Reconsideration of tumor size threshold for total thyroidectomy in differentiated thyroid cancer

Revisiting the Relationship Between Tumor Size and Risk in Well-Differentiated Thyroid Cancer

Introduction: Large tumor size is associated with poorer outcomes in well-differentiated thyroid cancer, yet it remains unclear whether size >4 cm alone confers increased risk, independent of other markers of aggressive disease. The goal of this study was to assess the relationship between tumor size, other high-risk histopathological features, and survival in well-differentiated thyroid cancer and to evaluate the significance of 4 cm as a cutoff for management decisions. Methods: Patients with well-differentiated thyroid cancer were identified from the National Cancer Database (2010-2015) and categorized by tumor size (i.e., small [≤4 cm] or large [>4 cm]) and presence of high-risk histopathological features (e.g., extrathyroidal extension). First, propensity score matching was used to identify patients who were similar across all other observed characteristics except for small versus large tumor size, and a multivariable Cox proportional hazards model was used to estimate the relationship between tumor size and survival. Second, we assessed whether the presence of high-risk features demonstrates conditional effects on survival based on the presence of tumor size >4 cm using an interaction term. Finally, additional models assessed the relationship between incremental 1 cm increases in tumor size and survival. Analyses were repeated using a validation cohort from the Surveillance, Epidemiology, and End Results Program (2008-2013). Results: Of 193,133 patients in the primary cohort, 7.9% had tumors >4 cm, and 30% had at least one high-risk feature. After matching, tumor size >4 cm was independently associated with worse survival (HR 1.63, p < 0.001). However, tumor size >4 cm and one or more other high-risk features together yielded worse survival than either size >4 cm alone (MMD: 0.70, p < 0.001) or other high-risk features alone (MMD: 0.49, p < 0.001). When assessed in 1 cm increments, the largest increases in hazard of death occurred at 2 cm and 5 cm, not 4 cm. Results from the validation cohort were largely consistent with our primary findings. Conclusions: Concomitant high-risk features confer worse survival than large tumor size alone, and a 4 cm cutoff is not associated with the greatest increase in risk. These findings support a more nuanced approach to tumor size in the management of well-differentiated thyroid cancer.

SOX4 is a pivotal regulator of tumorigenesis in differentiated thyroid cancer

The SOX family consists of about 20 transcription factors involved in embryonic development, reprogramming, and cell fate determination. In this study, we demonstrated that SOX4 was significantly upregulated in differentiated thyroid cancer. Immunohistochemical analysis revealed that high SOX4 expression was associated with papillary histology, extrathyroidal extension, lymph node metastasis, and advanced disease stage. Patients whose tumors exhibited high SOX4 expression had a shorter recurrence-free survival, though significance was lost in multivariate Cox regression analysis. SOX4 silencing in thyroid cancer cells slowed cell growth, attenuated clonogenicity, and suppressed anoikis resistance. Additionally, SOX4 knockdown impeded xenograft tumor growth in nude mice. Knockdown of SOX4 expression was accompanied by reduced phosphorylation of AKT and ERK. Furthermore, CRABP2 expression correlated with SOX4 expression, and SOX4 silencing decreased CRABP2 expression and its downstream effectors such as integrin β1 and β4. These results indicate that SOX4 has both prognostic and therapeutic implications in differentiated thyroid cancer, and targeting SOX4 may modulate tumorigenic processes in the thyroid.

A clinically useful and biologically informative genomic classifier for papillary thyroid cancer

Clinical management of papillary thyroid cancer depends on estimations of prognosis. Standard care, which relies on prognostication based on clinicopathologic features, is inaccurate. We applied a machine learning algorithm (HighLifeR) to 502 cases annotated by The Cancer Genome Atlas Project to derive an accurate molecular prognostic classifier. Unsupervised analysis of the 82 genes that were most closely associated with recurrence after surgery enabled the identification of three unique molecular subtypes. One subtype had a high recurrence rate, an immunosuppressed microenvironment, and enrichment of the EZH2-HOTAIR pathway. Two other unique molecular subtypes with a lower rate of recurrence were identified, including one subtype with a paucity of BRAFV600E mutations and a high rate of RAS mutations. The genomic risk classifier, in addition to tumor size and lymph node status, enabled effective prognostication that outperformed the American Thyroid Association clinical risk stratification. The genomic classifier we derived can potentially be applied preoperatively to direct clinical decision-making. Distinct biological features of molecular subtypes also have implications regarding sensitivity to radioactive iodine, EZH2 inhibitors, and immune checkpoint inhibitors.

