Insights into the Management of Papillary Microcarcinoma of the Thyroid

Surgical Considerations in Thyroid Cancer: What the Radiologist Needs to Know

Management of thyroid cancer requires a multidisciplinary approach including head and neck/endocrine surgeons, endocrinologists, oncologists, and radiologists. The radiographic evaluation of thyroid cancer is critical for complete and precise staging and affects the surgical approach to address these cancers. The purpose of this article is to briefly review the common thyroid cancer pathologies and surgical considerations in thyroid cancer, focusing on the extent of surgery and the influence of preoperative imaging on surgical decision-making. This article assumes that a diagnosis of thyroid cancer has been made and does not discuss the workup or surveillance of thyroid nodules.

Long-Term Efficacy of Ultrasound-Guided Percutaneous Laser Ablation for Low-Risk Papillary Thyroid Microcarcinoma: A 5-Year Follow-Up Study

Objective

To evaluate the long-term efficacy and safety of ultrasound-guided percutaneous laser ablation (PLA) for the treatment of low-risk papillary thyroid microcarcinoma (PTMC).

Methods

From June 2012 to May 2015, 105 patients with solitary, pathologically confirmed PTMC lesions were treated with ultrasound-guided PLA. Nodule location, nodule volume, thyroid function, and clinical symptoms were evaluated before ablation. Contrast-enhanced ultrasound (CEUS) was performed 1 h after treatment to evaluate whether the ablation was complete. Ultrasound examination was performed at 1, 3, 6, and 12 months after ablation and every 6 months thereafter to determine the size of the ablation area and search for recurrence in the thyroid parenchyma and lymph node metastasis. Thyroid function was examined before and 1 month after ablation. Fine needle aspiration biopsy was performed for any suspicious metastatic lymph nodes and recurrent lesions in the thyroid.

Results

All 105 lesions were completely inactivated after one ablation, making the success rate for single ablation 100%. The average ablation time was 2.78 ± 1.05 min, and the average ablation energy was 505 ± 185 J. All patients could tolerate and complete the ablation. No serious complications occurred during the treatment; only minor side effects such as pain and local discomfort were reported. The volume reduction rates were −781.14 ± 653.29% at 1 h posttreatment and −268.65 ± 179.57%, −98.39 ± 76.58%, 36.78 ± 30.32%, 75.55 ± 21.81%, 96.79 ± 10.57%, and 100% at 1, 3, 6, 12, 18, and 24 months after ablation, respectively. This rate remained 100% at the later follow-up times. Overall, 28 (26.67%), 74 (70.48%), 96 (91.43%), and 103 (100%) were completely absorbed by 6, 12, 18, and 24 months after PLA. One patient developed another lesion 12 months after ablation, and two patients had central cervical lymph node metastasis 24 months after ablation.

Conclusion

PLA is a safe and effective alternative clinical treatment for low-risk PTMC.

Efficacy and safety of ultrasound-guided radiofrequency ablation for low-risk papillary thyroid microcarcinoma in patients aged 55 years or older: a retrospective study

PURPOSE

To evaluate the efficacy and safety of radiofrequency ablation for low-risk papillary thyroid microcarcinoma (PTMC) in patients aged 55 years or older.

METHODS

This retrospective study included 95 patients aged 55 years or older who underwent radiofrequency ablation (RFA) for PTMCs between June 2014 and January 2019. Incidence and duration of postoperative complications were recorded and evaluated. Tumor volume and volume reduction rate (VRR) changes were calculated. Patients were also closely monitored for tumor recurrence, regrowth, and lymph node metastasis.

RESULTS

All nodules were completely ablated. The mean initial volume of the ablated thyroid nodules was 107.27 ± 99.10 mm³, and the volume decreased significantly during the follow-up time. The VRR in 1st, 3rd, 6th, 12th, 18th, 24th and 36th month were -591.64 ± 623.65%, -170.89 ± 319.51%, 9.74 ± 128.43%, 77.99 ± 45.26%, 99.35 ± 3.61%, 99.45 ± 3.05% and 99.78 ± 1.54%, respectively. No patient had any life-threatening complications. One patient had lymph node metastasis and one had a recurrence; both underwent a second radiofrequency ablation treatment and achieved satisfactory treatment results.

CONCLUSIONS

Our study suggests that radiofrequency ablation is a safe and effective option for low-risk PTMC in patients aged 55 years or older who are at a high risk of general anesthesia and postoperative complications or those who refuse surgery.

Bilateral multifocality, a marker for aggressive disease, is not an independent prognostic factor for papillary thyroid microcarcinoma: A propensity score matching analysis

CONTEXT

Multifocality and bilaterality are common in patients with papillary thyroid microcarcinoma (PTMC). However, their clinical behaviours and prognostic implications remain controversial.

OBJECTIVE

To investigate the relationship between multifocality and classically aggressive characteristics and outcomes in patients with PTMC.

METHODS

Clinical data of 3005 patients with PTMC were retrospectively reviewed at a tertiary medical centre. The role of unilateral and bilateral multifocality in aggressive characteristics and clinical outcomes of PTMC was evaluated using propensity score matching (PSM).

RESULTS

A total of 573 patients had bilateral multifocal disease (B-MFD), 272 had unilateral multifocal disease (U-MFD), and 2160 had unifocal disease (UFD). Univariate analysis showed that patients in the multifocal disease (MFD) groups showed significantly different characteristics compared to patients in the UFD group in terms of age, chronic lymphocytic thyroiditis (CLT), follicular variant PTMC, tumour diameter, aggressive growth, including extrathyroidal extension (ETE), central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM), and TNM stage, and underwent radioactive iodine (RAI) therapy. Further stratified analysis revealed that patients in the B-MFD group reflected the differences between the MFD and UFD groups. However, those in the U-MFD group showed slight differences only in sex, CLT and cell subtypes, compared to the UFD group. In addition, PSM indicated differences in ETE, CLNM and LLNM between the B-MFD and UFD groups (p < .001), while only ETE differed between the U-MFD and UFD groups (p < .001). After a median follow-up period of 60 months, no difference was observed in recurrence-free survival between the UFD and B-MFD (p = .294) or U-MFD (p = .603) groups using PSM.

CONCLUSION

This propensity score matching analysis provides strong evidence that bilateral multifocality, rather than unilateral multifocality, should be considered as an aggressive marker at presentation, and neither is an independent prognostic factor for clinical outcome in PTMC.

Impact of Molecular Testing on the Management of Indeterminate Thyroid Nodules Among Western and Asian Countries: a Systematic Review and Meta-analysis

Molecular testing has a potential to improve the management of patients with indeterminate thyroid nodules considered for surgery. This study examined the influence of molecular tests on the treatment of indeterminate nodules, particularly the differences between Western and Asian countries. Electronic databases including PubMed and Web of Science were searched for relevant articles from 2010 to March 2019. We computed meta-analysis of proportion and their 95% confidence intervals (CIs) utilizing the random-effect model. We used independent samples t test to compare the resection rate (RR), rate of malignancy (ROM), rate of preoperative molecular testing (RMT), and rate of positive test (RP) between subgroups. We included a total of 34 studies with 7976 indeterminate nodules. The multigene panel testing methods were exclusively used in the USA. Compared with the non-molecular era, molecular testing was associated with a significantly increased ROM (47.9% versus 32.1%; p = 0.001). The ROM of indeterminate nodules in Asian institutes was significantly higher than that in Western countries (75.3% versus 36.6%; p < 0.001, respectively). Institutes employing single-gene tests achieved a higher ROM (59.8% versus 37.9%; p = 0.013). Molecular testing is a promising method to tailor the clinical management for indeterminate thyroid FNA. Certain differences in routine thyroid cytopathology practice among the West and the East are still present. The combination of molecular testing and active surveillance enhances the accuracy of case selection for surgery in Asian countries.

Impact of high-quality ultrasound following community ultrasound on surgical planning and active surveillance in patients with thyroid cancer

OBJECTIVE

Ultrasound (US) has gained a critical role in thyroid cancer treatment planning, yet it is limited by its user-dependent nature. The aim of this study was to compare the impact of US performed by radiologists specializing in thyroid imaging (hqUS) and US performed by radiographers in the community (cUS) on treatment plans of patients diagnosed with well-differentiated thyroid malignancies.

DESIGN

Retrospective single-centre case series with chart review.

