Estimation of the lifetime probability of disease progression of papillary microcarcinoma of the thyroid during active surveillance

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.

Management of Small Papillary Thyroid Cancers

Thyroid cancer is the most common endocrine malignancy. With increasing imaging utilization, there has been an increase in the recognition of small, indolent cancers that would otherwise go undiagnosed. Historically, the surgical recommendation for all patients with thyroid cancer was a total thyroidectomy. However, over the last 20 years, there have been numerous studies evaluating the de-escalation of interventions for low-risk thyroid cancers, transitioning from total thyroidectomy to thyroid lobectomy or active surveillance when indicated. Here, we review the current literature and recommendations with each of these treatment options.

Adequacy of clinical guideline recommendations for patients with low-risk cancer managed with monitoring: systematic review

OBJECTIVES

The aim of this systematic review was to summarize national and international guidelines that made recommendations for monitoring patients diagnosed with low-risk cancer. It appraised the quality of guidelines and determined whether the guidelines adequately identified patients for monitoring, specified which tests to use, defined monitoring intervals, and stated triggers for further intervention. It then assessed the evidence to support each recommendation.

STUDY DESIGN AND SETTING

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses, we searched PubMed and Turning Research into Practice databases for national and international guidelines' that were written in English and developed or updated between 2012 and 2023. Quality of individual guidelines was assessed using the AGREE II tool.

RESULTS

Across the 41 published guidelines, 48 different recommendations were identified: 15 (31%) for prostate cancer, 11 (23%) for renal cancer, 6 (12.5%) for thyroid cancer, and 10 (21%) for blood cancer. The remaining 6 (12.5%) were for brain, gastrointestinal, oral cavity, bone and pheochromocytoma and paraganglioma cancer. When combining all guidelines, 48 (100%) stated which patients qualify for monitoring, 31 (65%) specified which tests to use, 25 (52%) provided recommendations for surveillance intervals, and 23 (48%) outlined triggers to initiate intervention. Across all cancer sites, there was a strong positive trend with higher levels of evidence being associated with an increased likelihood of a recommendation being specific (P = 0.001) and the evidence for intervals was based on expert opinion or other guidance.

CONCLUSION

With the exception of prostate cancer, the evidence base for monitoring low-risk cancer is weak and consequently recommendations in clinical guidelines are inconsistent. There is a lack of direct evidence to support monitoring recommendations in the literature making guideline developers reliant on expert opinion, alternative guidelines, or indirect or nonspecific evidence.

Risk factors for tumor enlargement in low-risk papillary thyroid microcarcinoma patients: a systematic review and meta-analysis

PURPOSE

The current management guidelines for low-risk papillary thyroid microcarcinoma (PTMC) do not specify how to screen for growing tumors. We sought to explore the possible risk factors for tumor enlargement in patients with low-risk PTMC under active surveillance (AS).

METHODS

We searched the PubMed and Embase databases for high quality studies up to January 10th, 2024. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included studies, and Review Manager 5.4 was used to analyze possible risk factors and calculate pooled risk ratios (RRs) via the inverse-variance calculation method.

RESULTS

Eleven studies were included in our meta-analysis. Among the 8880 participants, 464 experienced tumor growth, and the incidence of tumor growth varied from 3.4% to 19.4%. The results of the meta-analysis showed that tumor enlargement was associated with younger age (pooled RR = 2.32, 95% CI = 1.85-2.90, p < 0.00001; 8 studies), and higher serum thyroid-stimulating hormone (TSH) levels (pooled RR = 2.28, 95% CI = 1.19-4.37, p = 0.01; 6 studies), and could be related to pregnancy (pooled RR = 2.54, 95% CI = 1.17-5.52, p = 0.02; 2 studies). However, these following factors showed no significant association with tumor growth: sex (pooled RR = 1.07, 95% CI = 0.63-1.84, p = 0.79; 7 studies), tumor size at diagnosis (pooled RR = 1.08, 95% CI = 0.63-1.85, p = 0.77; 5 studies), and Hashimoto's thyroiditis (HT) (pooled RR = 1.56, 95% CI = 0.93-2.60, p = 0.09; 2 studies).

CONCLUSION

Our analysis identified that younger age and higher serum TSH levels were higher risk factors for tumor enlargement in low-risk PTMC patients. Pregnancy is a suspected risk factor.

Tumor growth manifested in two-fifths of low-risk papillary thyroid microcarcinoma patients during active surveillance: data from a tertiary center in China

Purpose

To assess tumor growth using tumor doubling rate (TDR) during active surveillance (AS) in China.

Methods

Between January 2016 and June 2020, a total of 219 patients with low-risk papillary thyroid microcarcinoma (PTMC) (aged 23-75 years) were consecutively enrolled in the AS program.

Results

Four sections of TDR, >0.5, 0.1~0.5, -0.1~0.1 and <-0.1, corresponded with four categories of tumor volume kinetics: rapid growth, slow growth, stable, and decreased size. We found that 10.5% of PTMCs exhibited rapid growth, 33.33% exhibited slow growth, 26.48% were stable, and 29.68% decreased in size. Tumor growth was associated with two factors: age and volume of PTMC at diagnosis. 85.72% of elderly patients (≥ 61 years old) had tumors that remained stable or even shrank and rapidly growing tumors were not found in them. When the volume was small (≤14.13 mm3), the proportion of rapid growth was high (41.67%), whereas when the volume was large (> 179.5 mm3), the proportion of non-growth was 68.75%.

Conclusion

TDR may be a better metric for evaluating tumor growth in observational PTMCs. A certain proportion of PTMCs grow during the period of AS and tumor growth was associated with age and volume of PTMC at initial diagnosis. Therefore, how to block tumor growth during the AS period, especially for young patients and patients with early-stage PTMC (size ≤ 5 mm), will be a new challenge.

Active Surveillance for Low-Risk Thyroid Cancers: A Review of Current Practice Guidelines

The indolent nature and favorable outcomes associated with papillary thyroid microcarcinoma have prompted numerous prospective studies on active surveillance (AS) and its adoption as an alternative to immediate surgery in managing low-risk thyroid cancer. This article reviews the current status of AS, as outlined in various international practice guidelines. AS is typically recommended for tumors that measure 1 cm or less in diameter and do not exhibit aggressive subtypes on cytology, extrathyroidal extension, lymph node metastasis, or distant metastasis. To determine the most appropriate candidates for AS, factors such as tumor size, location, multiplicity, and ultrasound findings are considered, along with patient characteristics like medical condition, age, and family history. Moreover, shared decision-making, which includes patient-reported outcomes such as quality of life and cost-effectiveness, is essential. During AS, patients undergo regular ultrasound examinations to monitor for signs of disease progression, including tumor growth, extrathyroidal extension, or lymph node metastasis. In conclusion, while AS is a feasible and reliable approach for managing lowrisk thyroid cancer, it requires careful patient selection, effective communication for shared decision-making, standardized follow-up protocols, and a clear definition of disease progression.

Integrated Diagnostics of Thyroid Nodules

Thyroid nodules are common findings, particularly in iodine-deficient regions. Our paper aims to revise different diagnostic tools available in clinical thyroidology and propose their rational integration. We will elaborate on the pros and cons of thyroid ultrasound (US) and its scoring systems, thyroid scintigraphy, fine-needle aspiration cytology (FNAC), molecular imaging, and artificial intelligence (AI). Ultrasonographic scoring systems can help differentiate between benign and malignant nodules. Depending on the constellation or number of suspicious ultrasound features, a FNAC is recommended. However, hyperfunctioning thyroid nodules are presumed to exclude malignancy with a very high negative predictive value (NPV). Particularly in regions where iodine supply is low, most hyperfunctioning thyroid nodules are seen in patients with normal thyroid-stimulating hormone (TSH) levels. Thyroid scintigraphy is essential for the detection of these nodules. Among non-toxic thyroid nodules, a careful application of US risk stratification systems is pivotal to exclude inappropriate FNAC and guide the procedure on suspicious ones. However, almost one-third of cytology examinations are rendered as indeterminate, requiring "diagnostic surgery" to provide a definitive diagnosis. 99mTc-methoxy-isobutyl-isonitrile ([99mTc]Tc-MIBI) and [18F]fluoro-deoxy-glucose ([18F]FDG) molecular imaging can spare those patients from unnecessary surgeries. The clinical value of AI in the evaluation of thyroid nodules needs to be determined.

Age-stratified comparison of active surveillance versus radiofrequency ablation for papillary thyroid microcarcinoma using decision analysis

BACKGROUND

Papillary thyroid microcarcinomas may be treated with radiofrequency ablation, active surveillance, or surgery. The objective of this study was to use mathematical modeling to compare treatment alternatives for papillary thyroid microcarcinomas among those who decline surgery. We hypothesized that radiofrequency ablation would outperform active surveillance in avoiding progression and surgery but that the effect size would be small for older patients.

METHODS

We engaged stakeholders to identify meaningful long-term endpoints for papillary thyroid microcarcinoma treatment-(1) cancer progression/surgery, (2) need for thyroid replacement therapy, and (3) permanent treatment complication. A Markov decision analysis model was created to compare the probability of these endpoints after radiofrequency ablation or active surveillance for papillary thyroid microcarcinomas and overall cost. Transition probabilities were extracted from published literature. Model outcomes were estimated to have a 10-year time horizon.