Risk staging with prophylactic unilateral central neck dissection in low-risk papillary thyroid carcinoma

OBJECTIVE

Current guidelines favor thyroid lobectomy for intrathyroidal cT1bT2cN0 papillary thyroid carcinoma. Prophylactic neck dissection (PND) is not recommended for these low-risk tumors due to the lack of high-level evidence on improvement in outcomes, but the information from PND may be used for staging. The aim of this study was to evaluate the rate of upstaging with ipsilateral PND.

MATERIALS AND METHODS

Retrospective study of patients with intrathyroidal unifocal cT1bT2cN0 papillary thyroid carcinoma from 2008 to 2021. All patients underwent total thyroidectomy and PND. Tumors were classified as low or intermediate risk based on the information from pathological analysis of the primary tumor and then from adding the analysis of the lymph nodes. The difference between the tumor-only and the PND-added risk staging was evaluated.

RESULTS

Three hundred three patients (241 women, median age 45, median tumor size 17 mm) were included. Microscopic extrathyroidal extension was found in 23.4%, aggressive histology in 6.6%, vascular invasion in 29.3%, and lymph node metastases in 37.3%. One hundred ten patients (36.3%) were intermediate-risk based on the primary tumor. An additional 26 (8.6%) were upstaged to intermediate-risk based on the ipsilateral PND and 2% based on the contralateral PND. Kaplan-Meier 10-year event-free survival in tumors upstaged with ipsilateral PND was not statistically different from intermediate-risk tumors based on the primary tumor characteristics (92% versus 90.9%, Log Rank p = 0.943).

CONCLUSIONS

Ipsilateral PND upstaged low-risk cT1bT2cN0 patients to intermediate risk in only 8.6% of cases, and contralateral PND in an additional 2%. Routinely performing PND may not be warranted.

Impact of completion thyroidectomy on postoperative recovery in patients with differentiated thyroid cancer

While an increasing number of patients now undergo lobectomy for low-risk differentiated thyroid cancer, a subset of patients require completion thyroidectomy to facilitate radioactive iodine therapy. Completion thyroidectomy is generally as safe as the initial operation, but a previous study showed that a longer hospitalization is required for completion thyroidectomy. In this study, we reviewed 61 consecutive patients who had been treated with an initial lobectomy and subsequent completion thyroidectomy at our institution from 2012 to 2021. We detected a changepoint in 2016 for the proportion of patients who were treated with a thyroid lobectomy (Pettitt's test P = 0.049). The rate of completion thyroidectomy remained stable throughout the study period. There was no difference in operating time, intraoperative blood loss, perioperative drop in calcium levels, and postoperative hospital stay between surgeries. The patients reported higher pain scores on the day of operation (P = 0.007) and the postoperative day 1 (P = 0.022). Occult papillary microcarcinomas were identified in the contralateral thyroid lobe in 13 (21%) patients. Multifocality was the only predictor for residual malignancy in multivariate regression. In conclusion, patients with differentiated thyroid cancer experienced more pain in the immediate postoperative period following completion thyroidectomy. Hospital stays do not change with appropriate opioid-free pain control.

Modulating the extension of thyroidectomy in patients with papillary thyroid carcinoma pre-operatively eligible for lobectomy: reliability of ipsilateral central neck dissection

PURPOSE

Pre-operative work-up and macroscopic intraoperative inspection could overlook occult central neck nodal metastases in patients with papillary thyroid carcinoma (PTC). An occult N1a status is able to change the initial risk stratification in small, clinically unifocal PTC potentially scheduled for thyroid lobectomy (TL) making total thyroidectomy (TT) the preferable option. We aimed to verified the reliability of an intraoperative management protocol based on frozen section examination (FSE) of ipsilateral central neck nodes (IpsiCND) to identify, among patients scheduled for TL, those who could benefit of a more extensive surgical resection (TT plus bilateral central neck dissection -CND-).

METHODS

Thirty PTC patients preoperatively classified as T1N0 underwent TL plus IpsiCND-FSE (TL-group). In case of positive FSE, TT plus bilateral CND was accomplished during the same surgical procedure. A comparative analysis was performed between TL-group and a control group (C-group), who underwent TT plus IpsiCND-FSE, matched by a propensity score analysis.

RESULTS

Nodal metastases (>2 mm) were found at final histology in 5/30 patients in the TL-group and in 6/30 in the C-group (p = 1.00). Micrometastases (≤2 mm) were retrieved in 5/30 TL-group patients and in 4/30 C-group patients (p = 1.00). Final histology staged as pN1a 10 (33.3%) patients for each group. FSE correctly identified five patients with occult nodal metastases >2 mm (16.6%) in TL-group, who underwent TT plus bilateral CND during the same surgical procedure. No permanent complications occurred. At a mean follow-up of 22.2 months, no local and/or nodal recurrence were observed.

