and 42%. Conclusion This study (the largest cohort to date) shows that local-control and long-term survival can be achieved with acceptable toxicity in this population with limited therapeutic options. An accurate motion management (with 40% of the lesions being treated with either DIBH or tracking) is mandatory. 1 UZ Leuven Gasthuisberg, Radiation Oncology, Leuven, Belgium; 2 UZ Leuven Gasthuisberg, Pneumology, Leuven, Belgium; 3 KULeuven, Laboratory of Experimental Radiotherapy, Leuven, Belgium Purpose or Objective Considering the different co-morbidities of the patients and the potential toxicities of combined chemo- and radiotherapy when treating stage III unresectable non-small cell lung cancer (NSCLC), early mortality rates are a concern. With this study our aim was to assess the 90 day mortality of the stage III NSCLC patients treated at our center, and explore predictive factors. Materials and Methods Consecutive patients were included who commenced concurrent or sequential chemoradiotherapy between 04-2011 and 06-2018. Baseline clinical case-mix variables (age, performance status, pack years, T-stage, pathology, N-stage, charlson comorbidity Index (CCI) and baseline pulmonary function) and treatment-related variables (number of chemotherapy cycles, sequential vs concurrent chemotherapy, fractionation dose, overall treatment time, tumor volume heart V5, V20, V50, mean heart dose, Lung V5 and mean lung dose) were retrieved. The 90 day mortality was calculated from the last day of radiotherapy to the date of death. Univariable logistic regression was performed for all clinical case-mix and treatment related factor. Multivariable logistic regression was performed with the uncorrelated (r<0.6) variables that had a univariable p<0.1 (age, sequential vs concurrent, performance status, Lung V5). Results A total of 148 patient were included in this preliminary analysis. Ninety days mortality in this population was 8.8%. Univariable analysis of all factors are depicted in table 1. After multivariable analysis performance status remained significantly associated with 90 day mortality after radical chemo-radiotherapy (p=0.003, OR=0.85 (0.77; 0.95)), while the lung V5 remained borderline correlated (p=0.08, OR 1.040 (0.995;1.095)). Sequential versus concurrent chemotherapy and age were no longer significant. PO-1247 Predictive factors for 90 day mortality in stage III NSCLC patients treated with chemo-radiotherapy M. Lambrecht 1 , A. Van de Velde 1 , S. Verfaillie 2 , G. Defraene 3 , P. Berkovic 1 , C. Dooms 2 , J. Vansteenkiste 2 , E. Wauters 2