RESULTS

The primary outcome yielded a number needed to treat of 18.1 for the avoidance of progression and 27.4 for the avoidance of lifelong thyroid replacement therapy for radiofrequency ablation compared to active surveillance. However, as patient age increased, the number needed to treat to avoid progression increased from 5.2 (age 20-29) to 39.1 (age 60+). The number needed to treat to avoid lifelong thyroid replacement therapy increased with age from 7.8 (age 20-29) to 59.3 (age 60+). The average 10-year cost/treatment for active surveillance and radiofrequency ablation were $6,400 and $11,700, respectively, translating to a cost per progression-avoided of $106,500.

CONCLUSION

As an alternative to active surveillance, radiofrequency ablation may have a greater therapeutic impact in younger patients. However, routine implementation may be cost-prohibitive for most patients with papillary thyroid microcarcinomas.

Safety and efficacy of microwave ablation for the treatment of low-risk papillary thyroid microcarcinoma: a prospective multicenter study

OBJECTIVES

To assess the safety and efficacy of ultrasound-guided thermal ablation for low-risk papillary thyroid microcarcinoma (PTMC) via a prospective multicenter study.

METHODS

From January 2017 through June 2021, low-risk PTMC patients were screened. The management details of active surveillance (AS), surgery, and thermal ablation were discussed. Among patients who accepted thermal ablation, microwave ablation (MWA) was performed. The main outcome was disease-free survival (DFS). The secondary outcomes were tumor size and volume changes, local tumor progression (LTP), lymph node metastasis (LNM), and complication rate.

RESULTS

A total of 1278 patients were included in the study. The operation time of ablation was 30.21 ± 5.14 min with local anesthesia. The mean follow-up time was 34.57 ± 28.98 months. Six patients exhibited LTP at 36 months, of whom 5 patients underwent a second ablation, and 1 patient received surgery. The central LNM rate was 0.39% at 6 months, 0.63% at 12 months, and 0.78% at 36 months. Of the 10 patients with central LNM at 36 months, 5 patients chose ablation, 3 patients chose surgery and the other 2 patients chose AS. The overall complication rate was 1.41%, and 1.10% of patients developed hoarseness of the voice. All of the patients recovered within 6 months.

CONCLUSIONS

Thermal ablation of low-risk PTMC was observed to be safe and efficacious with few minor complications. This technique may help to bridge the gap between surgery and AS as treatment options for patients wishing to have their PTMC managed in a minimally invasive manner.

CLINICAL RELEVANCE STATEMENT

This study proved that microwave ablation is a safe and effective treatment method for papillary thyroid microcarcinoma.

KEY POINTS

Percutaneous US-guided microwave ablation of papillary thyroid microcarcinoma is a very minimally invasive treatment under local anesthesia during a short time period. The local tumor progression and complication rate of microwave ablation in the treatment of papillary thyroid microcarcinoma are very low.

Surgical Outcomes in Patients With Low-risk Papillary Thyroid Microcarcinoma From MAeSTro Study: Immediate Operation Versus Delayed Operation After Active SurveillanceA Multicenter Prospective Cohort Study

OBJECTIVE

To investigate surgical, and clinical outcomes in patients with low-risk papillary thyroid microcarcinoma (PTMC) according to treatment options [immediate operation (IOP) vs delayed operation after active surveillance (AS) (DOP)].

BACKGROUND

AS has been adopted as an alternative to immediate surgery in patients with low-risk PTMC. Although some patients undergo surgery during AS, there is little information on surgical, and clinical outcomes after delayed operation after AS.

METHODS

A multicenter prospective cohort study including 1177 patients was conducted at 3 tertiary hospitals in Korea from June 2016 to January 2020. Patients with low-risk PTMC were enrolled. The participants were self-assigned into AS or IOP, and during AS, the patients underwent surgery if there were signs of disease progression or if the patient's choice changed.

RESULTS

A total of 516 patients underwent operation; 384 (74.4%) in the IOP group and 132 (25.6%) in the DOP group. Compared with the IOP group, the DOP group was significantly associated with a larger tumor size ( P =0.002), higher rates of lymphatic invasion ( P =0.002), and multifocality ( P =0.008). However, the rates of total thyroidectomy, postoperative hypoparathyroidism and vocal cord palsy did not differ significantly between the groups ( P = 0.283, P =0.184, and P =0.284, respectively). Of the 132 patients in the DOP group, disease progression was present in 39 (29.5%) patients. The DOP group with disease progression had a significantly higher rate of lymph node metastasis ( P =0.021) and radioiodine therapy ( P =0.025) than the DOP group without disease progression.

CONCLUSIONS

These results suggest that AS might be considered an alternative treatment option for patients with low-risk PTMC regarding the extent of thyroidectomy and postoperative complications in the DOP group. To assess oncologic outcomes, long-term follow-up will be needed.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02938702.

US Predictors of Papillary Thyroid Microcarcinoma Progression at Active Surveillance

Background Active surveillance (AS) is an accepted strategy for patients with low-risk papillary thyroid microcarcinoma (PTMC). While previous studies have evaluated the prognostic value of US features, results have been inconsistent. Purpose To determine if US features can help predict tumor progression in patients with low-risk PTMC undergoing AS. Materials and Methods This prospective study enrolled 1177 participants with PTMC from three hospitals between June 2016 and January 2021. Participants were self-assigned to either immediate surgery or AS, and those with two or more US examinations in the absence of surgery were included in the analysis. A χ2 test was used to compare estimated tumor progression rate at 4 years between participants stratified according to US features. Multivariable Cox regression analysis was used to assess the association of clinical and US features with overall tumor progression and specific progression criteria. Results Among 699 participants included in the analysis, 68 (mean age, 49 years ± 12 [SD]; 40 female participants) showed tumor progression (median follow-up, 41.4 months ± 16 [SD]). Tumor progression was associated with the US features of diffuse thyroid disease (DTD) (hazard ratio [HR], 2.3 [95% CI: 1.4, 3.7]; P = .001) and intratumoral vascularity (HR, 1.7 [95% CI: 1.0, 3.0]; P = .04) and the participant characteristics of male sex (HR, 2.8 [95% CI: 1.7, 4.6]; P < .001), age less than 30 years (HR, 2.9 [95% CI: 1.2, 6.8]; P = .01), and thyroid-stimulating hormone level of 7 µU/mL or higher (HR, 6.9 [95% CI: 2.7, 17.4]; P < .001). The risk of tumor progression was higher for participants with DTD (14%, P = .001) or intratumoral vascularity (14%, P = .02) than for participants without these features (6%). DTD and intratumoral vascularity were associated with tumor enlargement (HR, 2.7 [95% CI: 1.4, 5.1]; P = .002) and new lymph node metastasis (HR, 5.0 [95% CI: 1.3, 19.4]; P = .02), respectively. Conclusion DTD and intratumoral vascularity were associated with an increased risk of tumor progression in participants with PTMC undergoing AS. Clinical trial registration no. NCT02938702 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Reuter and the review "International Expert Consensus on US Lexicon for Thyroid Nodules" by Durante et al in this issue.

Management of thyroid dysfunction and thyroid nodules in the ageing patient

Thyroid dysfunction is a common endocrine disorder in the general population, with a reported prevalence of 10-15%. However, this rate is even higher in older adults, with an estimated prevalence of ≈25% in some populations. Since elderly patients usually present more comorbidities than younger individuals, thyroid dysfunction may carry a synergistic negative health impact, mainly due to increased cardiovascular disease risk. Moreover, thyroid dysfunction in the elderly can be more difficult to diagnose due to its subtle or even asymptomatic clinical presentation, and the interpretation of thyroid function tests may be affected by drugs that interfere with thyroid function or by the coexistence of several diseases. On the other hand, thyroid nodules are also a prevalent condition in older adults, and its incidence increases with age. The assessment and management of thyroid nodules in the ageing patient should take into account several factors, as risk stratification, thyroid cancer biology, patient´s overall health, comorbidities, treatment preferences, and goals of care. In this review article, we summarize the current knowledge on the pathophysiology, diagnosis, and therapeutic management of thyroid dysfunction in elderly patients and we also review how to identify and manage thyroid nodules in this population.

Survival outcomes of low-risk papillary thyroid carcinoma at different risk levels: a corollary for active surveillance

Background

This study aims to compare the outcomes of active surveillance (AS) in low-risk papillary thyroid carcinoma (PTC) patients with different tumor sizes and lymph node metastasis status, in order to establish appropriate management strategies. By analyzing these results, this study provides valuable insights for the effective management of such patients, addressing the issues and challenges associated with AS in practical clinical practice.

Methods

The study utilized the SEER database supported by the National Cancer Institute of the United States, extracting data of PTC diagnosed between 2000 and 2015. Statistical analyses were conducted using inverse probability weighting (IPTW) and propensity score matching (PSM), including Kaplan-Meier survival curves and Cox regression models, to evaluate the impact of different tumor sizes and lymph node metastasis status on thyroid cancer-specific survival (TCSS).