CONCLUSIONS

Intraoperative assessment of N status obtained with IpsiCND plus FSE allows for an accurate risk stratification. IpsiCND plus FSE real time modulated thyroidectomy seems a safe and effective surgical strategy reducing the need of a subsequent completion surgery and, theoretically, the risk of local recurrence.

Ultrasonography-guided radiofrequency ablation vs. surgery for the treatment of solitary T1bN0M0 papillary thyroid carcinoma: A comparative study

OBJECTIVE

Ultrasonography-guided radiofrequency ablation (RFA) has been used to treat low-risk small papillary thyroid carcinoma (PTC) and yielded promising results. However, little research has been conducted on the application of RFA for the management of T1bN0M0 PTC. Therefore, this study was to compare the midterm outcome of RFA with that of surgery for the treatment of clinical solitary T1bN0M0 PTC.

DESIGN

This is a retrospective study.

PATIENTS

In total, 182 patients with solitary T1bN0M0 PTC between April 2014 and May 2019 were treated with RFA or surgery (n = 91/group).

MEASUREMENTS

The primary end points were local tumour progression and complication rates. Local tumour progression were defined as: (a) new or persistent PTC confirmed by core needle biopsy; (b) cervical lymph node metastasis (LNM) confirmed by core needle biopsy or surgery; (c) ablation zone increased in the RFA group.

RESULTS

In the RFA group, local tumour progression was seen in four patients (4.4%, three persistent PTC and one LNM). In the surgery group, two patients (2.2%) developed LNM; no new or persistent PTC was confirmed. There was no significant difference between the two groups in local tumour progression. Permanent hypoparathyroidism was observed in four patients (4.4%) in the surgery group, while no major or minor complications were observed in the RFA group.

CONCLUSIONS

Ultrasonography-guided RFA is feasible and safe for treating solitary T1bN0M0 PTC, so it may be considered an alternative to surgery in select patients, especially those who are ineligible for or refusal of surgery.

Decline in radioiodine use but not total thyroidectomy in thyroid cancer patients treated in the United Arab Emirates - A retrospective study

Objectives

To assess the trend of clinicopathological features and treatment modalities in patients with thyroid cancer (TC) in the largest oncology center in the United Arab Emirates (UAE).

Methods

A retrospective analysis of patients with TC presenting to a tertiary care hospital in Al Ain, UAE between September 2008 and December 2018 identified using ICD 9 & 10 codes was performed. Data on demographics, histopathology, surgical extent, and use of Radioiodine (RAI) were extracted. Exact logistic and ordinal logistic regressions were performed to analyze the annual trend in features and management of TC, and logistic regression analysis was performed to identify predictors of total thyroidectomy and RAI use.

Results

A total of 762 patients were included in the analysis (mean age: 39.6 ± 12.6 years, 45 (60%) women). The majority (92.2%) were diagnosed with papillary thyroid cancer (PTC) and 83.9% had tumor size of <4 cm. All patients underwent surgery (93.8% total thyroidectomy, 6.2% lobectomy) and 77.4% received RAI therapy overall with a significant (p < 0.001) decline from 100% in 2008 to 60% in 2018. In multivariate analysis, nationality, and lymph node (LN) involvement were significant predictors of total thyroidectomy, while nationality, LNs, year of diagnosis, and tumor size significantly predicted RAI use.

Conclusion

Most patients in our cohort were diagnosed with localized PTC with no significant change in the extent of surgical approach but a substantial decline in RAI therapy administration over time. Nationality and LN involvement were significant predictors of surgical extent and RAI use.

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This is the largest study evaluating clinicopathological features and treatment modalities in TC patients in the UAE.

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Most patients were diagnosed with localized PTC.

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A substantial decline in RAI therapy administration but not the extent of thyroidectomy was observed during the study period.

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Nationality and LN involvement were significant predictors of surgical extent and RAI use.

Pros and cons of hemi-thyroidectomy for low-risk differentiated thyroid cancer

The debate regarding the surgical management of low-risk differentiated thyroid cancer (DTC) is ongoing. The recommended extent of surgery in DTC is based on an assessment of the predicted risk of recurrence and recent guidelines reflect an evolving philosophy of de-escalation of surgical management, informed by a growing understanding of the determinants of tumour biology and important prognostic factors. However, our current clinical and pathological risk stratification processes are imperfect and hence there is significant variation in clinical practice. Surgeons face the challenge of finding the balance between avoiding overtreatment, minimizing complications and providing adequate oncological management. This article discusses the nuances of the current management guidelines as well as the important considerations in preoperative decision making.

