The effect of cancer treatment on the gut microbiota of pediatric patients

Abstract

Gut microbiota’s implications on health has been extensively studied during the recent decade. There is growing evidence that gut microbiota has both facilitating and protecting effect against the development of cancer, but exact mechanisms are still not well known. Existing studies on the impact of cancer treatments on the gut microbiota, particularly in pediatric patients, is still rather scarce. The topic is important, as survivors of childhood cancer have been shown to suffer from increased morbidity and mortality compared to regular population even after decades after the diagnosis. Typical long-term health implications include obesity, metabolic syndrome and cardiovascular diseases. Also, a higher risk of cancer has been reported.

Early childhood is vital in terms of the gut microbiota development. Gut microbiota develops in parallel with the immune system in a continuous crosstalk. Disruptions of the microbiota due to, for instance, pre-term birth, birth via cesarean section, or early use of antibiotics, may result in gut microbiota dysbiosis and induce a lasting impact on the immune system. Dysbiosis has been linked to a higher risk of obesity, allergies, autoimmune diseases, infectious diseases, cardiovascular diseases, type 2 diabetes mellitus and cancer.

According to existing preclinical and clinical studies, chemotherapy, radiation therapy, hematopoietic stem cell transplantation as well as immunotherapy may influence the gut microbiota of childhood cancer patients. Such treatments have an impact on the microbial abundance, diversity, and relative proportions, increase the inflammation inducing bacteria, decrease the beneficial bacteria, have metabolic interactions with gut microbes and change the effect of microbial products, such as endotoxins. Typically, the patients treated with chemotherapy or radiation therapy suffer from diarrhea, which has been linked to altered microbiota. Furthermore, microbiota alterations caused by chemotherapy play a role in gastrointestinal mucositis, bloodstream infections (BSI) and C. difficile infections (CDI).

The existing studies relating to pediatric cancer demonstrate that the gut microbiota of pediatric cancer patients is different from healthy controls already prior to chemotherapy treatments. Probiotic/prebiotic intervention may alleviate the adverse effects of chemotherapy.