Endocrine Abstracts

Background: Patients with type 2 diabetes (T2DM) are generally known to have increased risk of various types of cancer. However, the studies addressing the association between T2DM and thyroid cancer are heterogeneous and inconclusive. The aim of our study was to evaluate the patients who have already undergone thyroid surgery with histologically confirmed results as the ‘gold standard’.

Methods: A retrospective study in 102 patients (74 women and 28 men) was performed. Three cohorts were established according to histology; malignant (M), benign (B) and low-risk carcinoma (MB). Only patients which were known to have prediabetes/T2DM and/or were screened for DM following the standards of the American Diabetes Association and the European Association for the Study of Diabetes, in the same year as the thyroid surgery was performed, were included. History of the patients, biochemical testing, thyroid ultrasound and FNA with molecular testing were performed. DNA from FNA samples was used for next generation sequencing to identify mutations in genes: BRAF, HRAS, KRAS, NRAS and TERT. RNA was used for Real Time PCR to detect RET/PTC1, RET/PTC3 and ETV6/NTR3 rearrangements. Fisher’s exact test and Kruskal-Wallis one-way ANOVA of ranks were used for statistical analysis.

Results: Histologically, 44 findings were malignant (43.2%); especially papillary thyroid carcinoma (68.2%); 52 were benign (50.9%) and 6 (5.9%) were low-risk carcinomas. T2DM and prediabetes were present in 28 patients. Autoimmune thyroid disease was present in 40.6% and multinodular thyroid gland in 46.3% of the patients. The mutations were detected in 29/102 (28.4%), the most common mutation was BRAFV600E in 17/29 (58.6%). Men had presented significantly with larger thyroid nodules (P = 0.014), thyroid gland (P < 0.001), minimal thyroid cancer (TC) invasion (P = 0.048), advanced TC staging (P = 0.041) and T2DM (P = 0.028) in comparison to women. In contrast, M, B and MB cohorts had comparable age (P = 0.353), BMI (P = 0.430), thyroid nodule size (P = 0.164), thyroid gland volume (P = 0.391), glycaemia (P = 0.718) and Hb1AC (P = 0.654). In a smaller number of the patients (n =31) we were able to calculate Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) without any difference between the cohorts (P = 0.221).

Conclusion: Type 2 diabetes and obesity as the principal cause of T2DM pandemic are not likely to be risk factors for thyroid cancer. We propose that histological confirmation is crucial in these studies. In conclusion, we would like to turn the attention to male population, because they seem to come with more advanced thyroid diseases.