Current surgical treatment of intermediate risk differentiated thyroid cancer: a systematic review

Introduction: Surgical treatment of thyroid cancer has become less aggressive but for many patients, the threshold for performing total thyroidectomy (TT), as opposed to thyroid lobectomy (TL), has remained unclear. Current American Thyroid Association (ATA) guidelines encourage more individualization of treatment options, which necessitates explicit review of the pros and cons of the different options with patients.Areas covered: This review focuses on the extent of surgery for treatment of intermediate-risk differentiated thyroid cancer, restricted to relevant literature available after publication of the 2015 ATA guidelines.Expert opinion: Dynamic risk-stratification facilitates a tailored approach when deciding on the extent of surgery for thyroid cancer. Treatment with TT allows for a lower recurrence risk, a simpler follow-up regimen, and treatment with adjuvant post-operative radioactive iodine. Treatment with TL has a lower associated risk of complications and avoidance of lifelong thyroid hormone replacement but has a significant risk of requiring a completion thyroid lobectomy (CT). Overall, treatment with TL and TT have comparable survival outcomes, but TL is the more cost-effective option. Larger cancer size is correlated with worse clinical outcomes, and numerous subgroup analyses have shown poorer outcomes for cancers with a diameter that is 2-4 cm compared to 1-2 cm.

Risk Factors That Influence Surgical Decision-Making for Patients with Low-Risk Differentiated Thyroid Cancer with Tumor Diameters of 1-4 cm

Background

There are several controversies between thyroid lobectomy and total thyroidectomy for surgical management of low-risk differentiated thyroid cancer (DTC) with a tumor diameter of 1–4 cm.

Patients and Methods

In this study, we explore the factors related to selection of type of surgical procedure for 103 low-risk DTC patients with a tumor diameter of 1–4 cm.

Results

Among 103 low-risk DTC patients with tumor diameters of 1–4 cm, 43 patients underwent total thyroidectomy and 60 patients underwent thyroid lobectomy based on postoperative pathology. A ROC curve showed that the optimal diagnostic threshold for selecting surgical modality was a tumor diameter of 2.15 cm. For these low-risk DTC patients, the sensitivity and specificity for predicting thyroid lobectomy when tumor diameter <2.15 cm while total thyroidectomy when tumor diameter ≥2.15 cm are 46.5% and 78.3%, respectively. There were significant differences between the selection of type of surgical procedure in patient groups with 1) tumors with multiple foci group vs a single focus (P<0.05), and 2) tumor diameter of ≥2.15 cm vs <2.15 cm (P<0.05). There was no significant difference between gender and age groups (P>0.05). Multivariate analysis confirmed that tumors with multiple foci and diameter ≥2.15 cm were the primary risk factors for implementation of total thyroidectomy (P<0.05).

Conclusion

The diameter and multifocal nature of low-risk DTC tumors are the primary factors related to preferred surgical modality. This study revealed that thyroid lobectomy is more applicable to patients with tumor diameter <2.15 cm and a single focus, whereas, total thyroidectomy was preferred in patients with tumor diameter ≥2.15 cm and/or multiple foci.

Patient and tumor factors contributing to distant metastasis in well-differentiated thyroid cancer: a retrospective cohort study

BACKGROUND

Distant metastasis in thyroid cancer significantly reduces survival in patients with well-differentiated thyroid carcinoma (WDTC). There is limited information available to clinicians regarding pathological features that confer a higher risk of distant metastasis (DM). This study aimed to identify patient and tumor factors that were associated with the development of DM over time in patients with WDTC.

METHODS

A retrospective cohort analysis of patients with WDTC (n = 584) at our institution was performed between 2007 and 2017. A total of 39 patients with DM and 529 patients with no DM (NDM) were included. Patient demographics, tumor characteristics and patient survival were compared between the DM and NDM groups using a univariate analysis. Multivariate Cox-proportional hazards model was used to evaluate the risk of developing distant metastasis over time. Kaplan-Meier analysis was used to compare survival between the DM and NDM groups.

