Management of low-risk papillary thyroid carcinoma: Unique conventional policy in Japan and our efforts to improve the level of evidence

Outcomes of Patients with an Intermediate-Risk Group According to the Japanese Risk Classification of Papillary Thyroid Carcinoma

BACKGROUND

The management of intermediate-risk group of papillary thyroid cancer (PTC) is still vague, particularly regarding whether or not total thyroidectomy, postoperative radioactive iodine ablation (RAI-a), and postoperative TSH suppression are mandatory.

METHODS

This retrospective study evaluated 680 PTC patients from 2010 to 2017, who were classified into the three risk groups as low, intermediate, and high-risk groups according to the criteria of the Japanese Association of Endocrine Surgeons (JAES) 2010 and underwent surgery according to the JAES guidelines. We retrospectively collected patient data for analyses of disease-free survivals in the intermediate-risk group patients.

RESULTS

We performed surgery on 680 PTC patients from 2010 to 2017. Of them, 297 were classified as the intermediate-risk group. DFS was not statistically significantly different in patients with/without total thyroidectomy and postoperative TSH suppression therapy. For RAI-a, DFS (95% confidence interval) at 3, 5, and 8 years were 93.2% (84.6 ~ 97.2), 81.6% (68,3 ~ 90.2), and 70.7% (51.4 ~ 84.6) in patients with postoperative RAI-a and 100%, 100%, and 100% in patients without postoperative RAI-a after total thyroidectomy, respectively. DFS of patients without RAI-a was superior to those with RAI-a (P < 0.0004). Multivariable analysis by stepwise selection method revealed that postoperative RAI-a was a risk factor with a hazard ratio of 5.69. (95% CI 1.998-16.21) (P = 0.001131).

CONCLUSIONS

Our study did not show the efficacy of RAI-a in patients with intermediate-risk PTC. This study implies that judging the efficacy of adjuvant therapy such as RAI or TSh suppression in intermediate-risk patients is difficult.

Long-Term Outcomes After Lobectomy for Patients with High-Risk Papillary Thyroid Carcinoma

BACKGROUND

Guidelines universally recommend total thyroidectomy for high-risk papillary thyroid carcinoma (PTC). However, in Japan, thyroid-conserving surgery had been widely applied for such patients until recently. We investigated long-term outcomes for this strategy.

METHODS

A prospectively recorded database was retrospectively analyzed for 368 patients who had undergone curative surgery for high-risk PTC without distant metastasis between 1993 and 2013. High-risk PTC was defined for tumors showing tumor size > 4 cm, extrathyroidal extension, or large nodal metastasis ≥ 3 cm.

RESULTS

Median age was 59 years and 243 patients were female. Mean duration of follow-up was 12.7 years. Lobectomy was conducted for 207 patients (LT group) and total or near-total thyroidectomy for 161 patients (TT group). The frequency of massive extrathyroidal invasion and large nodal metastasis was lower in the LT group than in the TT group. After propensity score matching, no significant differences were seen between groups for overall survival, cause-specific survival or distant recurrence-free survival. In the overall cohort, multivariate analysis identified age ≥ 55 years, large nodal metastasis, tumor size > 4 cm and massive extrathyroidal invasion as significantly associated with cause-specific survival, whereas extent of thyroidectomy was not.

CONCLUSIONS

For patients with high-risk PTC without distant metastasis, curative surgery with lobectomy showed almost identical oncological outcomes compared to total thyroidectomy. The benefits of total thyroidectomy for high-risk PTC should be reevaluated in the future prospective studies.

Factors That Inform Individual Decision Making Between Active Surveillance, Hemithyroidectomy and Total Thyroidectomy for Low-Risk Thyroid Cancer: A Scoping Review

