ESTRO 2020 Abstract book

S33 ESTRO 2020

Results ITACs were observed in 43% of treatments and in 47% of patients. Out of all ITACs recorded, the majority (96%) were graded as a yellow action level, and only 4 % were graded as red action level (Table 2). ITACs regarding tumour regression (R3) were most often reported, but never led to plan adaptation due to local policy of not adapting the treatment to tumor response. For the total of graded ITACs (i.e. non green), the majority (86%) did not require any further action after investigation; in 5 cases (10% of the ITACs) a new CT scan was made; in 2 cases (4% of the ITACs) a plan adaptation was required due to possible tumor progression (GTV out of PTV; R2) or baseline shift (GTV out of PTV; R5) (Figure 2).

The results show that our TLP is effective and adequate for identifying patients in need of adaptive re-planning. The data obtained further supports the findings of Hattu et al. regarding the workload decrease as the criteria presented in figure 2 did not led to any false alert, hence no protocol adaptation was needed. A secondary analysis limited to primary lung cancer (i.e. excluding patients treated for lung metastases) would be interesting to determine the potential pattern linking set- up time (time from 1st CBCT to beam delivery) to ITAC grade for SBRT treatments vs non-SBRT treatments. Conclusion Our TLP has been proven effective for identifying patients requiring an adaptive re-planning. The data obtained support that there is no need for a protocol modification because no false alerts were found, and so no changes in workload are proposed. PD-0073 Outcomes in patients aged 70 and above treated with radical radiotherapy for head and neck cancer L. Hay 1 , S. Borgaonkar 2 , P. McLoone 3 , A. James 2 , D. Grose 2 , C. Wilson 2 , C. Lamb 2 , S. Schipani 2 , M. Thomson 1 , C. Paterson 2 1 The Beatson West of Scotland Cancer Centre, Radiotherapy, Glasgow, United Kingdom ; 2 The Beatson West of Scotland Cancer Centre, Oncology, Glasgow, United Kingdom ; 3 University of Glasgow, Institute of Health & Wellbeing, Glasgow, United Kingdom Purpose or Objective Radical radiotherapy (RT) for head and neck (H&N) cancer results in significant acute and late toxicity. In our current practice we review performance status and co-morbidities when evaluating patients’ suitability for radical treatment. However, the use of a formal geriatric or frailty assessment tool is increasingly being indicated as a potential method in assessing older patient’s fitness. This