RESULTS

Distant metastasis had a substantial impact on disease-specific survival (DSS) at 5 and 10-years in the DM group; 71.0% (SE 8.4%) and 46.9% (SE 11.6%) respectively, compared to 100% survival in the NDM group (p < 0.001). The DM group had significantly higher proportions of males, lymphovascular invasion (LVI), nodal metastasis (NM), large tumor size (TS), extrathyroidal extension (ETE), positive resection margins, multifocality, follicular thyroid cancer (FTC), tall cell variant of papillary thyroid cancer (PTC), and Hurthle cell carcinoma (HCC), when compared to the NDM group (p < 0.05). A TS ≥ 2 cm (Hazard Ratio (HR) 1.370), NM (HR 3.806) and FTC (HR 7.068) were associated with a significantly increased hazard of developing distant metastasis in patients with WDTC.

CONCLUSIONS

TS ≥ 2 cm, NM and FTC are associated with a significantly increased propensity for developing DM in our cohort of WDTC patients.

Thyroid Lobectomy for Low to Intermediate Risk Differentiated Thyroid Cancer

Simple Summary

Total thyroidectomy used to be recommended for all thyroid cancers. We now know that some thyroid cancers have a relatively low risk of recurrence. Today, for some of these cancers, depending on the type of tumor, its’ size and other tumor characteristics, a thyroid lobectomy (or hemithyroidectomy) can be performed without increasing the patient’s risk of cancer recurrence. Thyroid lobectomy has the advantages of having less risk of surgical complications and a less frequent need for thyroid hormone replacement therapy. This approach is not optimal for all thyroid cancers, however, and careful tumor and patient selection are necessary. This review explains the rationale and criteria for patient selection for thyroid lobectomy for selected thyroid cancers.

Abstract

Many recent publications and guidelines have promoted a “more is less” approach in terms of treatment for low to intermediate risk differentiated thyroid cancer (DTC), which comprise the vast majority of thyroid cancers: less extensive surgery, less radioactive iodine, less or no thyroid hormone suppression, and less frequent or stringent follow-up. Following this approach, thyroid lobectomy has been proposed as a means of decreasing short- and long-term postoperative morbidity while maintaining an excellent prognosis for tumors meeting specific macroscopic and microscopic criteria. This article will examine the pros and cons of thyroid lobectomy for low to intermediate risk cancers and discuss, in detail, criteria for patient selection and oncological outcomes.

Preoperative Factors Associated with Extrathyroidal Extension in Papillary Thyroid Cancer

OBJECTIVE

Extrathyroidal extension may not be accurately recognized during thyroidectomy and can increase the risk of positive margins and even recurrence. This study aimed to investigate the preoperative factors associated with extrathyroidal extension.

METHODS

We analyzed 887 patients with papillary thyroid cancer (PTC) who underwent surgery in the period of 2005-2017. Binary logistic regression analyses and generalized additive models were used to identify associations.

RESULTS

Minimal extrathyroidal extension was present in 233 (26%) patients and advanced extrathyroidal extension was found in 60 (7%) patients. Age, BMI, and tumor size were independent predictors of all or advanced extrathyroidal extension. Among the 493 patients whose BRAF mutation status was available, age (OR = 1.025), BMI (OR = 1.091), tumor size (OR = 1.544), and BRAF V600E mutation (OR = 2.311) were independently associated with extrathyroidal extension.

CONCLUSIONS

Older age, a greater BMI, a larger tumor size, and presence of the BRAF mutation were predictive of extrathyroidal extension. These factors should be taken into consideration in decision-making before surgery is performed.

Lymphovascular invasion of papillary thyroid carcinoma revisited in the era of active surveillance

INTRODUCTION

Lymphovascular invasion (LVI) is associated with disease recurrence and compromised survival in patients with thyroid cancer. Nonetheless, LVI is not identifiable on preoperative ultrasound or cytologic assessment. We aimed to explore the clinicopathological features associated with LVI.

PATIENTS AND METHODS

We conducted a retrospective review of our prospectively maintained database from 2009 to 2018. Multivariate analyses were performed to determine the associations between clinicopathological parameters and LVI. Generalized additive models were used to examine the nonlinear relationship between continuous variables and LVI.

RESULTS

A total of 795 patients were included in the analysis, and 174 (22%) had LVI. Patients' age (odds ratio [OR] = 0.982), tumor size (OR = 1.466), clinical lymphadenopathy (OR = 6.975), and advanced extrathyroidal extension (OR = 2.938) were independently associated with LVI. In the subset analysis of 198 patients with available genetic information, tumor size (OR = 1.599), clinical lymph node metastasis (OR = 3.657), and TERT promoter mutation (OR = 4.726) were predictive of LVI. Among 573 patients who had no clinical lymphadenopathy or advanced extrathyroidal extension, tumor size was the only predictor of LVI. Tumor size >1.5 cm had an increased risk of LVI based on the generalized additive model plot and receiver operating characteristic curve analysis.

