Trends in Diagnosis of Noninvasive Follicular Thyroid Neoplasm With Papillarylike Nuclear Features and Total Thyroidectomies for Patients With Papillary Thyroid Neoplasms

Low Ki-67 labeling index is a clinically useful predictive factor for recurrence-free survival in patients with papillary thyroid carcinoma

BACKGROUND

We report a new risk stratification of invasive stage papillary thyroid carcinomas (PTCs) by combining invasive status, using extrathyroid invasion (Ex) status, and tumor growth speed using the Ki-67 labeling index (LI).

METHODS

We examined tumor recurrence in 167 patients with PTC who were surgically treated at the Kindai University Nara Hospital between 2010 and 2022. The patients were classified according to the degree of invasion [negative (Ex0) or positive (Ex1, Ex2, and Ex3)] and tumor growth speed expressed with Ki-67 LI, as low (<5%) or high (>5%). This study confirmed previous findings that the disease-free survival (DFS) rate in PTCs significantly differed between patients with a high and low Ki-67 index.

RESULTS

When combining Ex status (negative or positive) and Ki-67 proliferation status (low or high), the DFS rate of invasion in the negative, low Ki-67 LI group was only 1.1%, while that of invasion in the positive, high Ki-67 LI was 44.1%. This study reports for the first time that recurrence risks can be stratified accurately when combining carcinoma's essential two features of extrathyroid invasion status and tumor growth speed.

CONCLUSIONS

We believe the evidence for low tumor recurrence risk may contribute to use of more conservative treatment options for invasive-stage PTCs and help alleviate patient anxiety about tumor recurrence and death.

Can we diagnose noninvasive follicular thyroid neoplasm with papillary-like nuclear features before surgery?

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) can be differentiated from invasive encapsulated follicular variant of papillary thyroid carcinoma (eFV-PTC) by the presence of a tumor capsule or blood vessel invasion in histological examination. The objective of this study was to investigate whether it is possible to distinguish between NIFTP and invasive eFV-PTC before surgery. Patients diagnosed with NIFTP and invasive eFV-PTC from 2017 to 2023 were analyzed for biochemical, ultrasonographic, and cytological features. No differences were found in thyroid function tests, thyroid autoantibody levels, tumor size, or ultrasonographic characteristics. However, patients with invasive eFV-PTC had higher preoperative neutrophil-to-lymphocyte ratio (NLR) values and a higher Bethesda cytology category compared to those with NIFTP. In the multivariable analysis, NLR was the only significant predictor of invasive eFV-PTC. Nevertheless, there was no reliable NLR cutoff for distinguishing between the two entities. Overall, this study substantiates considerable overlap in demographic and clinical data between NIFTP and invasive eFV-PTC. Although the higher NLR observed in thyroid cancer does not provide strong discrimination, it suggests that the invasive nature of tumor cells might elicit a more profound systemic inflammatory or immune response.

Prophylactic central lymph node dissection for low-risk papillary thyroid cancer-Impact on subsequent therapy

BACKGROUND

For small papillary thyroid cancers (PTCs) with no lateral nodal involvement, American Thyroid Association guidelines recommend performing prophylactic central lymph node dissection (pCLND) if it influences further management. Our cohort study explored to what extent performing pCLND for small PTCs can de-escalate subsequent therapy including completion thyroidectomy and adjuvant radioactive iodine (RAI) ablation.

METHODS

Adults with T1, T2, and cN0 PTCs were identified from 42 centers across the prospectively maintained Australian and New Zealand Thyroid Cancer Registry (ANZTCR) between 2017 and 2023. Patients were excluded if they had clinical nodal involvement or distant metastases. Subsequent therapy and complication rates were compared between patients with and without pCLND.

RESULTS

Out of 1290 patients with T1, T2, and cN0 PTCs (78% female and median age 53 years), 660 (51%) received a total thyroidectomy and 630 (49%) received a hemithyroidectomy. Prophylactic CLND was performed for 477 patients (37%) and 36% uncovered occult lymph node metastases. After adjusting for differences in age, sex, and tumor characteristics, absence of lymph node metastasis after pCLND was independently associated with fewer completion thyroidectomies (adjusted relative risk [aRR] = 0.65 and p = 0.008) and reduced RAI ablation (aRR 0.55 and p < 0.001). Additionally, pCLND was not associated with higher risks of recurrent laryngeal nerve injury (p = 0.33), temporary hypocalcemia (p = 0.21), or permanent hypoparathyroidism (p = 0.48).