PATIENTS

Patients diagnosed with thyroid cancer during 2017-2019 that had cUS followed by hqUS pre-operative counselling were included in this retrospective analysis.

MEASUREMENTS

The main outcome was management alternations based on one of two sonographic measures: (1) extrathyroid extension (ETE); (2) The presence of central or lateral lymph nodes suspicious for metastases (LNM), which were compared with the final pathology.

RESULTS

Among those with non-recurrent tumour (n = 76), ETE was reported 22 times more by hqUS compared with cUS (28.9% vs 1.3%, P < .001). Central and lateral LNM were reported approximately 6.5 and 1.5 times more by hqUS, respectively (25.0% vs 3.9%, P < .001 and 15.8% vs., 9.2%, P = .227, respectively). Overall, hqUS altered the initial treatment plan of 35.5% of patients. In 27.6% of patients, hqUS and its subsequent surgery resulted in a change to the patients' 2015 ATA risk stratification system. In 40% of patients with microcarcinomas, hqUS findings mandated surgery according to findings that were not reported by cUS. False-positive rate was 5.2%.

CONCLUSIONS

Community US may under-diagnose important features such as ETE and LNM, leading to potential under-treatment in many patients. High-quality US of the neck should be considered in patients with differentiated thyroid carcinoma before making any treatment decisions.

Research trends for papillary thyroid carcinoma from 2010 to 2019: A systematic review and bibliometrics analysis

BACKGROUND

Thyroid carcinoma comprises the fastest rising incidence of carcinomas over the past decade. Papillary thyroid carcinoma (PTC) is the most predominant type of thyroid carcinoma. This study aimed to assess the research trends in the field of PTC.

METHODS

Publications from January 2010 to December 2019 were retrieved from the Web of Science Core Collection database using Thompson Reuters. Searching strategies were determined according to Medical Subject Heading terms. Different kinds of bibliometrics software, such as HistCite and VOSviewer, and online bibliometrics analysis platforms were utilized to evaluate and visualize the results.

RESULTS

A total of 8102 publications across 93 countries were identified, with the annual number of publications showing an increasing trend. The United States, China, and South Korea showed their dominant position in PTC publication outputs, H-index, total citations, and international collaborations. Thyroid was the most productive journal. Akira Miyauchi published the most articles, and the most productive institution was Yonsei University. The hotspots keywords proliferation, invasion and metastasis, diagnoses and prognoses, therapeutic resistance, recurrence, and microcarcinomas appeared earlier and were sustained over the last 3 years.

CONCLUSIONS

This bibliometric study provides a comprehensive analysis delineating the scientific productivity, collaboration, and research hotspots within the PTC field, which will be very helpful when focusing on the direction of research over the next few years.

An aqueous extract of Prunella vulgaris L. inhibits the growth of papillary thyroid carcinoma by inducing autophagy in vivo and in vitro

The continued global rise in papillary thyroid carcinoma (PTC) combined with potential adverse effects of regular treatments calls for an alternative therapy. Prunella vulgaris L. (PV) is commonly used as a herbal remedy for thyroid diseases in China, but its influence on PTC is unclear. This study investigated the effect of PV aqueous extract on PTC and its underlying mechanism using a mouse xenograft model and the human PTC cell line K1. PV suppressed tumor growth in PTC-bearing mice at 0.05 and 0.1 g/kg bw, accompanied by improvements in autophagy-related protein expressions in xenografts. In K1 cells, PV inhibited cell growth and induced autophagic flux, manifesting as changes in autophagy-related proteins, the presence of autophagosomes, and a further increase in LC3-II by co-incubation with bafilomycin A1. Autophagy inhibitor 3-methyladenine ameliorated the autophagic cell death caused by PV. The mammalian target of rapamycin (mTOR) activator MHY1485 blocked the antiproliferative activity of PV by regulating mTOR, unc-51-like autophagy activating kinase 1 (ULK1), autophagosomes formation, and autophagy-related proteins. The adenosine monophosphate-activated protein kinase (AMPK) inhibitor compound C attenuated PV-induced inhibition of mTOR. Our results suggest that PV inhibits the growth of PTC in vivo and in vitro via autophagy, which is associated with the AMPK/mTOR/ULK1 pathway. Thus, PV has the potential to function as a therapeutic agent against PTC.

Thyroid Cancer Active Surveillance Program Retention and Adherence in Japan

Importance

Small papillary thyroid cancers are the most common type of thyroid cancer, with the incidence increasing across the world. Active surveillance of appropriate cancers has the potential to reduce harm from overtreatment but is a significant de-escalation from prior practice. Mechanisms that inform the rates of retention and adherence have not been described and need to be understood if broader uptake is to be considered.

Objective

To evaluate patient retention, adherence, and experience in the largest and most long-standing thyroid cancer active surveillance program, to our knowledge.

Design, Setting, and Participants

A cohort study using convergent design mixed-methods analysis of attendance data, semistructured interviews, and field observation was conducted at Kuma Hospital, Kobe, Japan. Participants included 1179 patients who were enrolled in surveillance between February 1, 2005, and August 31, 2013, and followed up through December 31, 2017. Data analysis was performed from January 25, 2018, through September 30, 2020.

Main Outcomes and Measures

Patients were considered adherent if they underwent ultrasonography within at least 13 months of the previous ultrasonographic examination. Patients were considered retained if they continued surveillance with an ultrasonographic examination at least every 2 years, without having had surgery for patient preference or clinical reasons.

Results

Of the 1179 patients included in the study, 1037 (88%) were women. The mean (SD) age was 56 (13.5) years (median, 57 years). Patients were followed up for up to 12.76 years (median, 5.97 years) and underwent a median of 9 ultrasonographic examinations (range, 2-50); 76 patients (6.4%) had surgery for clinical reasons. In analysis of retention, 53 of 1179 patients (4.5%) changed to surgery after a mean (SD) of 2.14 (1.53) years (median, 1.47; range, 0.14-7.17 years); at the study end point, 101 of 1179 patients (8.6%) had not been seen at Kuma Hospital in at least the past 2 years. Kaplan-Meier analysis to 10 years of follow-up time without structural progression estimated that 21.5% (95% CI, 17.0%-28.2%) of patients would not have had an ultrasonographic examination within at least the past 2 years. Mean adherence over a surveillance period of 10 follow-up ultrasonographic examinations (8878 person-examinations) was 91% (range, 85%-95%). Receipt of detailed test results, education regarding active surveillance, and supportive/collaborative style interactions with their physician were identified by patients as key factors for continuing surveillance.

Conclusions and Relevance

For patients with low-risk papillary thyroid cancer participating in active surveillance, retention in the program and adherence to follow-up ultrasonographic examination do not appear to be barriers to broader implementation of surveillance. The program's success may benefit from an approach analogous to traveler (patient) and their guide (clinician): the clinician advising on options, advocating for the optimal path over time, and supportively reaffirming the care plan or recommending alternatives as conditions change.

Incidence of thyroid carcinomas in an extended retrospective study of 526 autopsies

Thyroid cancer accounts for 1% of all malignancies, and is becoming increasingly common worldwide. The literature reports a prevalence of ~50% of thyroid nodules detected during autopsies in subjects with unknown thyroid pathology. An extended retrospective study of 526 autopsy cases was performed to identify the prevalence of thyroid carcinoma, among various types of thyroid nodules identified incidentally. Tissue samples were taken from thyroid nodules, for investigation of the presence of thyroid carcinoma, along with their macroscopic and microscopic features by means of histopathology and immunohistochemistry (IHC) methods. Histopathological diagnosis of malignancy was found in 51 cases of analyzed thyroid samples. Systematic detailed studies demonstrated that a thyroid gland, apparently normal on macroscopic examination, may be the site of pathological manifestations, sometimes presenting carcinomatous findings. Among thyroid carcinomas, the highest frequency was that of papillary microcarcinomas, which have a long evolution, and are incidentally detected during autopsies. Papillary microcarcinoma is an extremely common incidental finding and the vast majority of these tumors pursue a benign course. Furthermore, it is therefore necessary to create national screening programs for the early detection of thyroid carcinoma.

