Prognostic value of the 8th tumor-node-metastasis classification for follicular carcinoma and poorly differentiated carcinoma of the thyroid in Japan

Prognosis of Poorly Differentiated Thyroid Carcinoma: A Systematic Review and Meta-Analysis

BACKGRUOUND

Poorly differentiated thyroid carcinoma (PDTC) accounts for a small portion of thyroid carcinomas but contributes to a significant proportion of thyroid carcinoma-associated deaths. The clinicopathological prognostic factors and clinical outcomes of PDTC remain unclear. We aimed to evaluate the clinical outcomes of patients with PDTC after curative treatment.

METHODS

A comprehensive search was performed up to September 2023. We included studies investigating treatment outcomes in patients with PDTC who underwent initial surgery. The 5-year disease-free survival (DFS) and overall survival (OS) were extracted. In this meta-analysis, the enrolled PDTC histological criteria included 3rd, 4th, and 5th World Health Organization (WHO) and Memorial Sloan Kettering Cancer Center (MSKCC) classification. A random-effects model was used for the pooled proportion analysis. Meta-regression analysis was conducted to evaluate the prognostic factors.

RESULTS

Twenty retrospective studies published between 2007 and 2023, including 1,294 patients, met all inclusion criteria. Studies that diagnosed PDTC based on various histological criteria including 3rd WHO (n=5), 4th WHO (n=12), 5th WHO (n=2), and MSKCC (n=1) were included. Overall, 5-year DFS and 5-year OS were 49.4% (95% confidence interval [CI], 42.3 to 56.4) and 73.8% (95% CI, 66.5 to 79.9), with moderate heterogeneity of 58% and 55%, respectively. In meta-regression analysis, extrathyroidal extension (ETE) was a prognostic factor for OS.

CONCLUSION

The meta-analysis of DFS and OS in patients with PDTC show the moderate heterogeneity with a variety of histological criteria. ETE appears to have a significant impact on OS, regardless of histological criteria.

Risk factors for death of follicular thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

There are conflicting reports on the factors that increase the likelihood of patients dying from follicular thyroid carcinoma (FTC). Therefore, it is critical to identify risk factors of patients with FTC. This study aimed to identify the factors that increase the risk of death of patients with FTC and help clinicians make better treatment and follow-up decisions.

METHODS

A systematic literature review was conducted in PubMed and Web of Science databases for relevant studies published before January 31, 2023. Their reference lists were also analyzed. Two reviewers extracted data and evaluated the quality of eligible studies independently. Studies on patients who had open thyroidectomy procedures with or without neck dissection were included in this review. The RevMan 5.3 software was used to analyze the data.

RESULTS

This meta-analysis included thirteen studies with a total of 2075 patients. The following variables were associated with an increased risk of death in FTC patients: age > 45 years, male, tumor diameter > 4 cm, multifocality, extrathyroidal extension (ETE), widely invasive (WI), cervical lymph node metastasis (CLNM), distant metastases (DM) and non-radical resection tumor. Lobectomy and no radioactive iodine (RAI) treatment was not associated with the death of FTC patients.

CONCLUSION

Clinicians should pay closer attention to the following significant risk factors associated with the death of FTC patients: age (> 45), male, multifocality, tumor diameter > 4 cm, ETE, WI, non-radical resection tumor, CLNM, and DM. Individualized initial treatment and close follow-up are needed FTC patients who have these risk factors.

Newly proposed survival staging system for poorly differentiated thyroid cancer: a SEER-based study

OBJECTIVE

Despite the recent release of the 8th edition TNM staging system, the risk stratification for poorly differentiated thyroid cancer (PDTC) remains controversial.

STUDY DESIGN

Retrospective study.

SETTING

SEER database and the First Hospital of China Medical University (FHCMU) database.

METHODS

Between 2004 and 2015, 1201 PDTC patients from the SEER database were enrolled to propose a new staging system. 38 PDTC patients were included from the FHCMU.

RESULTS

A retrospective analysis of 1201 PDTC cases was performed, and a new staging classification was developed as follows: stage I: age < 55 and T1/any N/M0 (n = 127, 10.57%); stage II: age < 55 and T2-4/any N/M0 or age ≥ 55 and T1-2/any N/M0 (n = 523, 43.55%); stage III: age < 55 and any T/N0/M1 or age ≥ 55 and any T3/any N/M0 (n = 239, 19.90%); stage IV: age < 55 and any T/N1/M1 or age ≥ 55 and T4/any N/M0, and T/any N/M1 (n = 312, 25.98%). The 10-year disease-specific survival rates of patients in the new stages I, II, III, and IV were 97.9%, 77.9%, 35.3%, and 12.1%, respectively. The proportion of variation explained (PVE) for disease-specific survival of the proposed system was higher than that of the 8th AJCC TNM staging (30.61% vs. 27.15%). The accuracy of the staging system was verified in 38 PDTC patients from the FHCMU.

