Cancer is a global challenge that threatens human health. Low treatment efficacy and resistance to chemoradiotherapy limits the treatment outcomes in cancer patients. The microbiota in the human body has a symbiotic relationship with the human body and plays an important role in cancer treatment.
These microorganisms attach themselves to the mucosal surface of almost every organ, although most of them reside in the intestinal tract and oral cavity and are called gut microbiota and oral microbiota, respectively. Others live in different regions of the human body. Increasing studies implicated that microbiota are critical to the development of chemoradiotherapy resistance, therefore a greater insight into microbiota is urgently required.
The microbiota can interact with cancer treatments in a two‐way way; on the one hand, anticancer treatments can destroy the microbial composition in intestine and cause malnutrition in patients, then microbiota affects the effectiveness of cancer treatment on the other hand.
Radiotherapy could break both single‐strand and double‐strand of DNA through radiation that penetrates tumor tissues directly and reduces tumor genotoxicity. The frequency and severity of the tumor radio sensitivity and the toxicity caused by radiotherapy is the main reason of resistance.
Consequently, it is important for people to understand the correlations among the microbiota and radiotherapy sensitivity and toxicity. But research on the mechanism of radiotherapy resistance generation is not comprehensive, and the research is primarily focused on esophageal cancer, neuroglioma, lung cancer, and cervical cancer.
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