Cancer is one of the major diseases that seriously endanger human health
worldwide. The risk of developing cancer depends on genetic factors and the body's
immune system. The intestinal microbiome plays an essential role in maintaining
homeostasis in the human body. After cardiovascular disease, the second-largest illness
in terms of morbidity and mortality rate is cancer. Cancer has always been the focus of
human attention worldwide, which makes it a research hotspot in the medical field. In
recent years, the consumption of probiotics has been fetching in health-promoting
foods for humans, therapeutic, prophylactic and growth supplements for animal
production and human health. In medicine, various studies have demonstrated that
probiotics can help in improving the immune system and intestinal health and the effect
of probiotic therapy on antitumor treatment-related side effects; combined use of
probiotic strains did have a positive protective effect for patients with specific immune
function. Healthy gut microbiota has positive impacts not just on immune system
activity but also on thyroid function. Dysbiosis has been detected in autoimmune thyroid diseases (AITD) and thyroid cancer, where many carcinogenic and inflammatory
bacterial strains were found. The nature of the gut microbiome also influences the
availability of important micronutrients for the thyroid gland. Iodine, iron, and copper
are required for thyroid hormone synthesis, selenium and zinc are required for T4 to T3
conversion, and vitamin D aids in immune response regulation. These micronutrients
are frequently lacking in AITDs, and lead to thyroid dysfunction. Thyroid-stimulating
hormone (TSH) and T3 levels may fluctuate due to bariatric surgery, resulting in
insufficient absorption of essential nutrients. Probiotic supplementation positively
affected thyroid hormones and thyroid function in general. This chapter summarizes
the role, mechanism of probiotics, clinical trials and effects of probiotics in thyroid
cancer.
Keywords: Antitumor, Human health, Immune system, Probiotics, Thyroid cancer.
