Immune-checkpoint inhibition for resectable non-small-cell lung cancer - opportunities and challenges

Therapeutic strategies harnessing the immune system to eliminate tumour cells have been successfully used for several cancer types, including in patients with advanced-stage non-small-cell lung cancer (NSCLC). In these patients, immune-checkpoint inhibitors (ICIs) can provide durable responses and improve overall survival either as monotherapy, or combined with chemotherapy or other immunotherapeutic agents. However, the implementation of ICIs in early stage NSCLC has been hampered by the continuous struggle to develop robust end points to assess their efficacy in this setting, especially those enabling a fast and reproducible evaluation of the clinical activity of neoadjuvant strategies. Several trials are testing ICIs, alone or in combination with chemotherapy, in early stage NSCLC as an adjuvant, neoadjuvant or perioperative approach. As a novelty, most trials in the neoadjuvant setting have adopted pathological response as a primary end point. ICIs have been approved for use in the neoadjuvant and adjuvant settings on the basis of event-free survival and disease-free survival benefit, respectively; however, the correlation of these end points with overall survival remains unclear in these settings. Unresolved challenges for the optimal use of ICIs with curative intent include concerns about their applicability in daily clinical practice and about improving patient selection based on predictive biomarkers or assessment of pathological response and minimal residual disease. In this Review, we discuss the rationale, available strategies and current trial landscape for the implementation of ICIs in patients with resectable NSCLC, and we further elaborate on future approaches to optimize their clinical benefit.