Background: Due to the excellent prognosis and relatively high incidence of small low-risk thyroid cancers, more conservative management strategies such as active surveillance (AS) or hemithyroidectomy (HT) may be preferable to total thyroidectomy (TT) for patients seeking to balance long-term survival rates with the potential adverse effects of overtreatment. The aim of this review was to synthesize key factors or variables that inform patient decision making about treatment for low-risk thyroid cancer, from current primary investigations that presented participants with information facilitating this choice. Methods: Studies were identified from the Medline, Cochrane, and Embase databases up until March 2022. Study characteristics were extracted into a pre-piloted form. Factors were hypothesized to include treatment-related risks and possible outcomes and identified from a review of studies with consensus by discussion. Results: The search identified 444 unique studies: 397 were excluded on review of abstract and title with 47 studies undergoing a full text review and 6 studies identified to be eligible. Four were cross-sectional: one a prospective cohort study and one a mixed-methods study with both a prospective observational and qualitative component. The decisions addressed included: the choice between AS versus surgery (HT and/or TT) and HT versus TT and enrolled participants ranging from healthy volunteers to thyroid cancer patients. Treatment choice was the primary outcome in five studies. Across the studies, participants who were given the option of AS or surgery predominately chose the more conservative pathway, with a range of 70-84%. The major factors represented by information provision in the studies were risk of cancer recurrence or spread, need for hormone replacement therapy, and voice change. Conclusions: A framework of key factors informing patient treatment choice may be derived from current studies involving information provision for low-risk thyroid cancer management. Further research evaluating the efficacy and optimal timing for decision support interventions would help inform the design and clinical use of these tools to promote shared decision making.

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.

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.

Factors associated with physicians' recommendations for managing low-risk papillary thyroid cancer

BACKGROUND

The 2015 American Thyroid Association endorsed less aggressive management for low-risk papillary thyroid cancer (LR-PTC). We aimed to identify factors influencing physicians' recommendations for LR-PTC.

METHODS

We surveyed members of three professional societies and assessed respondents' recommendations for managing LR-PTC using patient scenarios. Multivariable logistic regression models identified clinical and non-clinical factors associated with recommending total thyroidectomy (TT) and active surveillance (AS).

RESULTS

The 345 respondents included 246 surgeons and 99 endocrinologists. Physicians' preference for their own management if diagnosed with LR-PTC had the strongest association with their recommendation for TT and AS (TT: OR 12.3; AS: OR 7.5, p < 0.001). Physician specialty and stated patient preference were also significantly associated with their recommendations for both management options. Respondents who received information about AS had increased odds of recommending AS.

CONCLUSIONS

Physicians' recommendations for LR-PTC are strongly influenced by non-clinical factors, such as personal treatment preference and specialty.

Long-Term Results of Treating With Ethanol Ablation 15 Adult Patients With cT1aN0 Papillary Thyroid Microcarcinoma

Background

Currently acceptable management options for patients with adult papillary thyroid microcarcinoma (APTM) range from immediate surgery, either unilateral lobectomy or bilateral lobar resection, to active surveillance (AS). An alternative minimally invasive approach, originally employed for eliminating neck nodal metastases, may be ultrasound-guided percutaneous ethanol ablation (EA). Here we present our experience of definitively treating with EA 15 patients with APTM.

Patients and Methods

During 2010 through 2017, the 15 cT1aN0M0 patients selected for EA were aged 36 to 86 years (median, 45 years). Tumor volumes (n = 17), assessed by sonography, ranged from 25 to 375 mm³ (median, 109 mm³). Fourteen of 15 patients had 2 ethanol injections on successive days; total volume injected ranged from 0.45 to 1.80 cc (median, 1.1 cc). All ablated patients were followed with sonography and underwent recalculation of tumor volume and reassessment of tumor perfusion at each follow-up visit.

Results

The ablated patients have now been followed for 10 to 100 months (median, 64 months). There were no complications and no ablated patient developed postprocedure recurrent laryngeal nerve dysfunction. All 17 ablated tumors shrank (median 93%) and Doppler flow eliminated. Median tumor volume reduction in 9 identifiable avascular foci was 82% (range, 26%-93%). After EA, 8 tumors (47%) disappeared on sonography after a median of 10 months. During follow-up no new PTM foci and no nodal metastases have been identified.

Conclusions

Definitive treatment of APTM by EA is effective, safe, and inexpensive. Our results suggest that, for APTM patients who do not wish neck surgery and are uncomfortable with AS, EA represents a well-tolerated and minimally invasive outpatient management option.

BRAF Status in Papillary Microcarcinomas of the Thyroid Gland: a Brief Review

Papillary thyroid microcarcinoma (PTMC) is defined by the World Health Organization as papillary cancer measuring 10 mm or less in diameter. Generally, PTMC shows an indolent clinical behavior with a good prognosis, although a minority of PTMC is characterized by an aggressive course. However, efforts to identify this aggressive subset of PTMC after surgery remain inconclusive. Several oncogenic pathways have been identified in thyroid cancer and have been applied translationally to improve prognosis and clinical management. In particular, the BRAFV600E mutation was found more frequently in large, aggressive, recurrent and advanced tumors. We aimed at reviewing studies on BRAFV600E mutation as a prognostic factor in PTMC.

