Diet and Probiotics Influence Immunotherapy Responses in Melanoma

Diet and supplement use may influence the microbiome and subsequent responses to immunotherapy, according to Jennifer McQuade, MD.

McQuade, an assistant professor of medical melanoma oncology at The University of Texas MD Anderson Cancer Center, recently spoke with Oncology Nursing News® about recently published study findings, which suggest that high-fiber diets and lower probiotic use may be associated with improved immunotherapy response rates among patients with melanoma.

“We know that the microbiome is actually mostly not genetically determined, but shaped by our environment, and very specifically by things that we consume,” said McQuade. “What we did [was conduct] a cohort study where we asked our patients about diet and supplement use when they were starting immunotherapy, and we were collecting microbiome specimens.”

“We found that patients that were consuming a high-fiber diet were actually significantly more likely to respond to immunotherapy. This is consistent with the fact that the bacteria that have been associated with response are bacteria that have no roles in fiber fermentation.”

“We followed up that finding with preclinical studies,” she concluded. “In mice, we actually found that by doing fiber deprivation, and fiber manipulation, we are able to then change response to cancer immunotherapy. On the flip side, [when] we also looked at probiotic use, we found that 31% of our patients were actually taking over the counter probiotics—and that's probably driven by all of the attention that the microbiome has been getting—but those patients were actually less likely to respond to immunotherapy.”