CONCLUSIONS

In specialized settings across Australia and New Zealand, identifying negative lymph nodes from pCLND is associated with reduced completion thyroidectomies and RAI ablation amongst low risk cN0 PTCs. There were no additional complications rates when performed by experienced thyroid surgeons.

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP): what do we need to know?

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a recently defined thyroid nodule category characterized by follicular architecture with papillary nuclear features but lacking classical papillary carcinoma features like papillae or psammoma bodies. The diagnosis of NIFTP is based on histological examination and excludes cases with high-risk mutations like BRAFV600E. NIFTP carries a low risk of recurrence and distant metastasis, prompting a more conservative surgical approach compared to classical papillary thyroid carcinoma. The management of NIFTP typically involves lobectomy with postoperative monitoring of thyroglobulin levels and performing neck ultrasounds. While the identification of NIFTP represents a significant advancement in thyroid cancer diagnosis, challenges remain in refining preoperative diagnostic tools and establishing optimal long-term follow-up strategies. The objective of this review is to provide a comprehensive overview of NIFTP, including its histopathological characteristics, molecular profile, clinical presentation, diagnostic criteria, management strategies, and future research directions.

Management of Incidental Thyroid Nodules

Thyroid nodules are widely prevalent, and often discovered incidentally. Malignancy rates are low for incidental thyroid nodules, and overall outcomes are favorable regardless of diagnosis. Patients with thyroid nodules should be evaluated with TSH levels followed by ultrasound of the thyroid and cervical lymph nodes. It is important to recognize sonographic features suspicious for thyroid malignancy and obtain biopsies when indicated according to major society guidelines. The Bethesda System for Reporting Thyroid Cytopathology along with molecular testing can help guide management decisions regarding thyroid nodules. Surgical resection and other emerging technologies are safe and effective for the treatment of thyroid nodules needing intervention.

Comprehensive analysis of cellular senescence and immune microenvironment in papillary thyroid carcinoma

Senescence-induced therapy was previously considered as an effective treatment for tumors, and cellular senescence was initially regarded as an effective mechanism against cancer. However, whether cell senescence-related genes can be used to predict the prognosis of papillary thyroid carcinoma (PTC) and immunotherapy remains unclear. We developed and validated a cell senescence-related signature (CSRS) by analyzing the gene expression of 278 genes related to cellular senescence in 738 patients with PTC. Additionally, further analysis showed that CSRS was a reliable predictor of patient outcomes in combination with immune checkpoint expression and drug susceptibility, and patients with high risk scores may benefit from immunotherapy. The findings of this study demonstrate that CSRS serves as an immunotherapeutic response and prognosis biomarker affecting the tumor immune microenvironment of PTC.

Challenges in Encapsulated Follicular-Patterned Tumors: How Much Is Enough? Evaluation of Nuclear Atypia, Architecture, and Invasion

Thyroid pathology is notoriously fraught with high interobserver variability, and follicular-patterned tumors are among some of the most challenging to assess accurately and reproducibly. Given that encapsulated or well-circumscribed follicular-patterned tumors often have similar molecular profiles, that is, frequent RAS or RAS-like alterations, the diagnosis usually relies on histopathologic examination alone. Unfortunately, many of the features that are used for diagnosis and prognosis of these tumors have long been controversial and frequently debated topics, both due to their subjectivity and their evolving (or not yet resolved) definitions. In more recent years, the introduction of noninvasive follicular thyroid neoplasm with papillary-like nuclear features has added further complexity to this discussion. In particular, the criteria and significance of nuclear features of papillary thyroid carcinoma, architectural patterns, and invasive growth still pose significant diagnostic challenges and confusion. This review explores some of the challenges in evaluating encapsulated follicular-patterned tumors, focusing on those histologic elements.

Non-invasive follicular thyroid neoplasm with papillary-like nuclear feature: clinical, pathological, and molecular update 5 years after the nomenclature revision

The term non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was proposed in 2016 and incorporated as a new entity in the World Health Organization (WHO) classification of tumours of endocrine organs in 2017. Since then, there has been debate regarding the histological criteria for the diagnosis, the need for molecular studies or the risk of lymph node metastasis or recurrence associated with this entity. Over the years, the concept of NIFTP evolved, now including both small (<1 cm) and large (>4 cm) tumours and oncocytic lesions. On the other hand, recent data on NIFTP in the setting of thyroid follicular nodular disease or frequent coexistence of malignant tumours raised concerns regarding the follow-up of these patients. Today, both pathologists and clinicians still face several challenges in the diagnosis, treatment, and follow-up of patients with NIFTP.

