Adjusting gut bacteria may improve response to cancer treatment

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Gut bacteria may play a role in cancer treatment. Researchers at the National Cancer Institute (NCI) Center for Cancer Research found that adjusting the type of microorganisms in the gut helped people with advanced melanoma (an aggressive type of skin cancer) respond to immunotherapy treatments that didn’t work on them in the past. The study, which was published Feb. 4, 2021, in Science, looked at 15 people with melanoma who didn’t respond to one of two immunotherapy medications, pembrolizumab (Keytruda) and nivolumab (Opdivo). The researchers performed fecal transplants on these nonresponders. This procedure is designed to introduce microorganisms from one person’s gut to the gut of another by transplanting fecal material from the donor into the colon of the recipient. In this case, the transplants came from people with cancer who had responded to the therapy. Once the researchers performed this procedure, many of the nonresponders showed an improved response to the immunotherapy drug. In six of them, the tumors shrank or their condition stabilized. While more research is needed, the study authors said this is a first step in unlocking the mechanisms behind the role of gut microorganisms in cancer treatment.