Incidental papillary thyroid carcinoma: clinical characteristics and prognostic factors among patients with Graves' disease and euthyroid goiter, Cleveland Clinic experience.

Objective: The prevalence and clinical significance of incidental differentiated thyroid cancer (DTC) in patients with Graves' disease (GD) remain uncertain. Thyroid stimulating antibody (TSI Ab)-titers were thought to be responsible for the potentially increased incidence or aggressiveness of PTC in that setting. The aim of this study was to compare the prevalence of incidental DTC among patients with GD and euthyroid goiter (EG), to assess the ability of TSI to predict DTC in GD and to investigate the clinical features that may predict incidental DTC in GD and EG.
Methods: Two hundred and forty eight patients with EG and 245 patients with GD patients who had undergone total thyroidectomy at our institution between 2005 and 2013 were retrospectively selected from our data base. An analysis of incidentally discovered DTC was conducted comparing GD group with EG group.
Results: Incidental micro-papillary thyroid cancer (MPTC) was found in 28% in EG group, as compared to 26% in GD group. PTC Patients with GD were significantly younger (44 vs 59) and less likely to have compressive symptoms than with EG before surgery (p<0.001). In GD group, patients with MPTC were also significantly older (p=0.009) than those without, were more likely to have symptomatic goiter (p<0.001), and to have a nodular disease (p<0.001). TSI ab titer did not predict MPTC in GD group (The AUC curve was 0.55 (95% CI: 0.46, 0.64). Among patients with GD and incidental MPTC, 58% of patients had at least one nodule.
Conclusion: The prevalence of incidental DTC in GD is comparable to EG. Each is increased compared to general population. Age of presentation of PTC was significantly lower in GD suggesting an increased risk for MPTC in GD. Nodule size greater than 1cm predicted incidental DTC whereas TSI ab titers and disease duration did not.
(Published by Elsevier Inc.)