Abstract
In recent decades was observed a gradual increase in the detection of thyroid nodules in the adult population. Given the increase in prevalence of nodules, a similar trend to the growth in the incidence of thyroid cancers was found. The reasons for this increased incidence for thyroid cancer are controversial. Increased incidence is caused by an improvement in diagnostic techniques or does not result from an overdiagnosis, but represents a real increase in the incidence of thyroid cancer? Whatever the reality, the fact of an increased incidence of thyroid cancer for certain involves problems to global health which in any case must be evaluated and corrected.
Author Contributions
Copyright© 2020
Mango Lucio.
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Introduction
In recent decades, the epidemiology of nodular thyroid disease has changed, with a gradual increase in the detection of thyroid nodules in the adult population In Italy, for example, the prevalence of thyroid nodules in this population is 50% with peaks of up to 75% in some regions The observed increase is more pronounced in women (8.1%/year) than men (6.2%/year) Compared to the various histological forms in which thyroid carcinoma occurs, the truly significant increase concerns papillary carcinoma However, with increasing incidence of thyroid cancer, mortality from this disease has remained stable at about 0.5 deaths per 100,000 population
Discussion
The reasons for this increased incidence for thyroid cancer are controversial. Many experts say that the increased incidence is caused by an improvement in diagnostic techniques However, there is the possibility that the increase does not result from an overdiagnosis, but represents a real increase in the incidence of thyroid cancer. In favor of this hypothesis contributes the mentioned detection of increase of not only small tumors and in an early stage of development, but also medium or large and in a more advanced stage. Also the finding of an increase almost only for papillary carcinomas contributes to the hypothesis that in any case the increased incidence also derives from real reasons. The increase of some specific papillary carcinoma carcinogens might explain the above phenomenon, think eg. the increase of the presence of BRAF-positive papillary carcinomas Even if a different screening intensity depending on the age and sex can not be excluded, the different trend observed in the two sexes and the age coincidences suggest that the detection gain is not the only cause of the increased incidence of thyroid cancer. Race-specific trends also do not support a detection effect as reason for the increasing incidence One of the causes of real increase may be due to the increase in radiation, especially those arising from medical diagnostics. The effect of radiation as a cause of cancer is known and the thyroid gland is very exposed for its position in the human body. Moreover, as demonstrated by the increase in thyroid cancers, especially in children after the Chernobyl disaster for131 iodine fallout It has also been found that high TSH values can influence the onset of thyroid cancer And yet autoimmune thyroiditis could influence cancer risk, not only by increasing TSH levels but also by the autoimmune process itself, through the production of proinflammatory cytokines and oxidative stress Furthermore, there is a striking correlation between thyroid cancer, obesity and insulin resistance. These associations can be explained by various proposed pathophysiological mechanisms. So the increase in the prevalence of thyroid cancer is not only due to better detection, but from the known increase in the prevalence of obesity worldwide, which is associated with insulin resistance