Lung cancer after allogeneic hematopoietic stem cell transplantation

Long-term outcomes of allogeneic hematopoietic cell transplantation (HCT) are improving, increasing the relevance of secondary malignancies, including lung cancer. The clinical utility of immune checkpoint inhibitors (ICIs) in this setting remains unclear and concerns regarding graft-versus-host disease (GvHD) persist.

In this international cohort study, we evaluated clinical characteristics, survival outcomes, and toxicities in patients diagnosed with non-small cell lung cancer (NSCLC) or small-cell lung cancer (SCLC) and a history of HCT.

A total of 77 patients from 18 centers in six countries were included. Median time from HCT to diagnosis was 4.2 years (95%CI, 0.5-30.4), 64% of patients were male, and 81% were current or former smokers. In advanced NSCLC, patients treated with ICI-based therapies (n=20) had longer overall survival than those receiving chemotherapy alone (n=16) (median 17.4 vs 4.7 months; HR 0.32, 95%CI: 0.13-0.77). Across 77 lines of therapy in 54 patients receiving systemic treatment, grade 3-5 immune-related adverse events (irAEs) or GvHD occurred in 2/30 ICI-containing lines (7%) and 1/47 lines that did not include ICIs (2%). However, patients receiving ICIs had longer intervals from HCT to treatment initiation (median, 7.1 vs 3.0 years) and did not require GvHD treatment (0% vs 25%), indicating improved host immune tolerance.

In our study, ICI-based therapies were associated with prolonged survival in selected patients with advanced NSCLC and presumed host immune tolerance. We did not observe a clear signal of excess irAEs/GvHD. Our results support considering the use of ICIs in this population.