Results

A total of 57,000 PTC patients were included, with most covariates having standardized mean differences below 10% after IPTW and PSM adjustments. The TCSS of PTC with a diameter smaller than 13mm is significantly better than that of tumors with a diameter larger than 13mm, regardless of the presence of lymph node metastasis. Among PTC cases with a diameter smaller than 13mm, the TCSS of patients is similar, regardless of the presence of lymph node metastasis. However, in PTC cases with a diameter larger than 13mm, the presence of lateral neck lymph node metastasis (N1b stage) significantly impacts the TCSS, although the absolute impact on TCSS rate is minimal.

Conclusion

The treatment strategy of AS is safe for patients with T1a stage papillary thyroid microcarcinoma (PTMC). However, for patients with T1b stage, if the tumor diameter exceeds 13mm or there is lymph node metastasis in the lateral neck region, the TCSS will be significantly affected. Nevertheless, the absolute impact on survival is relatively small.

Cost-effectiveness of active surveillance versus early surgery for thyroid micropapillary carcinoma based on diagnostic and treatment norms in China

Objectives

In this study, we compared the cost-effectiveness comparison of the active surveillance (AS) and early surgery (ES) approaches for papillary thyroid microcarcinoma (PTMC) from the perspective of the Chinese healthcare system.

Methods

We performed a cost-effectiveness analysis using a Markov model of PTMC we developed to evaluate the incremental cost-effectiveness ratio of AS and ES. Our reference case was of a 40-year-old woman diagnosed with unifocal (<10 mm) PTMC. Relevant data were extracted after an extensive literature review, and the cost incurred in each state was determined using China Medicare data on payments for ES and AS. The willingness-to-pay threshold was set at ¥242,928/quality-adjusted life-year (QALY) gained. Sensitivity analyses were performed to account for any uncertainty in the model's variables. Additional subgroup analyses were performed to determine whether AS was cost-effective when different initial monitoring ages were used.

Results

ES exhibited an effectiveness of 5.2 QALYs, whereas AS showed an effectiveness of 25.8 QALYs. Furthermore, the incremental cost-effectiveness ratio for ES versus AS was ¥1,009/QALY. The findings of all sensitivity analyses were robust. Compared with ES, AS was found to be the cost-effective strategy at initial monitoring ages of 20 and 60 years, with an incremental cost-effectiveness ratio of ¥3,431/QALY and -¥1,316/QALY at 20 and 60 years, respectively. AS was a more cost-effective strategy in patients with PTMC aged more than 60.

Conclusions

With respect to the norms of the Chinese healthcare system, AS was more cost-effective for PTMC over lifetime surveillance than ES. Furthermore, it was cost-effective even when the initial monitoring ages were different. In addition, if AS is incorporated into the management plan for PTMC in China at the earliest possible stage, a predicted savings of ¥10 × 108/year could be enabled for every 50,000 cases of PTMC, which indicates a good economic return for future management programs. The identification of such nuances can help physicians and patients determine the best and most individualized long-term management strategy for low-risk PTMC.

A novel cuproptosis-related lncRNA prognostic signature in thyroid cancer

Aims: We aimed to investigate the value of cuproptosis-related lncRNA in screening out high-risk thyroid cancer patients. Materials & methods: RNA sequencing data of thyroid cancer were obtained from The Cancer Genome Atlas. A cuproptosis-related lncRNA signature was constructed by using Cox regression. Results: Four cuproptosis-related lncRNAs were used to construct a survival prognosis model for thyroid cancer. The receiver operating characteristic curve showed that the area under the curve reached 0.830 at 1 year, 0.790 at 3 years and 0.824 at 5 years. Conclusion: The model may help to screen out thyroid cancer patients at high risk, and thus develop more appropriate treatment strategies.

Survival benefit of active surveillance for papillary thyroid carcinoma: a propensity score matching analysis based on SEER database

Background

Over-treatment of papillary thyroid microcarcinoma (PTMC) has become a common issue. Although active surveillance (AS) has been proposed as an alternative treatment to immediate surgery for PTMC, its inclusion criteria and mortality risk have not been clearly defined. The purpose of this study was to investigate whether surgery can achieve significant survival benefits in patients with larger tumor diameter of papillary thyroid carcinoma (PTC), in order to evaluate the feasibility of expanding the threshold for active surveillance.

Methods

This study retrospectively collected data of patients with papillary thyroid carcinoma from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2019. The propensity score matching (PSM) method was used to minimize confounding factors and selection bias between the surgery and non-surgery groups, and to compare the clinical and pathological characteristics between the two groups based on the SEER cohort. Meanwhile, the impact of surgery on prognosis was compared using Kaplan-Meier estimates and Cox proportional hazard models.

Results

A total of 175,195 patients were extracted from the database, including 686 patients who received non-surgical treatment, and were matched 1:1 with patients who received surgical treatment using propensity score matching. The Cox proportional hazard forest plot showed that age was the most important factor affecting overall survival (OS) of patients, while tumor size was the most important factor affecting disease-specific survival (DSS) of patients. In terms of tumor size, there was no significant difference in DSS between PTC patients with tumor size of 0-1.0cm who underwent surgical treatment and those who underwent non-surgical treatment, and the relative survival risk began to increase after the tumor size exceeded 2.0cm. Additionally, the Cox proportional hazard forest plot showed that chemotherapy, radioactive iodine, and multifocality were negative factors affecting DSS. Moreover, the risk of death increased over time, and no plateau phase was observed.

Conclusion

For patients with papillary thyroid carcinoma (PTC) staged as T1N0M0, AS is a feasible management strategy. As the tumor diameter increases, the risk of death without surgical treatment gradually increases, but there may be a threshold. Within this range, a non-surgical approach may be a potentially viable management strategy. However, beyond this range, surgery may be more beneficial for patient survival. Therefore, it is necessary to conduct more large-scale prospective randomized controlled trials to further confirm these findings.

Active Surveillance May Be the Best Initial Management for Papillary Thyroid Microcarcinoma

Active surveillance for low-risk papillary thyroid microcarcinoma (PTMC; T1aN0MI) was initiated at Kuma Hospital (Kobe, Japan) in 1993, based on a proposal by Akira Miyauchi. Favorable outcomes of such surveillance have been reported. Our latest study revealed 5- and 10-year tumor enlargement rates (by ≥ 3 mm) of 3.0% and 5.5% and 5- and 10-year node metastasis appearance rates of 0.9% and 1.1%, respectively. The postoperative prognosis did not differ between patients who underwent immediate surgery and those who underwent conversion surgery after progression. These findings suggest that active surveillance may be the best initial management of PTMCs.

Conservative management of low-risk papillary thyroid carcinoma: a review of the active surveillance experience

The detection of low-risk thyroid carcinoma has increased in recent decades, although disease-specific mortality remained without changes. The high prevalence of occult carcinomas in autopsy studies, and hence the underlying indolent course of this entity, prompted the emergence of active surveillance as an alternative approach to these tumors. This strategy aims to recognize the minority group of patients who will develop clinical progression and probably benefit from deferred surgery. Experience around the world has shown that during active surveillance these tumors are mostly unchanged in size, with very-slow growth and even a decrease in diameter. Moreover, the rates of lymph node metastases were low and easily handled by rescue surgery, and distant metastases have not been reported. Given the high prevalence of small thyroid carcinomas and the excellent outcomes for observation, active surveillance provides a safe and feasible alternative in properly selected patients with low-risk thyroid cancer.

Effect of Having Concurrent Mutations on the Degree of Aggressiveness in Patients with Thyroid Cancer Positive for TERT Promoter Mutations

This study aimed to examine whether concurrent mutations with a TERT promoter mutation are associated with a greater likelihood of more aggressive disease than a TERT promoter mutation alone. The medical records of 1477 patients who underwent thyroid surgery at two tertiary hospitals between 2017 and 2022 were reviewed. Twenty-four patients had TERT promoter mutations based on molecular profile testing. Clinicodemographic data, mutational profiles, and histopathological features were assessed. Descriptive analysis, Fisher's exact test, and binary logistic regression were performed. Seven patients had single-gene TERT promoter mutations, and 17 had concurrent mutations, including BRAF V600E, HRAS, NRAS, PIK3CA, and EIF1AX. The overall prevalence of malignancy was 95.8%, of which 78.3% were aggressive thyroid cancers. There was a statistically significant association between concurrent mutations and disease aggressiveness. The odds of having aggressive disease were 10 times higher in patients with a TERT promoter mutation and a concurrent molecular alteration than in those with a TERT promoter mutation alone. This is an important finding for thyroid specialists to consider when counseling patients concerning risk stratification and management options.

Active surveillance of low-risk papillary thyroid microcarcinoma

Recently, the incidence of thyroid carcinoma has been increasing rapidly worldwide. This is interpreted as an increase in the incidental detection of small papillary thyroid carcinomas by the widespread use of high-resolution imaging techniques such as ultrasonography. However, the mortality rates of thyroid carcinoma have not changed, suggesting that small papillary thyroid carcinomas may be overdiagnosed and overtreated. Active surveillance management has been introduced from Japan since the 1990s, as one of the measures to prevent overtreatment of low-risk papillary thyroid microcarcinoma. Based on the favorable outcomes, active surveillance has been gradually adopted worldwide as an alternative to immediate surgery. The management should be carried out with strict eligibility criteria and close monitoring for cancer progression, under a multidisciplinary team. In addition, an adequate shared decision-making is mandatory for individual patients. Papillary thyroid microcarcinomas with clinically apparent lymph node metastasis, distant metastasis, or invasion to adjacent organs should have surgery.

