Pathological Features and Differential Efficacy of Cisplatin-Based Adjuvant Chemotherapy in Lung Cancer Harboring Epidermal Growth Factor Receptor Mutations.

Purpose: We aimed to elucidate the efficacy of conventional cisplatin-based adjuvant chemotherapy for patients with lung cancers harboring epidermal growth factor receptor (EGFR) mutation.

Methods: This retrospective cohort study included 110 patients (EGFR mutation group: n = 51; EGFR wild-type group: n = 59) receiving cisplatin-based adjuvant chemotherapy following complete resection of non-small-cell non-squamous-cell lung cancer (2010-2021). Clinicopathological characteristics, recurrence-free survival (RFS), and overall survival (OS) were investigated.

Results: The pStage distribution was not statistically different. The EGFR mutation group was characterized by more advanced pN, papillary predominance, and presence of micropapillary components, whereas the EGFR wild-type group exhibited more advanced pT and solid predominant patterns. The median RFS was significantly worse in the EGFR mutation group (23.0 vs. 76.1 months, p = 0.017). Nevertheless, the median OS was not significantly different (85.6 months vs. not reached, p = 0.151). Multivariable analysis demonstrated that EGFR mutation and lymphatic invasion were significant risk factors in RFS; however, no independent factors were identified in OS.

Conclusions: Cisplatin-based adjuvant chemotherapy might be less effective in patients with EGFR-mutated lung cancer. The style of progression and histological pattern related with EGFR mutation may be associated with the efficacy of adjuvant chemotherapy and poor RFS.