Marked Decrease Over Time in Conversion Surgery After Active Surveillance of Low-Risk Papillary Thyroid Microcarcinoma

Background: Active surveillance for low-risk papillary microcarcinoma (PMC) of the thyroid is an accepted and safe management strategy. However, some patients undergo conversion surgery after the initiation of active surveillance for various reasons. We investigated the reasons for conversion surgery and whether and how they changed over time. Methods: We enrolled 2288 patients with PMC who underwent active surveillance. Of these, 162 (7.1%) underwent conversion surgery >12 months after initiating active surveillance due to disease progression (57 patients), patient preference (43 patients), physician preference (31 patients), other associated thyroid or parathyroid diseases (24 patients), and other reasons (7 patients). We analyzed cumulative conversion rates not only in the whole cohort but also in the first three major subsets based on the reasons for surgery. We also divided our whole cohort into two groups based on the period of active surveillance commencement: the first-half group (February 2005-November 2011; 561 patients) and the second-half group (December 2011-June 2017; 1727 patients). Results: The criteria for PMC progression did not differ between the first- and second-half groups. The proportion of female patients in the physician preference group was significantly higher than that in the disease progression and the patient preference groups. Tumor size at surgery was larger, and tumor volume-doubling rate was higher in the disease progression group than in the other two groups. Patients in the second-half group were significantly less likely to undergo conversion surgery than those in the first-half group. Furthermore, conversion surgery rates in the second-half group were significantly lower than those in the first-half group in the patient preference, physician preference, and disease progression groups. Conclusions: Patients with PMC in the second-half group were significantly less likely to undergo conversion surgery than those in the first-half group regardless of the reason. This is probably because data accumulation of favorable outcomes with active surveillance significantly contributed to physicians' confidence and patients' trust and understanding of this disease.

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.

Cytomorphologic features as predictors of aggressiveness in patients with pT1 papillary thyroid carcinoma: a retrospective study of associations with clinicopathological parameters in 226 fine-needle aspirates

Background

Distinguishing aggressive pT1 papillary thyroid carcinomas (PTCs) from indolent PTCs before or during surgery is important. To the best of our knowledge, few reports in the literature have examined the value of the cytomorphologic features of PTC as predictors of aggressiveness.

Methods

This retrospective study included 226 pT1 PTC patients who underwent preoperative fine-needle aspiration cytology (FNAC) and surgery at Peking University Cancer Hospital between January 2018 and December 2019. Data on the clinical characteristics and pathological results were obtained from the electronic medical record database. All FNAC smears were blindly reviewed by two independent cytopathologists, and the associations between nine cytomorphologic features (lymphocytes, multinucleated giant cells, cellularity, cellular adhesiveness, nuclear size, nuclear pleomorphism, nuclear membrane regularity, intranuclear pseudoinclusions and the amount of cytoplasm) and clinicopathological parameters were statistically analyzed.

Results

Univariate analysis showed that cellularity, intranuclear pseudoinclusions, cellular adhesiveness, nuclear size, and nuclear pleomorphism were strong predictors of some clinicopathological parameters such as extracapsular invasion (ECI) and lymph node metastasis (LNM). Multivariate analysis confirmed that cellular adhesiveness was a strong independent predictor of ECI (P=0.001) and LNM (P<0.001), and the amount of cytoplasm can also predict LNM (P=0.024).

Conclusions

Cytomorphologic features including cellular adhesiveness and the amount of cytoplasm in preoperative FNAC smears could be a valuable tool for predicting ECI or LNM and may be predictors of aggressiveness in patients with pT1 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.

The Efficacy and Safety of Radiofrequency Ablation for Bilateral Papillary Thyroid Microcarcinoma

OBJECTIVE

To investigate the long-term clinical results of radiofrequency ablation (RFA) for bilateral papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

From October 2014 to February 2018, 47 patients (37 females, 10 males, mean age 43.39 ± 9.26 years) with 100 bilateral PTMC (mean volume 75.22 ± 73.87 mm³) treated by RFA were included in this retrospective study. Bilateral PTMC was defined as at least one tumor located in the contralateral lobe. Patients were followed up at 1, 3, 6, 12 months and every 6-12 months thereafter. Volume, volume reduction ratio (VRR) and local tumor recurrence were evaluated during the follow-up period.

RESULTS

After a mean follow-up period of 47.77 ± 11.54 months, the mean volume of bilateral PTMC decreased from 75.22 ± 73.87 mm³ to 0.09 ± 0.44 mm³. The mean VRR was 99.94 ± 0.28% and the complete disappearance rate was 92.00%. During the follow-up, one patient (2.13%) developed lymph node metastasis and two patients (4.26%) had recurrent PTMC. All the recurrent lesions underwent additional RFA and two of them disappeared completely. No life-threatening or delayed complications occurred.

CONCLUSIONS

With sufficient preoperative evaluation, RFA might be a promising alternative for bilateral PTMC patients who were unsuitable for surgery or refused surgery.

Thermal Ablation for Papillary Thyroid Microcarcinoma: How Far We Have Come?

Purpose

Thermal ablation (TA), as one of the most currently remarkable technologies, has achieved great success in many malignant diseases including but not limited to hepatic and renal carcinoma. In recent years, this technology was gradually introduced to the treatment of papillary thyroid microcarcinoma (PTMC) and even papillary thyroid carcinoma (PTC). Thereby, we summarized the current progress of TA development in the treatment of PTMC.

Methods

The latest relevant literature from the PubMed database with keywords "thermal ablation", "papillary thyroid microcarcinoma", "microwave ablation", "radio-frequency ablation", and "laser ablation", among others, were comprehensively reviewed in this article. The follow-up outcomes of patients in these articles were analyzed.

Results

The efficacy and safety of TA including microwave ablation (MWA), laser ablation (LA), and radiofrequency ablation (RFA) in the treatment of PTC and PTC have been intensively studied. Based on existing clinical trials, the relatively long-term follow-up (range, from 6 to 64.2 months) results in MWA, LA, and RFA were satisfactory that tumor volume reduction rate (VRR) reached and even surpass 99%. Compared with routine surgery methods (total thyroidectomy and lobectomy), the incidence rate of complications was relatively lower and the recurrence rate of TA techniques was not statistically significant, whereas the operative time, blood loss, length of hospital stay, and hospital cost were significantly decreased.

Conclusion

TA presents the same satisfactory therapeutic effects but minimal postoperative trauma can significantly improve the patients' quality of life. However, future larger sample, multicenter, and prospective randomized controlled trials are urgently needed to validate the feasibility of TA in dealing with PTMC.

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.

Clinical Outcomes after Early and Delayed Radioiodine Remnant Ablation in Patients with Low-Risk Papillary Thyroid Carcinoma: Propensity Score Matching Analysis

BACKGROUND

The clinical outcomes of delayed radioiodine remnant ablation (RRA) therapy in patients with low-risk papillary thyroid carcinoma (PTC) are unclear. We aimed to evaluate the clinical impact of the interval between total thyroidectomy (TT) and RRA therapy in patients with low-risk PTC.

METHODS

We included 526 patients who underwent TT and RRA for low-risk PTC with a primary tumor size of >1 cm between 2000 and 2012. Patients were divided into the early (<90 days) and the delayed (≥90 days) RRA groups based on the interval between TT and RRA. The results of diagnostic whole-body scan (DxWBS), ongoing risk stratification (ORS; response to therapy), and disease-free survival (DFS) were evaluated before and after propensity score matching (PSM).

RESULTS

Among the 526 patients, 75 (14.3%) patients underwent delayed RRA; they had more cervical lymph node metastasis and received a higher RRA dose than those who underwent early RRA. The median follow-up period was 9.1 years after initial therapy, and the structural recurrence rate was 1.9%. In DxWBS, 60 patients had focal iodine uptake limited in operative bed, with no significant difference between groups. According to ORS, 78%, 20%, 1%, and 1% patients were classified into excellent, indeterminate, biochemical incomplete, and structural incomplete response groups, respectively. There was no significant difference in ORS or DFS between groups before and after PSM.

CONCLUSION

The timing of the first RRA had no clinical impact in patients with low-risk PTC. Thus, the clinical decision for RRA can be determined >3 months after TT considering other prognostic factors.

Survival with Follicular and Hurthle Cell Microcarcinoma Compared to Papillary Thyroid Microcarcinoma: A Population Study of 84,532 Patients

BACKGROUND

This study compares survival in patients with the rare subtypes of follicular (FTmC) and Hurthle cell (HCmC) microcarcinoma compared to that of papillary thyroid (PTmC) microcarcinoma.

