Immune-related adverse events between elderly patients with gastrointestinal and lung cancers: A real-world study

Immune checkpoint inhibitors (ICIs) are known for their durable efficacy and favorable tolerance profiles. However, elderly patients are often underrepresented in clinical trials. The manifestation of immune-related adverse events (irAEs) in elderly patients with different tumor types remains unclear. This study aimed to compare irAEs in elderly patients with gastrointestinal and lung cancers receiving ICIs and to provide real-world safety data.

This retrospective study included elderly patients (≥70 years) with gastrointestinal (GI) tumors or lung cancer who received ≥2 cycles of ICIs across multiple departments within a single academic medical center between January 2016 and February 2022. A 2:1 propensity score matching was used to balance baseline characteristics between the cohorts. The primary endpoint was the incidence of any-grade irAEs between GI tumors and lung cancer, whereas secondary analyses focused on organ-specific toxicities. Statistical comparisons were performed using the chi-squared test.

The overall incidence of any-grade irAEs was higher in elderly patients with lung cancer than in those with GI tumors (61.0% vs . 47.9%; P = 0.013). After matching for baseline characteristics, the lung cancer group still showed a trend toward a higher incidence of irAEs (61.7% vs . 50.8%; P = 0.056). Notably, patients with GI tumors had a higher incidence of skin toxicity (28.7% vs . 15.1%; P = 0.002), whereas patients with lung cancer had a higher incidence of thyroid dysfunction (28.1% vs . 11.9%, P <0.001).

Elderly patients with lung cancer were more likely to experience irAEs during immunotherapy than those with GI tumors. However, dermatological toxicities were more common in elderly patients with GI tumors, whereas thyroid dysfunction was more frequently observed in those with lung cancer.