Thyroid-Stimulating Hormone, Age, and Tumor Size are Risk Factors for Progression During Active Surveillance of Low-Risk Papillary Thyroid Microcarcinoma in Adults

BACKGROUND

Active surveillance (AS) of low-risk papillary thyroid microcarcinoma (PTMC) was initiated at Kuma Hospital in 1993 and is gradually spreading worldwide. We assessed the effect of thyroid-stimulating hormone (TSH) levels on PTMC enlargement in patients on AS.

METHODS

We enrolled 2705 patients with cytologically diagnosed PTMC who had undergone AS between January 2005 and July 2019. Patients with Graves disease were excluded. The median AS period was 5.5 years (range 1.0-15.7 years). Tumor enlargement was defined as a size increase ≥3 mm. Chi-square test, Kaplan-Meier method, log-rank test, Cox proportional hazard, and logistic regression were used to compare variables.

RESULTS

Ninety-two patients (3.4%) experienced tumor enlargement; the 5-, 10-, and 15-year enlargement rates were 3.0%, 5.5%, and 6.2%, respectively. Young age (<40 years, p < 0.001), large tumor size (≥9 mm, p = 0.017), and high detailed TSH score (≥3, higher than the lower normal limit, p = 0.011) were significant factors relating to tumor enlargement in the multivariate analysis. In a subset of patients aged <40 years, a low detailed TSH score (<3) was an independent factor against tumor enlargement (p = 0.039). Only 22 patients (0.8%) experienced novel lymph node metastasis; the 5-, 10-, and 15-year node metastasis rates were very low, at 0.9%, 1.1%, and 1.1%, respectively.

CONCLUSIONS

Young patients with PTMC are more likely to experience tumor growth. Mild TSH suppression to achieve a low normal range may prevent carcinoma enlargement; however, prospective studies are needed to draw more reliable conclusions.

Feasibility of a snowball sampling survey to study active surveillance for thyroid microcarcinoma treatment among endocrinologists and surgeons of Brazil

OBJECTIVES

This study aims to investigate if a sampling method using virtual networks is feasible to survey AS adoption among this "hard-to-reach" population of Brazilian doctors.

METHODS

An online piloted 11-point structured survey questionnaire (designed using Googleforms®) probed the actual treatment patterns for adult patients with PTMCs, including treatment decision-making nonoperative options, was undertaken between 10 November and 30 November 2020. Participants were reached by the mobile phone Application (APP) and a snowball sampling strategy was used to recruit a total of 4783 members (maximum number of potential reach), which is the total of doctors of the all 21 social media WhatsApp® groups.

RESULTS

From a total of 4783 members (maximum number of potential reach), there were 657 (13.7%) doctors (actual reach) who clicked the web link of the questionnaire, out of whom 512 (10.7%) fully completed the online survey. Among the survey respondents, 361 were endocrinologists (70.5%) and 151 were surgeons (29.5%). Overall, for low-risk PTMCs in an elderly patient, 118 responders (23%) recommend AS, while 390 (76%) recommend immediate surgery as the management, including lobectomy (18.5%) and Total Thyroidectomy (58.2%). The present responders tended to recommend surgery for PTMCs that were located adjacent to the dorsal surface of the thyroid, were multiple, or raised the size during the follow-up.

CONCLUSION

Using snowball sampling strategy as an innovative route to conduct surveys was feasible and applicable but the rate of response was still very low. Our data also suggests the need to investigate if AS is embraced by Brazilian doctors.

Prognostic significance of patient age in papillary thyroid carcinoma with no high-risk features

Older age is recognized as a predictor of poor prognosis in papillary thyroid carcinoma (PTC) patients. However, young age is associated with disease progression of PTC measuring 1 cm or smaller in patients on active surveillance. In this study, we investigated the relationship between patient age and prognosis of PTC belonging to very low-, low-, and intermediate-risk groups based on the guidelines published by the Japan Association of Endocrine Surgery in 2018. We enrolled 4,870 PTC patients with no high-risk features and assigned each to one of three categories: very low risk (N = 1,161), low risk (N = 1,746), and intermediate risk (N = 1,963). In very low-risk patients, the local recurrence-free survival (RFS) rate of young patients (<55 years) was significantly worse (p = 0.0437) than that of older patients (≥55 years). In low-risk patients, although age did not affect local recurrence, older patients were more likely to show distant recurrence on univariate (p = 0.0005) and multivariate analyses (p = 0.0017). In the intermediate-risk series, the local RFS rate of older patients tended to be poor (p = 0.0538), and older age was significantly associated with distant RFS (univariate, p = 0.0356; multivariate, p = 0.0439) and carcinoma death (univariate, p < 0.0001; multivariate, not done because of no other suitable factors). The prognostic significance of patient age depends on risk classification: younger age significantly predicts local recurrence in very low-risk PTC, while older age predicts worse prognosis in low- and intermediate-risk patients. These findings indicate that young age is related to rapid growth in early-phase PTC.

Clair J, Chen MM, Vasquez M, Fan X, van Deen WK, Haile RW, Daskivich TJ, Zumsteg ZS, Braunstein GD, Sacks WL. Expanded Parameters in Active Surveillance for Low-risk Papillary Thyroid Carcinoma: A Nonrandomized Controlled Trial

Importance

Unlike for prostate cancer, active surveillance for thyroid cancer has not achieved wide adoption. The parameters by which this approach is feasible are also not well defined, nor is the effect of patient anxiety.

Objective

To determine if expanded size/growth parameters for patients with low-risk thyroid cancer are viable, as well as to assess for cohort differences in anxiety.

Design, Setting, and Participants

This prospective nonrandomized controlled trial was conducted at a US academic medical center from 2014 to 2021, with mean [SD] 37.1 [23.3]-month follow-up. Of 257 patients with 20-mm or smaller Bethesda 5 to 6 thyroid nodules, 222 (86.3%) enrolled and selected treatment with either active surveillance or immediate surgery. Delayed surgery was recommended for size growth larger than 5 mm or more than 100% volume growth. Patients completed the 18-item Thyroid Cancer Modified Anxiety Scale over time.

Interventions

Active surveillance.

Main Outcomes and Measures

Cumulative incidence and rate of size/volume growth.

Results

Of the 222 patients enrolled, the median (IQR) age for the study population was 46.8 (36.6-58) years, and 76.1% were female. Overall, 112 patients (50.5%) underwent treatment with active surveillance. Median tumor size was 11.0 mm (IQR, 9-15), and larger tumors (10.1-20.0 mm) comprised 67 cases (59.8%). One hundred one (90.1%) continued to receive treatment with active surveillance, 46 (41.0%) had their tumors shrink, and 0 developed regional/distant metastases. Size growth of more than 5 mm was observed in 3.6% of cases, with cumulative incidence of 1.2% at 2 years and 10.8% at 5 years. Volumetric growth of more than 100% was observed in 7.1% of cases, with cumulative incidence of 2.2% at 2 years and 13.7% at 5 years. Of 110 patients who elected to undergo immediate surgery, 21 (19.1%) had equivocal-risk features discovered on final pathology. Disease severity for all such patients remained classified as stage I. Disease-specific and overall survival rates in both cohorts were 100%. On multivariable analysis, immediate surgery patients exhibited significantly higher baseline anxiety levels compared with active surveillance patients (estimated difference in anxiety scores between groups at baseline, 0.39; 95% CI, 0.22-0.55; P < .001). This difference endured over time, even after intervention (estimated difference at 4-year follow-up, 0.50; 95% CI, 0.21-0.79; P = .001).

Conclusions and Relevance

The results of this nonrandomized controlled trial suggest that a more permissive active surveillance strategy encompassing most diagnosed thyroid cancers appears viable. Equivocal-risk pathologic features exist in a subset of cases that can be safely treated, but suggest the need for more granular risk stratification. Surgery and surveillance cohorts possess oppositional levels of worry, elevating the importance of shared decision-making when patients face treatment equivalence.

Trial Registration

ClinicalTrials.gov Identifier: NCT02609685.

Treatment strategies for low-risk papillary thyroid carcinoma: a position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM)

Increasingly sensitive diagnostic methods, better understanding of molecular pathophysiology, and well-conducted prospective studies have changed the current approach to patients with thyroid cancer, requiring the implementation of individualized management. Most patients with papillary thyroid carcinoma (PTC) are currently considered to have a low risk of mortality and disease persistence/recurrence. Consequently, current treatment recommendations for these patients include less invasive or intensive therapies. We used the most recent evidence to prepare a position statement providing guidance for decisions regarding the management of patients with low-risk PTC (LRPTC). This document summarizes the criteria defining LRPTC (including considerations regarding changes in the TNM staging system), indications and contraindications for active surveillance, and recommendations for follow-up and surgery. Active surveillance may be an appropriate initial choice in selected patients, and the criteria to recommend this approach are detailed. A section is dedicated to the current evidence regarding lobectomy versus total thyroidectomy and the potential pitfalls of each approach, considering the challenges during long-term follow-up. Indications for radioiodine (RAI) therapy are also addressed, along with the benefits and risks associated with this treatment, patient preparation, and dosage. Finally, this statement presents the best follow-up strategies for LRPTC after lobectomy and total thyroidectomy with or without RAI.

