Time Toxicity of Systemic Anticancer Therapy for Metastatic Lung Cancer in Routine Clinical Practice: A Nationwide Cohort Study

PURPOSE The concept of time toxicity of cancer treatment, defined as proportion of days from physical contact with the health care system, has been suggested as simple, patient-centered measure useful for shared decision making, particularly in incurable cancer. We investigated the extent of health care contacts in clinical practice in Danish patients with stage IV lung cancer starting first-line systemic anticancer therapies. METHODS This is a nationwide cohort study of newly diagnosed patients with stage IV lung cancer in Denmark who initiated treatment during 2019-2021 and followed for up to 1 year. The time toxicity after treatment initiation was calculated as the proportion and mean cumulative number of days with physical health care system contacts recorded in Danish registries. The remaining days without any physical contact were defined as home days. One-year cumulative mortality was also assessed. RESULTS We included 4,384 patients with stage IV lung cancer. One year survival was 45% after treatment initiation. Of days alive, the mean cumulative number of days with physical health care contacts was 56 days within 1 year. The corresponding number of home days was 198. Overall, 22% of days alive involved physical contact with the health care system, broadly similar for patients with non–small cell lung cancer (22%) and small cell lung cancer (24%). For specific regimens, the corresponding proportions were chemotherapy (24%), immunotherapy (21%), immunochemotherapy (21%), and targeted therapy (16%). CONCLUSION More than 1 in 5 days after initiation of systemic treatment for metastatic lung cancer was spent in physical contact with the health care system. This information may aid shared decision making by informing about expected burdens in relation to cancer therapy.