Minimally invasive follicular thyroid cancer: treat as a benign or malignant lesion?

Extent of Surgery for Follicular Thyroid Carcinoma

OBJECTIVES

To examine the association between the extent of surgery and overall survival in follicular thyroid cancer (FTC) patients.

STUDY DESIGN

Retrospective analysis of the National Cancer Database (NCDB).

METHODS

Patients who underwent surgical intervention for FTC from 2004 to 2015 were selected. Patients were >18 years old, with tumor size 1-4 cm, no other malignancies, and >0 follow up time. Patients were divided into two cohorts based on extent of surgery: lobectomy (≥1 lobe resected) and thyroidectomy (total or near total resection). Pearson's chi-squared analysis was used to compare cohorts. Kaplan-Meier survival and Cox hazards models were utilized to determine overall survival between two cohorts with p < 0.05 used for significance.

RESULTS

A total of 6871 patients were identified with FTC, of which 1507 patients underwent lobectomy and 5364 patients underwent total thyroidectomy. There were no significant differences in patient demographics, comorbidity index, local spread, or tumor grade. Patients undergoing lobectomy had mean survival of 12.94 versus 12.71 years for those undergoing thyroidectomy. Extent of surgery was not associated with a significant difference in survival (5 years OS = 96% in lobectomy and 95.5% in total thyroidectomy, p = 0.08). Stratification by tumor grade resulted in no significant difference in survival between lobectomy and thyroidectomy.

CONCLUSION

Survival time was not significantly different in patients with more extensive resection of FTC.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:993-999, 2023.

Encapsulated Angioinvasive Follicular Thyroid Carcinoma: Prognostic Impact of the Extent of Vascular Invasion

BACKGROUND

Previous studies have reported an association between four or more foci of vascular invasion (VI) and thyroid cancer prognosis, while the current study aimed to investigate the association between extent of VI and outcome of encapsulated angioinvasive follicular thyroid carcinoma (FTC).

METHODS

The records of 303 patients with encapsulated angioinvasive FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were retrospectively reviewed. Thirteen patients had distant metastasis at diagnosis and were classified as M1.

RESULTS

Among the 290 patients with M0 encapsulated angioinvasive FTC, the 10-year disease-free survival (DFS) rate was 85.6%. Those with a VI of 1 (n = 131) or ≥ 2 (n = 159) had a 10-year DFS rate of 94.9% and 77.9% (p < 0.001), respectively, and those with a VI of 1-3 (n = 211) or ≥ 4 (n = 79) had a 10-year DFS rate of 86.3% and 83.3% (p = 0.311), respectively. Multivariate analysis identified age ≥ 55 years (p = 0.031) and VI ≥ 2 (p = 0.002) as independent negative prognostic factors for DFS. Patients with M0 encapsulated angioinvasive FTC aged ≥ 55 years and VI ≥ 2 had significantly poorer prognosis and a 10-year DFS rate of 66.4% (p < 0.001).

CONCLUSIONS

Patients with encapsulated angioinvasive FTC who had two or more foci of VI, especially patients aged ≥ 55 years, should be carefully followed-up.

Long Noncoding RNA GAS5 Targeting miR-221-3p/Cyclin-Dependent Kinase Inhibitor 2B Axis Regulates Follicular Thyroid Carcinoma Cell Cycle and Proliferation

INTRODUCTION

Follicular thyroid carcinoma (FTC) is more aggressive than the most common papillary thyroid carcinoma (PTC). However, the current research on FTC is less than PTC. Here, we investigated the effects of long noncoding RNA (lncRNA) GAS5 and miR-221-3p in FTC.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to detect GAS5 and miR-221-3p expression in the FTC tissues and cells. Cell proliferation was assessed by CCK8 and EdU assays. Flow cytometry was performed to determine the cell cycle. The dual-luciferase reporter assay was employed to validate the binding relationship of GAS5/miR-221-3p and miR-221-3p/cyclin-dependent kinase inhibitor 2B (CDKN2B). Western blot was conducted to measure the protein level of CDKN2B.

