ESTRO 2021 Abstract Book

S965

ESTRO 2021

Verbeeten, Radiation Oncology, Tilburg, The Netherlands; 11 Medisch Spectrum Twente, Radiation Oncology, Enschede, The Netherlands; 12 Maastro, Radiation Oncology, Maastricht, The Netherlands; 13 RadboudUMC, Radiation Oncology, Nijmegen, The Netherlands; 14 Amsterdam UMC location VUMC, Radiation Oncology, Amsterdam, The Netherlands; 15 Radiotherapie groep, Radiation Oncology, Arnhem, The Netherlands; 16 UMCG, Radiation Oncology, Groningen, The Netherlands; 17 MC Haaglanden, Radiation oncology, Den Haag, The Netherlands; 18 Radiotherapeutisch Instituut Friesland, Radiation Oncology, Leeuwarden, The Netherlands; 19 ZRTI, Radiation Oncology, Vlissingen, The Netherlands; 20 Isala, Radiation Oncology, Zwolle, The Netherlands; 21 Netherlands Cancer Institute, Radiation Oncology, Amsterdam, The Netherlands Purpose or Objective The Dutch Lung Cancer Audit for Radiotherapy (DLCA-R) is a national registration for lung cancer patients in the Netherlands collecting tumor and treatment characteristics, and acute toxicity (< 3 months after the end of the irradiation). For inoperable stage III NSCLC cCRT is the preferred treatment. We analysed per participating institute variation in stage III NSCLC patients treated with sequential chemoradiation (sCRT) or concurrent chemoradiation (cCRT) in patient groups ≤75 years and >75 years of age. The identification of prognostic factors of toxicity and mortality was reported previously. Materials and Methods For each radiotherapy institute participating in the DLCA-R between 2015-2018, we analysed the total amount stage III NSCLC treated with cCRT or sCRT in elderly and non-elderly. We defined cCRT in case the irradiation started within 30 days after the start of chemotherapy. Radiotherapy institutes were grouped into 4 categories based on the number of patients treated with cCRT or sCRT over four years: low volume (<50 patients), medium volume (50-99 patients), high volume (100-149 patients) and very high volume (≥150 patients). Results Nineteen (out of twenty) radiotherapy departments in the Netherlands participated in the registration. 2953 stage III NSCLC patients were treated with cCRT or sCRT and 2944 patients were analysed. 14.5% were >75 years (median 78 years) and 50.6% of these patients were treated with cCRT, while for the ≤75-year group (median 65 years) 73.4% was treated with cCRT. We scored 1 low volume institute, 8 institutes with medium volume, 3 institutes with high volume and 7 institutes with very high volume. In 18 institutes, the amount of elderly patients treated with cCRT or sCRT was lower than 50 patients in 4 years, while in 1 institute 71 elderly were treated. There was a large variation in the percentage elderly versus non-elderly per institute treated with cRT ranging from 6% to 25%. Figure 1 depicts the variation of the numbers of treated patients between the departments (numbered 1-19) in cCRT (orange) versus sCRT (dark orange) and in non-elderly (Y: ≤ 75 years) versus elderly (O: >75 years). Each bar represents the number of patients. The elderly patients in the single low volume institute were treated with cCRT. In the medium volume institutes, 64% of the elderly was treated with cCRT. In the high volume institutes 27% was treated with cCRT, and in the very high volume institutes, the elderly group was treated with cCRT in 51% (p<0.001).

Conclusion This Dutch audit on lung cancer treatment provides real-world data for elderly and non-elderly NSCLC patients treated with CRT. The non-elderly group is mostly treated with cCRT 73.4%, while this is 50.6% elderly. It is still a relatively small group of elderly patients treated with definitive cCRT for stage III NSCLC in the Netherlands with variation between hospitals. PO-1163 Incidence of cardiovascular events in advanced NSCLC patients treated with chemo- radiotherapy. C.F. Carmen 1 , C.R. Joaquin José 1 , G.M. Jose María 2 , O.S. Beatriz 1 , B.P. Beatriz 1 , G.D. María 1 , V.B. Victoria 1 , S.S. Paula 1 , Q.R. Juan 1 , R.K. Yesika 1 , R.C. Francisca 1 , G.U. Fernando 1 , M.G. Julia Luisa 1 1 Hospital Universitario de Badajoz, Radiation Oncology, Badajoz, Spain; 2 Hospital Universitario de Badajoz, Cardiology, Badajoz, Spain

Purpose or Objective