• A recent “Hope With Answers: Living With Lung Cancer” podcast discussed the relationship between lung cancer and the body’s microbiomes.
• An expert panel discussed how the makeup of a person’s intestinal bacteria may predict how well their advanced lung cancer will respond to treatment.
• Researchers hope that their studies will comprise part of the “microbial revolution” — adding to the development of genomic and immunotherapeutic therapies for lung cancer.

For people living with lung cancer, the effectiveness of their treatment may relate to their gut microbiome — the makeup of microorganisms in their stomach. Three doctors — Dr. Jarushka Naidoo, Dr. Daniel Spakowicz, and Dr. Zoltan Loinai — discussed the relationship between the body’s microbiome, lung cancer, and lung cancer treatment in an episode of the Lung Cancer Foundation of America (LCAF) “Hope With Answers: Living With Lung Cancer” podcast. The three recently received the LCAF’s Young Investigator grants.

The human body is host to a vast array of microorganisms, including bacteria, fungi, viruses, and more. These organisms, referred to collectively as microbiota, play a number of key roles — including helping us digest food and protecting us from illness. These organisms are found in the highest concentration in our intestines. These are referred to as gut microbiota.

“So you have about 10 trillion human cells on your body and roughly the same number of microbes, either bacteria, viruses, fungi, and other things,” said Dr. Spakowicz. “They live all over, but mostly in your gut in terms of concentration. And they’ve got something like a hundredfold more genes than you do for being able to degrade different carbohydrates, make different molecules. And we’re just starting to understand how they affect many different things, including cancer.”

Gut Microbiome Health May Be Linked to Immunotherapy Effectiveness

Research has found that the gut microbiome affects the body’s immune system on a local and systemic level. As recent studies have revealed, dysbiosis — or the reduction of these beneficial microorganisms in diversity and number — can disrupt the immune balance of the lungs, putting a person at risk of developing diseases like lung cancer.

The doctors noted that the composition of the gut’s microbiota may have a significant impact on how well those with advanced lung cancer respond to immunotherapy. Immunotherapy is a form of lung cancer treatment that employs the body’s own immune system in the fight against cancer.

“We know that certain cells that line the gut are very important for modifying or changing our immune response. And now that we have new treatments that harness our immune response to fight cancers ... it becomes very important to understand why some immune responses are the way they are in certain patients,” said Dr. Naidoo during the podcast.

Certain individuals may have different responses to immunotherapy than others, Dr. Naidoo noted. Oncologists like herself may be able to utilize the gut’s microbiota to understand why these different responses occur — utilizing the bacteria as biomarkers of lung cancer. Further, they may be able to adjust a person’s medications to minimize the severity or frequency of side effects experienced.

Studying this microbiome may also allow doctors to intentionally modify an individual’s gut bacteria — including through diet — before starting immunotherapy in the hopes of increasing the treatment’s efficacy. “We may be able to propose an intervention to change the microbiome so that we can harness that change and make a patient either a better responder to immunotherapy, or try to help them with the side effects of immunotherapy through an intervention that uses the microbiome,” said Dr. Naidoo.

Preparing for the Microbial Revolution

Dr. Naidoo emphasized that immunotherapy was the second of two previous “revolutions” in lung cancer treatment — the first being the genomic revolution, which led to the development of targeted oral therapies. She hopes that she and her fellow researchers will be part of the third wave of innovation.

“I think, and I hope that our projects are the start of the microbial revolution. That we will understand that our microbiome is somehow intrinsically related to perhaps how lung cancer develops, why lung cancer grows, and how lung cancer is treated,” said Dr. Naidoo. “And we may be able to understand how to harness that microbial intervention to help patients and pave the way for the future.”