Trends and variations in treatment of stage I?III non-small cell lung cancer from 2008 to 2018: A nationwide population-based study from the Netherlands

Introduction: This Dutch population-based study describes nationwide treatment patterns and its variations for stage I-III non-small cell lung cancer (NSCLC). Materials and methods: Patients diagnosed with clinical stage I-III NSCLC in the period 2008-2018 were selected from the Netherlands Cancer Registry. Treatment trends were studied over time and age groups. Use of radiotherapy versus surgery (stage I-II), and concurrent versus sequential chemoradiotherapy (stage III) were analyzed by logistic regression. Results: In stage I, the rate of surgery decreased from 58 % (2008) to 40 % (2018) while radiotherapy use increased over time (from 31 % to 52 %), which mostly concerned stereotactic body radiotherapy (74 %). In stage II, 54 % of patients received surgery, and use of radiotherapy alone increased from 18 % to 25 %. The strongest factors favoring radiotherapy over surgery were WHO performance status (OR > 2 vs 0: 23.39 (95% CI: 18.93-28.90)), increasing age (OR > 80 vs <60 years: 14.52 (95% CI: 13.02-16.18)) and stage (OR stage II vs I: 0.61 (95% CI: 0.57-0.65)). In stage III, the combined use of chemotherapy and radiotherapy increased from 35 % (2008) to 39 % (2018). In all years, 23 % received concurrent chemoradiotherapy, 9 % sequential chemoradiotherapy, 23 % radiotherapy or chemotherapy alone, and 25 % best supportive care. The strongest factors favoring concurrent over sequential chemoradiotherapy were age (OR > 80 vs <60 years: 0.14 (95% CI: 0.10-0.19)), WHO Performance status (OR > 2 vs 0: 0.33 (95% CI: 0.24-0.47)) and region (OR east vs north: 0.39 (95% CI: 0.30-0.50)). Conclusions: The use of radiotherapy became more prominent over time in stage I NSCLC. Combined use of chemotherapy and radiotherapy marginally increased in stage III: only one third of patients received chemoradiotherapy, mainly concurrently. Treatment variation seen between patient groups suggests tailored treatment decision, while variation between hospitals and regions indicate differences in clinical practice.