CONCLUSION

Tumor size is positively associated with the risk of LVI in papillary thyroid cancer. To avoid delayed treatment in patients with LVI, a tumor size of 1.5 cm may be considered as the safe upper limit for active surveillance.

Association between subjective symptoms and obesity and postoperative recurrence in differentiated thyroid cancer: a matched-pair analysis

Several patients with thyroid cancer experience symptom distress after diagnosis and surgery. Data on the association between symptomatology and disease recurrence are limited. A retrospective review of a prospectively maintained database was performed, and 57 patients who had recurrence after operation of differentiated thyroid cancer were identified. Controlling for age, sex, surgery, and tumour stage, 114 patients without recurrent disease were selected by case-control matching. Subjective symptoms at follow-up visits were extracted from medical records and classified into three symptom clusters: pharyngolaryngeal, psychoneurological, and gastrointestinal. Compared to the control group, patients with recurrence had higher symptom totals in the pharyngolaryngeal (P < 0.001) and psychoneurological clusters (P = 0.005). Symptom score >3 yielded a sensitivity of 61.4% and a specificity of 80.7% to predict recurrence. Multivariate Cox regression analysis revealed that high symptom score (hazard ratio [HR] = 4.184), family history of thyroid cancer (HR = 2.463), and obesity (HR = 1.981) were independently associated with disease recurrence. Taken together, the likelihood of postoperative recurrence seemed to increase with high self-perceived symptom burden, family history, and obesity in patients with thyroid cancer. The results could be applied to the recurrence surveillance and symptomatic management of thyroid cancer post-operation.

The Identification of Intraoperative Risk Factors Can Reduce, but Not Exclude, the Need for Completion Thyroidectomy in Low-Risk Papillary Thyroid Cancer Patients

Background: The extent of initial surgical resection for low-risk papillary thyroid cancer (PTC) remains debatable. Since the 2015 American Thyroid Association (ATA) guidelines, several retrospective studies have reported that 40-60% of patients initially treated with lobectomy would require a completion thyroidectomy (CTx) due to high-risk pathological features (HRFs). These studies are limited by variable preoperative stratification and inability to quantify the value of intraoperative assessment. The study objectives were to determine whether diligent preoperative and intraoperative assessment improves the appropriateness of initial surgery for low-risk PTCs and whether varying the criteria for lobectomy reduces the need for CTx. Methods: A prospectively collected province-wide database was analyzed over a 10-year period (2008-2017) for patients who underwent a total thyroidectomy (TT) for PTC without preoperative HRFs. All patients had preoperative ultrasound and fine-needle aspirates. Unique to this database are mandatory synoptic operative fields that identify intraoperative risk factors such as positive lymph nodes and local invasion. Results: In total, 74% of patients (709/959) were deemed eligible for lobectomy. Of those eligible, 149 (21%) had intraoperative risk factors that would necessitate conversion to TT at the initial operation. A further 209 (30%) would require CTx due to HRFs on final pathology. Varying the preoperative criteria for lobectomy did not significantly affect intraoperative conversion or CTx rates. Conclusions: Although intraoperative assessment reduced the need for CTx in 21%, up to 30% of patients would still require a second operation. Altering the preoperative criteria does not influence this outcome. Patients deemed eligible for lobectomy should be informed that despite careful pre- and intraoperative assessment, there is up to a 30% risk of requiring CTx.

Total thyroidectomy versus thyroid lobectomy in the treatment of papillary carcinoma

Extent of thyroidectomy for papillary thyroid carcinoma is still matter of debate. Indeed, recently, international guidelines endorsed thyroid lobectomy as initial surgical approach for low risk, small medium-sized (T1-T2), N0 papillary thyroid carcinoma in absence of extrathyroidal extension. When dealing with a conservative surgery for oncologic disease is of utmost importance to exclude effectively more advanced disease, which could benefit from a more aggressive initial operation. However, in the setting of surgery for papillary thyroid carcinoma, despite an accurate preoperative work up could led to identify some suspicious characteristics as macroscopic evidence of multifocality or extrathyroidal extension, and/or evidence of lateral neck lymph node metastases, it is difficult to reliably assess the central neck nodal status both pre- and intra-operatively. Frozen section examination of the central neck nodes ipsilateral to the side of the tumor has been proposed in patients scheduled for thyroid lobectomy, in order to modulate the extension of both thyroidectomy and central neck dissection. Future molecular and genetic evidences are needed to establish high-risk patients with small papillary thyroid carcinoma in which thyroid lobectomy could be not and adequate surgical treatment.

