Chemotherapy disrupts the microbiome

Chemotherapy disrupts the microbiome

Conventional myelosuppressive chemotherapy for solid tumours disrupts the intestinal microbiome, causing a loss of helpful and good bacteria needed for survival but an increase in pathogens, that can even result in infection. 

Myelosuppressive therapies - chemotherapy and radiotherapy - kill normal cells and cancer cells in the bone marrow. This lowers the number of normal red blood cells, white blood cells, and platelets in the blood and bone marrow. This is well-established.

This research, published on May 22nd 2021 in BMC Cancer, commented in the introduction as follows: ‘The gut microbiota influences many aspects of host physiology, including immune regulation, and is predictive of outcomes in cancer patients.

However, whether conventional myelosuppressive chemotherapy affects the gut microbiota in humans with non-haematological malignancy, independent of antibiotic exposure, is unknown’.

Yes, it really did say that:

  1. Your microbiome strength predicts how well you fight cancer, and your survival.
  2. There has never been any research before on what damage Chemotherapy does to the microbiome of people with solid tumours.

But a third thing became clear in the research - 

19 people were followed - with microbiome analysis (stool samples) before treatment, after 7-12 days, and after the first cycle of treatment.

Crucially, the team from Flinders University observed that there was a significant LOSS in the commensal (good, beneficial) species Firmicutes, but an INCREASE in pathogens, specifically, the members of Bacteroidetes and  Proteobacteria - both gram-negative bacteria and associated with higher infection levels.

Chris Woollams, former Oxford University Biochemist and a founder of CANCERactive said, “Sometimes I worry about why we need to research the blindingly obvious. And I am even more concerned that this is supposed to be the first ever study. The American ‘Human Microbiome Project’ finished in 2011. It said that ‘You can’t get better until your gut gets better’. Here the researchers stress the importance of microbiome health to your survival. They confirmed the two things we’ve been telling our readers for more than a decade.

Still, it's nice to have clear research back us up!"

Go To: Colorectal cancer linked to taking antibiotics


  1. Conventional myelosuppressive chemotherapy for non-haematological malignancy disrupts the intestinal microbiome; Lito E. Papanicolas et al; BMC Cancer Article 591 2021


  Approved by the Medical Board. Click Here 


2021 Research
CancerAcitve Logo
Subscribe (Free e-Newsletter)

Join Chris'

Join Chris' NewsletterSignup today for free and be the first to get notified on new updates.