TERT Promoter Mutation and Extent of Thyroidectomy in Patients with 1-4 cm Intrathyroidal Papillary Carcinoma

There are concerns regarding overtreatment in papillary thyroid carcinoma (PTC). BRAF V600E and TERT promoter mutations play important roles in the development of PTC. However, initial surgical approaches for PTC based on genetic characteristics remain unclear. The present study aimed to identify genetic mutations as predictors of prognosis and to establish proper indications for lobectomy (LT) in patients with 1–4 cm intrathyroidal PTC. Prospectively accumulated data from 685 consecutive patients with PTC who underwent primary thyroid surgery at the Cancer Institute Hospital, Tokyo, Japan, between 2001 and 2012 were retrospectively reviewed. Of the 685 patients examined, 538 (78.5%) had BRAF V600E mutation and 133 (19.4%) had TERT promoter mutations. Patients with TERT promoter mutations displayed significantly worse outcomes than those without mutations (10-year cause-specific survival (CSS): 73.7% vs. 98.1%, p < 0.001; 10-year disease-free survival (DFS): 53.7% vs. 93.3%, p < 0.001). As for extent of thyroidectomy among TERT mutation-negative patients with 1–4 cm intrathyroidal PTC, patients who underwent LT showed no significant differences in 10-year CSS and 10-year DFS compared to patients who had total thyroidectomy (TT) under propensity score-matching. Avoiding TT for those patients indicates a possible pathway to prevent overtreatment and reduce postoperative complications.

The Impact of the Extent of Surgery on the Long-Term Outcomes of Patients with Low-Risk Differentiated Non-Medullary Thyroid Cancer: A Systematic Meta-Analysis

Recently, the management of patients with low-risk differentiated non-medullary thyroid cancer (DTC), including papillary and follicular thyroid carcinoma subtypes, has been critically appraised, questioning whether these patients might be overtreated without a clear clinical benefit. The American Thyroid Association (ATA) guideline suggests that thyroid lobectomy (TL) could be a safe alternative for total thyroidectomy (TT) in patients with DTC up to 4 cm limited to the thyroid, without metastases. We conducted a meta-analysis to assess the clinical outcomes in patients with low-risk DTC based on the extent of surgery. The risk ratio (RR) of recurrence rate, overall survival (OS), disease-free survival (DFS) and disease specific survival (DSS) were estimated. In total 16 studies with 175,430 patients met the inclusion criteria. Overall, low recurrence rates were observed for both TL and TT groups (7 vs. 7%, RR 1.10, 95% CI 0.61-1.96, I² = 72%), and no statistically significant differences for OS (TL 94.1 vs. TT 94.4%, RR 0.99, CI 0.99-1.00, I² = 53%), DFS (TL 87 vs. TT 91%, RR 0.96, CI 0.89-1.03, I² = 85%), and DSS (TL 97.2 vs. TT 95.4%, RR 1.01, CI 1.00-1.01, I² = 74%). The high degree of heterogeneity of the studies is a notable limitation. Conservative management and appropriate follow-up instead of bilateral surgery would be justifiable in selected patients. These findings highlight the importance of shared-decision making in the management of patients with small, low-risk DTC.

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.

Wolf in Sheep's Clothing: Papillary Thyroid Microcarcinoma in the US

BACKGROUND

The presumptive overdiagnosis of papillary thyroid microcarcinoma (PTMC) has led to an emerging trend of less-extensive operation and an inclination toward active surveillance when possible. In this study, we aimed to examine the risk of advanced PTMC at presentation.

STUDY DESIGN

We conducted a retrospective analysis using the National Cancer Database (2010 to 2014). Patients with PTMC who underwent surgical intervention were included and patients with a history of any cancer were excluded.

RESULTS

A total of 30,180 adult patients with PTMC were identified; 5,628 patients (18.7%) presented with advanced features, including central lymph node (LN) metastasis (8.0%), lateral LN metastasis (4.4%), microscopic extrathyroidal extension (ETE; 6.7%), gross ETE (0.3%), lymphovascular invasion (LVI; 4.4%), and distant metastasis (0.4%). All of those features were associated with a significantly lower survival rate (p < 0.05 each) except for microscopic ETE and LVI. There was a significant interrelation among those features, distant metastasis was associated with central LN metastasis (odds ratio [OR] 2.44; 95% CI, 1.48 to 4.23; p < 0.001), lateral LN metastasis (OR 3.18; 95% CI, 1.77 to 5.71; p < 0.001), and gross ETE (OR 9.91; 95% Cl, 3.83 to 25.64; p < 0.001). In turn, nodal metastasis was associated with microscopic ETE (OR 4.23; 95% CI, 3.82 to 4.70; p < 0.001) and LVI (OR 7.17; 95% CI, 6.36 to 8.08; p < 0.001).