Overexpression of Histone H3 Lysine 27 Trimethylation Is Associated with Aggressiveness and Dedifferentiation of Thyroid Cancer

A variety of epigenetic dysregulations are observed in thyroid malignancies. EZH2, the catalytic subunit of polycomb repressive complex 2, is upregulated in advanced thyroid cancers. EZH2 can catalyze trimethylation of histone H3 at lysine 27 (H3K27me3) and contribute to transcriptional silencing of target genes. Here, we investigated the immunohistochemical expression of H3K27me3 in neoplastic and normal thyroid tissues. Normal thyroid epithelial cells typically exhibited nuclear staining of moderate intensity. A similar expression pattern was observed in nodular goiters and follicular adenomas. By contrast, strong H3K27me3 expression was evident in 80% (8/10) lymphocytic thyroiditis, 63% (80/127) papillary thyroid cancer, 41% (7/17) follicular thyroid cancer, and 73% (8/11) poorly differentiated and anaplastic thyroid cancer. In differentiated thyroid cancer, strong H3K27me3 expression was associated with extrathyroidal extension (p < 0.001), lymphovascular invasion (p = 0.029), lymph node metastasis (p = 0.006), and higher risk of recurrence (p = 0.003). Our results indicate that H3K27me3 overexpression may be implicated in aggressiveness and dedifferentiation of thyroid cancer. In addition to prognostication, the predictive value of H3K27me3 expression deserves further investigation given the recent development of epigenetic targeting agents.

Unexpected high-risk pathologic features following thyroidectomy in the chinese immigrant population

OBJECTIVE

To compare rates of unexpected high-risk pathologic features between Chinese and non-Asian patients who underwent thyroidectomy for papillary thyroid cancer.

METHODS

This was a retrospective cohort study at a tertiary academic urban medical center. Patients who underwent thyroidectomy for papillary carcinoma from 2015 to 2017 were included. Patient demographics, tumor characteristics, and tumor histopathology were analyzed. Primary outcome was the presence of adverse histopathologic features such as lymphovascular invasion (LVI) or microscopic/minimal extrathyroidal extension (mETE). Differences between the groups were analyzed using multivariate logistical regression analysis and propensity score-weighted analysis.

RESULTS

One hundred seventy-nine patients were included: 58 Chinese-born and 121 non-Asian. The median age of the cohort was 47 years old (36-58). Twenty-nine percent of patients were male, and 71% were female. There was no statistically significant difference between the two cohorts in rates of LVI, multifocality, extent of surgery, or presence of thyroiditis. Patients with mETE were more likely to have larger tumors (P = 0.00247). Both the multivariate and propensity-weighted models demonstrated that Chinese ancestry was independently associated with an increased rate of unexpected mETE (adjusted prevalence ratio, 2.52; 95% confidence interval, 1.82-3.48).

CONCLUSION

mETE is significantly higher in the immigrant Chinese compared to the non-Asian population. Given the high prevalence of unexpected mETE in the Chinese population, the added risk of this finding should be brought into the discussion during initial surgical planning.

LEVEL OF EVIDENCE

3 Laryngoscope, 130:1844-1849, 2020.

Need for Completion Thyroidectomy in Patients Undergoing Lobectomy for Indeterminate and High-Risk Nodules: Impact of Intra-Operative Findings and Final Pathology

INTRODUCTION

Current guidelines increasingly suggest the use of thyroid lobectomy for indeterminate (Bethesda 3 and 4) and high-risk (Bethesda 5 and 6) thyroid nodules; however, the clinical reality is often very different.

MATERIALS AND METHODS

The aim of this study was to determine the rate of completion thyroidectomy (CTx) for indeterminate and high-risk thyroid nodules which are pre-operatively classified as suitable for unilateral resection (lobe eligible) based on current guidelines. Seven hundred consecutive patients with thyroid nodules and FNA cytology over four years (2015-2018) were reviewed.

RESULTS

Distribution of the dominant nodules by Bethesda was: non-diagnostic 3.9%, benign 28.1%, atypia of unknown significance 19.0%, follicular neoplasm 23.6%, suspicious for malignancy 6.1% and malignancy 19.3%. Of 298 indeterminate nodules, 68.8% (205/298) had relative but independent indications for a total thyroidectomy (TTx) and the remainder were candidates for lobectomy. For these lobe eligible patients, the overall risk of ultimately needing a TTx was 19.4% (18/93), comprising 4.3% (4/93) from intra-operative findings and 15.7% (14/89) from final pathology. Similarly, of 170 high-risk nodules, 63.5% (108/170) had upfront indications for a TTx and the remaining 62 nodules were lobe eligible. Of the patients taken to the operating room for a lobectomy, 21.0% (13/62) were upgraded to a TTx intra-operatively and 26.5% (13/49) post-operatively. The lobe success rate for indeterminate nodules was 25.2% and for high-risk nodules was 21.2%. The rate of CTx, or the proportion of patients needing a second operation was 15.7% (14/89) and 26.5% (13/49), respectively.