Non-invasive follicular neoplasm with papillary-like nuclear features: a challenging and infrequent entity in Argentina

PURPOSE

Non-invasive encapsulated follicular variant of papillary thyroid cancer was reclassified as non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). These neoplasms have an extremely low malignant potential. The aim of this study was (1) to assess the prevalence of NIFTP in patients with papillary thyroid carcinoma, (2) to evaluate their outcomes, and (3) to determine their molecular profile.

METHODS

Multicenter, descriptive, retrospective study. Patients with papillary thyroid cancer diagnosed from January 2006 to December 2016 from 11 referral centers were included. Diagnosis of NIFTP was based on criteria described by Nikiforov et al. in 2018. At least two pathologists agreed on the diagnosis. Two thousand six hundred and seventy-seven papillary thyroid cancer patients were included; 456 (17%) of them were follicular variant papillary thyroid cancer, and 30 (1.12%) fulfilled diagnostic criteria for NIFTP.

RESULTS

Each of the 30 included patients underwent a total thyroidectomy, and 50% were treated with radioiodine (median dose 100 mCi). After a median follow-up of 37 months, 84% of patients had an excellent response, 3% had an indeterminate response and data was missing in the remaining 13%. No metastatic lymph nodes, distant metastases or recurrences were found. RAS mutations were detected in 4 patients (13%).

CONCLUSION

The prevalence of NIFTP in our series is amongst the lowest reported. Excellent outcomes of patients underscore their low malignant potential. Molecular findings differ from other series, probably related to environmental or ethnic features of our population and the meticulous criteria for diagnosing NIFTP.

Complication Rates of Total Thyroidectomy vs Hemithyroidectomy for Treatment of Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-analysis

Importance

Papillary thyroid microcarcinomas (PTMCs) have been associated with increased thyroid cancer incidence in recent decades. Total thyroidectomy (TT) has historically been the primary treatment, but current guidelines recommend hemithyroidectomy (HT) for select low-risk cancers; however, the risk-benefit ratio of the 2 operations is incompletely characterized.

Objective

To compare surgical complication rates between TT and HT for PTMC treatment.

Data Sources

SCOPUS, Medline via the PubMed interface, and the Cochrane Central Register of Controlled Trials (CENTRAL); through January 1, 2021, with no starting date restriction. Terms related to papillary thyroid carcinoma and its treatment were used for article retrieval. This meta-analysis used the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline and was written according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) proposal.

Study Selection

Original investigations of adults reporting primary surgical treatment outcomes in PTMC and at least 1 complication of interest were included. Articles evaluating only secondary operations or non-open surgical approaches were excluded. Study selection, data extraction, and risk of bias assessment were performed by 2 independent reviewers and conflicts resolved by a senior reviewer.

Data Extraction and Synthesis

Pooled effect estimates were calculated using a random-effects inverse-variance weighting model.

Main Outcomes and Measures

Cancer recurrence and site, mortality (all-cause and disease-specific), vocal fold paralysis, hypoparathyroidism, and hemorrhage/hematoma. Risk of bias was assessed using the McMaster Quality Assessment Scale of Harms scale.

Results

In this systematic review and meta-analysis, 17 studies were analyzed and included 1416 patients undergoing HT and 2411 patients undergoing TT (HT: pooled mean [SD] age, 47.0 [10.0] years; 1139 [84.6%] were female; and TT: pooled mean [SD] age, 48.8 [10.0] years; 1671 [77.4%] were female). Patients undergoing HT had significantly lower risk of temporary vocal fold paralysis compared with patients undergoing TT (3.3% vs 4.5%) (weighted risk ratio [RR], 0.4; 95% CI, 0.2-0.7), temporary hypoparathyroidism (2.2% vs 21.3%) (weighted RR, 0.1; 95% CI, 0.0-0.4), and permanent hypoparathyroidism (0% vs 1.8%) (weighted RR, 0.2; 95% CI, 0.0-0.8). Contralateral lobe malignant neoplasm recurrence was 2.3% in the HT group, while no such events occurred in the TT group. Hemithyroidectomy was associated with a higher overall recurrence rate (3.8% vs 1.0%) (weighted RR, 2.6; 95% CI, 1.3-5.4), but there was no difference in recurrence in the thyroid bed or neck.

Conclusions and Relevance

The results of this systematic review and meta-analysis help characterize current knowledge of the risk-benefit ratio of HT vs TT for treatment of PTMC and provide data that may have utility for patient counseling surrounding treatment decisions.