Certain bacteria in the gut affect the success of cancer treatment
There are several reasons why certain therapies are not very effective against cancer. Of course, this also applies to the treatment of skin cancer and other types of cancer. Even new therapies for treatment do not seem to work in a quarter of the diseases. The reason for this is probably the presence of certain bacteria in the intestine.
Two groups of scientists from the United States and France independently determined that our diverse intestinal flora can have a strong impact on the success of cancer immunotherapy. The experts published the results of their studies in the English-language journal "Science".
Antibiotics should never be taken before immunotherapy for cancer
The human microbiome has a decisive influence on the success of treatment for cancer treatments. The doctors explained that it is imperative to avoid taking antibiotics before cancer immunotherapy. Additional treatment, such as a so-called fecal transplant, should be carried out. In this way, many affected people can be helped more effectively, the scientists explain. The experts speculate that the results of the current studies could lead to improved immunotherapy in the near future.
Checkpoint inhibitor therapy for melanoma only works in a few patients
Immunotherapy for cancer has been well established for several years. In the treatment of so-called black skin cancer (melanoma), checkpoint inhibitor therapy is now used as the standard. With such a treatment, an antibody is used to help the immune system to recognize the tumor and to fight it permanently. However, the form of therapy only works in about a quarter of patients with metastatic melanoma, the scientists from the Anderson Cancer Center at the University of Texas in Houston explain in a press release.
Microorganisms in the mouth had no effect on the treatment
For their investigation, the experts analyzed the data from a total of 112 melanoma patients who had microbiomes in the mouth and intestine. They had participated in a so-called checkpoint inhibitor therapy. The doctors found that microorganisms in the mouth had no effect on the success of the treatment. When the prescribed treatment was successful in the patients, a much richer flora could be found in the affected person's intestine. This particularly affected the bacteria in the intestine, which came from the group of the Ruminococcaceae.
Successful treatment is often influenced by the microbiome
The French scientists from a research group led by Laurence Zitvogel from the French Gustave Roussy Cancer Center (GRCC) in Villejuif came to a similar conclusion. These researchers examined nearly 250 subjects with bladder cancer, non-small cell lung cancer (NSCLC) and renal cell carcinoma (RCC). With these types of cancer, too, the doctors found that the success of the therapy is influenced by the microbiome.
Antibiotics can cause relapses in treatment
A certain germ called Akkermansia muciniphila, which lives in the intestinal mucosa of humans, is related to a good response to immunotherapy, the scientists explain. However, if sick people take antibiotics, relapses in treatment are more common. In addition, the affected patients died earlier.
Results were checked on mice
In both studies, the effect of the intestinal flora on immunotherapy was also investigated in mice. For this purpose, intestinal germs were transplanted from patients into previously sterile mice, the scientists from the USA explain. When these laboratory mice were given microorganisms from patients who had had treatment well, the result was that existing tumors grew significantly more slowly.
Akkermansia muciniphila improves treatment success
The French experts' investigation found the same results. When the Akkermansia muciniphila germ was administered to mice that did not normally respond to cancer therapy, the likelihood of treatment success increased. Apparently, such an intestinal microbiome can significantly improve the result of checkpoint inhibitor therapy in mice and patients, the researchers explain.
More research is needed
The experts from the United States now want to launch a new study and check whether and how manipulation of the intestinal flora could lead to improved immunotherapy. The microbiome can be manipulated relatively easily. The results of the studies could therefore open up great opportunities for further treatment, the researchers say. (as)