Last update:
05-Jun-2022

Thyroid cancer is the most common cancer (90%) of the endocrine system, and is responsible for 0.5% of all cancer deaths. The incidence of thyroid cancer appears to be rapidly and steadily increasing in recent decades, and studies have reported thyroid cancer to be the 4th most common cancer today, up from 14th in the early 1990s. This increase is due mainly to a variety of environmental factors, including radiation, smoking, obesity, pollutants such as pesticides, phthalates, polychlorinated biphenyls, perfluorinated compounds, bromine flame retardants, perchlorates, nitrates and various elements such as metals, non-metals and metalloids. Some metals, including iron, copper, cadmium, lead, vanadium, chromium, manganese and nickel, are positively correlated with thyroid cancer, while others such as zinc and magnesium show a negative correlation. Other metals, such as molybdenum, tin and cobalt, appear to increase the incidence of thyroid cancer in combination, while sodium, mercury, aluminum and silver show no evidence of thyroid carcinogenicity. Of the non-metals, iodine and selenium deficiency are associated with carcinogenic effects on the thyroid, while there is no information on any relevant activity of phosphorus. Among the metalloids, boron is considered a goitrogenic element, and probably increases the incidence of thyroid cancer when it acts in combination with cadmium and molybdenum, taken in small non-toxic doses, for a long time. Finally, air pollution has been studied, and waste gases are associated with an increased incidence of cancer in various anatomical areas, including the thyroid.

Key words: Air pollution, Environmental factors, Thyroid cancer.