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Understanding the microbiome may improve colon cancer care

OCTOBER 24, 2018
Clinical Congress Daily Highlights, Wednesday Second Edition

Scientists are increasingly attuned to the role the microbiome plays across the spectrum of human health. This shifting outlook is especially pronounced in colon cancer, as discoveries reveal how gut microbes directly influence cancer development. In Wednesday’s Commission on Cancer Oncology Lecture, Heidi Nelson, MD, FACS, Mayo Clinic, Rochester, MN, discussed recent advances in characterizing the gut microbiome, its relationship to colon cancer, and future directions for personalizing prevention and treatment.

While genetic factors contribute to colon cancer, environmental factors are thought to drive upwards of 90 percent of cases. Specifically, a Western diet is associated with a higher risk of colon cancer, as supported by data demonstrating that the adoption of a Western diet in non-Western countries leads to a concomitant increase in colon cancer. Recent advances in genetic sequencing of microbial DNA have also helped to identify the particular organisms that may be driving these effects. However, thus far these microbes have not proved to be ideal biomarkers, as they can produce noisy results and show overlapping distributions across cancer and noncancer samples.

Dr. Nelson presented emerging work on the development of a metabolic influence network – a quantified network of microbes and their relationships with each other – that could provide a more comprehensive and personalized snapshot of each person’s microbiome. These algorithms could predict an individual’s metabolic reaction to certain foods, such as glycemic response in the pursuit of improved nutrition. They could also support personalized nutrition to help prevent cancer. Ultimately, Dr. Nelson said, “we’re trying to get to personalized nutrition that may be able to tell us what diet is going to work for you as compared to everybody else.”

Dr. Nelson highlighted new directions in the field, including studies examining the impact of antibiotics on cancer treatment. Recent research shows that antibiotics may enhance the anticancer activity of the chemotherapy gemcitabine in a mouse model of colorectal cancer, whereas they may inhibit the clinical benefit of immune checkpoint inhibitors. She stressed the need for ongoing research and active participation from the community to further characterize these finding.

“There’s no question that we’re going to see a different future, hopefully in the next few years. And I do hope you will participate and help accelerate these fields of investigation, because I think it will make a major difference to our patients.”

Additional information

The lecture, Microbes and Cancer: A Missing Link, was held October 24 at the 2018 Clinical Congress of the American College of Surgeons in Boston, MA. Program, webcast and audio information is available online at

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