ESTRO 2024 - Abstract Book

S1457

Clinical - Head & neck

ESTRO 2024

Results:

Between July 28, 2016 and January 25, 2022, 199 patients were randomly assigned to radiotherapy with reduced elective dose and 101 to the standard elective dose. Two patients withdrew consent early and 3 went off-study due to major eligibility infringement, resulting in 196 eligible patients in the dose reduction group and 99 in the control group. Median follow-up was 26 months (IQR 23-27). The normalcy of diet score at 12 months after treatment was 91.6 (95% CI: 88.4-94.7) and 93.0 (95% CI: 88.5-97.4) in the dose reduction and control groups respectively (p=0.61). Tube feeding was required significantly less in the first 3 months after start of radiotherapy for patients in the dose reduction group compared to the control group (11% vs. 19%; p=0.045) [5]. At 1 year after treatment, 1.4% (2/145) of the patients in the dose reduction group (insufficient dietary intake as a result of symptomatic local recurrence or osteoradionecrosis of mandibula) versus 1.4% (1/72) of the patients in the control group had tube feeding (insufficient dietary intake as a result of dysphagia). The 2-year actuarial recurrence rate in electively irradiated lymph nodes was 5.0% (95% CI: 1.9-8.1%) and 4.3% (95% CI: 0.2-8.4%) in the dose reduction and control groups respectively (p=0.96) (Figure 1). Recurrence in electively irradiated lymph nodes occurred in 78% (10/13) of the patients synchronously with recurrence in the GTV (i.e. primary tumor and/or pathologic lymph nodes). The 2-year actuarial overall survival rate was 85.1% (95% CI: 80.0 90.2) and 80.6% (95% CI: 72.8-88.4) in the dose reduction and control groups respectively (p=0.42) (Figure 2).