The Bidirectional Impact of Cancer Radiotherapy and Human Microbiome - Microbiome as Potential Anti-tumor Treatment Efficacy and Toxicity Modulator

Sep 23, 2026

Uploaded by Himbo

Microbiome and radiotherapy interact bidirectionally, with the human microbiome acting as a key modulator of radiotherapy efficacy and toxicity. Evidence also indicates that radiotherapy can reciprocally alter microbiome composition. This review systematically examines radiotherapy-induced microbial changes both within the treatment field and in distant microbiomes, emphasizing the oral and gut microbiome. It synthesizes how these shifts relate to cancer development and progression and concludes with recommendations to guide future studies on microbiome modification for improved antitumor effects and toxicity control.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages18

Reading Time45 min

AccessFree to download

Methodology

Eligibility criteria

Search strategy

Site-specific Microbiome and its Association With Anticancer Radiotherapy

Head and neck cancer

(Other cancer types investigated)

in vivo 39: 37-54 (2025) doi:10.21873/invivo.13803 Review The Bidirectional Impact of Cancer Radiotherapy and Human Microbiome: Microbiome as Potential Anti-tumor Treatment Efficacy and Toxicity Modulator MARTIN PALKOVSKY 1,2 , NIKOL MODRACKOVA3 , VERA NEUZIL-BUNESOVA3 , MARIAN LIBERKO 1,2 and RENATA SOUMAROVA 1,2 1Department of Oncology, University Hospital Kralovske Vinohrady, Prague, Czech Republic; 2Charles University, Third Faculty of Medicine, Department of Oncology, Prague, Czech Republic; 3Czech University of Life Sciences Prague, Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Prague, Czech Republic Abstract. Microbiome and radiotherapy represent bidirectionally interacting entities. The human microbiome has emerged as a pivotal modulator of the efficacy and toxicity of radiotherapy; however, a reciprocal effect of radiotherapy on microbiome composition alterations has also been observed. This review explores the relationship between the microbiome and extracranial solid tumors, particularly focusing on the bidirectional impact of radiotherapy on organ-specific microbiome. This article aims to provide a systematic review on the radiotherapyinduced microbial alteration in-field as well as in distant microbiomes. In this review, particular focus is directed to the oral and gut microbiome, its role in the development and progression of cancer, and how it is altered throughout radiotherapy. This review concludes with recommendations for future research, such as exploring microbiome modification to optimize radiotherapy-induced toxicities or enhance its anti-cancer effects. Correspondence to: Dr. Martin Palkovsky, Department of Oncology, University Hospital Kralovske Vinohrady, Srobarova 1150/50, Prague 110 00, Czech Republic. Tel: +420, 267162231, Fax: +420 267163232, [e-mail: martin.palkovsky@fnkv.cz](e-mail: martin.palkovsky@fnkv.cz) [Key Words:](Key Words: Radiotherapy)[ Radiotherapy](Key Words: Radiotherapy), [microbiome](microbiome) , [cancer](cancer), [radiosensitivity](radiosensitivity), [gut](gut) organ axis, dysbiosis, review. ©2025 The Author(s) . Published by the International Institute of Anticancer Research. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license ([https://creativecommons.org/licenses/by-nc-nd/4.0](https://creativecommons.org/licenses/by-nc-nd/4.0)). The association between microbial dysbiosis and cancer has gained extensive attention and is being widely explored. Since the discovery of Helicobacter pylori in the 1980s, many other cancerogenic bacterial, viral, protozoal, and parasitic entities have been successfully identified. The microbiome has also been closely linked to the treatment response to chemotherapy and immunotherapy; however, its association with radiotherapy has been ambiguous for a long time. Microbiome and radiotherapy represent bidirectionally interacting entities that can, directly and indirectly, affect each other. Dysbiosis was observed to affect development, characteristics, progression, and even radiotherapy response and toxicity in cancer. Radiotherapy, on the other hand, has a major impact on the diversity and incidence of microbial taxa in the irradiated and even non-irradiated field. The exact mechanisms are, however, still unknown. In this review, we aimed to provide a complex state-of-the-art insight into the problematics of radiotherapy and microbiome across various cancer types. Methodology Eligibility criteria. For the use of this review, only extracranial cancers routinely treated with radiotherapy were included. By consensus of the authors (MP, ML, RS), head and neck cancer (HNC), lung cancer, esophageal cancer, gastric cancer, pancreatic cancer, prostate cancer, gynecological cancers, colorectal cancer, and urinary bladder cancer were chosen for further investigation.

FAQs

How does the human microbiome influence radiotherapy outcomes?

The microbiome modulates both the efficacy and toxicity of radiotherapy. Dysbiosis can affect cancer progression and radiotherapy response.

What does the review focus on regarding radiotherapy-induced microbiome alterations?

It covers microbial alteration in-field and also in distant microbiomes. Particular attention is given to the oral and gut microbiome during radiotherapy.

Which extracranial cancers are included in the review’s eligibility criteria?

Included cancers are routinely treated with radiotherapy and include head and neck, lung, esophageal, gastric, pancreatic, prostate, gynecological, colorectal, and urinary bladder cancers.

Why are the mechanisms of microbiome–radiotherapy interaction considered uncertain?

While dysbiosis affects radiotherapy response and radiotherapy impacts microbial diversity and taxa incidence, the exact mechanisms remain unknown, according to the review.

Sep 23, 2026

Uploaded by Himbo