Predictive Factors for Bilateral Disease in Papillary Microcarcinoma: A Retrospective Cohort Study

Background: Based on risk stratification, the therapeutic options in papillary microcarcinoma (PTMC) can be active surveillance or surgery. Multifocal tumor occurrence can be decisive in determining the treatment strategy. The objective of this study was to identify risk factors for bilateral tumor occurrence in PTMC to enable individual therapy planning. Methods: A total of 545 PTMC patients who underwent thyroidectomy from 2008 to 2020 were retrieved. Univariate and multivariate analyses were performed to evaluate risk factors for bilateral PTMC. Results: 25.1% (n = 137) of all patients had multifocal PTMC, and 13.2% (n = 72) bilateral PTMC, respectively. In contrast to the maximum tumor size, the total tumor size significantly influenced a bilateral tumor manifestation (median total tumor size 5 mm versus 8.5 mm for bilateral PTMC, p < 0.001). A cut-off level for the total tumor size of >10 mm resulted in a sensitivity and specificity of 29.2% and 94.7%, respectively, in predicting a bilateral tumor manifestation, AUC 0.680 (95% CI, 0.611−0.748, p < 0.001). A cut-off of >4 tumors showed a sensitivity of 99.4% and a specificity of 97.5%, AUC 0.897 (95% CI, 0.870−0.924, p < 0.001) in predicting bilaterality. Conclusion: We could demonstrate for the first time that a total tumor size of >10 mm and more than four tumors significantly increased the risk of bilateral PTMC tumor involvement. These findings enable a risk-adjusted patient treatment.

Research Review of Thermal Ablation in the Treatment of Papillary Thyroid Carcinoma

Background

Minimally invasive treatment of thyroid tumors has become increasingly common, but has mainly focused on benign thyroid tumors, whereas thermal ablation of thyroid cancer remains controversial. Clinical studies analyzing the efficacy of thermal ablation of papillary thyroid carcinoma (PTC) have been conducted in several countries to verify its safety. Here, we screened and reviewed recent studies on the efficacy and safety of thermal ablation of PTC as well as psychological assessment, patient prognosis, recurrence, and factors affecting ablation.

Summary

The most significant controversy surrounding ablative treatment of PTC centers on its effectiveness and safety, and >40 studies have been conducted to address this issue. The studies include papillary thyroid microcarcinoma (PTMC) and non-PTMC, single PTC and multiple PTC, and controlled studies of ablative therapy and surgical treatment. In general, ablation techniques can be carefully performed and promoted under certain conditions and with active follow-up of postoperative patients. Ablation is a promising alternative treatment especially in patients who are inoperable.

Conclusions

Clinical studies on PTC ablation have provided new perspectives on local treatment. However, because PTC grows very slowly, it is an indolent tumor; therefore, studies with larger sample sizes and extended post-procedure follow-ups are necessary to confirm the investigators’ hypotheses.

Less-Intensive Management Options for Low-Risk Thyroid Cancer

The incidence of thyroid cancer is increasing, whereas mortality remains relatively stable. An increasing body of research supports the use of less-intensive treatment for low-risk thyroid cancer, as the overall prognosis is excellent. Although total thyroidectomy was the gold standard for many years, the options of lobectomy alone, active surveillance, and other ablative modalities are increasingly being used. The clinicohistologic features of any thyroid cancer are important to help determine the optimal management for a given tumor. However, the patient's own desires and goals in their cancer treatment must be evaluated.

Sonographic assessment of minor extrathyroidal extension of papillary thyroid microcarcinoma involving the posterior thyroid capsule

OBJECTIVES

This study aimed to determine sonographic features and clinical significance of minor extrathyroidal extension (ETE) to the posterior thyroid capsule in papillary thyroid microcarcinoma (PTMC) patients.

METHODS

We retrospectively reviewed the records of 506 PTMC patients consisting of 151 patients with minor ETE and 355 patients without ETE. Significant clinicoradiologic features associated with ETE were identified by logistic regression analyses. The diagnostic performance of sonographic features, including the presence of capsular abutment, capsular abutment degree (< 25%, 25-50%, ≥ 50%), and protrusion, were assessed for the diagnosis of posterior minor ETE. Interobserver agreement was calculated.

RESULTS

PTMC patients with posterior minor ETE were more likely to have lymphovascular invasion and lateral neck lymph node metastasis (OR = 2.636, 95%CI: 1.754, 3.963 and OR = 2.897, 95%CI: 1.069, 7.848). Regarding the diagnostic performance, the capsular abutment yielded the highest sensitivity (81.5%), followed by ≥ 25% abutment, protrusion, and ≥ 50% abutment (57.0%, 21.9%, and 4.6%, respectively), with similar levels of diagnostic accuracy (71.3-75.1%). The specificity was highest for the sonographic feature of ≥ 50% abutment (99.7%), followed by protrusion, ≥ 25% abutment, and capsular abutment (97.8%, 82.0%, and 68.7%, respectively). Abutment assessment had a moderate interobserver agreement (K = 0.705), and abutment degree and protrusion assessment had a fair and slight interobserver agreement (K = 0.553 and 0.287).

CONCLUSIONS

Sonographic features of posterior capsular abutment are sensitive and reliable for diagnosis of posterior minor ETE and are associated with lymphovascular invasion and lateral neck lymph node metastasis in PTMC patients. The assessment of posterior minor ETE is important for considering candidates for active surveillance among PTMC patients.

KEY POINTS

• PTMC patients with posterior minor ETE were more likely to have lymphovascular invasion and lateral neck lymph node metastasis. • Sonographic features of posterior capsular abutment are sensitive and reliable for the diagnosis of posterior minor ETE. • The assessment of posterior minor ETE is important for considering candidates for active surveillance among PTMC patients.

Papillary Thyroid Microcarcinoma: Active Surveillance Against Surgery. Considerations of an Italian Working Group From a Systematic Review

Introduction

Active surveillance is considered a viable option for papillary thyroid microcarcinoma. Since the last decade of the 20th century, this method has spread from Japan to other countries, but has not yet been fully accepted and validated by the major Western Scientific Societies. In 2016, a systematic review on the results of active surveillance was published, based on two articles that showed encouraging results. Other reviews published subsequently, were mainly based on articles from the Far East. The aim of this review is to assess the most recent results published from 2017 to 2020 on this subject.

Materials and Methods

A systematic literature search was performed on MEDLINE via PUBMED, Web of Science, and Scopus according to PRISMA criteria. The MESH terms “papillary thyroid microcarcinoma” and “active surveillance” were adopted. Tumor progression, secondary localizations, and quality of life were the main benchmarks.

Results

Nine studies met the inclusion criteria. The increase in volume ranged from 2.7% and 23.2%; the occurrence of lymph node metastases from 1.3% to 29%; QoL was improved in both articles that addressed this topic. The level of evidence is considered low due to the retrospective and uncontrolled nature of most of the studies included in the review.

Conclusion

The evidence from the literature currently available on AS falls into two strands: a robust data set from the Japanese experience, and an initial experience from Western countries, whose data are still limited but which show a lack of substantial alerts against this practice. Further data is useful to validate the spread of Active Surveillance.

Surgery and Radioactive Iodine Therapeutic Strategy for Patients Greater Than 60 Years of Age with Differentiated Thyroid Cancer

Purpose: The purpose of the current study was to determine whether older patients with differentiated thyroid cancer (DTC) who received surgical treatment had a better cause-specific survival (CSS) than patients who were recommended surgery, but declined, and whether patients who underwent postoperative RAI-131 therapy had an impact on CSS based on TNM staging and number of lymph node metastases for all total or near-total thyroidectomy patients. Patients and Methods: This retrospective, population-based study analyzed the clinical data of 162 DTC patients from signal institution in China and 26,487 cases from the Surveillance, Epidemiology, and End Results (SEER) program registry. The patients were divided into two groups (underwent surgery and surgery recommended, but not performed) in the SEER cohort. Furthermore, patients were grouped as follows: T4; N1b; M1; T1-3N0-1a; specific number of lymph node metastases; and total or near-total thyroidectomy. Results: The 120-month cause-specific survival (CSS) rate of women and men showed a gradual declining trend from 60–64 to ≥80 years of age in the group that underwent surgery. The CSS rate of women and men showed a marked downward and irregular trend with an increase in age in the recommended, but no surgery group in the SEER cohort. Univariate analysis indicated that the surgery group had a higher 120-month CSS in women in most stages and men, compared with the no surgery group in the SEER cohort. The analysis of the SEER cohort showed that RAI-131 therapy was associated with an improved 80-month CSS in T4/N1b/M1 women (P < 0.0183) and men (P < 0.0011). However, there were no CSS differences between the RAI-131 therapy and the no-RAI-131 group for the patients with T4/N1b/M1 (AJCC 7th) thyroid cancer in the Chinese cohort. There was no CSS difference in women or men between the T1-3N0 and T1-3N1a patients in the SEER cohort. And similar findings were observed in T1-3N1a patients in the Chinese cohort. There was no statistical difference between the two subgroups. Conclusions: Surgical treatment should be recommended for elderly DTC patients because surgery can lead to a better CSS. High-risk patients achieve a higher benefit-to-risk ratio with RAI-131 therapy. To avoid the adverse effects associated with RAI-131 therapy, a multidisciplinary discussion should be arranged for intermediate- and low-risk patients.

