The study, in mice and humans, contributes to evidence that gut bacteria play an integral role in the immune system.
But specialists worried it is too soon to make recommendations to cancer patients — such as whether they ought to take “probiotic” nutritional supplements.
The two studies looked at if there is a connection between patients’ gut bacteria and their answers into newer cancer drugs known as PD-1 inhibitors. The drugs, including Keytruda (pembrolizumab) and Opdivo (nivolumab), operate by freeing up the immune system to attack cancer cells.
The medications are approved for many cancers, including complex cases of melanoma, lung, bladder and stomach cancers.
In 1 study, researchers concentrated on 112 patients with advanced melanoma, the deadliest type of skin cancer. The researchers found that those who had reacted to PD-1 treatment tended to get a bowel “microbiome” which was different from those of individuals who didn’t respond.
Those who had responded normally had more diversity into their germs, also higher concentrations of ordinary germs known as Ruminococcus and Faecalibacterium.
Nevertheless, the researchers said the findings don’t prove that those germs improve the probability of performing well on PD-1 treatment.
“Just a clinical trial could demonstrate that. This Has to Be examined,” said senior researcher Dr. Jennifer Wargo, an associate professor in University of Texas M.D. Anderson Cancer Center at Houston.
But, the findings build on signs of a “clear connection between the bowel microbiome and immune function,” she explained.
The “microbiome” identifies the trillions of bacteria and other germs which reside in the human body.
Studies have found that the majority of these bugs — especially from the gut — is closely connected to the dangers of different health conditions, such as those associated with immune function.
In general, studies have found, the more diversity at the intestine microbiome, the greater.
Wargo’s analysis included a group of melanoma patients who had responded to some PD-1 inhibitor — meaning that their cancer had stabilized or regressed for at least six months — along with a group which didn’t respond.
Total, the responders revealed an “abundance” of Ruminococcus and Faecalibacterium. By comparison, the non-responders needed a higher concentration of Bacteroidales bacteria.
To check if the microbes may have an immediate effect on therapy response, the investigators transplanted gut bacteria in the patients into laboratory mice.
Those critters also reacted better to PD-1 treatment, versus mice which had transplants from non-responding patients, according to the report.
At the next study, French researchers centered on 249 patients medicated using a PD-1 inhibitor for lung cancer, kidney or urinary tract infections. Only over one-quarter had taken antibiotics to treat a disease soon before or after beginning PD-1 therapy. (Antibiotics are medications that kill germs).
Total, these antibiotic patients had reduced survival chances. Plus, 69 percent of individuals who reacted to PD-1 therapy had detectable quantities of germs known as Akkermansia muciniphila, versus 34 percent of individuals who didn’t respond.
All of it increases “exciting possibilities,” Wargo said. Significantly, could restraining the intestine microbiome improve the odds of reacting to cancer therapy?
However, there are lots of unanswered queries. For starters, “We do not really understand what constitutes a ‘positive’ microbiome,” Wargo mentioned. So there’s absolutely no way to inform cancer patients if any probiotic may benefit them.
In actuality, she stated, if patients were to choose a random nutritional supplement, it may wind up causing injury. Additionally, there also has to be more research to gut bacteria and answers to other cancer treatments, Wargo added.
Dr. Nikhil Khushalani specializes in treating skin cancer in Moffitt Cancer Center, in Tampa, Fla.. He cautioned that the research findings are a “first step,” but also a “very fascinating” one.
Khushalani explained the findings raise the prospect of analyzing patients’ stool samples to find out who has a higher likelihood of reacting to PD-1 treatment. “That could assist us in really aligning therapy,” he proposed.
Then there is the chance of really changing patients’ microbiomes — if through probiotics or perhaps fecal transplants, Khushalani added.
Like Wargo, he cautioned patients contrary to self-treating with probiotics, given that the unknowns.
“But this may be where we are heading,” Khushalani explained. “Hopefully, this may open the door to much more study in this arena.”