METHODS

Patients with FTmC and HCmC were selected from the National Cancer Database 2004-2015 and compared with PTmC. Patient clinicopathological characteristics and overall survival (OS) were analyzed. Multivariable logistic and Cox regression analysis evaluated binary outcomes and predictors of survival. A propensity score matched analysis using age, gender, race, extrathyroidal extension (ETE), nodal status, distant metastasis, radiation, and operation was performed to evaluate the difference in OS with FTmC, HCmC, and PTmC.

RESULTS

We identified 858 FTmC, 476 HCmC, and 82,056 PTmC. FTmC was less likely to have macroscopic ETE compared to PTmC (2.6% vs. 3.1% p = 0.03), but more likely to have distant metastasis (2.3% vs. 0.2%, p < 0.01). FTmC and HCmC were less likely to have nodal metastasis (2.7%, 2.5% vs. 10.9%, p < 0.01). Ten-year OS was decreased in patients with FTmC (91.4%, p = 0.04) and HCmC (89.8%, p < 0.01) compared to PTmC (93.5%). On multivariable analysis, histology was not associated with OS. With HCmC, older age (OR 1.13, p < 0.01) and male gender (OR 2.72, p = 0.03) were associated with decreased OS. In propensity matched analysis, there was no difference in 10-year OS with FTmC and PTmC (91.4% vs. 93.7%, p = 0.54), but HCmC had decreased OS compared to PTmC (89.8% vs. 94.3%, p = 0.04).

CONCLUSIONS

Patients with FTmC have comparable OS to those with PTmC, but HCmC has decreased OS especially in older and male patients.

Routine Chest Computed Tomography at Presentation Does Not Identify Distant Metastasis in cT1aN0 Papillary Thyroid Carcinoma

Background: Active surveillance is accepted as a first-line management for patients with low-risk papillary thyroid microcarcinoma (PTMC) without metastasis or extrathyroid extension. While the lung is the most frequent site of distant metastasis of papillary thyroid carcinomas (PTCs), it is unclear if chest computed tomography (CT) is necessary at the initiation of active surveillance. In our institution, we usually did not perform chest CT for candidates identified for active surveillance. However, routine preoperative chest CT for patients with thyroid cancers, including PTMCs, was standard practice. The present study aimed to evaluate the clinical value of chest CT for patients with PTMCs. Methods: We retrospectively reviewed preoperative chest CT images from 1000 consecutive patients (88.5% women; median age, 55 years) with cT1aN0 PTC who underwent surgery between January 2006 and May 2012 in our hospital. The median maximum size of PTMCs was 8 mm. Results: Abnormal findings were detected in 326 (32.6%) of the 1000 patients. Of these, 290 patients had presumed benign or inflammatory lesions of no clinical importance. In total, 36 patients (3.6%) were referred to specialized departments for further evaluation of the lesions, and 9 patients (0.9%) received invasive tests and/or treatments. Five patients (0.5%) benefited from the chest CT (lung cancer was detected in four, and a cardiac lesion was detected and treated in one), while the lesions in the other four patients were benign, not necessarily requiring treatment. The remaining 27 patents were followed for presumed benign or inflammatory lesions. Thus, none of the present 1000 patients was found with distant metastasis of thyroid cancer. Conclusions: Routine chest CT did not detect thyroid cancer lung metastasis in patients with PTMC. Thus, routine chest CT at the time of presentation is not required for patients with cT1aN0 PTCs.

Active surveillance of low-risk papillary thyroid microcarcinomas

In 1993, active surveillance of low-risk papillary thyroid microcarcinomas (PTMCs) started in Kuma Hospital, Kobe, Japan. It has spread globally after the publishing of American Thyroid Association (ATA) guidelines. During our hospital's active surveillance program, few patients (8.0%) showed tumor size enlargement ≥3 mm or the new appearance of node metastasis (3.8%) at 10-year follow-up. Conversion surgery was recommended for patients with disease progression. To date, no patients showed significant recurrence or metastasis or died with thyroid carcinoma when patients underwent active surveillance or after surgery due to PTMC progression. Unlike clinical papillary thyroid carcinoma (PTC), elderly patients' PTMCs were less progressive compared to those of young and middle-aged patients, indicating that elderly patients are strong candidates for the active surveillance of their PTMC. Although young patients' PTMCs are the most progressive, >50% and >75% of patients in their 20s and 30s would avoid conversion surgical treatment in their lifetime, respectively (according to estimated lifetime probability), indicating that such young patients are still candidates for active surveillance. It can thus be concluded that active surveillance is appropriate to be first management for PTMCs, based on the accumulation of favorable outcomes of PTMC patients who have undergone active surveillance, as well as the lower incidences of unfavorable events and lower medical cost than immediate surgery.

CKS1B promotes cell proliferation and invasion by activating STAT3/PD-L1 and phosphorylation of Akt signaling in papillary thyroid carcinoma

Objective

To investigate role of GKS1B and its relationship between STAT3/PD‐L1 and p‐Akt in papillary thyroid carcinoma (PTC).

Methods

Expression of GKS1B and PD‐L1 was determined in PTC cell lines. GKS1B was overexpressed or knocked down by transfection with overexpression plasmids or si‐CKS1B. STAT3 inhibitor WP1066 was used to suppress STAT3, and PD‐L1 inhibitor Pembrolizumab was used to block PD‐L1. Cell viability and invasion were evaluated by MTT and transwell assay, respectively. The expression of STAT3, p‐STAT3, Akt, and p‐Akt was measured using Western blotting.

Results

Both protein levels and mRNA levels of CKS1B and PD‐L1 were remarkably up‐regulated in PTC cell lines. Knockdown of CKS1B significantly inhibited cell viability and invasion of PTC cells and suppressed STAT3/PD‐L1 signaling and Akt phosphorylation, while overexpression of CKS1B led to opposite results. Inhibition of STAT3 or PD‐L1 reversed the effects of overexpressed CKS1B on PTC cells.

Conclusion

The overexpression of CSK1B could promote cell viability and invasion of PTC cells through activation of STAT3/PD‐L1 signaling and Akt phosphorylation.

Predicting non-small-volume central lymph node metastases (>5 or ≥2 mm) preoperatively in cN0 papillary thyroid microcarcinoma without extrathyroidal extension

The ability to identify patients with aggressive papillary thyroid microcarcinoma (PTMC) from the low-risk patients is critical to planning proper management of PTMC. Lymph node metastases showed association with recurrence and low survival rate, especially in patients with >5 or ≥2 mm metastatic lymph nodes. Therefore, this study aimed to investigate the preoperatively predictive factors of non-small-volume (metastatic lymph nodes >5 or ≥2 mm in size) central lymph node metastases (NSVCLNM) in PTMC patients. A total of 420 patients with clinically node-negative (cN0) PTMC without extrathyroidal extension underwent thyroidectomy plus central neck dissection (CND) between January 2013 and December 2015, were retrospectively analyzed. Of the 420 patients, 33 (7.9%) had NSVCLNM. The 5-year recurrence-free survival was significantly less in cN0 PTMC patients with NSVCLNM, when compared with patients without NSVCLNM (80.8% vs 100%, P < .001). Multivariate logistic regression revealed age ≤36 years (P < .001), male sex (P = .002), ultrasonic tumor sizes of >0.65 cm (P < .001), and ultrasonic multifocality (P = .039) were independent predictive factors of NSVCLNM. A prediction equation (Y = 1.714 × age + 1.361 × sex + 1.639 × tumor size + 0.842 × multifocality -5.196) was developed, with a sensitivity (69.7%) and a specificity (84.0%), respectively, at an optimal cutoff point of -2.418. In conclusion, if the predictive value was >-2.418 according to the equation, immediate surgery including CND rather than active surveillance might be considered for cN0 PTMC patients.

Long-term outcomes of radiofrequency ablation for unifocal low-risk papillary thyroid microcarcinoma: a large cohort study of 414 patients

OBJECTIVES

The purpose of this study was to evaluate the long-term efficacy and safety of radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) in a large population.

METHODS

From June 2014 to December 2017, 414 patients (323 females, 91 males, mean age 43.56 ± 9.79 years, range 18-73 years) with unifocal low-risk PTMC confirmed by core-needle biopsy (CNB) were treated by RFA. Patients were followed up at 1, 3, 6, and 12 months and every 6-12 months thereafter by ultrasound and contrast-enhanced ultrasound (CEUS). The volume and the volume reduction ratio (VRR) were calculated. Recurrence and lymph node or distant metastasis were evaluated.

