Impact of antibiotic exposure before immune checkpoint inhibitor treatment on overall survival in older adults with cancer

A population-level retrospective study in Ontario evaluated the impact of antibiotic exposure before starting immune checkpoint inhibitor therapy on overall survival among older adults with cancer. Any antibiotic exposure within one year before ICI was associated with poorer OS and in antibiotic class analysis, exposure to fluoroquinolones within one year or 60 days bbefore ICI was associated with worse OS, with a dose effect seen on the basis of total weeks of of fluoroquinolone exposure over one year and 60 days.