Longitudinal recurrence risk of adjuvant cytotoxic chemotherapy and gefitnib in resected lung cancer: A combined analysis of phase III studies.

Background: In patients with completely resected non-small cell lung cancer, it is not fully understood whether the longitudinal recurrence risk differs by the types of adjuvant treatment in EGFR-mutated patients.

Methods: Individual data from two phase 3 trials (JIPANG and IMPACT) were collected and patients were categorized into three groups (A [EGFR wild-type, chemotherapy: n = 299], B [EGFR mutant, chemotherapy: n = 211], and C [EGFR mutant, gefitinib: n = 116]). Disease-free survival (DFS) and overall survival (OS) were analyzed using the Kaplan-Meier method. Hazard ratio (HR) was estimated using Cox proportional hazard models. The longitudinal recurrence risk was analyzed by estimating hazard function among the groups.

Results: Median follow-up time was 69.3 months. Median DFS in groups A, B, and C were 42.2, 30.3, and 35.9 months, respectively. As referring to group A, the adjusted HR was 1.00 (95 %CI: 0.74-1.34) with group B, and 1.16 (95 %CI: 0.83-1.61) with group C. In the longitudinal recurrence risk analysis, groups A and B had a higher hazard level than group C for the first two years. However, they gradually decreased and reached a plateau, whereas group C sustained a similar recurrence risk even after gefitinib. As a result, DFS rates at 8 years in groups A, B, and C were 40.4 %, 33.9 %, and 22.3 %, respectively.

Conclusions: Longitudinal recurrence risk with chemotherapy did not differ regardless of EGFR mutation status, whereas gefitinib showed a sustained recurrence risk after completion. Meeting Presentation This data was presented at the American Society of Clinical Oncology Annual Meeting 2024 (general poster session, abstract 8023).