RESULTS

The mean initial volume was 92.74 ± 83.43 mm³ (range 4.19-490.07 mm³), which decreased significantly to 1.37 ± 7.94 mm³ (range 0-67.97 mm³) at a mean follow-up time of 42.15 ± 11.88 months (range 24-69 months) with a mean VRR of 98.81 ± 6.41% (range 50-100%). No life-threatening or delayed complications occurred. After RFA, 366 tumors (88.41%) completely disappeared. The overall incidence of local tumor progression rate was 3.62%. Among them, one patient (0.24%) was diagnosed to have residual cancer by CNB and underwent additional RFA. Four patients (0.97%) developed metastatic lymph node, and 10 patients (2.42%) had recurrent PTMC. A total of 13 patients underwent additional RFA, and 11 lesions completely disappeared during the follow-up.

CONCLUSIONS

RFA is an effective and safety treatment for low-risk PTMC after a long-term follow-up period for a large cohort with careful patient enrollment evaluation.

KEY POINTS

• Radiofrequency ablation is an effective and safe alternative for low-risk PTMC. • The overall incidence of local tumor progression rate was low. • No life-threatening or delayed complications occurred.

Tumor border pattern and size help predict lymph node status in papillary microcarcinoma: A clinicopathologic study

OBJECTIVE

Lymph node metastasis occurs in a subset of papillary microcarcinoma patients. We aimed to analyze the differences between metastatic and non-metastatic papillary microcarcinomas in order to identify a high-risk subgroup that is likely to require more aggressive treatment.

MATERIALS AND METHODS

126 thyroidectomies with lymph node dissections (central ± lateral), diagnosed as papillary microcarcinoma, were reviewed.

RESULTS

Mean age of 126 patients (F/M = 3.3) was 42 years. Mean size of the largest tumor was 7 mm. Classical was the most frequently (89%) encountered subtype. Multiple histologic subtypes co-occurred in 19%. Lymphovascular invasion was present in 16% (n = 20). 55 (44%) and 71 (56%) cases were unifocal and multifocal, respectively. 90 cases (71%) were non-encapsulated with overall infiltrative tumor borders, whereas in 36 cases (29%), the tumor had a well-defined capsule. Among those, 23 (64%) had tumor capsule invasion. 47 (37%) cases had metastasis in lymph nodes. In univariate analysis, metastasis was associated with tumor size of >5 mm (p = 0.02), tumor burden of >5 mm (p = 0.03), lymphovascular invasion (p = 0.02) and non-encapsulation (p = 0.01). No associations were found regarding sex, age, histologic subtype, lymphocytic thyroiditis, tumor capsule invasion (in capsulated tumors), laterality and multifocality (p > 0.05). In multivariate analysis, lymphovascular invasion (p = 0.01, OR = 3.97, 95% CI 1.35-11.67), tumor size >0.5 cm (p = 0.031, OR = 2.92, 95% CI 1.10-7.71) and non-encapsulation (p = 0.033, OR = 2.85, 95% CI 1.08-7.51) were independent risk factors.

CONCLUSION

Size (largest tumor or sum of all foci) of >5 mm, non-encapsulation and lymphovascular invasion were independent predictors of LNM in PMs. Unifocal tumors metastasize the same as multifocal tumors, suggestive of the contribution of other factors. Patients with sporadically resected microcarcinomas should be carefully followed-up, especially those that harbor risk factors in histology.

Influence of Care Pathway on Thyroid Nodule Surgery Relevance: A Historical Cohort Study

Background: Guidelines recommend using fine-needle aspiration cytology (FNAC) to guide thyroid nodule surgical indication. However, the extent to which these guidelines are followed remains unclear. This study aimed to analyze the quality of the preoperative care pathway and to evaluate whether compliance with the recommended care pathway influenced the relevance of surgical indications. Methods: Nationwide historical cohort study based on data from a sample (1/97th) of French health insurance beneficiaries. Evaluation of the care pathway of adult patients operated on between 2012 and 2015 during the year preceding thyroid nodule surgery. The pathway containing only FNAC was called “FNAC”, the pathway including an endocrinology consultation (ENDO) with FNAC was called “FNAC+ENDO”, whereas the no FNAC pathway was called “NO FNAC”. The main outcome was the malignant nature of the nodule. Results: Among the 1080 patients included in the study, “FNAC+ENDO” was found in 197 (18.2%), “FNAC” in 207 (19.2%), and “NO FNAC” in 676 (62.6%) patients. Cancer diagnosis was recorded in 72 (36.5%) “FNAC+ENDO” patients and 66 (31.9%) “FNAC” patients, against 119 (17.6%) “NO FNAC” patients. As compared to “NO FNAC”, the “FNAC+ENDO” care pathway was associated with thyroid cancer diagnosis (OR 2.67, 1.88–3.81), as was “FNAC” (OR 2.09, 1.46–2.98). Surgeries performed in university hospitals were also associated with thyroid cancer diagnosis (OR 1.61, 1.19–2.17). Increasing the year for surgery was associated with optimal care pathway (2015 vs. 2012, OR 1.52, 1.06–2.18). Conclusions: The recommended care pathway was associated with more relevant surgical indications. While clinical guidelines were insufficiently followed, compliance improved over the years.

Experience with Active Surveillance of Thyroid Low-Risk Carcinoma in a Developing Country

Background: The incidence of thyroid carcinoma is growing worldwide. More than 50% of new malignant tumors are classified as classical papillary carcinomas in low-risk category with a low rate of recurrence and high long-term survival. Active surveillance is a strategy to control low-risk tumor evolution with the intention to avoid unnecessary treatments and maintain thyroid function. The aim of this study was to report a cohort of patients with thyroid nodules classified as Bethesda V-VI and who are under active surveillance in Colombia. Methods: A prospective cohort was assembled since January 2015. All patients had been evaluated clinically, biochemically with ultrasonography and fine needle aspiration biopsy previous to the first evaluation. Active surveillance was proposed to patients with asymptomatic low-risk carcinoma (<1.5 cm, encapsulated, without evidence of lymph node metastasis), independent of sex or age. The strategy included a specific discussion about the surgical option and expected risk of complications, risk of long-term thyroxine support, and the active surveillance strategy. The data on age, sex, reason for an ultrasound examination, ultrasound risk by American Thyroid Association (ATA) classification, size and volume of the nodule, reason to consider active surveillance and follow-up ultrasounds, and surgical decision were recorded prospectively. A Kaplan-Meier curve was constructed for the rate of growth and increase in volume of the nodule, growth >3 mm and increase in volume >50%, and need of operation. Results: One hundred two patients were analyzed. Seventy-five percent of patients had a nodule smaller than 1 cm. Only 24/102 (23%) nodules were classified as ATA low risk. Thirty-four of 102 (33.3%) nodules were classified as Bethesda VI and the others were Bethesda V. The median follow-up was 13.9 months, and 32.3% of patients had more than 24 months of follow-up. Only 11/102 (10.8%) nodules grew more than 3 mm and 26/102 (25.5%) nodules grew more than 50% in volume. 12.7% patients were submitted to surgery. The overall stability rate without growth >3 mm, without volume increase >50%, and without surgery at 24 months were 89.8%, 77.0%, and 85.5%, respectively Conclusions: Active surveillance is possible in developing Western countries with similar results to those provided by Asian and American authors.

Papillary thyroid carcinomas are highly obscured by inflammatory hypoechoic regions caused by subacute thyroiditis: a longitudinal evaluation of 710 patients using ultrasonography

Subacute thyroiditis is a self-limited inflammatory disease and very few patients undergo ultrasonographic re-examination if no nodules are found at the initial examination. The objective of the study was to assess the diagnostic accuracy of ultrasonography in detecting nodular lesions in patients with subacute thyroiditis. We conducted a longitudinal study involving 710 patients with subacute thyroiditis who underwent ultrasonographic examinations in a single center between 2008 and 2018. These examinations were performed at initial diagnosis and during follow-up, with subsequent evaluation of nodules using fine needle aspiration cytology. Ultrasonographic examination used for the initial screening of thyroid nodules in patients with subacute thyroiditis showed a sensitivity of 72.4%, specificity of 89.0%, positive predictive value of 80.4%, and negative predictive value of 83.8%. Twenty-two patients (3.1%) had concomitant papillary thyroid carcinoma, 10 of whom underwent thyroidectomy while the remaining 12 opted for active surveillance owing to having low-risk microcarcinomas. Approximately 30% of papillary carcinomas (7/22) were identified during follow-up ultrasonography, but not during the initial scan. All tumors in this false-negative group were latently localized in the bilateral hypoechoic regions of the thyroid and showed no calcified components. Of the 15 tumors that were detected during both initial and follow-up examinations, 7 exhibited calcified components and 5 were located in unaffected areas apart from the inflammatory hypoechoic region. Subacute thyroiditis highly obscures any coexisting papillary carcinoma when inflammatory hypoechoic regions are present. Ultrasonographic re-examination after a sufficient interval is indispensable for patients with subacute thyroiditis.

