ESTRO 2021 Abstract Book

S960

ESTRO 2021

Conclusion We found significant association between lung V20 and respiratory type hospital admission within the first year after RT. As expected, COPD status and DLCO are also strongly correlated with admissions post RT. Further analysis including mapping of dose distribution and lung density is warranted. Further work on predictive modelling of respiratory type hospitalisations after radiotherapy is underway. PO-1155 Real world radiotherapy protocol compliance for patients with Stage I-III Non-Small Cell Lung cancer X. Huang 1 , S. Vinod 2 , P. Keall 1 , M. Field 3 , V. Batumalai 4 , L. Holloway 4 1 University of Sydney, Faculty of Medicine and Health, Sydney, Australia; 2 Liverpool Hospital, Cancer Therapy Centre, Sydney, Australia; 3 University of New South Wales, Faculty of Medicine, Sydney, Australia; 4 Ingham Institute, Medical Physics, Sydney, Australia Purpose or Objective Despite the availability of radiotherapy treatment protocols for lung cancer, there is considerable variation in clinical practice. The purpose of this study is to investigate protocol compliance rate and the factors affecting guideline compliance in non-small cell lung cancer (NSCLC) patients treated with radiotherapy. Materials and Methods The Australian eviQ treatment protocol for curative radiotherapy treatment of Stage I-III NSCLC was taken as the reference to measure compliance. All inoperable patients with Stage I-III NSCLC and documented ECOG performance status treated with radiotherapy between 2007 and 2019 at two cancer centres were eligible for analysis. Guideline compliance rates were calculated. 22 variables were assessed for association with guideline compliance. A logistic regression model was developed to determine the significant factors influencing compliance. Survival analysis is conducted for both compliant and non-compliant patients. Results 656 patients were eligible for the guideline compliance analysis. Compliance to the eviQ protocol ranged from 14%-21%. Alternative dose/fractionation was responsible for 75% of non-compliant cases. Four of 22 variables (tobacco use, alcoholism, renal function and age) showed significant associations with guideline compliance on multivariate analysis. The survival time of compliant patients and non-compliant patients shows no statistically significant difference. The median value of survival months is 14.11 for non-compliant patients and 14.88 for compliant patients. Conclusion Adherence to the EviQ curative radiotherapy protocol for Stage I-III NSCLC was low. Alternative dose/fractionation schemes were the main reason for non-compliance. PO-1156 Temporal muscle thickness as a potential biomarker of OS in NSCLC patients with BM treated with SRT G. Gadducci 1 , F. Pasqualetti 2 , A. Gonnelli 1 , N. Giannini 1 , M. Gabelloni 1 , R. Morganti 3 , E. Neri 4 , G. Malfatti 2 , F. Paiar 1 1 AOUP, Department of Radiation Oncology, University Hospital of Pisa, PISA, Italy; 2 AOUP, Department of Radiation Oncology, University Hospital of Pisa, pisa, Italy; 3 AOUP, Department of Statistics, University Hospital of Pisa, PISA, Italy; 4 AOUP, Department of Radiology, University Hospital of Pisa, PISA, Italy Purpose or Objective Temporal muscle thickness (TMT) was described as a surrogate marker of skeletal muscle mass. The purpose of this study was to evaluate the prognostic relevance of TMT in non-small-cell lung cancer (NSCLC) patients with newly diagnosed of single brain metastasis (BM) treated with stereotactic radiotherapy (SRS). Materials and Methods TMT was retrospectively assessed in 89 NSCLC patients (81 adenocarcinoma and 8 squamous cancer cell, median age 67,5,range 27-81,M:F 1,5:1) with a single newly diagnosed brain metastasis and which subsequently underwent to SRS between 2011 and 2019 . The following were the inclusion criteria: available MRI examination of the brain or computer tomography (CT); the temporal muscle had to be depicted in its whole extension; BM were treated with SRS. TMT was assessed by an expert radiologist at the time of diagnosis of brain metastases on axial T1-weighted MR images or on axial CT scan with contrast. The measurements were taken perpendicular to the long axis of the temporal muscle using the orbital roof (cranio-caudal) and the Sylvian fissure (anterior–posterior) as anatomical landmarks as reported by Furtener et al. TMT was measured on the left and on the right side in each patient and then a media was performed. Disease-specific graded prognostic assessment (DS-GPA), the presence of extracranial metastases, histology and survival times were evaluated. For the present study, overall survival (OS) was defined as days between the diagnosis of brain metastasis and death or date of last follow-up. Results Patients with a TMT above the median (7.39 mm) had a significantly improved survival prognosis compared to those who had a TMT > median ( p= 0,003; HR 0.459,IC 0.274-0.767). The risk of death was increased by 20 % with every millimeter reduction in TMT. In the multivariate analysis, TMT (HR 0.479; 95% 0.279– 0.825;p=0,008), histology adenocarcinoma (HR 0.411, CI 0.299-0.798,p=0.003) showed a statistically significant correlation with OS. Conclusion In our study we have demonstrated that TMT is an independent predictor of survival in NSCLC patients harboing BM, which is consistent with the present literature. This is based on the fact that muscle wasting is associated with cancer-related cachexia.This parameter may aid patient selection for the choice of different