How Microbiome can be used in Cancer Treatment

Mayda Asif
Nov 28, 2025
3 min read

Infographic illustrating how the gut microbiome, diet, and fecal microbiota transplantation (FMT) influence cancer treatment response and immunotherapy outcomes.

Understanding how the Microbiome can be used in Cancer Treatment

The human microbiome comprises a diverse array of microorganisms that can be found in various parts of the body. The presence of these microorganisms is extremely vital in the gut, where they synergistically interact with their host's immune system to maintain health and harmonise the defence system. By carefully interacting with the immune system, the microbiome can modify and improve the innate and adaptive immunity. Thus, regulating how the immune system responds to harmless and harmful agents. These functions can define how Microbiome can be used in Cancer Treatment

Gut microbes can impact the morphology of tumours by carefully modulating the microenvironment of cancer cells and activating the targeted immune response. The microbiota in the gut can alter drug metabolism by modifying the chemotherapeutic agents through enzymatic reactions and by regulating how the host metabolism works. These actions can potentially impact the efficacy and adverse effects related to conventional cancer treatments. The anti-tumour immune response is augmented as certain gut bacteria can stimulate the action of cytotoxic T cells and minimise the function of regulatory T cells.

The Impact of Microbome on Cancer Therapy Outcomes

The following data from clinical evidence shows the critical role of the microbiome in the outcomes of cancer therapy:

Certain types of bacterial species (e.g, Enterococcus hirae, bacteroids intestinihominis) can amplify the efficacy of chemotherapy treatment by modulating the patient's immune mechanism.
Distinct patterns created from the combination of gut microbiome and from the intratumor bacteria can predict how well a patient might respond to treatments in gastrointestinal cancers.
The microbiome can enhance immunity by regulating the T cell-related immune responses. This mechanism can boost the efficacy of chemotherapy and immunotherapy treatment plans. Moreover, it can lower the risk of developing treatment-related side effects such as diarrhoea.

Diversity and the composition of the gut microbiome can significantly influence the outcomes of immunotherapy by altering the microenvironment of immune cells surrounding the tumour.

Implementing Microbiome Strategies in Cancer Treatment

The following are the strategies that exerts can use to improve cancer care through microbiome support.

Dietary Interventions :
High-fibre diets can help bacteria to produce more short-chain fatty acids (SCFA). These fats can strengthen mucosal barriers of the intestines, which is associated with enhanced responses to immunotherapy (such as PD-1 inhibitors used in melanoma and lung cancer).

Ketogenic diets can help increase the production of certain bacteria that can be extremely helpful in the metabolism and effectiveness of chemotherapeutic drugs.
A combination of personalised diets with a set ratio of vegetables and unsaturated fats can increase the variety of microbiota to overcome the treatment-induced dysbiosis. 9
Probiotics and Synbiotics
Bacterial strains such as Bifidobacterium spp., Lactobacillus rhamnosus, and Akkermansia muciniphila can diminish the associated diarrhoea from radiotherapy and toxicity from chemotherapy.

The use of these strains can accelerate the T cell infiltration for better checkpoint inhibitor outcome (better tumour shrinkage and survival, sometimes with acceptable or fewer side effects).
Microbiome-Focused Therapies
FMT from responders can transfer beneficial microbiomes and achieve 65% response rates when combined with PD-1 inhibitors in the treatment of melanoma, as the donor bacteria successfully take hold and start living and multiplying in the recipient's gut.

Studies are being conducted on the synthesis of engineered bacteria and phage therapies to create antitumor metabolites, based on interindividual variability.

References

[1] Turco L, Della Monica R, Giordano P, Cuomo M, Biazzo M, Mateu B, et al. Case report: Tracing in parallel the salivary and gut microbiota profiles to assist Larotrectinib anticancer treatment for NTRK fusion–positive glioblastoma. Front Oncol 2024;14. https://doi.org/10.3389/fonc.2024.1458990.

[2] Yan J, Yang L, Ren Q, Zhu C, Du H, Wang Z, et al. Gut microbiota as a biomarker and modulator of anti-tumor immunotherapy outcomes. Front Immunol 2024;15:1471273. https://doi.org/10.3389/fimmu.2024.1471273.

[3] Aghamajidi A, Maleki Vareki S. The Effect of the Gut Microbiota on Systemic and Anti-Tumor Immunity and Response to Systemic Therapy against Cancer. Cancers (Basel) 2022;14:3563. https://doi.org/10.3390/cancers14153563.

[4] Lau HCH, Sung JJ-Y, Yu J. Gut microbiota: impacts on gastrointestinal cancer immunotherapy. Gut Microbes n.d.;13:1869504. https://doi.org/10.1080/19490976.2020.1869504.

[5] Zhang Z, Tang H, Chen P, Xie H, Tao Y. Demystifying the manipulation of host immunity, metabolism, and extraintestinal tumors by the gut microbiome. Signal Transduct Target Ther 2019;4:41. https://doi.org/10.1038/s41392-019-0074-5.

[6] Xie Y, Liu F. The role of the gut microbiota in tumor, immunity, and immunotherapy. Front Immunol 2024;15:1410928. https://doi.org/10.3389/fimmu.2024.1410928.

[7] Sun J, Chen F, Wu G. Potential effects of gut microbiota on host cancers: focus on immunity, DNA damage, cellular pathways, and anticancer therapy. ISME J 2023;17:1535–51. https://doi.org/10.1038/s41396-023-01483-0.

Assessed and Endorsed by the MedReport Medical Review Board