Predictive Factors for Level V Lymph Node Metastases in Papillary Thyroid Carcinoma with BRAFV600E Mutation and Clinicopathological Features

Background

Therapeutic lateral neck dissection (LND) is recommended in papillary thyroid carcinoma (PTC) patients with clinically lateral lymph node metastasis (LLNM), whether underwent level V LND remains controversial for lacking of sensitive predicting system. BRAF^V600E mutation is associated with aggressive tumor behavior, recurrence, and disease-specific mortality of PTC. However, the relationship between BRAF^V600E mutation and level V LNM is unclear.

Methods

Univariate and multivariate analyses were retrospectively conducted on the potential predictive factors of 252 PTC patients who underwent initial treatment of neck lymph node dissection from September 2015 to October 2018 in our institute. BRAF^V600E mutation and the clinicopathological characteristics of the two groups were compared.

Results

LLNM was presented in 208 (82.5%) patients and level II-V LNM was present in 42.8%, 71.2%, 85.1%, 17.8% patients, respectively. BRAF^V600E mutation was observed in 188 (74.6%) patients and was significantly associated with patients' age, lymphocytic thyroiditis, capsule invasion, bilateral central lymph node metastasis (CLNM) and level V LNM in PTC. Univariate analysis revealed that lymphocytic thyroiditis, tumor size, number of CLNM, Level II LNM, Level III LNM, simultaneous Level II+III, simultaneous Level III+IV and simultaneous Level II+III+IV were significantly correlated with Level V LNM. In addition, multivariate analysis revealed that tumor size ≥2.5 cm, number of CLNM≥3, level II metastases and BRAF^V600E mutation were independent Level V LNM predictors (odds ratio 3.910, 3.660, 8.410, 0.439; 95% CI 1.737-10.135, 1.054-12.713, 1.233-57.355, 0.280-0.827, respectively).

Conclusion

In summary, we presented several independent predictive factors for level V LNM in PTC patients. We constructed a risk prediction model consisting of tumor size ≥2.5 cm, number of CLNM≥3 and level II metastases and BRAF^V600E mutation that may guide surgeons to evaluate the nodal status in PTC and perform tailored therapeutic LND.

Total tumor diameter: the neglected value in papillary thyroid microcarcinoma

BACKGROUND

Tumor multifocality is not uncommon in papillary thyroid carcinoma (PTC), especially in micro-PTC. However, assessing the size of the largest tumor may underestimate effect of additional foci. We aimed to investigate the effect of total tumor diameter (TTD) on clinicopathological features of micro-PTC.

METHODS

Data from 442 patients who underwent thyroidectomy with cervical lymph node dissection for PTC were retrospectively analyzed. Patients were classified into subgroups according to multifocality and TTD. The relationships of clinicopathological features among these groups were analyzed.

RESULTS

Multifocality was observed in 119 patients (26.9%). TTD > 1 cm and presence of extrathyroidal extension (ETE) were significantly higher in multifocal tumors compared to unifocal tumor (P < 0.001, P = 0.016, respectively). When comparing multifocal micro-PTC with TTD > 1 cm to those with unifocal micro-PTC or multifocal micro-PTC with TTD ≤ 1 cm, the proportions of cases with ETE, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM) were significantly higher (all P < 0.05). There was no significant difference in terms of these parameters between multifocal micro-PTC with TTD > 1 cm and macro-PTC or multifocal macro-PTC. The risk of CLNM was 2.056 (P = 0.044) times higher in multifocal micro-PTC with TTD > 1 cm than in unifocal micro-PTC.

CONCLUSION

For multifocal micro-PTC, TTD can better assess the aggressiveness of the tumor. Multifocal micro-PTC with TTD > 1 cm was more aggressive than unifocal micro-PTC or multifocal micro-PTC with TTD ≤ 1 cm.

Surgical Complications and Referral Patterns in 567 Patients with Differentiated Thyroid Cancer in the Northern Region of the Netherlands: A Population-Based Study Towards Clinical Management Implementation

BACKGROUND

In the Netherlands, differentiated thyroid cancer (DTC) is treated surgically in three different hospital types, including university, teaching, and non- teaching peripheral hospitals. This study evaluates postoperative complications and referral patterns in patients with DTC in the northern region of the Netherlands to gain an understanding on how to improve management implementation.

METHODS

Data from 567 patients diagnosed between 1989 and 2009 were obtained from the Netherlands Cancer Registry and were supplemented with information from hospital digital information systems and patient records from 15 hospitals: 1 university, 3 teaching, and 11 peripheral hospitals. Surgically treated patients with a histologically proven DTC derived from the original pathology reports were included.

RESULTS

Surgical treatment could be performed in a single procedure in 234 patients (41.3%), but several surgeries were needed in the remaining 333 patients (58.7%). Recurrent laryngeal nerve (RLN) palsy occurred after all types of thyroid surgical procedures, but mostly after initial (hemi)thyroidectomy and reoperations. RLN was temporary in 3.2% of the nerves at risk and persistent in 1.8%. Temporary hypocalcemia developed in 13.7% of patients, and persistent hypocalcemia occurred in 4.8%. Patients were mainly referred to the university hospital from a non-teaching (40.7%, 48/118) or teaching hospital (11.1%, 16/144); however, 80% of patients were not referred.

CONCLUSIONS

The complication rate and number of multiple surgeries support the efforts in optimizing clinical management in thyroid cancer. Careful considerations prior to initial surgical treatment by early discussion in telemedicine-based regional tumor boards could possibly prevent reoperations and potentially diminish complications.

Low-risk papillary thyroid microcarcinoma: Optimal management toward a more conservative approach

The incidence of papillary thyroid microcarcinoma (microPTC) has dramatically increased in the last decades. Most of these tumors remain small and clinically "silent", only small number progress. Although thyroid surgery used to be the only therapeutic approach, recent guidelines now consider active surveillance for low-risk microPTC. For this reason, more accurate risk stratification of microPTC is needed. The optimal management of low-risk microPTC through accurate risk stratification represents a major clinical issue.

Patient Experience of Thyroid Cancer Active Surveillance in Japan

Importance

The burden of concern for patients with thyroid cancer who undergo surgical intervention with or without radioactive iodine is known to be substantial. For patients under active surveillance, this aspect of the patient experience has not been described to date and could be a potential barrier to broader acceptance of surveillance as a cancer management strategy.

Objective

To describe the experiences of patients in the longest-standing and largest thyroid cancer active surveillance program.

Design, Setting, and Participants

This study used a mixed method of survey, semistructured interviews, and field observation and was conducted at Kuma Hospital in Kobe, Japan. The survey was administered from September 4, 2017, through October 18, 2017, and the field observation was conducted from August 28, 2017, to October 20, 2017. Survey participants were a consecutive sample of 249 patients under active surveillance who were attending the hospital for a surveillance visit, and the semistructured interviewees were a subset of 21 patients. The English-language survey instrument was translated by native Japanese speakers, back-translated into English, and then further refined by a panel of Japanese speakers with expertise in health research.

Main Outcomes and Measures

Survey and interview responses and field observations.

Results

In total, 249 surveys were distributed to patients with thyroid cancer on active surveillance. Two hundred forty-three patients (97.6%) completed the survey. Among the respondents, 195 (80.2%) were female and 20 (8.2%) were male (28 [11.5%] responses were missing). Among the subset of 21 patients who participated in the semistructured interview, 3 were male (14.3%), and the mean (range) age was 64 (32-85) years. Thirty-seven percent rated the frequency of cancer worry as occurring sometimes or more. Thirty-two percent said their worry affected their mood somewhat or a lot. Fourteen percent reported that their worry affected their ability to carry out daily activities somewhat or a lot. Cancer spread, later need for surgical intervention, and difficulty with interpreting bodily experiences in the general location of the cancer were among the main sources of worry. Most respondents (60.0%) said their worry was less than it was when they first found out about their cancer. By 3 years after diagnosis, the proportion of participants who reported they were not at all worried increased from 14% (95% CI, 12%-16%) to 25% (95% CI, 23%-26%). Eighty percent (95% CI, 79%-81%) of respondents agreed or strongly agreed that their decision to do active surveillance matched their personal values, and 83% (95% CI, 82%-84%) agreed or strongly agreed that choosing active surveillance was the best decision for them personally. Most patients (77%) had not heard of active surveillance before they were offered the option.

