ESTRO 2021 Abstract Book

S995

ESTRO 2021

(42.7%) stage 3. 812 (60.3%) had NSCLC, 140 (10.4%) had SCLC and 394 (29.3%) had a radiological diagnosis of lung cancer. 18 (1.3%) patients tested positive for SARS-CoV-2. 98 (7.3%) had RT instead of surgery. 231 (17.1%) patients had a change in their RT treatment from their local standard of care, the largest change (69 patients, 28.4%) was seen in May 2020. Monthly variation of changes in RT treatment compared to standard of care is demonstrated in Figure 1.

Multivariable logistic regression against patient PS, age, number of comorbidities, respiratory comorbidities , cardiac comorbidities and stage found a better PS 0-1 was significantly associated with having a change in RT treatment compared to PS 2-3 (p = 0.00131). There was no significant association with the other variables. In patients with a change in RT treatment, there was an increase in hypofractionation, particularly the ˃ 3 – 5Gy/fraction group, and almost no ≤2Gy/fraction treatments delivered (Figure 2).

Median number of fractions was 15 (range 1-36) in patients with a change in RT, and 20 (range 1-42) in patients with no change to treatment. Conclusion This multicentre UK study demonstrates that patients with stage 1-3 lung cancer had changes in curative- intent RT treatment according to UK guidelines. RT changes occurred more frequently in the earlier period of the COVID-19 pandemic and were more likely in patients with a better PS. Furthermore, an increase in hypofractionation was seen if RT treatment was changed. Data is being collected on disease recurrence and survival for future assessment of RT treatment changes on patient outcomes. PO-1199 Cardiac disease and tumour below T7 confer poorer prognosis following radical radiotherapy for NSCLC A. Colori 1 , M. Hawkins 2 , A. Mitchell 3 , C. Hiley 3 , S. Dubash 2 , U. Johnson 1 , J. Fenwick 4 , R. Mendes 2 , D. Carnell 2 , J. Wilson 2 1 University College London NHS Foundation Trust, Department of Clinical Oncology, London, United Kingdom;