ESTRO 2023 - Abstract Book

S1059

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ESTRO 2023

had a CV event: four atrial fibrillation, two supraventricular tachycardia, one atrioventricular block (second degree), and one patient presented heart failure. The cardiac dosimetric parameters analyzed were described in Table 1. The analysis of cardiac dosimetry was shown in Table 2. Patients who developed CV and no-CV have higher mean values of PTV volume (442 vs 310 p=0.031), heartDmean (17.72 vs 11.89 p=0.032), V30 (24 vs 13 p=0.009), V45 (10.79 vs 5.68 p=0.007), V50 (7 vs 3.85 p=0.030), resulting all in prediction of CV events. In particular, PTV volume (AUC 0.75), HeartDmean (AUC 0.73), V30 (AUC=0.76), V45 (AUC=0.79) and V50 (AUC=0.72) were significant.

Conclusion This preliminary data have shown that all parameters evaluated, except of left anterior descending artery (LAD) dose, were found to be predictive of cardiovascular damage after CRT. These results encourage us to continue the study in order to estimate the overall and individual incidence of any early cardiac event and to identify additional variables that cause an increased risk of acute cardiac events.

PO-1323 Re-irradiation in NSCLC High-dose RT: Control, Survival and Toxicity

J. Germain 1 , F. Celada 2 , O. Prato 2 , I. Solero 2 , M. Borras 2 , M.J. Perez-Calatayud 2 , M. Berenguer 2 , M. Estornell 2 , N. Tejedor 2 , A. Conde 2

1 Hospital la Fe, Radiation oncology, Valencia, Spain; 2 Hospital La Fe, Radiation Oncology, Valencia, Spain

Purpose or Objective Patients affected with non-small cell lung cancer (NSCLC) may present local recurrences inside the irradiated area after receiving external beam radiotherapy (EBRT). Re-irradiation with High dose radiotherapy appears as a promising approach, showing long-term control with acceptable toxicity. This is a descriptive study reviewing the clinical outcomes of patients treated in our hospital with High dose re-irradiation either with SBRT or hypofractionated EBRT after local recurrence of NSCLC Materials and Methods We retrospectively reviewed patients treated with thoracic SBRT or hypofractionated EBRT from 2012 through 2021. We identified 17 patients treated with prior thoracic radiation therapy for NSCLC with subsequent “in field” re-irradiation, defined as overlapping of PTV of both treatments; or “border field”, defined as overlapping of the recurrence PTV with the previous 30 Gy isodose. Overall survival, local control, recurrences and toxicity were assessed. Results Median age at the time of re-irradiation was 66 years (47-83). The re-irradiation dose ranged from 50 to 60 Gy (BED 75 180Gy) given in 3-10 fractions. Median follow-up was 23 months. Local control was 81% at 1 year, with a median of 16 months of local control, a median of 10 months of progression-free survival and a median of 24 months for overall survival. One patient died of hemoptysis after re-irradiation, no other patients presented toxicity above grade 3. Conclusion Results indicate that lung re-irradiation with High dose radiotherapy may offer disease control in carefully selected patients.

PO-1324 Body composition as a predictor of an in-field recurrence in stage III NSCLC patients

B. Tomasik 1 , M. Dró ż ka 1 , M. Konkel 1 , R. Dziadziuszko 1 , A. Kumaravel 1 , J. Jassem 1 , M. Skrzypski 1