Conclusions and Relevance

Cancer concern was common among patients with thyroid cancer under active surveillance, which is comparable to the worry among actively treated patients. Levels of cancer worry reported by patients under active surveillance decreased over time, and patients expressed satisfaction with their disease management decision. These findings suggest that the possibility of cancer worry should not be viewed as prohibitive to successful active surveillance in thyroid cancer.

Parallels Between Low-Risk Prostate Cancer and Thyroid Cancer: A Review

Importance

Across many countries, a rapid escalation of the incidence of thyroid cancer has been observed, a surge that nonetheless underestimates the true extent of the disease. Most thyroid cancers now diagnosed comprise small, low-risk cancers that are incidentally found and are unlikely to cause harm. In many ways, prostate cancer similarly harbors a well-behaved subclinical reservoir, a long natural history, and superlative outcomes that have made active surveillance the de facto guideline recommendation for low-risk disease. This review highlights the parallels and differences between prostate cancer and thyroid cancer regarding screening, diagnosis, risk stratification, and considerations for active surveillance.

Observations

Prostate cancer and thyroid cancer have undergone recalibrated, de-escalatory shifts to counter changing epidemiologic landscapes. The US Preventive Services Task Force has issued cautionary recommendations on screening via prostate-specific antigen testing or neck ultrasonography, while the thresholds to performing biopsy have increased. Comparable changes to cancer terminology and staging have also helped alleviate patient anxiety and minimize pressure for overtreatment. Long-term, randomized prospective clinical trials for prostate cancer have established active surveillance as a first-line treatment approach for properly stratified low-risk patients, while observational trials for thyroid cancer have also made strides in defining risk and eligibility for surgery. Caveats requiring deeper investigation include aggressive disease in older patients, underestimation of the extent of the disease, and patient-physician bias in shared decision making. For prostate cancer, survival may not improve and function will likely worsen after intervention; for thyroid cancer, patients are younger, surgery is safer, and the bar for surveillance will likely be higher.

Conclusions and Relevance

Despite similarities in biological indolence between low-risk prostate and thyroid malignant neoplasms, key distinctions in life expectancy and treatment sequelae may ultimately confer somewhat disparate management paradigms for the 2 diseases. Nevertheless, the experience forged by prostate cancer trials serves as a model for thyroid cancer management, potentially reshaping the perception of active surveillance into a credible, valuable treatment modality.

Diagnostic Performance of Different Thyroid Imaging Reporting and Data Systems (Kwak-TIRADS, EU-TIRADS and ACR TI-RADS) for Risk Stratification of Small Thyroid Nodules (≤10 mm)

Due to the widespread use of ultrasound, small thyroid nodules (TNs) ≤ 10 mm are common findings. Standardized approaches for the risk stratification of TNs with Thyroid Imaging Reporting and Data Systems (TIRADS) were evaluated for the clinical routine. With TIRADS, the risk of malignancy in TNs is calculated by scoring the number or combination of suspicious ultrasound features, leading to recommendations for further diagnostic steps. However, there are only scarce data on the performance of TIRADS for small TNs. The aim was to compare three different TIRADS for risk stratification of small TNs in routine clinical practice. We conducted a retrospective cohort analysis of TNs ≤ 10 mm and their available histology. Nodules were classified according to three different TIRADS. In the study, 140 patients (n = 113 female) with 145 thyroid nodules (n = 76 malignant) were included. Most of the malignant nodules were papillary carcinoma (97%), and the remaining 3% were medullary carcinoma. For all tested TIRADS, the prevalence of malignancy rose with increasing category levels. The highest negative predictive value was found for ACR TI-RADS and the highest positive predictive value for Kwak-TIRADS. All tested variants of TIRADS showed comparable diagnostic performance for the risk stratification of small TNs. TIRADS seems to be a promising tool to reliably assess the risk of malignancy of small TNs.

Active surveillance of low-risk papillary thyroid microcarcinomas in Japan and other countries: a review

Introduction: Active surveillance of low-risk papillary thyroid microcarcinomas (PTMCs) was initiated in Japan in 1993 and has since been adopted in many countries, especially after its approval by the American Thyroid Association in 2015.Areas covered: We performed a literature review in Medline/PubMed to identify studies that used active surveillance for PTMCs. Moreover, we performed a literature review about the increased incidence of thyroid microcarcinomas in relation to the relative stability of deaths due to thyroid carcinomas.Expert opinion: No patients showed life-threatening metastasis/recurrence or died of thyroid carcinoma during active surveillance or after conversion surgery following PTMC progression. Thus, active surveillance should be the first-line management of PTMCs without high-risk features. In the future, molecular testing of actively growing PTMCs using cytology specimens could be useful to guide the treatment plan.

Kinetic Analysis of Growth Activity in Enlarging Papillary Thyroid Microcarcinomas

Background: Although papillary thyroid microcarcinoma (PMC) is generally stable on active surveillance, conversion surgery is recommended for enlarging tumors. However, it remains unclear which enlargement threshold should be considered sufficient to trigger surgery. This study analyzed changes in the growth activity of PMC, before and after enlargement. Methods: We enrolled 824 patients with PMC, in whom active surveillance was initiated between 2005 and 2011 (median duration of follow-up: 6.04 years). Changes in the maximal tumor size and tumor volume were evaluated. Point of enlargement (PE) was defined as the time at which maximal tumor size or tumor volume had increased by ≥3 mm (PE-M) or by ≥50% (PE-V), respectively. In patients with PMC who underwent at least three ultrasound examinations during the study period, we compared the tumor doubling rates (TDRs, designated as the inverse of doubling time) between pre- and post-PEs. Results: Ten-year enlargement-free survival rates based on maximal tumor size and tumor volume were 86.9% and 54.9%, respectively. The median post-PE TDRs was significantly lower than that of pre-PEs (-0.091/year vs. 0.509/year [p < 0.001] for PE-M, and -0.058/year vs. 0.370/year [p < 0.001] for PE-V), indicating decreased tumor growth after PEs. After PE-M and PE-V, the PMCs continued to rapidly enlarge (TDR >0.5/year) in only 6 (7.7%) and 11 (3.8%) patients and moderately enlarge (TDR 0.1-0.5/year) in 10 (12.8%) and 35 (12.1%) patients, respectively. Conversely, tumors shrank (TDR < -0.1/year) in 37 (47.4%) and 105 (36.1%) patients, respectively, and remained stable (TDR ranged between 0.1/year and -0.1/year) in 25 (32.1%) and 140 (48.1%) patients, respectively. Conclusion: Since most PMCs demonstrate a significant decrease in growth activity after enlargement, performing surgery immediately after the PE may be premature.

Risk of Mortality between Untreated and Treated Papillary Thyroid Cancer: A Matched Cohort Analysis

OBJECTIVES

To examine the association between treatment status and mortality risk among patients with papillary thyroid cancer (PTC).

METHODS

We identified 3,679 adults with PTC. Thirty-one untreated patients were matched to 155 treated patients. Hazards ratios (HR) and 95% confidence intervals (CIs) were calculated to estimate all-cause and disease-specific mortality. A low-risk subgroup was analyzed for differences in all-cause mortality.

RESULTS

The adjusted HRs (95% CIs) for all-cause mortality at 5 and 10 years were 4.2 (1.7-10.3) and 4.1 (1.9-9.4) and for disease- specific mortality were 14.1 (3.4-59.3) and 10.2 (2.9-36.4), respectively, for untreated versus treated patients. The adjusted HRs (95% CIs) for all- cause mortality was 0.7 (0.1-6.4) for low-risk untreated versus matched treated patients.

CONCLUSIONS

Compared to treated patients, untreated PTC patients were at higher risk of death while low-risk untreated PTC patients had comparable rate of metastasis and no increased risk of all-cause mortality. Level of evidence: 3.

