Spectrum of Surgically Treated Thyroid Carcinoma in Latvia

Introduction Health care statistics provides a solid evidence of increasing thyroid cancer prevalence in Latvia. However, in order to characterise the problem of thyroid cancer more completely, histological type and stage of carcinomas as well as demographic characteristics of the affected patients would be as important as the total burden of new cases.

Aim of the study was to provide detailed characteristics of the spectrum of surgically treated primary thyroid carcinoma.

Materials and methods. The study was designed as retrospective research. Archives of a single university hospital were searched for consecutive, surgically treated or histologically proved cases of primary thyroid carcinoma (2008 - 2012). Each case was characterised by histological type, local tumour spread, largest diameter of the carcinoma, patient’s age and sex as well as extent of surgical treatment. Descriptive statistics was carried out by CIA software.

Results. Archive search yielded 323 primary thyroid carcinoma cases, including 255 cases (78.9%; 95% confidence interval (CI) = 74.2 - 83.0) of papillary carcinoma, 54 cases (16.7%; 95% CI = 13.1 - 21.2%) of follicular carcinoma and 7 cases (2.2%; 95% CI = 1.1 - 4.4%) of medullary and anaplastic carcinoma. Although the youngest cases (aged 18 and 20 years) were diagnosed with papillary and follicular carcinoma, respectively, the mean age did not show statistically significant differences between the groups. Strong female predominance was observed regardless of cancer type. Regarding local tumour spread, pT1a was significantly more frequent in papillary carcinoma: 50.2% (95% CI = 44.1 - 56.3) in contrast to 18.5% (95% CI = 10.4 - 28.9) in case of follicular carcinoma. Total thyroidectomy was the most frequent type of operation that was applied for 28.6 - 71.4% cases in relation to histological type.

Conclusions. This is the first research work in Latvia that comprehends the overall review of the morphological spectrum of thyroid carcinoma in the surgical material. Papillary and follicular carcinomas are the most frequently identified types in accordance with the global data. Much less common morphological forms of thyroid tumours were also diagnosed - medullary carcinoma and anaplastic thyroid carcinoma. The large mean diameter of follicular carcinoma in the surgery material and the fact that more than half of follicular carcinomas are revealed as pT2-T3 tumours highlights the necessity for up-to-dated diagnostics and elaboration of reliable novel molecular tests.