A team of researchers from China conducted the study and published their findings in BMC Cancer.
Despite being the “recommended first-line therapy for advanced EGFR-mutated” NSCLC, investigators acknowledged that the effect of antibiotic exposure before the initiation of therapy with third-generation EGFR-TKIs “on treatment efficacy and survival outcomes remains unclear.”
Eligible patients included individuals diagnosed with NSCLC “who received third-generation EGFR-TKIs at West China Hospital of Sichuan University between January 2017 and November 2024.”
Investigators “retrospectively identified” eligible patients via electronic medical records, and for the purposes of the study, defined antibiotic exposure “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,” investigators explained. “Multivariable Cox models were performed to evaluate the association between antibiotic exposure and progression-free survival (PFS) and overall survival (OS).”
A total of 64 patients were categorized in the “matched antibiotic group,” and 156 patients were categorized in the “matched non-antibiotic group.”
The results revealed that patients who received antibiotics before treatment “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.”
Furthermore, multivariable adjustment demonstrated that “antibiotic exposure remained an independent predictor of worse PFS (HR [hazard ratio] 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).”
Investigators concluded that although their study found that antibiotic exposure correlated with worse survival outcomes in patients with NSCLC undergoing therapy with third-generation EGFR-TKIs, “further larger prospective studies are needed to confirm these findings.”