Site-Specific Response and Resistance Patterns in Patients with Advanced Non-Small-Cell Lung Cancer Treated with First-Line Systemic Therapy.

Simple Summary: Immunotherapy or combined chemoimmunotherapy is currently first-line therapy for patients with metastatic NSCLC without a driver mutation. Despite immunotherapy contributing to improved survival outcomes, the estimated 5-year OS rate for metastatic NSCLC remains poor. The aim of our retrospective study was to assess how patients with different anatomical metastatic sites respond or develop resistance to immunotherapy, combination chemoimmunotherapy, or chemotherapy alone. We confirmed that patients with bone metastases have poorer survival outcomes compared to those without bone metastases. This highlights a group of patients that may benefit from a specific clinical trial evaluation to assess the benefit of additional novel therapeutics or upfront radiotherapy. Patients with advanced NSCLC have heterogenous responses to immune checkpoint inhibitors (ICIs) with or without chemotherapy. In NSCLC, the impact of the distribution of metastatic sites and the response to systemic therapy combinations remain poorly understood. In a retrospective cohort study of patients with unresectable stage III/IV NSCLC who received first-line systemic therapy, we sought to assess the association between the site of metastases with patterns of response and progression. Data regarding demographics, tumour characteristics (including site, size, and volume of metastases), treatment, and outcomes were examined at two cancer care centres. The endpoints included organ site-specific response rate, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Two-hundred and eighty-five patients were included in the analysis. In a multivariate analysis, patients with bone metastases had a reduced ORR, PFS, and OS. Primary resistance was also more likely in patients with bone metastases. Patients with bone or liver metastases had a shorter OS when receiving ICIs with or without chemotherapy, but not with chemotherapy alone, suggesting an immunological basis for therapeutic resistance. A directed assessment of the tumour microenvironment in these locations and a deeper understanding of the drivers of organ-specific resistance to immunotherapy are critical to optimise novel combination therapies and sequencing in these patients. [ABSTRACT FROM AUTHOR]