Lung Cancer Research Studies / Lung Cancer Treatments and Mutations · Journal article

Impact of antibiotic exposure on survival outcomes in NSCLC patients treated with third-generation EGFR-TKIs

BMC Cancer · August 14, 2026

Promising Why this matters to you Expert discussion

Encouraging direction, but not yet definitive.

AI Summary

This retrospective cohort study of 220 NSCLC patients treated with third-generation EGFR-TKIs reports that prior antibiotic exposure (within 60 days) was independently associated with shorter median progression-free survival (16.2 vs 22.4 months) and overall survival (38.1 vs 62.9 months). The finding persists after multivariable adjustment and propensity score matching, but the observational design and single-centre setting limit causal inference and generalizability.

What was studied

Retrospective cohort study with propensity score matching. Patients with NSCLC treated with third-generation EGFR-TKIs at West China Hospital of Sichuan University; EGFR-mutated status implied as target of third-generation TKIs.. Intervention: Prior antibiotic exposure (any antibiotic prescription within 60 days before TKI initiation). Compared with: No antibiotic exposure in the 60 days before TKI initiation. n = 220. West China Hospital of Sichuan University (single centre, China).

Key findings

Median PFS in antibiotic group 16.2 months vs 22.4 months in non-antibiotic group (P = 0.001) Median OS in antibiotic group 38.1 months vs 62.9 months in non-antibiotic group (P = 0.003) Antibiotic exposure independently predicted worse PFS with HR 1.625 (95% CI, 1.152 to 2.291; P = 0.006)

Safety

Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.

Who this may help

This finding suggests a potential link between peritreatment antibiotic use and reduced efficacy of third-generation EGFR-TKIs in EGFR-mutated NSCLC. If replicated in prospective studies, it may inform decisions about antibiotic prescription timing in this population, though causation remains unestablished and the mechanism is unclear.

Plain-language summary

A retrospective cohort study with propensity score matching showing a clear association between antibiotic exposure and worse survival in EGFR-mutated NSCLC, but limited by single-centre design, modest sample size, and observational methodology that cannot establish causation.

Study design

As stated by the source record.

MethodsPatients with EGFR-mutated NSCLC receiving third-generation EGFR-TKIs between January 2017 and November 2024 were retrospectively identified from electronic medical records at a single centre. Antibiotic exposure was defined as any antibiotic prescription within 60 days prior to TKI initiation. Propensity score matching was used to balance baseline characteristics between antibiotic and non-antibiotic groups. Multivariable Cox proportional hazards models were applied to evaluate the association between antibiotic exposure and PFS and OS.

DesignRetrospective cohort study with propensity score matching

PopulationPatients with NSCLC treated with third-generation EGFR-TKIs at West China Hospital of Sichuan University; EGFR-mutated status implied as target of third-generation TKIs.

Sample size220

InterventionPrior antibiotic exposure (any antibiotic prescription within 60 days before TKI initiation)

ComparatorNo antibiotic exposure in the 60 days before TKI initiation

SettingWest China Hospital of Sichuan University (single centre, China)

Reported figures

Quoted from the source exactly as published.

Median PFS antibiotic group16.2 months

Median PFS non-antibiotic group22.4 months

Median OS antibiotic group38.1 months

Median OS non-antibiotic group62.9 months

Hazard ratio for PFS (antibiotic vs control)1.625

95% CI for PFS HR1.152 to 2.291

P-value for PFS HR0.006

Hazard ratio for OS (antibiotic vs control)1.801

Clinical bottom line

Caveats

Single-centre retrospective study limits generalizability and cannot establish causation; confounding by indication and unmeasured variables (e.g. reason for antibiotic use, microbiome composition) not controlled.
Antibiotic exposure defined broadly as any use within 60 days; type, duration, timing relative to TKI initiation, and specific indications not reported.
Post-matching sample is modest (220 total); no power analysis reported.
Authors acknowledge need for larger prospective studies; no biological mechanism or exploratory analyses of antibiotic class or microbiome effects provided.

Evidence assessment

Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.

Study design

moderate

Retrospective cohort with propensity score matching to reduce confounding; observational design limits causal inference.

Directness

strong

Directly measures antibiotic exposure and hard clinical outcomes (PFS, OS) in the target population.

Consistency

insufficient

Single study; no prior evidence reported for comparison within the source text.

Risk of bias

moderate

Propensity score matching employed but inherent confounding by indication and unmeasured variables possible in retrospective design.

Sample adequacy

limited

Post-matching sample of 220 patients (64 antibiotic, 156 non-antibiotic) is modest for multivariable survival analysis.

Source abstract

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the recommended first-line therapy for advanced EGFR-mutated non-small-cell lung cancer (NSCLC). However, the impact of antibiotic exposure prior to initiating third-generation EGFR-TKIs on treatment efficacy and survival outcomes remains unclear. Patients with NSCLC who received third-generation EGFR-TKIs at West China Hospital of Sichuan University between January 2017 and November 2024 were retrospectively identified from electronic medical records. Antibiotic exposure was defined as any antibiotic prescription within 60 days prior to TKIs initiation. Patients were matched using propensity scores to reduce differences in baseline characteristics between the antibiotic and non-antibiotic groups. Multivariable Cox models were performed to evaluate the association between antibiotic exposure and progression-free survival (PFS) and overall survival (OS). After propensity score matching, 64 patients remained in the matched antibiotic group, and 156 in the matched non-antibiotic group. Patients in the antibiotic group had significantly shorter median PFS (16.2 vs. 22.4 months; P = 0.001) and OS (38.1 vs. 62.9 months; P = 0.003) compared with those in the non-antibiotic group. After multivariable adjustment, antibiotic exposure remained an independent predictor of worse PFS (HR 1.625; 95% CI, 1.152 to 2.291; P = 0.006) and OS (HR 1.801; 95% CI, 1.130 to 2.868; P = 0.013). Prior antibiotic exposure was associated with poorer survival outcomes in NSCLC patients receiving third-generation EGFR-TKIs. Further larger prospective studies are needed to confirm these findings.

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Lung Cancer Research StudiesJing ZhouLung Cancer Treatments and MutationsWanqin FangDan LiuYi LiuLinhui YangJiarui Zhang