Comparison between 2015 ATA guidelines and Italian Consensus for DTC management. A commented report

The 2015 ATA guidelines and 2018 Italian Consensus have produced a series of generally concordant recommendations on clinical and therapeutic management of thyroid nodules and thyroid carcinoma. Currently, the goals of treatment are to achieve the highest disease-free survival rates through the best ratio between minimum invasiveness and cost/impact on quality of life. By analysis and comparison of the ATA Guidelines and Italian Consensus, we highlighted and commented upon the key points of differentiated thyroid cancer management. Furthermore, the aim of this work is to identify and promote uniform clinical approaches among all specialists who treat differentiated thyroid cancer and represent a starting point for a consensus drafted by the Italian Society of Otolaryngology - Head and Neck Surgery.

Bibliometric insights in advances of papillary thyroid microcarcinoma: Research situation, hot points, and global trends

BACKGROUND

Thyroid cancer has been on the rise over the last decade. Papillary thyroid microcarcinoma (PTMC) accounts for more than half of all thyroid cancers. Micropapillary carcinoma of the thyroid is a common but non-fatal form of thyroid cancer. To better comprehend, nearly two decades of scientific outputs were analyzed and summarized using bibliometric methods in this study.

METHODS

Approximately 1098 publications from 2000 and 2021 were included in WoS database through systematic retrieval. The general information was characterized, and developmental skeleton and research frontiers were explored. CiteSpace, VOSviewer, and R, Tableau were used to evaluate and visualize the results.

RESULTS

A total of 1098 publications from across 75 countries were identified. The annual number of publications showed an increasing trend in the past 21 years. China, Korea, the United States of America (USA), Italy, and Japan made remarkable contributions to the research of PTMC. Thyroid was the most productive journal. Miyauchi Akira published maximum articles. The utmost productive institution was the University of Ulsan. Risk stratification, active surveillance, and thermal ablation garnered the attention of researchers leading to novel approaches in the clinical diagnosis and treatment of micropapillary thyroid carcinoma.

CONCLUSIONS

This bibliometric study provides a comprehensive analysis of global productivity, collaboration, and research hotspots within PTMC field, which will aid in directing research toward PTMC in the coming years.

Papillary thyroid microcarcinoma: Is active surveillance always enough?

The incidence of papillary thyroid carcinoma (PTC) has increased over recent decades. This apparent epidemic has been attributed to the overdiagnosis of small PTC ≤10 mm in diameter (papillary thyroid microcarcinoma [PTMC]) incidentally detected on imaging for unrelated presentations. Although most PTMCs follow an indolent disease course, there is a small but significant proportion of cases that display more biologically aggressive features such as early metastasis and lymph node involvement. Management of PTMC diagnosed preoperatively should be distinguished from managing those PTMCs incidentally discovered after thyroidectomy. Here, we will focus on the challenge of managing the preoperative patient. Current guidelines recommend against routine biopsy of nodules ≤10 mm, even if they display highly suspicious features on ultrasound; however, it is not known how to identify those PTMCs at higher risk of disease progression. In view of their good prognosis even without surgical resection, active surveillance has emerged as an alternative to operative management for low-risk PTMC without lymph node involvement or distant metastasis. This review aims to summarise active surveillance data for PTMC and identify clinical features that may differentiate the indolent majority from those PTMCs that exhibit early disease progression and metastasis.

Tumor Volume Doubling Time in Active Surveillance of Papillary Thyroid Microcarcinoma: A Multicenter Cohort Study in Korea

Background: Some papillary thyroid microcarcinomas (PTMCs) may progress with tumor enlargement or development of new lymph node (LN) metastasis during active surveillance (AS). This study evaluated the relevant predictors of disease progression, especially new cervical LN metastasis. Methods: This was a long-term follow-up study conducted using a previous multicenter cohort of AS in Korea. After excluding 54 (14.2%) patients with a short follow-up duration, 326 PTMC patients were evaluated for tumor kinetics, including changes in tumor volume (TV) and TV doubling time (TVDT). Results: During a median follow-up duration of 4.9 years, 17 (5.2%, 95% confidence intervals [CI] 2.7-7.6%) patients showed a maximal diameter increase of ≥3 mm after a median of 4.0 years follow-up, while 9 (2.8%, CI 1.0-4.5%) developed new LN metastasis after a median of 2.2 years follow-up. New cervical LN metastasis occurred exclusively of a maximal diameter increase of ≥3 mm. The prevalence of new development of LN metastasis was higher in patients with TVDT <5 years (7.4%) than in those with TV ≥50% (3.2%). Furthermore, only TVDT <5 years was significantly associated with LN metastasis (p = 0.002). In univariate and multivariate analyses, TVDT <5 years was an independent risk factor for disease progression with respect to new development of LN metastasis (hazard ratio [HR] = 6.51, CI 1.73-24.50; p = 0.002) and tumor enlargement (HR = 20.89, CI 5.78-75.48; p < 0.001). Finally, 86 (22.6%) patients underwent delayed surgery, and the most common reason was patient anxiety. Conclusions: TVDT <5 years is a predictor of disease progression during AS in terms of new LN metastasis development as well as tumor enlargement. Determination of TVDT in the early phase of AS could help in predicting disease progression, tailoring follow-up intensity of AS and in determining if early surgical intervention is needed.

How to identify indolent thyroid tumors unlikely to recur and cause cancer death immediately after surgery-Risk stratification of papillary thyroid carcinoma in young patients

Current histopathological diagnosis methods cannot distinguish the two types of thyroid carcinoma: clinically significant carcinomas with a potential risk of recurrence, metastasis, and cancer death, and clinically insignificant carcinomas with a slow growth rate. Both thyroid tumors are diagnosed as "carcinoma" in current pathology practice. The clinician usually recommends surgery to the patient and the patient often accepts it because of cancer terminology. The treatment for these clinically insignificant carcinomas does not benefit the patient and negatively impacts society. The author proposed risk stratification of thyroid tumors using the growth rate (Ki-67 labeling index), which accurately differentiates four prognostically relevant risk groups based on the Ki-67 labeling index, ≥30%, ≥10 and <30%, >5 and <10%, and ≤5%. Indolent thyroid tumors with an excellent prognosis have the following four features: young age, early-stage (T1-2 M0), curatively treated, and low proliferation index (Ki-67 labeling index of ≤5%), and are unlikely to recur, metastasize, or cause cancer death. Accurate identification of these indolent tumors helps clinicians select more conservative treatments to avoid unnecessary aggressive (total thyroidectomy followed by radio-active iodine) treatments. Clinicians can alleviate the fears of patients by confirming these four features, including the low proliferation rate, in a pathology report immediately after surgery when patients are most concerned.

Active Surveillance as an Effective Management Option for Low-Risk Papillary Thyroid Microcarcinoma

Active surveillance (AS) for low-risk papillary thyroid microcarcinoma (PTMC) has been accepted worldwide as safe and effective. Despite the growing acceptance of AS in the management of low-risk PTMCs, there are barriers to AS in real clinical settings, and it is important to understand and establish appropriate AS protocol from initial evaluation to follow-up. PTMC management strategies should be decided upon after careful consideration of patient and tumor characteristics by a multidisciplinary team of thyroid cancer specialists. Patients should understand the risks and benefits of AS, participate in decision-making and follow structured monitoring strategies. In this review, we discuss clinical outcomes of AS from previous studies, optimal indications and follow-up strategies for AS, and unresolved questions about AS.

Position paper from the Japan Thyroid Association task force on the management of low-risk papillary thyroid microcarcinoma (T1aN0M0) in adults

The incidence of thyroid carcinoma has been increasing worldwide. This is interpreted as an increase in the incidental detection of papillary thyroid microcarcinomas (PTMCs). However, mortality has not changed, suggesting overdiagnosis and overtreatment. Prospective clinical trials of active surveillance for low-risk PTMC (T1aN0M0) have been conducted in two Japanese institutions since the 1990s. Based on the favorable outcomes of these trials, active surveillance has been gradually adopted worldwide. A task force on the management of PTMC in adults organized by the Japan Thyroid Association therefore conducted a systematic review and has produced the present position paper based on the scientific evidence concerning active surveillance. This paper indicates evidence for the increased incidence of PTMC, favorable surgical outcomes for low-risk PTMC, recommended criteria for diagnosis using fine needle aspiration cytology, and evaluation of lymph node metastasis (LNM), extrathyroidal extension (ETE) and distant metastasis. Active surveillance has also been reported with a low incidence of disease progression and no subsequent recurrence or adverse events on survival if conversion surgery was performed at a slightly advanced stage. Active surveillance is a safe and valid strategy for PTMC, because it might preserve physical quality of life and reduce 10-year medical costs. However, some points should be noted when performing active surveillance. Immediate surgery is needed for PTMC showing high-risk features, such as clinical LNM, ETE or distant metastasis. Active surveillance should be performed under an appropriate medical team and should be continued for life.

