Survival outcome and optimal candidates of primary tumor resection for patients with metastatic medullary thyroid cancer.

CONTEXT: Medullary thyroid cancer (MTC) often exhibits aggressive growth with distant organ metastasis, leading to poor survival. OBJECTIVE: The question of whether primary tumor resection (PTR) is beneficial for patients with metastatic MTC remains a subject of debate. In this study, we evaluated the prognostic significance of organ-specific metastases and the number of metastatic organs in these patients, and we also conducted an analysis to determine the therapeutic value of PTR in managing this rare malignancy. MATERIALS AND METHODS: Patients initially diagnosed with metastatic MTC were identified within the Surveillance, Epidemiology, and End Results (SEER) database. Univariable and multivariable Cox proportional hazards regression models were performed to identify survival predictors. Survival outcomes were calculated using the Kaplan-Meier method and compared using the log-rank tests. RESULTS: A total of 186 patients with metastatic MTC at initial diagnosis from 2010 to 2020 were included. Bone, lung and liver were the most common metastatic organs. Patients with brain metastasis had significantly worse overall survival (OS) (p = 0.007) and cancer-specific survival (CSS) (p = 0.0013). Among all patients, 105 (56.45%) underwent PTR, and this group showed reduced overall mortality (OM) and cancer-specific mortality (CSM) (all p < 0.05). When analyzing different metastatic patterns, PTR significantly lowered the risk of OM and CSM for patients with bone, lung, liver, or distant lymph node (DLN) involvement (all p < 0.05). Additionally, among patients with one or two metastases, those undergoing surgical resection were significantly associated with favorable OS (p = 0.008) and CSS (p = 0.0247). CONCLUSIONS: PTR may confer therapeutic benefits for carefully selected individuals with metastatic MTCs. To integrate these insights into clinical decision-making settings, it is imperative to undertake multicenter prospective studies in the future.

Immune Checkpoint Protein Expression Defines the Prognosis of Advanced Thyroid Carcinoma.

Background: Patients with advanced thyroid carcinoma (TC), such as anaplastic thyroid carcinoma (ATC), poorly differentiated thyroid carcinoma (PDTC), and locally advanced papillary thyroid carcinoma (PTC), have poor prognoses and require novel treatments. Immune checkpoint (ICP) inhibitors have demonstrated encouraging and good results; nevertheless, their effect in advanced TCs remains largely unclear. Thus, we demonstrated ICP profiles and investigated their potential clinical significance. Methods: A total of 234 TC patients were involved, with 22 ATCs, 44 PDTCs, and 168 PTCs, including 58 advanced PTCs. Immunohistochemistry was performed to evaluate nine ICPs [programmed cell death ligand 1 (PDL1), Programmed cell death 1 (PD1), cytotoxic T lymphocyte-associated protein 4 (CTLA4), B and T lymphocyte attenuator (BTLA), T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), lymphocyte activation gene 3 (LAG3), V-domain immunoglobulin suppressor of T-cell activation (VISTA), B7 homolog 3 (B7-H3), and T-cell immunoglobulin and mucin domain- 3 protein (TIM3)] expression via tissue microarrays (TMAs), and clinical correlations were analyzed simultaneously. Results: ATC had the highest positive rate of ICPs among the three pathological types, as well as relatively high ICP co-expression. ATC with high expression of PDL1 positivity had a poor prognosis. Shorter survival was associated with VISTA, B7H3, TIM3, and TIGIT expression in PDTC. The greater the co-expression of these four ICPs, the poorer the prognosis in PDTC patients. VISTA and B7H3 were the two most commonly expressed ICPs in advanced PTC, both of which were linked to a poor prognosis. Conclusions: PDL1 is linked to the overall survival (OS) of ATC. A subset of PDTC is likely immunogenic with poor prognosis and co-expression of VISTA, B7H3, TIM3, and TIGIT. Furthermore, VISTA and B7H3 are prognostic biomarkers in advanced PTC. Single or combined blockade targeting these ICPs might be effective for advanced TCs in the future.

Correlation of mismatch repair deficiency with clinicopathological features and programmed death-ligand 1 expression in thyroid carcinoma.

BACKGROUND: Mutations in DNA mismatch repair (MMR) genes associated with thyroid carcinoma (TC) have rarely been reported, especially in East Asian populations. METHODS: We examined tumor tissue from a cohort of 241 patients diagnosed with TC between 2008 and 2020. MMR proteins were detected using tissue microarray-based immunohistochemistry in order to identify MMR-protein-deficient (MMR-D) and MMR-protein-intact (MMR-I) tumors. We retrospectively summarized the clinicopathologic characteristics of patients with MMR-D TC, measured the expression of PD-L1, and recorded overall survival (OS) and other clinical outcomes. RESULTS: In our cohort, there were 18 (7.5%) MMR-D (MLH1, MSH2, MSH6, and PMS2) patients, including 12 with papillary TC (PTC) (6.7%), 2 with poorly differentiated TC (PDTC) (4.7%), and 4 with anaplastic TC (ATC) (22.2%). Half of them (9/18) showed a specific deletion in MSH6, and 6 of them also carried variants in the MSH6 and PMS2 gene. Survival was significantly better in patients with MMR-D ATC than in those with MMR-I tumors (p = 0.033). Four of the 18 MMR-D patients (22%) were found to be PD-L1 positive. Their OS was much shorter than that of PD-L1-negative patients. CONCLUSIONS: MMR-D and PD-L1 positivity appear to be associated with clinicopathological characteristics and prognosis in TC. The results indicate that MMR status may have important prognostic significance in TC. Therefore, immune checkpoint inhibitors that target the PD-1/PD-L1 pathway may be a treatment option for TCs.