CONCLUSION

The proposed staging system provided a more accurate risk stratification for PDTC patients. The new staging model may facilitate the design of personalized treatment strategies for PDTC patients.

Clinical and Sonographic Features of Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features: A Retrospective Study

ABSTRACT

This study was designed to investigate the clinical and sonographic features of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTPs) as compared with classical papillary thyroid carcinoma (cPTC), follicular adenoma (FA), and follicular thyroid carcinoma (FTC). A total of 178 patients were enrolled in this study. The clinical characteristics and sonographic features of thyroid nodules were compared between NIFTP and cPTC or FA/FTC. All nodules were reclassified according to the Thyroid Ultrasound Imaging Reporting and Data System and American Thyroid Association guidelines classification. The mean size of NIFTP was 29.91 ± 14.71 mm, which was larger than that of cPTC ( P = 0.000). Significant difference was found in lymph node metastases between NIFTP and cPTC ( P = 0.000). Most NIFTPs showed solid composition, hypoechoic echogenicity, smooth margin, wider than tall shape, none echogenic foci, absence of halo, and perinodular vascularity, which were similar with FA and FTC. Compared with NIFTP, hypoechoic and very hypoechoic, taller than wide, irregular margin, punctate echogenic foci, absence of halo, and low vascularity were more commonly observed in cPTC. There were statistical differences both in American College of Radiology Thyroid Ultrasound Imaging Reporting and Data System and in American Thyroid Association classification between NIFTP and cPTC ( P < 0.05), but there were no significant differences between NIFTP and FTC/FA ( P > 0.05). The ultrasonographic characteristics of NIFTP were obviously different from cPTC but overlapped with FTC and FA. Ultrasound could help increase preoperative attention of NIFTP in an appropriate clinical setting, which may lead to a more conservative treatment approach.

Finding the Optimal Age Cutoff for the UICC/AJCC TNM Staging System in Patients with Papillary or Follicular Thyroid Cancer

Background: Differentiated thyroid cancer (DTC) is the only cancer entity for which the UICC/AJCC (Union for International Cancer Control and American Joint Committee on Cancer) TNM (tumor-node-metastasis) staging system involves an age cutoff as a prognostic criterion. However, the optimal age cutoff has not yet been determined in detail. The aim of our study was therefore to investigate the optimal age cutoff for the TNM staging system to predict disease-specific survival (DSS) with a focus on differences between patients with papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC). Methods: We retrospectively studied two large well-described cohorts of adult DTC patients from a Dutch and a German university hospital. DSS was analyzed for DTC overall, and for PTC and FTC separately, using several age cutoffs (per 5-year increment between 20 and 85 years and subsequently 1-year increments between 35 and 55 years), employing the histopathological criteria from the TNM staging system, eighth edition. Results: We included 3074 DTC patients (77% PTC and 23% FTC; mean age at diagnosis was 49 years). Median follow-up was seven years. For DTC and for PTC and FTC separately, the majority of the age cutoffs had a better statistical model performance than a model with no age cutoff. For DTC overall and for PTC, an age cutoff of 50 years had the best statistical model performance, while it was 40 years for FTC. Conclusions: In this large European population of DTC patients, when employing the histopathological criteria of the TNM system (eighth edition), the optimal age cutoff to predict DSS is 50 years rather than the 55 years currently in use. With the optimal age cutoff being 50 years for PTC and 40 years for FTC, there was a substantial difference in age cutoff for the respective histological entities. Therefore, implementation of different age cutoffs for PTC and FTC could improve the predictive value of the TNM staging system.

Clinicopathological Characteristics and Prognosis of Poorly Differentiated Thyroid Carcinoma Diagnosed According to the Turin Criteria

OBJECTIVE

Poorly differentiated thyroid carcinoma (PDTC) is the primary cause of death in patients with nonanaplastic follicular cell-derived thyroid carcinoma. We purposed to identify the clinical and pathological characteristics of PDTC and their relationship with prognosis.

METHODS

A retrospective analysis was conducted on patients diagnosed with PDTC at our institution from 2010 to 2018. All of their histopathology slides were reviewed by 2 experienced pathologists based on the Turin criteria. Furthermore, information regarding clinical characteristics, pathological characteristics, treatment strategy, and follow-up events were collected. The Kaplan-Meier method was used for survival analysis, while the log-rank test was used to compare survival curves. Then, the Cox proportional hazards model was used to perform univariate and multivariate analyses.

RESULTS

Twenty-six patients with PDTC who met the Turin criteria were enrolled in this study. The median follow-up period of the included 26 patients was 76 months, while the 3- and 5-year survival rates were 40% and 18%, respectively. Notably, univariate analysis revealed that tumor size >4 cm (P = .038), extrathyroidal extension (ETE) (P = .020), distant metastases (P = .047), poorly differentiated areas >60% (P = .049), and Ki-67 labeling index >30% (P = .040) were associated with poor prognosis. On the other hand, multivariate analysis identified ETE (P = .007) and distant metastases (P = .031) as independent risk factors for poor prognosis.

