Increased incidence of differentiated thyroid carcinoma and detection of subclinical disease

Thyroid cancer: is the incidence rise abating?

“…The incidence rates of the last 6 years are elevated, slightly higher than those reported for the more recent years, whether observed (4,(13)(14)(15) or estimated from French cancer registries covering 13% of the national population (9,16). The fact that the changes in papillary tumors and small-size tumors less than 1 cm in diameter parallel those of the general incidence suggest the major influence of small papillary cancers on incidence rates (1,6,13,15). The present study shows a near stabilization in incidence rates, and in the proportions of all groups of tumors classified by size and histopathology.…”

An update on molecular biology of thyroid cancers

“…Frequent use of sensitive diagnostic techniques such as high-resolution ultrasonography, computerized tomography, magnetic resonance or positron emission tomography may be responsible for incidental detection of thyroid tumors. Additionally, true increases in incidence rates of thyroid cancers can also be explained with increased environmental radiation and use of medical radiation, iodine intake, the Chernobyl disaster, carcinogens, environmental, ethnic and genetic factors or combinations of these factors [4][5][6][7].…”

An Epidemiological Analysis of Thyroid Cancer in a Spanish Population: Presentation, Incidence and Survival

“…Furthermore, thyroidectomy, in these areas seemed to mirror their respective regional changes in incidence. Supporting the hypotheses of recent changes in medical practice as the cause of the increase in thyroid cancer incidence, some authors (Davies & Welch, 2006;Kent et al, 2007) found a shift in the tumour size distribution of thyroid cancer toward smaller papillary cancers in recent years, suggesting an apparent (not real) increase in thyroid cancer incidence due to increased detection of subclinical tumours. However, besides MPTC, we did not observe a significant change in tumour size over time in differentiated thyroid carcinomas at presentation with a percentage of pT 2 , pT 3 and pT 4 lesions which remain stable over time.…”

“…; secondly, there has not been a shift over time in thyroid cancer tumour size, besides MPTC, and thirdly, there is no similar increase in the incidence of other histological types of thyroid cancer (Rego-Iraeta et al, 2009). Interestingly, Kent and colleagues (Kent et al, 2007) found that the incidence of medium-sized tumours (2-4 cm) remained stable over time, but were surprised to discover a slight increase in large tumours (larger than 4 cm). Several others papers from U.S. support the notion that the increase in incidence is not entirely due to increased screening and detection.…”

“…The reasons for the rise in thyroid cancer incidence are not completely understood and considerable controversy exists now about whether this increase is real or only apparent due to an increase in diagnostic activity (Leenhart et al, 2004a;Leenhart et al, 2004b;Colonna et al, 2007). Recently, some researchers (Colonna et al, 2007;Davies & Welch, 2006;Kent et al, 2007) have suggested that this increase is predominantly due to the increased detection of small, subclinical tumours through the use of medical imaging. Moreover, thyroid surgery is constantly increasing, with more systematic use of total thyroidectomies even for benign pathologies, which makes it easier to detect MPTC.…”