ESTRO 2023 - Abstract Book

S497

Sunday 14 May 2023

ESTRO 2023

SBRT with 8X7.5Gy in inoperable patients with central lung tumours is associated with high rate of local control; however, as far as can be judged from this small cohort with a high load of baseline cardiac and pulmonary comorbidities, the risk of severe late toxicity is clinically significant.

OC-0612 Dose and fractionation for palliative lung radiotherapy: 8 years of clinical practice C. Kristiansen 1 , T.L. Fink 2,3 , T.S. Hansen 3 , M.D. Lund 3 , R.S. Thing 3

1 Department of Oncology, Lillebaelt Hospital, Vejle, University Hospital of Southern Denmark, Vejle, Denmark; 2 Institute for Regional Health Research, University of Southern Denmark, Vejle, Denmark; 3 Department of Oncology, Lillebaelt Hospital, University Hospital of Southern Denmark, Vejle, Denmark Purpose or Objective In Denmark, about 50% of all new lung cancer patients are diagnosed with metastatic disease, and palliative radiotherapy (RT) is a very common treatment prescribed to this group of patients. Furthermore, palliative RT can be prescribed to patients with locally advanced lung cancer who are unfit for long course chemo-radiation. Palliative RT is therefore used both as first line treatment for some patients, and to relieve symptoms for other patients. Previous studies have shown that a substantial number of patients die before they achieve effect of palliative RT (i.e. 2 months), and for palliative RT, the optimal dose/fractionation schedule for lung cancer patients remains debated. Materials and Methods We performed a retrospective analysis of our practice for palliative RT for lung cancer patients, delivered to the thoracic region only, from 2014 to 2021. Our RT department treats around 1800 RT courses per year, of which 100-150 are palliative treatments in the thorax. Looking only at patients with lung cancer as primary diagnosis, we counted the number of treatments prescribed per year per dose/fractionation (8Gy/1F, 20Gy/4F, 20Gy/5F, 30Gy/10F and 39Gy/13F). The second part of the study focused on “long-term palliative RT”, i.e. 30Gy/10F and 39Gy/13F. A recent study from another center in Denmark showed no effect on overall survival when comparing 39Gy/13F to 30Gy/10F. As part of this study, we wanted to investigate if the same result emerged in our patient population. To ensure comparable patient characteristics, only patients with M0 disease where the entire tumor was irradiated were included in this part of the study. Results Figure 1 shows the distribution of palliative RT regimens prescribed per year in our department. For the last three years, fewer patients have been offered long-term palliative RT (10 or 13 fractions). Over the combined period, 62 patients were treated with 39Gy/13F, while 31 patients with similar characteristics were treated with 30Gy/10F. Figure 2 shows the survival curves for the two patient groups, with no difference observed in median overall survival (10.5 months and 7.7 months respectively, (p=0.5)). One patient died within the first 30 days, and 13% died within the first 90 days.