Gut bacteria may predict chemotherapy risk

May 24, 2016
Background of colorful, fanciful drawings of microbial cells.

Chemotherapy kills more than cancer. Evidence suggests that in certain patients it also damages the intestinal lining, allowing gut bacteria to leak into the bloodstream and cause an infection that overwhelms the patient’s weakened immune system and may result in death.

A study led by researchers at the University of Minnesota and Nantes University Hospital in France suggests that the makeup of a patient’s intestinal bacteria could predict the risk of a bloodstream infection. The researchers collected pre-chemotherapy fecal samples from 28 patients with non-Hodgkin’s lymphoma. They next sequenced the bacterial DNA to measure the health of the bacterial ecosystem in each patient’s gut.

They found that the 11 subjects who acquired a bloodstream infection following their chemotherapy had significantly different mixtures of gut bacteria than the patients who did not get infections. The researchers then created an algorithm that can determine which bacteria are relatively harmful or harmless in one set of patients and then predict—with about 85 percent accuracy—whether a new patient will get an infection.

The next step is to validate this approach in a much larger study, with patients from multiple treatment centers who have experienced different cancer types and different treatment regimens. The study was published April 28, 2016, in Genome Medicine.