RESULTS

Our results displayed that GAS5 was downregulated, while miR-221-3p was upregulated in FTC tissues and cells. What's more, overexpression of GAS5 or miR-221-3p inhibition induced G0/G1 phase arrest and inhibited cell proliferation of FTC cells. GAS5 acted as a sponge of miR-221-3p, and CDKN2B was a target gene of miR-221-3p. Additionally, GAS5 inhibited cell cycle and proliferation of FTC cells via reducing miR-221-3p expression to enhance CDKN2B expression.

CONCLUSION

GAS5 induced G0/G1 phase arrest and inhibited cell proliferation via targeting miR-221-3p/CDKN2B axis in FTC. Thus, GAS5 may be a potential therapeutic target for the treatment of FTC.

Management of Differentiated Thyroid Carcinoma in Pediatric Patients

Differentiated thyroid carcinomas are rare in young children but represent almost 10% of all malignancies diagnosed in older adolescents. Differentiated thyroid carcinoma in children is more likely to demonstrate nodal involvement and is associated with higher recurrence rates than seen in adults. Decisions regarding extent of surgical resection are based on clinical and radiologic features, cytology, and risk assessment. Total thyroidectomy and compartment-based resection of involved lymph node basins form the cornerstone of treatment. The use of molecular genetics to inform treatment strategies and the use of targeted therapies to unresectable progressive disease is evolving.

Frozen section in thyroid gland follicular neoplasms: It's high time to abandon it!

Thyroid nodules are a very common clinical condition. The 2015 American Thyroid Association (ATA) guidelines recommend surgical excision for Bethesda IV nodules. The use of intraoperative frozen section (FS) has been recommended as a strategy to tailor the extent of the initial surgery. We critically evaluated the literature that discusses the utility and cost-effectiveness of FS to make an intraoperative decision in patients with thyroid nodules classified as follicular neoplasm. FS should not be recommended as a routine intraoperative test to assess for malignancy in thyroid follicular patterned lesions due to its low performance; the high number of deferred results; the inability to adequately assess histologically defining features; the improvements in risk stratification guiding total thyroidectomy; and the low cost-effectiveness of FS.

Outcomes for Minimally Invasive Follicular Thyroid Carcinoma in Relation to the Change in Age Stratification in the AJCC 8th Edition

BACKGROUND

Completion total thyroidectomy with radioactive iodine (RAI) therapy is not uniformly recommended for minimally invasive follicular thyroid carcinomas (MI-FTCs) without distant metastasis, but may be considered for cases with a risk factor of recurrence, such as age ≥ 45 years.

OBJECTIVE

The present study aimed to investigate the outcomes for patients with MI-FTC using a stratification age of 55 years.

METHODS

The records of 478 patients with MI-FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were retrospectively reviewed. Twenty patients had distant metastasis at diagnosis and were subsequently classified as M1.

RESULTS

Among the 478 patients with MI-FTC, univariate analysis identified that age ≥ 55 years (p = 0.002) and M1 (p < 0.001) were related to cause-specific survival. In 458 patients with M0 MI-FTC, male sex (p = 0.041), age ≥ 55 years (p = 0.001), and tumor size > 40 mm (p < 0.001) were related to poor disease-free survival (DFS) in univariate analysis. Multivariate analysis showed that age ≥ 55 years (p = 0.005) and tumor size > 40 mm (p = 0.005) were independent prognostic factors for DFS. The 10-year DFS rates of patients aged < 45 years, 45 years ≤ age < 55 years, and ≥ 55 years were 97.0%, 95.5%, and 86.4%, respectively.

CONCLUSIONS

The change in the recommended age for completion total thyroidectomy with RAI, from 45 to 55 years, seemed reasonable.

