ESTRO 2023 - Abstract Book

S1060

Digital Posters

ESTRO 2023

1 Medical University of Gdansk, Department of Oncology and Radiotherapy, Gdansk, Poland

Purpose or Objective In-field relapses occur in around 30% of non-small cell lung cancer (NSCLC) patients treated with definitive radiochemotherapy (RCT). Changes in body composition (BC) may underpin biological processes that impact the radiosensitivity of NSCLC. We investigated potential associations between BC and in-field recurrence in patients managed with RCT for stage III NSCLC. Materials and Methods This retrospective, single-center study enrolled 34 patients treated with radical RCT with mean PTV doses of 60-66 Gy. Using CT imaging, total body subcutaneous and visceral adipose tissue (SAT, VAT), and skeletal muscle (SM) volumes were manually quantified at the 3rd lumbar vertebra level using SliceOmatic software. Body composition values were normalized considering gender and age-dependent variability against published demographically adjusted population reference curves obtained in > 12.000 non-cancer individuals (Magudia et al. Radiology 2020). Low body composition scores were defined as values below the 25th centile for all evaluated body composition parameters (SM, SAT and VAT). Results After a minimum follow-up of 4 years, in-field recurrence occurred in 19/34 cases (56%). Low body composition scores for SM, SAT and VAT were observed in 24% (8/34), 68% (23/34), and 47% (16/34) of patients, respectively. In-field recurrence was observed in the entire low SM subgroup (8/8 patients). In the univariate analysis, low SM was associated with a higher risk of in-field recurrence (p=0.014). GTV volume did not significantly differ between patients with and without in-field recurrence (p = 0.650). In a logistic regression model, low SM was predictive for in-field recurrence (p = 0.012), independently of sex, age, tumour histology, GTV volume, and smoking. Low SAT or VAT did not correlate with the risk of an in-field recurrence. Conclusion In patients with stage III NSCLC treated with RCT, low skeletal muscle, but not SAT or VAT, was independently associated with an increased risk of an in-field recurrence.

PO-1325 Brain metastasis burden and management in small cell lung cancer: an analysis of 8705 patients

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PO-1326 Predictors of post-chemoradiothearpy pulmonary complication for non-small cell lung cancer

T.H. Lee 1 , B. Kang 1 , H.J. Kim 1 , H. Wu 1 , J.H. Lee 1

1 Seoul National University Hospital, Department of Radiation Oncology, Seoul, Korea Republic of

Purpose or Objective We aimed to investigate the clinical effects and predictive factors of post-chemoradiotherapy pulmonary complication (PCPC) for locally advanced non-small cell lung cancer (NSCLC). Materials and Methods Medical records of 317 patients who underwent definitive concurrent chemoradiation (CCRT) for locally advanced NSCLC were reviewed retrospectively. PCPC was defined as an event of admission or emergency department visit for acute or subacute lung inflammatory complications within 6 months from CCRT initiation. The lung inflammatory complications included pneumonitis and pneumonia. Patient characteristics, baseline lung function tests, radiation dosimetric parameters, and laboratory tests were analyzed to investigate the association with PCPC. Prognostic endpoints were progression-free survival (PFS) and overall survival (OS). Results PCPC was reported in 53 (16.7%) patients. Patients with PCPC showed significantly worse OS (33.8% in 2 years) than those without PCPC (65.3% in 2 years, P < 0.001). However, the 2-year PFS rates were 25.7% with PCPC and 29.1% without PCPC, with no significant difference (P = 0.139). Actuarial rates of PFS and OS by presence of PCPC are illustrated in the following figure. In the multivariate logistic regression model, PCPC was independently associated with grade ≥ 1 hypoalbuminemia during CCRT (odds ratio [OR] 5.670, 95% confidence interval [CI] 2.487-13.40, P < 0.001), lower diffusing capacity of carbon monoxide (DLCO) (per ml/min/mmHg, OR 0.855, 95% CI 0.743-0.974, P = 0.022), and higher lung V5 (per 10%, OR 1.872, 95% CI 1.336-2.699, P = < 0.001).