Background: Indolent nature but a high incidence of differentiated thyroid cancer (DTC) remains a challenge for optimizing patient care. Therefore, prognostic factors present valuable information for determining an adequate clinical approach. Methods: This study assessed prognostic features of 1167 papillary (PTC) and 215 follicular (FTC) thyroid cancer patients that had undergone surgery between 1962 and 2012, and were followed-up up to 50 years in a single institution, till April 2020. Age, gender, tumor size, presence of local and distant metastases at presentation, extrathyroidal extension, disease recurrence, and cancer-specific survival were evaluated. Results: In multivariate analysis, factors affecting the worse outcome were age (p = 0.005), tumor size (p = 0.006), and distant metastases (p = 0.001) in PTC, while extrathyroidal extension (p < 0.001), neck recurrence (p = 0.002), and distant metastases (p < 0.001) in FTC patients. Loco-regional recurrence rate was 6% for PTC and 4.7% for FTC patients, while distant metastases were detected in 4.2% PTC and 14.4% of FTC patients. The 10-year cancer-specific survival rates for PTC and FTC were 98.6% and 89.8%, respectively (p < 0.001). Conclusions: Negative prognostic factors, besides distant metastases, were older age and greater tumor size in PTC, and extrathyroidal extension and neck recurrence in FTC patients. The recurrence and mortality rates were very low.

The early identification of aggressive forms of cancer is of high importance in treating papillary thyroid cancer (PTC). Disease dissemination is a major factor influencing patient survival. Mutation status of BRAF oncogene, BRAF V600E, is proposed to be an indicator of disease recurrence; however, its influence on PTC dissemination has not been deciphered. This study aimed to explore the association of the frequency of BRAF V600E alleles in PTC with disease dissemination. In this study, 173 PTC samples were analyzed, measuring the proportion of BRAF V600E alleles by qPCR, which was then normalized against the proportion of tumor cells. Semiquantitative analysis of BRAF V600E mutant protein was performed by immunohistochemistry. The BRAF V600E mutation was present in 60% of samples, while the normalized frequency of mutated BRAF alleles ranged from 1.55% to 92.06%. There was no significant association between the presence and/or proportion of the BRAF V600E mutation with the degree of PTC dissemination. However, the presence of the BRAF mutation was significantly linked with angioinvasion. This study’s results suggest that there is a heterogeneous distribution of the BRAF mutation and the presence of oligoclonal forms of PTC. It is likely that the BRAF mutation alone does not significantly contribute to PTC aggressiveness.

Objectives: The response to radioiodine therapy (RAI) in differentiated thyroid cancer (DTC) patients is one of the most important factors that determines the treatment outcome and overall prognosis. The objective of this study is to determine the correlation between BRAF^V600E and TERT promoter (TERTp) mutation in tumor samples of DTC patients with the response to RAI as well as correlation with clinical and pathohistological features. Methods: Samples of 110 DTC patients (80 with intermediate and high risk of disease recurrence-IHR and 30 with distant metastases) were analyzed for BRAF^V600E and TERTp mutation (BRAF/TERT) and 89 patients were assessed for the response to RAI. Results: Sixty-one (55.5%) patients had BRAF^V600E mutation, 30 (27.3%) had TERTp mutation, while 21 (19.1%) patients had both mutations. In the IHR group, the study showed a statistically significant association between genotype BRAF/TERTp and treatment outcome (p = 0.04). IHR DTC patients with BRAF-/TERT- finding showed in general an excellent response to RAI, while patients with BRAF/TERT co-mutation had a predominantly incomplete or indeterminate response. In DTC patients with BRAF/TERT co-mutation that presented with distant metastases, a tendency to a higher frequency of RAI-refractory (RAI-R) disease was recorded, but without statistical significance. The pathohistological and clinical features that significantly correlated with BRAF/TERT status are age at diagnosis, locoregional lymph node involvement, the largest positive lymph node diameter, tumor angioinvasion and the presence of distant metastases. Conclusions: BRAF/TERT co-mutation may be associated with a less favorable disease course and poorer response to RAI. However, findings in patients with distant metastases should be considered exploratory due to the limited sample size.