Pediatric differentiated thyroid carcinoma: An update from the APSA Cancer Committee

BACKGROUND

Differentiated thyroid carcinomas (DTCs) are rare in young children but represent almost 10% of all malignancies diagnosed in older adolescents.

METHODS

This article reviews the recent literature describing surgical therapeutic approaches to pediatric DTC, associated complications, and long-term recurrence and survival outcomes.

RESULTS

Similar to adult thyroid cancers, pediatric DTCs are more common in females and are associated with thyroid nodules, family history of thyroid cancer, radiation exposure, iodine deficiency, autoimmune thyroid disease, and genetic syndromes. Management of thyroid cancers in children involves ultrasound imaging, fine needle aspiration, and surgical resection with treatment decisions based on clinical and radiological features, cytology and risk assessment.

CONCLUSIONS

Total thyroidectomy and compartment based resection of clinically involved lymph node basins form the cornerstone of treatment of DTC. There is an evolving literature regarding the use of molecular genetics to inform treatment strategies and the use of targeted therapies to treat iodine refractory and surgically unresectable progressive disease.

TYPE OF STUDY

Summary review.

LEVEL OF EVIDENCE

This is a review article of previously published Level 1-5 articles that includes expert opinion (Level 5).

Histopathologic Assessment of Capsular Invasion in Follicular Thyroid Neoplasms-an Observer Variation Study

The assessment of capsular invasion is an essential but challenging step in the diagnosis of encapsulated follicular thyroid neoplasms. Therefore, interobserver agreement in the assessment of capsular invasion in these tumors was investigated among 11 thyroid pathologists by using virtual slides of 20 cases in which the original diagnosis considered the differential diagnosis of definite capsular invasion versus questionable capsular invasion. The assessment of capsular invasion was divided into three categories: (1) non-invasive, (2) questionable invasive, and (3) clear-cut invasive. The interobserver agreements for clear-cut invasive and non-invasive categories were fair (Kappa value = 0.578 and 0.404, respectively), whereas agreement for the questionable invasion was poor (Kappa value = 0.186). Disagreements in the assessment of invasion resulted in variable final pathological diagnoses. For example, the agreement for a diagnosis of malignancy was only fair (Kappa value = 0.545). Moreover, pathologists did not have a uniform approach for rendering a final diagnosis in cases with questionable capsular invasion, though nine of 11 pathologists did use the follicular tumor of uncertain malignant potential diagnosis as proposed by the World Health Organization classification of endocrine organs published in 2017. In conclusion, this study revealed considerable interobserver variation in the evaluation of capsular invasion, especially in follicular neoplasms with questionable invasion.

Systematic Review of Recurrence Rate after Hemithyroidectomy for Low-Risk Well-Differentiated Thyroid Cancer

BACKGROUND

Surgical extent in the management of well-differentiated thyroid cancer (DTC) remains a recurrent subject of debate. This is especially relevant in low-risk DTC of 1-4 cm, which represent the majority of new thyroid cancer diagnoses. With trends towards treatment de-escalation and recent guidelines from the American Thyroid Association and British Thyroid Association endorsing hemithyroidectomy (HT) alone for low-risk DTC of 1-4 cm, we sought to systematically appraise the literature to examine recurrence rate outcomes after HT in this low-risk group.

SUMMARY

Searching PubMed, Cochrane Library, and Ovid MEDLINE, we conducted a systematic review to assess the survival and recurrence rate data presented in all published studies that had a cohort of patients treated with HT for the treatment of DTC. Pooled 10-year survival and recurrence rates, odds ratios, and 95% confidence intervals were calculated for meta-analysis. We identified 31 studies (with a total of 228,746 patients (HT: 36,129, total thyroidectomy, TT: 192,617), which had published recurrence and/or survival data for patients having had HT for DTC. We discovered a pooled recurrence rate of 9.0% for HT, which is significantly higher than in previously published reports. Further, this rate is maintained when examining patients within low-risk cohorts established with recognised risk classifications. We also discovered that of those patients who develop recurrent disease, 48% recur outside the central neck.

