Background and purpose: Antibiotic treatment (ABT) has been associated with worse outcomes of cancer immunotherapy. However, this association might be confounded by other poor prognostic factors. We aimed to evaluate the use of ABT and outcomes of immune checkpoint inhibitors (ICI) in metastatic kidney cancer (mRCC).Patient/material and methods: We identified retrospectively 192 patients treated with ICI for mRCC between 2015 and 2021 at three academic hospitals in Finland. Information on patient characteristics, ABT, and immunotherapy was collected from electronic medical records. Cox regression and Kaplan-Meier methods were used for survival analyses. Results: A total of 61 (32%) patients had received early ABT (3 months before and 1 month after the first dose of ICI), of whom 31 (51%) had ABT > 7 days. Patients with early ABT had shorter median overall survival (mOS) than patients without early ABT (20.4 vs 27.9 months, p = 0.046). Patients with ABT > 7 days had shorter mOS than patients with ABT 0–7 days (17.2 vs 27.5 months, p = 0.015). After adjustment for International Metastatic Renal Cell Carcinoma Database Consortium risk groups, histological renal cell carcinoma subtype, baseline levels of C-reactive protein, and tumor burden, the risk of death was higher in patients with ABT > 7 days (hazard ratio 1.83 (95% confidence interval 1.06–3.17). No significant differences in progression-free survival times (PFS) were observed.Interpretation: Early ABT and prolonged ABT duration were associated with shorter OS, but not with PFS, in patients treated with ICI for mRCC. Prolonged ABT indicated poor prognosis regardless of other risk factors.
Kankkunen et al. (Tue,) studied this question.