Changing trends in the incidence of thyroid carcinoma in a single clinical centre
Ryszard Anielski1, Stanislaw Cichon1, Malgorzata Trofimiuk2, Pawel Orlicki1 & Alicja Hubalewska-Dydejczyk2
Introduction: The incidence of the thyroid carcinoma (TC) is relatively low, although its increase has been observed in the last 20 years.
Aim: A comparative clinical and epidemiological analysis of two cohorts of patients surgically treated for the thyroid diseases in the Endocrine Surgery Department in Cracow during two five-year periods: 19821986 and 20002005.
Material and methods: Two subsets of patients, who underwent thyroid surgery, were included: group I consisting of 988 subjects operated in 19821986 and group II of 4760 patients operated in 20002005. Data from both groups were analyzed for age, sex and TC frequency and from TC subgroups for histotypes and pTNM stage.
Results: Both groups did not differ demographically. The carcinoma percentage was 3.7% (n=37) in group I, and 11.3% (n=537) in group II (P<0.001). Papillary TC prevailed in both subgroups (40.6 and 67.9% in subgroup I and II, respectively; P<0.001). Both subgroups differed significantly in anaplastic TC (16.2 and 2.8%, respectively) and epithelial carcinoma frequency (5.5 and 0.4%, respectively) (P<0.05). The percentage of the follicular TC was similar in both subgroups (24.3 and 20.1%, respectively). The TC in subgroup I was more clinically advanced in subgroup I at the time of surgery. The pT1a stage was found in 8.1% of cases of subgroup I, and in 34.3% of subgroup II, whereas the pT4 stage in 40.5%, and 17.5%, respectively (P<0.001). The percentage of patients with N+ was similar, whereas M+ was higher in subgroup I (8.1 vs 0.6%, respectively) (P<0.01).
Conclusions: i) The increase in TC percentage, mostly papillary subtype, among patients surgically treated for thyroid diseases was observed.
ii) Nowadays patients are operated on at significantly earlier stage of TC.
iii) This trends most probably reflects the changing diagnostic approach to the nodular goiter and the influence of the iodine prophylaxis.