KEY MESSAGES

Our study provides a comprehensive systematic review of evidence aimed primarily at defining the recurrence rate in DTC after HT, and more specifically within the low-risk subgroup. We describe pooled recurrence and 10-year survival rates from a larger, broader, and more contemporary patient population than has been previously reported. Our findings indicate that there is a small but significantly higher recurrence rate after HT than TT, but the evidence base is heterogenous and subject to confounding factors and would ultimately benefit from prospective randomised trials to overcome these deficiencies.

Minimally invasive parathyroid carcinoma-A missing entity between parathyroid adenoma and carcinoma: Scintigraphic and histological features

PURPOSE

Minimally invasive parathyroid carcinoma (MIPC) is clinically and biochemically comparable with parathyroid adenoma (PA) though histopathologically differ from PA. MIPC is an intermediate of PA and parathyroid carcinoma (PC). In literature, there is no definite criterion to diagnose MIPC. Our aim was to evaluate and characterize the imaging and biochemical parameters with histological characteristics of MIPC.

METHODOLOGY

Ten patients with MIPC were recruited from (single centre) Indian PHPT registry (www.indianphptregistry.com) from January 2014 to July 2018. Clinical, biochemical, imaging and histological features of MIPC patients were reviewed.

RESULTS

The mean age of MIPC patients (n = 10; 3 males) was 39.9 ± 11.3 years (range: 17-50). All patients had an elevated preoperative parathyroid hormone (iPTH) level ranging from 427 to 2138 pg/mL (median: 1328). MIBI scan showed intensely avid and enlarged parathyroid tumours in all patients; LIPT in 6, RIPT in 3 and ectopic mediastinal in 1 with mean size of the tumours was 2.8 ± 1.1 cm. The mean of maximum standardized uptake value (SUVmax) of MIPC in F-18 fluorocholine PET/CT was 6.7 ± 1.1 (range 6.0-8.3). The mean tumour weight was 12 ± 9.5 g (range: 1.09-28). All MIPC patients had identified capsular invasion in 80% and vascular invasion in 50% only but there was no local invasion, lymph nodal or distant metastasis. The mean Ki-67 labelling index was 3.2 ± 2.7 (range 1.1-10).

CONCLUSION

The study concluded that MIPC patients are less aggressive (on the basis of imaging and histopathological findings) and should be differentiated from parathyroid adenoma and carcinoma.

Thyroidectomy Practice After Implementation of the 2015 American Thyroid Association Guidelines on Surgical Options for Patients With Well-Differentiated Thyroid Carcinoma

Importance

The recommended extent of surgery for well-differentiated thyroid carcinoma has been modified considerably in the updated 2015 American Thyroid Association guidelines published in January 2016. To date, the changes in clinical practice after publication of these new guidelines have not been demonstrated.

Objective

The aim of this study was to evaluate clinical practice changes associated with implementation of the updated guidelines on the surgical procedure rates of total thyroidectomy, thyroid lobectomy, and completion thyroidectomy at a single tertiary medical center.

Design, Setting, and Participants

This is a retrospective cohort study of 169 patients at the Hadassah-Hebrew University Medical Center, Jerusalem, Israel. Patients with pathologically proved, well-differentiated thyroid carcinoma who underwent surgery between January 1, 2013, and December 31, 2014, were compared with patients who underwent surgery from January 1 to December 31, 2016. A total of 434 thyroidectomy procedures were performed during the study period, and 251 had pathologically proved, well-differentiated thyroid carcinoma. Patients with tumors larger than 4 cm, involved lymph nodes, or bilateral nodules were excluded.

Main Outcomes and Measures

Primary outcomes were the rate of up-front total thyroidectomy vs lobectomy and the rates of completion thyroidectomy before and after the implementation of the new guidelines.

