ESTRO 2023 - Abstract Book

S117

Saturday 13 May

ESTRO 2023

Materials and Methods Patients with stage II/III NSCLC and ≥ 4cm diameter primary tumour were randomised in 7 European institutes to receive 24 fractions escalated fraction dose either to the primary tumour as a whole (arm A, n=54), or to an FDG-directed subvolume within the primary tumour (arm B, n=53). Patients completed EORTC QLQ-C30 and LC30 questionnaires at baseline, twice during treatment, and at 1,3,6,12, and 18 months after end of treatment. Scores were linearly transformed to a scale of 0-100. A linear mixed effect (LME) model was used to estimate the effect of treatment group and time on the QLQ-C30 Sum Score. Additionally, in individual patients, a difference of ≥ 10 was considered a clinically relevant difference in functioning and symptom scores. Changes from baseline at 3- and 12-months in physical functioning, dyspnea and overall health/QoL were endpoints of interest. Results In total, 50 and 52 patients were included in the current analysis in arm A and B, respectively. Most patients had stage III disease (88%), and received concurrent chemotherapy (73%). Median gross primary tumour volume was 110cm3 (IQR 65- 179). Median mean physical dose to primary tumour was 77.2Gy (IQR 74.2-80.4) and 74.3Gy (IQR 72.4-78.4), in arm A and B respectively. At baseline, 1, 3, 12, and 18-months, respectively, 86%, 62%, 85%, 80% and 72% of alive patients completed the questionnaire. Baseline C30 and LC13 scores were comparable between the two treatment arms. Fig.1 shows C30 sum score over time. In the LME model, the C30 sum score did not clinically relevant or statistically significantly differ between treatment arms over time. There were no statistically significant differences between the two arms in the change from baseline scores at 3- and 12- months in PF or overall health/QoL. At 3-months, 50.0% and 39.3% experienced a ≥ 10 point worsening in dyspnoea, while 20.6% and 39.3% experienced improvement (Mann-Whitney, p=0.20), in arms A and B, respectively. In dysphagia, 8.6% and 31.2% experienced a ≥ 10 point worsening, while 5.7% and 6.2% experienced improvement, respectively (p=0.05). In fatigue, 54.3% and 38.7% experienced a ≥ 10 point worsening, while 22.9% and 38.7% experienced improvement (p=0.15).

Conclusion We observed no statistically significant different impact of dose-escalation strategy on HRQoL through time. On an individual level, 32.8% experienced a clinically relevant deterioration, while 27% experienced improvement in overall health/HRQoL. PD-0156 Mortality after radiotherapy or surgery in the treatment of early stage non-small-cell lung cancer J.A. Müller 1 1 University hospital Halle (Saale), Radiation Oncology, Halle (Saale), Germany Purpose or Objective Stereotactic body radiotherapy (SBRT) is an established treatment method with favourable toxicity for inopera-ble early stage non-small-cell lung cancer (NSCLC) patients. This paper aims to evaluate the importance of SBRT in the treatment of early-stage lung cancer patients compared to surgery as standard of care. Materials and Methods The German clinical cancer registry of Berlin-Brandenburg was assessed. Cases of lung cancer were considered, if they had a TNM stage (clinical or pathological) of T1-T2a and N0/x and M0/x corresponding to the UICC stages I and II. In our analyses, cases diagnosed between 2000 and 2015 were included. We adjusted our models with propensity score matching. We compared patients treated with SBRT or surgery regarding age, Karnofsky performance status (KPS), sex, histological grade and TNM-classification. Further, we assessed the association of cancer-related parameters with mortality, hazard ratios (HR) from Cox proportional hazards models were computed. Results A total of 558 patients with UICC stages I and II NSCLC were analyzed. In univariate survival models, we found similar survival rates in patients who underwent radiotherapy compared with surgery (HR: 1.2, 95% CI 0.92-1.56, p=0,2). Our univariate subgroup analyses of patients >75 years showed a statistically non-significant survival benefit for patients treated with SBRT (HR: 0.86, 95% CI 0.54-1.35, p=0,5). Likewise, in our T1 sub-analysis survival rates were similar between the two treatment groups regarding overall survival (HR: 1.12, 95% CI 0.57-2.19, p=0,7). The availability of histological data might be slightly beneficial in terms of survival (HR: 0.89, 95% CI 0.68-1.15, p=0,4). This effect was also not significant. Regarding the availability of histological status in our subgroup analyses of elderly patients, we could show similar survival rates as well (HR: 0.70, 95% CI 0.44-1.23, p=0,14). T1-staged patients had also a statistically non-significant survival benefit if