ESTRO 2020 Abstract Book

S21 ESTRO 2020

up (FU), with the latter continuing to improve. Similar trends are seen in both interference subscales. Dry mouth scores in pts with moderate or severe symptoms at baseline do not significantly change after RT. In contrast those with low symptoms at baseline described a worsening of symptoms acutely post RT. In pain and difficulty with voice/speech subscales these return to baseline, while scores in dry mouth and difficulty with swallowing/chewing remain elevated throughout FU. For all subscales pts who were symptomatic pre-treatment continued to rate their symptoms more highly throughout FU. Although a smaller variation at 40-78 wks is seen, there is still a significant difference between groups in all subscales (p<0.05) except pain (p=0.058).

Conclusion There is a significant impact of the DARS dosimetric parameters on the swallowing outcomes in Re RT for head neck cancers. These parameters are however, different from those known to influence outcomes in the per primum setting. V30, V40 and V50 should be minimized to ensure good swallowing outcomes in these patients. PD-0054 Baseline symptom burden predicts patient reported well-being following curative (chemo)radiotherapy C. Barker 1 , G. Price 2 , K. Garcez 1 , L. Lee 1 , A. Sykes 1 , D. Thomson 1 , A. McPartlin 1 1 The Christie NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom ; 2 The Christie NHS Foundation Trust, Christie Radiotherapy, Manchester, United Kingdom Purpose or Objective Patients (pts) with Head and Neck SCC (HNSCC) may present with marked symptoms of pain and swallowing dysfunction. Few patient-reported outcome measures (PROMS) are available to quantify the effects of (chemo)radiotherapy ((CT)RT) on baseline symptoms, despite this being an important part of discussion during consent for therapy. The aim of this study was to determine the acute and late effects of (CT)RT on baseline symptoms in pts with HNSCC in clinical practice. Material and Methods All pts who completed a MD Anderson Symptom Inventory Head and Neck (MDASI-HN) questionnaire prior to (CT)RT for HNSCC, plus at least one post treatment time point (6- 9 weeks (wks), 10-19 wks, 20-39 wks and 40-78 wks after RT) from 2016-19 were considered. Any with subsequent disease relapse were excluded. Pts were considered symptomatic at baseline if a score was >/= 5 (moderate symptom burden) and dichotomised accordingly for that subscale. Clinically relevant MDASI-HN questions were considered: symptom subscales of pain, dry mouth, difficulty swallowing/chewing and difficulty with voice/speech and interference subscales of mood and enjoyment of life. The difference in PROM score evolution between patients with high and low initial symptom burden was assessed via likelihood ratio test of a linear mixed model containing baseline score as a fixed effect to one without. Patient identity was included as a random effect to account for individual differences. Results 320 patients were analysed (Table 1). A significant difference in overall score evolution after RT for all subscales (p<0.001) was shown (Figure 1). Those pts with moderate or severe symptoms at baseline in pain, difficulty swallowing/chewing, difficulty with voice/speech subscales experienced a reduction in scores by 6 wks post RT. Decreases persisted throughout follow-