Results

Of the 169 patients in the final analysis, 118 (69.8%) were included from 2013 to 2014 and 51 (30.2%) in 2016. The mean (SD) age for the entire cohort was 44 (13.8) years, and 129 (76.3%) were women. Up-front total thyroidectomy was performed in 72 of 118 patients (61.0%) prior to the 2015 American Thyroid Association guidelines and 16 of 51 (31.4%) following their implementation (odds ratio, 0.29; 95% CI, 0.14-0.59). The rate of completion thyroidectomy also significantly decreased between these periods (73.9% vs 20.0%; odds ratio, 0.09; 95% CI, 0.04-0.19).

Conclusions and Relevance

The updated 2015 American Thyroid Association guidelines implementation was associated with a significant decrease in the rates of both up-front total thyroidectomy and completion thyroidectomy. According to these findings, only 1 of 5 patients who undergoes thyroid lobectomy will require a completion procedure.

Modified Transverse-Vertical Gross Examination: a Better Method for the Detection of Definite Capsular Invasion in Encapsulated Follicular-Patterned Thyroid Neoplasms

The diagnosis of encapsulated follicular-patterned thyroid carcinoma (EFPTC) is challenging, and the detection of capsular invasion and/or vascular invasion is essential in distinguishing benign lesions from malignant lesions. In this study, we present a modified transverse-vertical gross examination method with additional vertical cuts at the upper and lower ends of thyroid nodules. In addition, we compared the clinicopathological characteristics of patients with EFPTC between conventional and modified methods. The diagnostic rate of follicular thyroid carcinoma and invasive encapsulated follicular variant of papillary thyroid carcinoma was higher with the modified method (p = 0.003 and p = 0.028, respectively). Furthermore, the paraffin block number and the number of capsular invasion per centimeter were significantly higher with the modified method (p < 0.001 and p = 0.007, respectively). However, vascular invasion was not significantly different between the two methods (p = 0.771). The possibility of identifying capsular invasion was around two times higher with the modified method (odds ratio = 1.91, 95% confidence interval = 1.20-3.07, p = 0.007). A total of 38 samples (23%) in the modified transverse-vertical group had capsular and/or vascular invasion in the additional vertical cuts of the upper/lower ends of the tumor. Our modified transverse-vertical gross examination method was more effective than the conventional transverse examination method for the detection of capsular invasion in EFPTC. This modified gross examination method might allow a better differential diagnosis among various encapsulated micro-follicular proliferative lesions.

Processing the entire capsule in thyroid follicular lesions improves diagnostic accuracy

BACKGROUND

There is contradictory evidence in literature with respect to diagnosis and management of follicular lesions of the thyroid gland. From surgical pathology stand point, pathologists require submission and processing of entire capsule for microscopic evaluation. This can be extremely challenging especially in larger lesions.

METHOD

We studied the impact of submitting entire capsule on final pathologic diagnosis in cases on which only representative sections were submitted initially and entire capsule was submitted subsequently.

RESULTS

A total of 80 specimens were identified. Mean size of the nodule in these cases was 4.4 ± 1.9 cm. Mean initial tissue sections submitted were 11.6 ± 3.6. Entire capsule was submitted subsequently in an additional 12.6 ± 13.3 sections. Submission of entire capsule contributed to final diagnosis in 3 (3.8%) cases whereby foci of capsular microinvasion were identified. There was no significant difference in the requirement of subsequent sections in specimens grossed by residents compared to those grossed by pathologist assistants (10.4 ± 10.8 vs. 14.4 ± 14.9, p = 0.18). The processing cost of additional sections of capsule was $ 4143 in these cases.

CONCLUSION

Processing of entire capsule in thyroid follicular lesions has a definitive yield that comes at a high cost. Thin slicing and looking for areas of gross abnormality such as mushrooming may be more practical especially in larger lesions.