The hysteria following Chernobyl caused very questionable data concerning both dose and incidence. See

VALIDITY OF THYROID CANCER INCIDENCE DATA FOLLOWING THE  CHERNOBYL ACCIDENT, Jargin, Sergei V.Health Physics December 2011, Volume 101, Number 6

Present day incidence is increasing because screening methods are more available and because screening has increased since Chernobyl. See

Garas G, Qureishi A, Palazzo F, et al. Should We Be Operating on All Thyroid Cancers? The Paradigm of Papillary Thyroid Microcarcinomas. Paper presented at: the Fifth World Congress of the International Federation of Head and Neck Oncologic Societies; July 26-30, 2014; New York, New York. Abstract P0085.

Hi... ALL the difference between increase of a disease and increase of its diagnosis... Sincerely yours

There has to be an environmental cause as well. The increase in surveillance cannot by itself explain the increase in incidence... because only papillary thyroid cancer is increasing, whereas the incidence of other types of thyroid cancer have remained the same.

An environmental cause is not necessary. Papillary cancer is on the order of 70 to 80% of reported thyroid cancers of living patients, but approaches 95% of occult thyroid cancers in autopsies, The increase in occult papillary cancers are micro-carcinomas. The increased incidence of thyroid cancer in increased screening is from micro-papillary carcinomas.

I get what you are saying, but why are we not finding more follicular, hurthle or anaplastic thyroid cancer with the increased surveillance we are doing? Why only is the incidence of papillary thyroid cancer increasing?

Papillary cancers do not metastasize  as readily as the others and generally stay only in the neck region. Again, most of the increase is in micro-papillary carcinomas that have little potential to develop further.

Probably one of the factors is the increased iodine diet. It is known that increasing iodine in the diet, induce papillary throid cancer in mice.

I believe it is a difficult issue. The increase in the incidence of papilliary thyroid cancer is certainly due, at least in part, to increased diagnosis, notably due to US scans.

There are, however, several points to be addressed. The prevalence of papillary in patients now appraches the autoptic prevalence, and it is still increasing (also the autoptic prevalence); I believe, therefore, it cannot all be due to increased diagnosis. On the other hand, also the incidence of large papillary tumours is increasing. The radiosensitivity of thyroid has recently been re-evaluated and it looks like it is much higher than previously measured (i.e. more inclined to develop tumours following irradiation). It is very much possible that increased exposure to medical use of radiation (especially CT scans of the neck, lungs and head) can be a possible cause. Also, one shopuld consider the general increase in autoimmunity, generally considered a cosenquence of various pollutants, and a specific increase in thyroid autoimmunity that is a well known riks factor for papillary thyroid cancer.

I think, therefore, that, both an improvement of diagnosis and an increase in risk factors for papillary thyroid cancer are responsible for the notable increase in the incidence of papillary TC. The risk factors remain to be identified but it would be very helpful to know them in order to try and control them.

thanks for u comments marco,

do u think, there r any common clinical or histological charcteristics for newly increasingly diagnosed thyroid cancers?

The incidence of autoimmune thyroiditis is also increased particularly in young women.It may also be a contributing factor for the development of papillary carcinoma.The dietary intake of iodine is now enhanced as all are using iodized salts and that may be a reason why follicular carcinomas are rare.