Real-world outcomes for patients with metastatic non-small cell lung cancer according to first-line treatment

Introduction Metastatic non-small cell lung cancer is a disease with a poor prognosis and things may improve with the rise of immunotherapy. Clinical trials proved that immunotherapy had better results on survival than chemotherapy as first-line treatment for patients with metastatic lung cancer (MLC). Although clinical trials have strong internal validity, they suffer from restrictive selection criterions and it can be difficult to generalize to real-life patients. We aimed to evaluate if the results of survival when comparing immunotherapy with chemotherapy as first-line therapy for MLC in real-life data are similar to those from clinical trials. Methods All consecutive patients included in the retrospective Epidemio-Strategy Medico Economic (ESME-AMLC– NCT03848052 ) program with a non-small cell MLC treated with a systemic treatment (either chemotherapy alone or immunotherapy alone) between January 2015 and December 2018. Patients diagnosed with a tumor with EGFR, KRAS, ROS or BRAF mutation were excluded. Confounding and indication biases were taken account by analyzing causal relation between treatment allocation and survival by constructing a directed acyclic graph. Progression-free survival was analyzed as secondary outcome. Results ESME database included 21,169 patients and 5,255 individuals were included in the study: 5055 treated with chemotherapy, 200 treated with immunotherapy. Median age at diagnosis was 63 years and male represented 67.7% of the population. Median OS in immunotherapy group was 16.4 months (95% CI = [14.1–NR]) and was higher than in chemotherapy group (11.6 months; 95% CI = [11.0–12.2]). In Cox models analyzes, immunotherapy group had better results after 3 months for subjects with performance status (PS) 0–1 (HR = 0.59; 95% CI = [0.42–0.83], P = 0.003) but had poor results before 3 months for subjects with 2, 3 or 4 PS (HR = 2.28; 95% CI = [1.17–4.47], P = 0.016). Conclusion Our results were in favor of benefits on survival of the immunotherapy as first-line treatment for MLC after 3 months for patients in good health condition, as found in clinical trials.