Increased incidence of thyroid carcinoma in france: a true epidemic or thyroid nodule management effects? Report from the French Thyroid Cancer Committee

Abstract

Thyroid cancer (TC) incidence, in France, has dramatically increased over the last two decades. In order to try and account for this observation, the French Department of Health requested the Public Health Agency to coordinate a multidisciplinary Thyroid Cancer Committee (TCC). The TCC analysed the temporal incidence trend in France, evaluated the contribution of changes in diagnostic practices of thyroid diseases to the observed increase of TC, and set up guidelines to improve the national surveillance system of TC. The increased incidence of TC is real (8.1% and 6.2% per year in women and in men, respectively), mainly due to papillary type with an epidemic of microcarcinomas (43% of operated cancers, period 1998-2001) associated to the extensiveness of thyroidectomies. Multicentric studies showed a significant increase, from 1980 to 2000, in ultrasonographic (3 to 84.8%) and cytological procedures (8 to 36% of patients with thyroid nodules) as well as a significant association between the increase in TC prevalence among operated patients (12.5 to 37%) and the spread of fine needle aspiration. Epidemiological evidence does not favour any link with the Chernobyl accident. The TCC recommended a national registry dedicated to thyroid cancer of the youths ( <18 years old). For adults, in addition with the strengthening of the French regional registries, a continuous registration of incident cases through the National Hospital Discharge Survey that covers all the territories is proposed. Such system, matched with pathological data derived from a national standardized collection, will provide a relevant model for epidemiological surveys of TC.