Real-world outcomes and immune-related adverse events in Canadian patients with non-small cell lung cancer receiving neoadjuvant platinum-based chemotherapy and nivolumab.

Abstract

710 Background: Lung cancer is the leading cause of cancer-related mortality in Canada. Patients with resectable non-small cell lung cancer (NSCLC) can receive curative intent surgery, though relapse rates are high. The addition of nivolumab to neoadjuvant platinum-doublet chemotherapy has recently become the standard of care for these patients based on improved event-free survival and pathologic complete response rates. We evaluated real-world outcomes in Canadian patients with NSCLC receiving this neoadjuvant chemoimmunotherapy regimen, with a focus on characterizing immune-related adverse events (IRAEs). Methods: We reviewed all patients with NSCLC starting neoadjuvant chemoimmunotherapy at The Ottawa Hospital between December 2023 and August 2025. Demographic, diagnostic, treatment, and toxicity data were collected. The primary objective was to characterize pre- and post-surgical IRAEs. Results: The cohort included 59 patients; median age of 70 years and 58% female. All patients had a former (61%) or current (39%) history of tobacco smoking. Baseline ECOG performance status was 0 in 63%, 1 in 36%, and 2 in 2% of patients. Clinical stage was IIA in 17%, IIB in 29%, IIIA in 41%, and IIIB in 14% of patients. Histology included adenocarcinoma (54%), squamous cell carcinoma (37%), and other subtypes (8%). Overall, 81% of patients completed neoadjuvant therapy, 92% underwent surgery, and 27% achieved pathologic complete response. IRAEs occurred in 21 patients (36%), including 8 pre-surgery and 13 post-surgery. Among pre-surgical IRAEs, 3 (38%) were grade ≥3 and 6 (75%) required systemic steroids. Among post-surgical IRAEs, 7 (54%) were grade ≥3 and 8 (62%) required systemic steroids. The mean time from first symptomatic presentation to a healthcare provider to IRAE diagnosis was longer in the post-surgical setting than in the pre-surgical setting (11.5 days [range, 0–59] vs 2.0 days [range, 0–6]). Healthcare utilization was also greater in the post-surgical setting, with more emergency department visits (4 vs 0), hospital admissions (8 vs 1), and total days hospitalized (63 vs 17). Median length of hospitalization for all IRAEs was 12 days. Conclusions: IRAEs represent an important clinical concern. Delayed recognition and greater healthcare utilization in the post-surgical setting highlight the need for quality improvement initiatives focused on improving patient education, healthcare provider training, and structured post-surgical toxicity follow-up.