Age-Stratified Long-Term Outcomes of Immune Checkpoint Inhibitors for Stage IV Melanoma and NSCLC in The Netherlands: A Population-Based Study

Background: Immune checkpoint inhibitors (ICIs) are standard treatment for melanoma and non-small cell lung cancer (NSCLC), yet evidence on their effectiveness in older adults remains limited due to underrepresentation in clinical trials. This study assessed long-term, age-stratified outcomes of ICI treatment in real-world clinical practice. Methods: This nationwide observational study used data from the Netherlands Cancer Registry on patients with synchronous stage IV melanoma or NSCLC who received first-line ICIs between 2018 and 2023. Melanoma treatments included nivolumab plus ipilimumab or anti-PD-1 monotherapy; NSCLC treatments included pembrolizumab with or without chemotherapy. Primary outcomes were five-year overall survival (5-yr OS) and three-year conditional survival (3-yr CS), stratified by age. Results: A total of 11,140 patients were included, consisting of 583 patients with melanoma and 10,557 with NSCLC. In the melanoma population, 5-yr OS was 43.8%. Patients aged ≥ 75 years had a 5-yr OS of 30.8% and a 3-yr CS of 58.7%. In NSCLC treated with pembrolizumab monotherapy, 5-yr OS was 23.1%; among patients aged ≥ 75 years, 5-yr OS was 15.6% and 3-yr CS was 46.6%. Pembrolizumab combined with chemotherapy resulted in a 5-yr OS of 14.6%, with corresponding 5-yr OS of 8.4% and 3-yr CS of 35.5% in patients aged ≥ 75 years. Conclusions: This registry-based analysis suggests that ICI are associated with durable long-term survival in real-world patients with stage IV melanoma or NSCLC, including selected older adults. These findings are in line with outcomes of clinical trials, but further research is needed on predictors of ICI effectiveness in the older population.