Understanding the natural history of papillary thyroid cancer: Case series

BACKGROUND

Papillary thyroid cancer (PTC) incidence continues to rise. We describe the natural history of untreated PTC patients.

METHODS

Retrospective case series of 31 untreated PTC patients.

RESULTS

We identified 31 untreated patients from the Kaiser Permanente Cancer Registry with PTC from 1973 to 2010. Patients were categorized as low risk (n = 16), high risk (n = 12), or low risk but medically contraindicated for surgery (n = 3). At diagnosis, 7 (58.3%) in the high-risk group had cervical lymph node metastases and 5 (41.7%) had distant metastases, compared to none in the low-risk group. Among the latter, three (18.8%) patients developed tumor growth >3 mm and one (6.3%) developed regional lymph node metastases without distant metastases. The 10-year overall survival was 71% and 35% for the low-risk and high-risk groups, respectively.

CONCLUSIONS

Patients with low-risk untreated PTC were less likely to develop new regional or distant metastases and had better overall survival than patients with high-risk untreated PTC.

LEVEL OF EVIDENCE

4.

Performance of a Genomic Sequencing Classifier for the Preoperative Diagnosis of Cytologically Indeterminate Thyroid Nodules

Importance

Use of next-generation sequencing of RNA and machine learning algorithms can classify the risk of malignancy in cytologically indeterminate thyroid nodules to limit unnecessary diagnostic surgery.

Objective

To measure the performance of a genomic sequencing classifier for cytologically indeterminate thyroid nodules.

Design, Setting, and Participants

A blinded validation study was conducted on a set of cytologically indeterminate thyroid nodules collected by fine-needle aspiration biopsy between June 2009 and December 2010 from 49 academic and community centers in the United States. All patients underwent surgery without genomic information and were assigned a histopathology diagnosis by an expert panel blinded to all genomic information. There were 210 potentially eligible thyroid biopsy samples with Bethesda III or IV indeterminate cytopathology that constituted a cohort previously used to validate the gene expression classifier. Of these, 191 samples (91.0%) had adequate residual RNA for validation of the genomic sequencing classifier. Algorithm development and independent validation occurred between August 2016 and May 2017.

Exposures

Thyroid nodule surgical histopathology diagnosis by an expert panel blinded to all genomic data.

Main Outcomes and Measures

The primary end point was measurement of genomic sequencing classifier sensitivity, specificity, and negative and positive predictive values in biopsies from Bethesda III and IV nodules. The secondary end point was measurement of classifier performance in biopsies from Bethesda II, V, and VI nodules.

Results

Of the 183 included patients, 142 (77.6%) were women, and the mean (range) age was 51.7 (22.0-85.0) years. The genomic sequencing classifier had a sensitivity of 91% (95% CI, 79-98) and a specificity of 68% (95% CI, 60-76). At 24% cancer prevalence, the negative predictive value was 96% (95% CI, 90-99) and the positive predictive value was 47% (95% CI, 36-58).

Conclusions and Relevance

The genomic sequencing classifier demonstrates high sensitivity and accuracy for identifying benign nodules. Its 36% increase in specificity compared with the gene expression classifier potentially increases the number of patients with benign nodules who can safely avoid unnecessary diagnostic surgery.

Risk of Thyroid Cancer in 1,504 Patients Referred for Thyroid Surgery with Assumed Benign Histology

OBJECTIVES

The aims of this study were to report the risk of thyroid malignancy in cases of either benign fine-needle aspiration (FNA) or without FNA performed, and to investigate possible predictive factors for thyroid malignancy in a population with recent moderately low iodine intake.

METHODS

All patients referred for thyroid surgery in a tertiary cancer centre between 2000 and 2016 were included (n = 3,703). After excluding cases indicating malignant histology, we included group 1: patients with benign FNA (n = 764), and group 2: patients without FNA (n = 740), leaving 1,504 eligible for further investigation. Information on age, gender, tracheal compression or dislocation, thyroid specimen weight, scintigraphy, ultrasound, medically treated thyrotoxicosis, serum stimulating thyroid hormone, indication for surgery, TNM classification, stage, and outcome were retrieved.

RESULTS

The malignancy risk was 7.6% (58/764) in group 1 and 6.8% (50/740) in group 2. Patients with T2-4 tumours constituted 2.2% (33/1,504). In the combined groups, ultrasound verified that solitary solid tumour was predictive for malignancy (p = 0.01 by χ², and OR = 1.69, p = 0.02 in multiple logistic regression). For group 1 patients, thyrotoxicosis (which in this case was medically treated) was a significant predictive factor for malignancy (p = 0.04).

CONCLUSIONS

The risk of malignancy of 7.6% and 6.8% was high, considering that patients with malignant FNA, suspicious FNA, or clinical findings indicating malignancy were excluded, and 2.2% of these malignancies were stages T2-4. In cases with solitary solid tumour on ultrasound, the risk of malignancy should not be ignored, even with benign FNA.

Association of Preferences for Papillary Thyroid Cancer Treatment With Disease Terminology: A Discrete Choice Experiment

Importance

Given recent evidence of overdiagnosis and overtreatment of small papillary thyroid cancers (PTCs) and other low-risk cancers, strategies are needed to help patients consider less invasive treatment options.

Objectives

To determine which factors influence treatment preferences for patients with PTC, and the trade-offs in treatment factors people are willing to accept, and to understand how terminology influences preferences and benefit-harm trade-offs.

Design, Setting, and Participants

Preferences in PTC treatment were evaluated using a discrete choice experiment (DCE) conducted as a web-based survey using an existing public online research panel. Participants were randomized to receive 1 of 2 frames of information based on the terminology used to describe the condition: "cancer" or "lesion." Participants chose between 3 treatment options for PTC (thyroidectomy, hemithyroidectomy, and active surveillance). Analyses were conducted using a mixed logit model.

Main Outcomes and Measures

The main outcome variable was treatment preference; attributes of treatment options and sociodemographic characteristics were explanatory variables.

Results

The DCE was completed by 2054 participants (993 [48.3%] men and 1061 [51.7%] women; mean [SD] age, 46.0 [16.5] years) with no history of thyroid cancer. Participants preferred options with less frequent follow-up, lower out-of-pocket costs, lower chances of having voice and calcium level problems, and a lower risk of developing invasive thyroid cancer and of dying of thyroid cancer. When trading benefits against harms, participants were willing to accept a higher number of extra patients experiencing adverse effects to avoid a thyroid cancer death when the condition was described as a cancer compared with a lesion. Specifically, participants for whom the condition was described as a cancer were willing to accept more patients requiring lifelong medication (mean, 273; 95% CI, 207-339 vs mean, 98; 95% CI, 66-131), experiencing calcium problems (mean, 110; 95% CI, 77-144 vs mean, 56; 95% CI, 55-58), and fatigue (mean, 958; 95% CI, 691-1224 vs mean, 469; 95% CI, 375-564). For both the cancer and lesion terminology, health literacy consistently was associated with preferences for treatment options. Those with lower health literacy had a significantly lower preference for less invasive treatment options.

Conclusions and Relevance

This study makes an important contribution to understanding how attributes of treatment options, terminology, and patient characteristics, in particular health literacy, influence treatment decision making for PTC. As a result of increasing evidence of the indolent nature of PTC and other low-risk cancers, strategies to deal with potential overtreatment are critically needed.

Trial Registration

Australian New Zealand Clinical Trials Registry: ACTRN12617000066381.

Active surveillance of low-risk papillary thyroid carcinoma: a promising strategy requiring additional evidence

PURPOSE

Papillary thyroid carcinoma (PTC), the most common malignant tumor of the thyroid, has been criticized as overtreated by some researchers in recent years. Active surveillance (AS) was first proposed at Kuma Hospital in 1993, and popularized in other institutes ever since. We provide a brief review of low-risk PTC active monitoring studies to date, and discuss the advantages of AS and limitations of existing studies.

RESULTS

Most papillary thyroid microcarcinomas do not show significant growth or new lymph node metastasis in a 10-year AS period. Patients who undergo delayed surgery during AS generally have a good prognosis. Tumor progression correlates with age, calcification pattern, and Ki-67 positivity. Serum thyroid stimulating hormone concentration and pregnancy might also influence tumor progression in some studies.

CONCLUSION

Active surveillance for low-risk PTC has shown its safety and feasibility in certain populations. In the future, it is warranted to determine valuable tumor progression predictors and most suitable PTC patients for AS.