Assessing a Suitable Radiotherapy Utilisation Benchmark for Older Patients With Head and Neck Cancer.

To (i) determine the actual radiotherapy utilization (RTU) stratified by age, (ii) develop an age- and co-morbidity adjusted optimal RTU model and (iii) examine the tolerance and toxicity of treatment of older patients with head and neck cancer. A retrospective cohort study based on New South Wales Cancer Registry records (2010–2014) linked to radiotherapy data (2010–2015) and admitted patient data (2008–2015) for patients diagnosed with head and neck cancer. We calculated the actual RTU, defined as the proportion of patients who received at least one course of radiotherapy within a year of diagnosis, by age group, including patients aged 80+ years. We also calculated the age and comorbidity-adjusted optimal RTU. For treatment tolerance, the radiotherapy dose for each age group and the completion rate for a seven week 70 Gray (Gy) course of curative intent radiotherapy were computed. The number of emergency department (ED) presentations were used as a surrogate measure of acute treatment toxicity for patients receiving 70 Gy. Of the 5966 patients diagnosed with head and neck cancer, 814 (13.6%) were aged 80+ years. For all age groups, the actual RTU was less than the optimal RTU. The age- and comorbidity-adjusted optimal RTU for patients aged 80+ was 52% (95% CI: 51%–53%), and the actual RTU was 40% (95% CI: 37%–44%). Only 4.4% of patients aged 80+ received 70 Gy, and the completion rate for a 70 Gy course of radiotherapy for these patients was 92%. The ED presentation rate was similar for all age groups. The actual RTU was less in the 80+ years patients and across all age groups. Fewer patients in the 80+ group received curative intent schedules compared to the actual RTU rate for younger age groups, despite similar rates of completion of curative intent radiotherapy and acute toxicity. • This population-based research highlights that even after adjusting for comorbidities, with increasing age, the actual radiotherapy utilisation rate (RTU) is less than the optimal RTU for patients with head and neck cancer. • The age- and comorbidity-adjusted optimal RTU rates for patients aged 80+ years using the cancer specific C3 'all sites' comorbidity index was 52% (95% CI: 50%–52%) and the actual RTU was 40% (95% CI: 37%–44%). • The completion rate and acute toxicity of a 70 Gy radiotherapy course were similar in all age groups. This suggests good treatment tolerance in carefully selected cases. • Further work, however, is required for the older cohort of patients to determine the reasons for the lower receipt of curative intent schedules and for all age groups, reasons for the underutilisation of RT. [ABSTRACT FROM AUTHOR]