Research presented at the Society for Immunotherapy of Cancer (SITC) shows that the community of bacteria living in the human gut, known as the microbiome, can significantly influence how well patients respond to cancer immunotherapy. According to the report, specific strains of gut bacteria appear to either boost or dampen the immune system’s ability to attack tumors, particularly in patients receiving checkpoint inhibitors. Scientists are now working to develop microbiome-based treatments that could be given alongside existing immunotherapies to improve their effectiveness.

Key Takeaways

  • The gut microbiome can affect how well cancer immunotherapy works, especially checkpoint inhibitors.
  • Certain bacteria appear to help the immune system recognize and attack cancer cells, while others may hinder the response.
  • Researchers are testing fecal transplants, probiotics, and antibiotics to manipulate the microbiome in cancer patients.
  • Personalized microbiome profiling may one day be used to choose the best immunotherapy for each patient.
  • Clinical trials are underway, but many questions remain about which bacteria are most important and how to deliver them safely.

What Is the Microbiome and How Does It Relate to Cancer?

The human microbiome consists of trillions of bacteria, viruses, and fungi that live in the digestive tract and other parts of the body. These microbes play a key role in digestion, metabolism, and immune function. The SITC report highlights that the gut microbiome helps “educate” the immune system, teaching it to distinguish between harmless substances and threats. In cancer, this education process can influence whether immune cells recognize and attack tumors. When the microbiome is imbalanced, a condition known as dysbiosis, the immune response may become less effective against cancer cells.

The Link to Checkpoint Inhibitors

Checkpoint inhibitors are a type of immunotherapy that blocks proteins used by cancer cells to hide from immune attack. Drugs such as pembrolizumab (Keytruda) and nivolumab (Opdivo) have transformed treatment for several cancers, including melanoma and lung cancer. However, not all patients respond to these drugs. The SITC report cites studies showing that patients with a diverse and healthy gut microbiome are more likely to respond well to checkpoint inhibitors. In contrast, patients with less diverse microbiomes or those who have taken antibiotics before treatment tend to have worse outcomes. Researchers believe that specific bacteria, such as Bifidobacterium and Akkermansia muciniphila, may help activate the immune cells that checkpoint inhibitors rely on.

How Scientists Plan to Use the Microbiome in Treatment

Several strategies are being tested to harness the microbiome for cancer therapy. One approach involves fecal microbiota transplantation, where stool from a healthy donor is given to the patient to restore beneficial bacteria. Early clinical trials reported by SITC have shown that this can improve response to checkpoint inhibitors in some patients. Another strategy uses specific probiotic bacteria or prebiotic supplements designed to feed helpful microbes. Researchers are also studying whether antibiotics that remove harmful bacteria can boost immunotherapy, though this idea is still controversial because antibiotics can also wipe out beneficial microbes. The ultimate goal, according to the report, is to develop a “microbiome signature” that predicts which patients will respond to which therapy, allowing doctors to tailor treatment.

Challenges and Next Steps

While the promise is significant, the SITC report emphasizes that the field is still young. The microbiome varies greatly from person to person due to diet, environment, and genetics, making it difficult to design a one size fits all treatment. Clinical trials are small, and results have not always been consistent. Safety is also a concern: fecal transplants carry a risk of infection if donors are not carefully screened. Moreover, it is not yet clear whether changing the microbiome can help patients who have already failed immunotherapy, or whether it works best as a preventive measure. Larger randomized trials are needed before these approaches become standard practice.

Frequently Asked Questions

Can changing your diet improve immunotherapy response?

Diet has a strong influence on the gut microbiome. The SITC report notes that high fiber diets and fermented foods are associated with greater microbial diversity, which may help immunotherapy. However, no specific diet has been proven to boost response in clinical trials yet. Patients should consult their oncologist before making major dietary changes during treatment.

Are there any approved microbiome treatments for cancer?

Not yet. No microbiome based therapy has been approved by the FDA for cancer treatment. Several are in clinical trials, including fecal transplants and oral bacterial preparations. The SITC report predicts that some may reach the clinic within the next few years if ongoing trials show clear benefits.

Should I take probiotics if I am on immunotherapy?

It is not recommended to take over the counter probiotics without medical guidance. The SITC report cautions that some probiotic strains may not interact well with immunotherapy or could even be harmful. Patients should discuss this with their care team before starting any supplement.

This is an original report by Vital Signs Today, informed by reporting from Google News. Read the original source.

This article is for information only and is not medical advice. See our Medical Disclaimer.