Association of probiotic use with nivolumab effectiveness against various cancers: A multicenter retrospective cohort study.

In total, 488 patients who received nivolumab therapy were included. In all cancers, no significant differences in treatment duration of nivolumab were observed between probiotic users and non-users (median 62.0 vs. 56.0, hazard ratio = 1.02, p = 0.825), whereas probiotic use, compared with non-use, in patients with gastric cancer was significantly associated with a longer duration of nivolumab treatment (55.0 vs. 31.0 days, hazard ratio = 0.69, p = 0.039). In conclusion, probiotics may improve the response to nivolumab and potentially prolong progression-free survival in patients with gastric cancer.