Fecal microbiota transplants: 10 questions, answered

If you’ve never heard of a fecal microbiota transplant before, the concept might seem a bit startling at first. 

But transferring healthy gut bacteria from one person to another is nothing new. It’s been the standard treatment for recurrent Clostridioides difficile (C. Diff) infections for years, and it is currently being studied in connection with Parkinson’s disease, autism, obesity, and inflammatory bowel disease. 

So, why might a cancer patient need a fecal microbiota transplant? And what happens during a fecal transplant? For answers to these questions and more, we went to Yinghong “Mimi” Wang, M.D., Ph.D., a gastroenterology specialist and researcher who has been studying this topic for six years.   

What is a fecal microbiota transplant?

The easiest way to describe it is giving a healthy person’s stool to a sick person to try to correct their imbalanced gut microbiome. 

Why are fecal microbiota transplants necessary?

Several medical conditions have been shown to have a clear correlation to dysbiosis — an imbalance in the bacteria that normally populate the gut. These include inflammatory bowel conditions and C. difficile infections. But they’re not just limited to the gastrointestinal (GI) tract.  

By correcting these imbalances with an infusion of healthy gut bacteria from a donor, we are often able to reverse these conditions — and even positively affect some of our patients’ other underlying issues, such as autism, Parkinson’s disease, insulin resistance and obesity. 

Once transplanted, the new bacteria proliferate and repopulate the GI tract. Eventually, they take over the entire colon. 

Why might a cancer patient need a fecal microbiota transplant?

Cancer and its treatment can make patients more prone to infections. But a fecal microbiota transplant might be a good choice to treat: 

• Recurrent bacterial infections caused by Clostridioides difficile (C. diff) 
• Colitis, or inflammation of the GI tract, which is a common side effect of some chemotherapy and immunotherapy drugs 

With more patients receiving immunotherapy, immunotherapy-related colitis is probably the biggest challenge right now.  

Immunotherapy is a highly effective cancer treatment, but it’s also well-known for having colitis as one of its major side effects. About 45% of patients who receive immunotherapy will develop colitis. And that can mean anything from mild diarrhea and bleeding to colon perforation and even death in very severe cases. So, it’s important to recognize immunotherapy-related colitis early on and get it treated quickly.  

What are the different methods of fecal microbiota transplantation?

Fecal microbiota transplants fall into one of two categories: 

• Lower GI tract: The colonoscopy method is used very frequently since it allows more thorough coverage of the colon’s interior walls and reduces the chance of leakage after the procedure. However, liquid donor stool can also be delivered via enema. 
• Upper GI tract: These include frozen or freeze-dried capsules that can be swallowed, as well as liquids that can be placed directly in the GI tract via a feeding tube or upper endoscopy procedure. 

Most patients prefer colonoscopy because they find the upper GI options a little off-putting. But the upper GI methods can still be very good options for people who no longer have an intact colon after major bowel surgery (e.g., ostomy bag for ileostomy, colostomy, ileoanal anastomosis or J-pouch).  

How quickly can cancer patients expect to see an improvement in their colitis symptoms after a fecal microbiota transplant?

The quickest response can be seen within 24 hours. Patients have reported having much better energy and appetite the next day. Some say they feel like a new person.

Usually, though, I’d recommend giving it at least a week. If two weeks pass by without any discernable benefit, it probably wasn’t effective.  

Do you ever recommend repeating a fecal microbiota transplant?

Yes. We consider a second transplant in select patients who did not respond as well as we’d hoped to the first one. Usually, for the second treatment, we’ll use a different donor.  

But the majority of our patients respond very well to a single fecal microbiota transplant. Only about 20% need to have a second one. In those cases, we’ll usually perform the second one within a month. 

Are there any reasons to avoid a fecal microbiota transplant?

Yes. That’s why we screen patients very carefully to make sure it’s safe for them to receive a fecal microbiota transplant. Common reasons not to have a fecal microbiota transplant include: 

• Neutropenia — We won’t perform a fecal microbiota transplant if someone’s white blood cell count has dropped to a low level (usually due to chemotherapy) as the risk of infection is much higher for such patients.  
• Active infections — If a patient has an active infection, such as a UTI or pneumonia, we wait until they’ve fully recovered, because the antibiotics needed to kill the infection may also kill the bacteria delivered in the fecal microbiota transplant. That would render the procedure ineffective. 

Where do fecal donations come from?

There are multiple sources of donor stool. But all potential donors have to complete a comprehensive questionnaire and pass multiple blood and stool screening tests to qualify.  

We also sometimes use Rebyota, a new, FDA-approved fecal microbiota product that can be given via enema. 

Are there any clinical trials underway right now related to fecal microbiota transplants?

Yes. Other than the immunotherapy-related colitis trials, we’re also actively running clinical trials to treat various cancers using combinations of immunotherapy and fecal microbiota transplants. Michael Overman, M.D., has a related Phase II clinical trial open for patients with colorectal cancer. And Florencia McAllister, M.D., has a related Phase I clinical trial open for patients with pancreatic cancer.

For those patients, the transplant material is taken from a cancer survivor with the same disease. The goal is to maximize the benefit of fecal microbiota transplants by getting donor material from someone who is cancer-free now and responded well to immunotherapy. 

Other fecal microbiota transplant clinical trials coming up involve gastrointestinal graft vs. host disease in patients who've received a stem cell transplant. 

What’s the one thing you want cancer patients to know about fecal microbiota transplants?

MD Anderson is a pioneer in this field, especially in using fecal microbiota transplants to treat immunotherapy-related colitis.  

We are very proud to be able to provide this new, cutting-edge service to our patients. 

Request an appointment at MD Anderson online or by calling 1-877-632-6789.