CONCLUSION

PDTC is a rare carcinoma with high invasiveness and poor prognosis. Patients with ETE or distant metastases may have adverse outcomes.

Poorly differentiated thyroid carcinoma : An underdiagnosed entity

Poorly differentiated thyroid carcinomas (PDTCs) are a rare subtype of thyroid carcinomas that are biologically situated between well-differentiated papillary/follicular thyroid carcinomas and anaplastic thyroid carcinomas (ATCs).

The diagnosis of conventional as well as oncocytic poorly differentiated thyroid carcinoma is difficult and often missed in daily routine. The current WHO criteria to allow the diagnosis of PDTCs are based on the results of a consensus meeting held in Turin in 2006. Even a minor poorly differentiated component of only 10%of a given carcinoma significantly affects patient prognosis and the oncocytic subtype may even have a worse outcome. Immunohistochemistry is not much help and is mostly used to exclude a medullary thyroid carcinoma with calcitonin and to establish a follicular cell of origin via thyroglobulin staining.

Due to the concept of stepwise dedifferentiation, there is a vast overlap of different molecular alterations like BRAF, RAS, CTNNB1, TP53 and others between different thyroid carcinoma subtypes. A distinctive molecular tumor profile is therefore currently not available.

PDTCs have a unique miRNA signature, which separates them from other thyroid carcinomas. The average relapse free survival is less than one year and about 50% of patients die of the disease. Modern tyrosine kinase inhibitors offer in conjunction with powerful molecular diagnostic new chances in these difficult to treat carcinomas.

Prognostic Impact of the Turin Criteria in Poorly Differentiated Thyroid Carcinoma

BACKGROUND

The Turin criteria including solid, trabecular, and/or insular architecture, lack of typical nuclear features of papillary carcinoma, and mitoses, necrosis, or convoluted nuclei were adopted in the recent 4th edition of the World Health Organization classification published in 2017.

MATERIALS AND METHODS

Between 2006 and 2017, 11,001 cases underwent initial surgery for primary malignant thyroid tumor derived from follicular cells. A total of 75 (0.7%) cases were diagnosed with PDTC according to the 2004 WHO classification. Based on the Turin criteria, 30 (40%) cases were re-classified as PDTC-Turin (+) and 45 (60%) cases were PDTC-Turin (-). Clinicopathological features and prognosis were compared between PDTC-Turin (+) and PDTC-Turin (-).

RESULTS

Seventy-five patients (48 females and 27 males) had a median age at the time of surgery of 57 years. Preoperative diagnosis was benign in 16 (21%), follicular tumor in 40 (53%), and malignant in 19 (25%). The 5-year cause-specific survival (CSS) and disease-free survival (DFS) rates were 97% and 44% for PDTC-Turin (+) and 100% and 88% for PDTC-Turin (-). On univariate analysis, CSS and DFS rates were significantly worse in the PDTC-Turin (+) than in the PDTC-Turin (-) (p = 0.0096, and p = 0.0016). Multivariate analysis showed that Turin criteria status, Ki-67 labeling index ≥ 10%, and age 55 ≥ years were the independent prognostic factors for recurrence.

CONCLUSIONS

The prevalence of PDTC diagnosed with the Turin criteria was low, but it showed more aggressive behavior. The 2017 WHO classification reflects the prognosis more accurately than the 2004 WHO classification.

[Poorly differentiated thyroid carcinoma : An underdiagnosed entity. German version]

Poorly differentiated thyroid carcinomas (PDTCs) are a rare subtype of thyroid carcinomas that are biologically situated between well-differentiated papillary/follicular thyroid carcinomas and anaplastic thyroid carcinomas (ATCs).The diagnosis of conventional as well as oncocytic poorly differentiated thyroid carcinoma is difficult and often missed in daily routine. The current WHO criteria to allow the diagnosis of PDTCs are based on the results of a consensus meeting held in Turin in 2006. Even a minor poorly differentiated component of only 10% of a given carcinoma significantly affects patient prognosis and the oncocytic subtype may even have a worse outcome. Immunohistochemistry is not much help and is mostly used to exclude a medullary thyroid carcinoma with calcitonin and to establish a follicular cell of origin via thyroglobulin staining.Due to the concept of stepwise dedifferentiation, there is a vast overlap of different molecular alterations like BRAF, RAS, CTNNB1, TP53 and others between different thyroid carcinoma subtypes. A distinctive molecular tumor profile is therefore currently not available.PDTCs have a unique miRNA signature, which separates them from other thyroid carcinomas.The average relapse free survival is less than one year and about 50% of patients die of the disease. Modern tyrosine kinase inhibitors offer in conjunction with powerful molecular diagnostic new chances in these difficult to treat carcinomas.