ESTRO 2023 - Abstract Book

S371

Sunday 14 May 2023

ESTRO 2023

and developing distant relapse or death was assessed using cox regression, adjusting for age, sex, performance score, RT change and dose per fraction. Results Complete records for 1280 patients were available. 18 (2.5%) stage 1-2 NSCLC, 48 (10.5%) stage 3 NSCLC and 11 (9.5%) SCLC developed ≥ grade 3 acute toxicity. Patients with stage 3 NSCLC who had a change to their RT dose/fractionation had increased odds of developing ≥ grade 3 acute toxicity (aOR=4.31 (1.96, 9.33), p<0.001), but not death (HR=0.980 (0.688, 1.40), p=0.912). These patients received fewer fractions (mean 17.35 vs 20.53 p<0.001) compared to patients who had no change. 59 (8.4%) stage 1-2 NSCLC, 87 (19.1%) stage 3 NSCLC and 34 (29.3%) SCLC patients had distant relapse, and 90 (12.7%), 123 (27.0%), 34 (29.3%) died respectively. For stage 3 NSCLC patients considered for chemotherapy, 48 (18.1%) had their chemotherapy omitted and 35 (13.2%) had a reduced dose. The patients who had their chemotherapy omitted had a higher rate of distant relapse compared to those who had no change (31.2% vs 14.8%), however multivariable analysis demonstrated no significant increase in distant relapse (HR=1.91 (0.947, 3.84), p=0.0706) or death (HR=1.71 (0.913, 3.19) P=0.0938). Kaplan-Meier curves are presented in Figures 1 and 2.

Conclusion Our data suggest changes to RT made during the COVID-19 pandemic led to increased ≥ grade 3 acute toxicity for patients with stage 3 NSCLC, but did not affect survival. Patients with stage 3 NSCLC who had their chemotherapy omitted had double the rate of distant relapse, but this was not significant in the multivariable analysis. This data is important as it can inform practice in the context of potential future emergency situations requiring a need to reduce hospital attendances.

MO-0468 Impact of gross vascular invasion on NSCLC outcomes: propensity matched cohort analysis A. Ushkempirov 1 , C. Faivre-Finn 1 , G. Price 1 , A. Salem 2