CONCLUSIONS

In counselling a patient for surgery, the risk of needing a more radical initial procedure or second surgery needs to be accurately explained. There are three points of care that can influence operative strategy, pre-operatively by way of high-risk clinical factors, intra-operatively via anatomical findings and post-operatively in response to unrecognized pathological features. Additionally, the patient's personal value judgment and level of risk aversion should be taken into consideration.

Risk-oriented concept of treatment for intrathyroid papillary thyroid cancer

Adapting treatment and follow-up according to the risk of recurrence and/or death from thyroid cancer is a relatively recent concept of "personnalized" medicine, developed particularly to avoid overtreatment of low-risk thyroid cancer which represents the majority of thyroid cancers diagnosed in the world today. For low-risk thyroid cancer, this decrease in extent of treatment involves the extent of surgery-total thyroidectomy, lobectomy or no surgery with active surveillance-but also the indications, doses and methods of stimulation when or if administering radioactive iodine (RAI), the indication for suppressive thyroxin therapy and the extent and modalities for follow-up that should be adapted to the risk of recurrence. The aim is to optimize medical resources and quality of life, particularly for low-risk patients whose life expectancy is that of the general population.

PGC1α downregulation and glycolytic phenotype in thyroid cancer

Increased aerobic glycolysis portends an unfavorable prognosis in thyroid cancer. The metabolic reprogramming likely results from altered mitochondrial activity and may promote cancer progression. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) plays a pivotal role in mitochondrial biogenesis and function. In the present study, we aimed to evaluate the clinicopathological significance of PGC1α expression and the potential effects of PGC1α modulation. Firstly, the expression of PGC1α in thyroid cancer samples was evaluated using western blot analysis and immunohistochemical staining. Compared with normal thyroid tissue, PGC1α expression was downregulated in thyroid cancer. PGC1α-negative papillary cancer was associated with BRAF V600E mutation, large tumor size, extrathyroidal or lymphovascular invasion, lymph node metastasis, and advanced stage. The results were consistent with the analysis of The Cancer Genome Atlas data. PGC1α expression correlated with oxygen consumption in thyroid cancer cells and was inversely related to AKT activity. The biologic relevance of PGC1α was further investigated by gain- and loss-of-function experimental studies. PGC1α overexpression led to augmented oxidative metabolism and accelerated tumor growth, whereas PGC1α knockdown induced a glycolytic phenotype but reduced tumor growth in vivo. In conclusion, PGC1α downregulation is associated with glycolytic metabolism and advanced disease in thyroid cancer. Nonetheless, manipulating PGC1α expression and metabolic phenotype does not necessarily translate into beneficial effects. It suggests that the metabolic phenotype is likely the consequence rather than the cause of disease progression in thyroid cancer.

An Increased Neutrophil-to-Lymphocyte Ratio Predicts Incomplete Response to Therapy in Differentiated Thyroid Cancer

Background: Previously we have shown that an elevated baseline neutrophil-to-lymphocyte ratio (NLR) was associated with a high risk of recurrence in patients with differentiated thyroid cancer. The clinical significance of the longitudinal changes in NLR following treatment remained unestablished. Methods: Adults patients with differentiated thyroid cancer were included in the study if the follow-up NLR data at 6 to 18 months after initial treatment were available. The response to treatment was categorized as excellent, indeterminate, biochemical incomplete, and structural incomplete as per guidelines of the American Thyroid Association. Results: Among 151 patients with thyroid cancer, a significant decrease in NLR following treatment was observed in those with stage I disease, those with low risk of recurrence, and those with an excellent response to therapy. Patients with a structural incomplete response had a significant increase in NLR at follow-up (p = 0.012). On multivariate analysis, incomplete response to therapy was associated with male sex (odds ratio [OR] = 3.35), tumor size (OR = 1.63), lymph node metastasis (OR = 4.80), distant metastasis (OR = 12.95), and increased NLR (OR = 13.68). Conclusions: An increase in systemic inflammation following treatment as measured by NLR is independently associated with an incomplete response to therapy in differentiated thyroid cancer.