Adjuvant Chemotherapy for Resected Stage-IA Lung Adenocarcinoma With Micropapillary Histologic Pattern

The micropapillary pattern (MP) is a high-risk factor for postoperative recurrence in lung adenocarcinoma (LUAD), but the role of adjuvant chemotherapy (ACT) in stage IA LUAD with MP (LUADmp) after resection remains unclear.

From September 2017 to August 2020, in the phase II trial, resected stage IA LUADmp patients received ACT (pemetrexed and carboplatin), forming the ACT-group. Patients who met the trial criteria but declining ACT during the same period were designated as the standard of care (SoC)-group. Recurrence-free survival (RFS) was compared between groups using univariate and multivariate analyses.

The numbers of patients in ACT-group and SoC-group were 81 and 75, respectively. Compared to SoC-group, patients in ACT-group were younger (60.0 vs 64.0 years, P = .019), had a lower proportion of EGFR/ALK mutations (58.0% vs 78.7%, P = .006), and had a higher proportion of spread through air spaces (59.3% vs 40.0%, P = .016). At the cut-off date of January 31, 2025, the median duration of follow-up was 65.6 months. Five-year RFS in ACT-group met the prespecified primary end-point, and no significant difference was observed between ACT-group and SoC-group (ACT-group vs SoC-group: 88.9% vs 86.7%, log-rank P = .534). Multivariate analysis showed ACT could not predict RFS independently (hazards ratio [HR], 0.865, 95% CI, 0.334-2.240, P = .765).

Adjuvant chemotherapy was not significantly associated with improved RFS for stage IA LUADmp patients postoperatively. This study was registered at ClinicalTrials.gov: NCT03351842.

ClinicalTrials.gov Identifier: NCT03351842.