Update on the Evaluation of Thyroid Nodules

Thyroid nodules (TN) are prevalent in the general population and represent a common complaint in clinical practice. Most are asymptomatic and are associated with a 7%-15% risk of malignancy (1). Methods: PubMed and Medline were searched for articles with a focus on the epidemiology, diagnosis, and management of TN over the past 5 y. Results: The increase in frequency of imaging has led to a rise in the incidence of incidentally diagnosed TN. The initial evaluation of a TN includes assessing thyroid function, clinical risk factors, and neck imaging. Ultrasound remains the gold standard for assessing TN morphology, and biopsy is the standard method for determining whether a TN is benign. Recently published risk stratification systems using morphologic characteristics on ultrasonography have been effective in reducing the number of unnecessary biopsies. Advances in molecular testing have reduced the number of surgical procedures performed for diagnostic purposes on asymptomatic TN with indeterminate cytology. Scintigraphy is the first-line study for assessing a hyperfunctioning nodule. Many TN can be followed clinically or with serial ultrasound after the initial diagnosis. Surgical intervention is warranted when local symptoms are present, in patients with clinical risk factors, as well as in most situations with malignant cytology. Active surveillance is an option in cases of micropapillary thyroid cancer. Emerging nonsurgical approaches for treating TN include ethanol ablation for TN; sclerotherapy for thyroid cysts; and thermal techniques, such as radiofrequency ablation, laser ablation, microwaves, and high-intensity focused ultrasound. Conclusion: Most TN are benign and can be safely monitored. The indications for biopsy and frequency of imaging should be tailored on the basis of risk stratification. Treatment options should be individualized for each patient's particular situation. Active surveillance should be considered in certain cases of papillary microcarcinoma.

Multifocality and Progression of Papillary Thyroid Microcarcinoma During Active Surveillance

BACKGROUND

Prospective trials of active surveillance (AS) have shown low rates of progression in low-risk papillary thyroid microcarcinoma (PTMC; T1aN0M0). However, the significance of multifocality as a prognostic factor remains controversial.

METHODS

Data from 571 patients (mean age, 53.1 years; 495 females) who underwent AS were reviewed. PTMC was unifocal in 457 patients (80.0%) and multifocal in 114 patients (20.0%), with 2-5 lesions each (261 tumors in total). Tumor progression was defined as tumor size enlargement ≥ 3 mm and/or development of clinically evident lymph node metastasis (LNM).

RESULTS

After a mean duration of AS of 7.6 years, 53 patients (9.3%) showed tumor enlargement and 8 patients (1.4%) developed LNM. The 10-year progression rate was 13.1%. Age, sex, and calcification pattern did not differ significantly between uni- and multifocal diseases. However, anti-thyroglobulin antibody and/or anti-thyroid peroxidase antibody was more frequently positive with multifocal PTMCs (46.7%) than with unifocal disease (34.4%, p = 0.024). Patients with uni- and multifocal disease showed no significant differences in 10-year rate of tumor enlargement (11.4% vs. 14.8%), LNM development (1.1% vs. 2.4%), or progression (12.4% vs 15.9%). Multivariate analysis of predictors for progression showed multifocality was not a significant risk factor (odds ratio, 1.45; 95% confidence interval, 0.79-2.54; p = 0.22). Eventually, 9 patients (7.9%) with multifocal PTMCs underwent surgery and 7 needed total thyroidectomy, although 7 still showed T1N0M0 low-risk cancer.

CONCLUSIONS

Even patients with multiple PTMCs (T1amN0M0) are good candidates for AS. Many patients can avoid total thyroidectomy and subsequent surgical complications.

Five-year follow-up results of thermal ablation for low-risk papillary thyroid microcarcinomas: systematic review and meta-analysis

OBJECTIVES

Confidence in long-term treatment results of thermal ablation for papillary thyroid microcarcinoma (PTMC) is required in comparison with active surveillance. The objective of this meta-analysis is to report 5-year follow-up results of thermal ablation for PTMC.

METHODS

Ovid MEDLINE and EMBASE databases were searched through May 30, 2020, for studies reporting outcomes in patients with PTMC treated with thermal ablation and followed up for at least 5 years. Data were extracted and methodological quality was assessed independently by two radiologists according to the PRISMA guidelines.

RESULTS

Three studies, involving 207 patients with 219 PTMCs, met the inclusion criteria through database searches. None of these patients experienced local tumor recurrence, lymph node metastasis, or distant metastasis or underwent delayed surgery during a mean pooled 67.8-month follow-up. Five new tumors appeared in the remaining thyroid gland of four patients, with four of these tumors successfully treated by repeat thermal ablation. The pooled mean major complication rate was 1.2%, with no patient experiencing life-threatening or delayed complications.

CONCLUSIONS

Thermal ablation is an excellent local tumor control method in patients with low-risk PTMC, with low major complication rates at 5 years.

KEY POINTS

• No local tumor recurrence, lymph node metastasis, or distant metastasis was noted by thermal ablation during follow-up of 5 years and none underwent delayed surgery. • The pooled mean major complication rate was 1.2%.

Microcarcinoma papilar de tiroides: ¿es adecuada la selección para protocolo de vigilancia activa?

Introducción. Los microcarcinomas papilares de tiroides son tumores de hasta 10 mm en su diámetro mayor. Su tratamiento es sujeto de debate y se propone, desde seguimiento clínico, hasta intervención quirúrgica temprana. Este estudio buscó identificar factores de riesgo relacionados con compromiso ganglionar, que permitan una mejor selección de los pacientes en nuestro medio, en quienes se propone manejo quirúrgico inmediato o vigilancia activa, en consonancia con la clasificación del riesgo de progresión. Métodos. Estudio de cohorte analítica ambispectiva que incluyó pacientes con microcarcinoma papilar de tiroides llevados a tiroidectomía más vaciamiento central. Se caracterizó la población y se realizó un análisis de regresión logística multivariado para definir factores preoperatorios asociados al compromiso ganglionar. Adicionalmente, se evaluó de manera retrospectiva la eventual asignación a grupos de riesgo de progresión, según los criterios de Miyauchi, y su comportamiento respecto al estado nodal. Resultados. Se incluyeron 286 pacientes. El 48,9 % presentó compromiso ganglionar, y de estos, el 33,5 % presentó compromiso ganglionar significativo, que modificó su clasificación de riesgo de recaída. De estos últimos, el 59,5 % hubiesen sido manejados con vigilancia activa, según los criterios propuestos por Miyauchi. Se identificó que la edad menor de 55 años, los ganglios sospechosos en la ecografía y los nódulos mayores de 5 mm, se relacionan con compromiso ganglionar significativo. Discusión. El manejo quirúrgico inmediato parece ser una opción adecuada para pacientes con sospecha de compromiso ganglionar en ecografía preoperatoria, pacientes menores de 55 años y nódulos mayores de 5 mm. Es posible que los actuales criterios para definir vigilancia activa no seleccionen adecuadamente a los pacientes en nuestro medio.

Indications and Strategy for Active Surveillance of Adult Low-Risk Papillary Thyroid Microcarcinoma: Consensus Statements from the Japan Association of Endocrine Surgery Task Force on Management for Papillary Thyroid Microcarcinoma

Background: The question of how to manage patients with low-risk papillary thyroid microcarcinoma (PTMC; T1aN0M0) has recently become an important clinical issue. Two Japanese centers have conducted prospective clinical trials of active surveillance (AS) for low-risk PTMC since the 1990s, reporting favorable outcomes. This policy has thus seen gradual adoption worldwide to avoid overtreatment. Not all PTMCs are suitable for AS, however, and many physicians still hesitate to apply the management policy in daily clinical practice. A task force on management for PTMC created by the Japan Association of Endocrine Surgery collected and analyzed bibliographic evidence and has produced the present consensus statements regarding indications and concrete strategies for AS to facilitate the management of adult patients diagnosed with low-risk PTMC. Summary: These statements provide indications for AS in adult patients with T1aN0M0 low-risk PTMC. PTMCs with clinical lymph node metastasis, distant metastasis, recurrent laryngeal nerve (RLN) paralysis due to carcinoma invasion, or protrusion into the tracheal lumen warrant immediate surgery. Tumors suspected of aggressive subtypes on cytology are recommended for immediate surgery. Immediate surgery is also recommended for tumors adherent to the trachea or located along the course of the RLN. Practical strategies include diagnosis, decision-making, follow-up, and monitoring related to the implementation of AS. The rate of low-risk PTMC progression is lower in older patients. However, we recommend continuing AS as long as circumstances permit. Future tasks in optimizing management for low-risk PTMC are also described, including molecular markers and patient-reported outcomes. Conclusions: An appropriate multidisciplinary team is necessary to accurately evaluate primary tumors and lymph nodes at the beginning of and during AS, and to adequately reach a shared-decision with individual patients. If appropriately applied, AS of low-risk PTMC is a safe management strategy offering favorable outcomes and preserves quality of life at low cost.

Association of Patient Age With Progression of Low-risk Papillary Thyroid Carcinoma Under Active Surveillance: A Systematic Review and Meta-analysis

Importance

Active surveillance is sometimes considered as a disease management option for individuals with small, low-risk papillary thyroid carcinoma.

Objective

To assess whether patient age is associated with progression of low-risk papillary thyroid carcinoma (tumor growth or incident metastatic disease) in adults under active surveillance.

Evidence Review

Eight electronic databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Emcare, PsycINFO, Web of Science, and ClincalTrials.gov) were searched from inception to March 2019, supplemented with a hand search. Two investigators independently screened citations, reviewed full-text articles, and abstracted data. Additional data were sought from authors. Random-effects meta-analyses were performed using incidence data (statistically adjusted for confounders and crude rates).

Findings

A total of 1658 unique citations were screened, and 62 full-text articles were reviewed, including 5 studies. Three studies included exclusively microcarcinomas and 2 included tumors up to 2 cm in maximal diameter. The mean age of participants was 51.0 to 55.2 years in 4 studies reporting this value. The mean or median follow-up was 5 years or more in 3 studies and approximately 2 years in 2 studies. The pooled risk ratio for tumor growth of 3 mm or more in maximal diameter in individuals aged 40 to 50 years compared with younger individuals was 0.51 when adjusted for confounders (95% CI, 0.29-0.89; 1619 patients, 2 studies), and the unadjusted risk ratio of this outcome for individuals 40 years or older was 0.55 (95% CI, 0.36-0.82; 2097 patients, 4 studies). In adults aged 40 to 45 years, the unadjusted risk ratio for any tumor volume increase compared with younger individuals was 0.65 (95% CI, 0.51-0.83; 1232 patients, 4 studies). The pooled risk ratio for incident nodal metastases in individuals 40 years or older was 0.22 (95% CI, 0.10-0.47; 1806 patients, 3 studies); however, in a secondary analysis, the risk difference was not significantly different. There was no statistically significant heterogeneity in any of the meta-analyses. There were no thyroid cancer-related deaths nor incident distant metastases.

Conclusions and Relevance

This study suggests that older age may be associated with a reduced risk of primary papillary thyroid carcinoma tumor growth under active surveillance. Incident metastatic disease is uncommon during active surveillance.

Clinical management of low-risk papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PTMC) is well known to have an indolent nature with an excellent prognosis. Surgery has been the standard treatment during the past several decades, with metastasis or recurrence being exceedingly rare. Active surveillance (AS) is a new risk-adapted approach alternative to surgery that involves just watching, but not giving any treatment unless needed, not addressing the tumor itself. The patients for whom AS is adopted spend their time "with tumors." In follow-up, it is possible that alarming factors such as tumor progression appear, causing anxiety about progression. Furthermore, endless follow-up is needed. However, considering the indolent nature and unfavorable events such as surgical complications caused by surgery, AS is a good management plan for selected PTMC patients. Decision making balancing between the prognosis and unfavorable events is needed for the treatment plan. Consideration of the factors and timing of surgical conversion is also needed. In this review article, how AS should be adopted as a new management option that is an alternative to surgery, which has been the absolute choice of treatment up to recently, is discussed. Concurrently, the characteristics of the two treatment strategies are reviewed, while introducing the background that explains how AS came to attention.

Ultrasound-Guided Radiofrequency Ablation Versus Surgical Resection for the Treatment of T1bN0M0 Papillary Thyroid Carcinoma in Different Age Groups

PURPOSE

We aimed to compare the efficacy and safety of radiofrequency ablation (RFA) to that of surgical resection (SR) in patients with T1bN0M0 papillary thyroid carcinoma (PTC) in different age groups.

METHODS

Totally, 204 patients with an isolated, solitary, intrathyroidal T1bN0M0 PTC, who underwent either RFA (n=94) or SR (n=110) between April 2014 and December 2019, were retrospectively enrolled and were divided into two subgroups according to age (<45 years, ≧45 years). Patients with pathologically aggressive or advanced lesions were excluded from the study. Tumor progression and procedural complications were the primary and secondary endpoints, respectively. Tumor recurrence in situ, newly discovered tumors, lymph node involvement, or distant metastases indicated tumor progression. Complications included pain, fever, voice change, choking, numbness in the limbs, and cardiac events. Incidence rates of all endpoint events were compared between different age subgroups.

RESULTS

There were no significant differences in age, sex, and tumor size between the treatment groups. While the RFA group incurred less cost and experienced significantly shorter operative duration than the SR group, no significant differences were observed in incidences of both tumor progression and complications. Further, subgroup analysis of patients <45 years versus those ≧45 years showed no significant differences in the incidence of tumor progression and complications within or between different treatment groups. Older patients in the SR group incurred higher hospital costs than younger counterparts, but this difference was not observed in the RFA group.

CONCLUSIONS

Our results indicated that RFA had a similar prognosis as that of SR but was associated with lower overall cost in both young (<45 years) and middle-aged patients (≧45 years) with T1bN0M0 PTC. Therefore, RFA may be an effective and safe alternative to surgery for the treatment of patients with T1bN0M0 PTC.

NATIONAL SURVEY OF ENDOCRINOLOGISTS AND SURGEONS REGARDING ACTIVE SURVEILLANCE FOR LOW-RISK PAPILLARY THYROID CANCER

OBJECTIVE

Active surveillance for low-risk papillary thyroid cancer (PTC) was endorsed by the American Thyroid Association guidelines in 2015. The attitudes and beliefs of physicians treating thyroid cancer regarding the active surveillance approach are not known.

METHODS

A national survey of endocrinologists and surgeons treating thyroid cancer was conducted from August to September 2017 via professional society emails. This mixed-methods analysis reported attitudes toward potential factors impacting decision-making regarding active surveillance, beliefs about barriers and facilitators of its use, and reasons why physicians would pick a given management strategy for themselves if they were diagnosed with a low-risk PTC. Survey items about attitudes and beliefs were derived from the Cabana model of barriers to guideline adherence and theoretical domains framework of behavior change.

RESULTS

Among 345 respondents, 324 (94%) agreed that active surveillance was appropriate for at least some patients, 81% agreed that active surveillance was at least somewhat underused, and 76% said that they would choose surgery for themselves if diagnosed with a PTC of ≤1 cm. Majority of the respondents believed that the guidelines supporting active surveillance were too vague and that the current supporting evidence was too weak. Malpractice and financial concerns were identified as additional barriers to offering active surveillance. The respondents endorsed improved information resources and evidence as possible facilitators to offering active surveillance.

CONCLUSION

Although there is general support among physicians who treat low-risk PTC for the active surveillance approach, there is reluctance to offer it because of the lack of robust evidence, guidelines, and protocols.

Life Expectancy and Treatment Patterns in Elderly Patients With Low-Risk Papillary Thyroid Cancer: A Population-Based Analysis

OBJECTIVE

Guidelines endorse active surveillance for low-risk papillary thyroid carcinoma (PTC), but this is not commonly utilized. Those with limited life expectancy due to age and comorbidity may be best suited for active surveillance given their higher likelihood of other-cause mortality compared to disease-specific mortality.

METHODS

Surveillance, epidemiology, and end results-Medicare was queried for patients >65 years with T1, N0, M0 PTC who received surgery. We evaluated the overall survival, disease-specific survival (DSS), and survival based on tumor size and extent of surgery (hemi- vs total thyroidectomy). We created a competing risk model to identify the cumulative incidence of other-cause mortality to define patient groups with life expectancies of less than 10 and 15 years.

RESULTS

A total of 3280 patients were included. The 20-year overall survival and DSS were 38.2% and 98.5%, respectively. DSS was comparable between patients based on tumor size and surgery. The cancer cohort had better survival compared to matched controls (P < .001). Life expectancy was less than 15 years for any patient aged >80 years regardless of Charlson comorbidity score (CCS ≥ 0) and any patient aged >70 years with CCS ≥ 1. Life expectancy was less than 10 years for any patient a >80 years with CCS ≥ 1 and aged >70 years with CCS ≥ 3.

CONCLUSION

Older patients with comorbidities have limited life expectancies but excellent DSS from low-risk PTC. Incorporating life expectancy into management decisions and guidelines would likely promote selection of less aggressive management for populations that are most suited for this approach.

[Current treatment strategies for papillary thyroid microcarcinoma]

Surgical treatment of papillary thyroid microcarcinoma (PTMC) is evolving more and more into a controversial issue. As in Japan more than 50% of PTMCs are only observed, an increasing number of physicians in the western world are calling for active surveillance instead of lobectomy or total thyroidectomy. Unifocal carcinomas of older patients without extrathyroidal growth or lymph node involvement seem to be candidates for active surveillance. First estimations for a lifelong observation show that patients <30 years old will have a probability of tumor progression of more than 60%. A decision for surgery versus active surveillance has to weigh up all the arguments for and against, which have to be discussed and planned in detail together with the patient.