CONCLUSIONS

PTMC could exhibit advanced features in 19% of patients who underwent operation and some of those, such as LVI and microscopic ETE, are undetectable with preoperative workup. Clinicians need to be cognizant of this considerable risk in the era of less-aggressive management of PTMC.

Active surveillance for prostate and thyroid cancers: evolution in clinical paradigms and lessons learned

The adverse effects of overdiagnosis and overtreatment observed in men with clinically insignificant prostate cancers after the introduction of prostate-specific antigen-based screening are now being observed in those with thyroid cancer, owing to the introduction of new imaging technologies. Thus, the evolving paradigm of active surveillance in prostate and thyroid cancers might be valuable in informing the development of future active surveillance protocols. The lessons learned from active surveillance and their implications include the need to minimize the use of broad, population-based screening programmes that do not incorporate patient education and the need for individualized or shared decision-making, which can decrease the extent of overtreatment. Furthermore, from the experience in patients with prostate cancer, we have learned that consensus is required regarding the optimal selection of patients for active surveillance, using more-specific evidence-based methods for stratifying patients by risk. In this Review, we describe the epidemiology, pathology and screening guidelines for the management of patients with prostate and thyroid cancers; the evidence of overdiagnosis and overtreatment; and provide overviews of existing international active surveillance protocols.

Clinical impact of a cytological screening system using cyclin D1 immunostaining and genomic analysis for the diagnosis of thyroid nodules

Background

Fine-needle aspiration (FNA) is the most reliable method for diagnosing thyroid nodules; however, some features such as atypia of undetermined significance or follicular lesion of undetermined significance can confound efforts to identify malignancies. Similar to BRAF, cyclin D1 may be a strong marker of cell proliferation.

Methods

One hundred two patients with thyroidal nodule were enrolled in this prospective study.

Expression of cyclin D1 in thyroid nodules was determined by immunohistochemistry using both surgical specimens and their cytological specimens. The identification of the optimal cut off points for the diagnosis of malignancy were evaluated using the receiver operating characteristic (ROC) curves and the assessment of the area under the ROC curve (AUC). The specificity, sensitivity, positive predictive value (PPV) of markers were evaluated from crosstabs based on cut off points and significance were calculated. We also analyzed genetic variants by target NGS for thyroid nodule samples.

Results

The positive predictive value (PPV) and median stain ratio (MSR) of cyclin D1 nuclear staining was determined in papillary thyroid carcinoma (PPV = 91.5%, MSR = 48.5%), follicular adenoma (PPV = 66.7%, MSR = 13.1%), and adenomatous goiter and inflammation controls (MSR = 3.4%). In FNA samples, a threshold of 46% of immunolabelled cells allows to discriminate malignant lesions from benign ones (P < 0.0001), with 81% sensitivity and 100% specificity. A 46% cutoff value for positive cyclin D1 immunostaining in thyroid cells demonstrated 81% sensitivity and 100% specificity. In surgical specimens, ROC curve analysis showed a 5.8% cyclin D1 immunostaining score predicted thyroid neoplasms at 94.4% sensitivity and 92.3% specificity (P = 0.003), while a 15.7% score predicted malignancy at 86.4% sensitivity and 80.5% specificity (P < 0.0001). Finally, three tested clinico-pathological variables (extra thyroidal extension, intraglandular metastasis, and lymph node metastasis) were significant predictors of cyclin D1 immunostaining (P < 0.001).

Conclusion

Our cytological cyclin D1 screening system provides a simple, accurate, and convenient diagnostic method in precision medicine enabling ready determination of personalized treatment strategies for patients by next generation sequencing using cytological sample.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5452-4) contains supplementary material, which is available to authorized users.

Thyroid cancer burden and economic impact on the Brazilian public health system

OBJECTIVE

Recent data indicates an increasing incidence of thyroid cancer not accompanied by a proportional increase in mortality, suggesting overdiagnosis, which may represent a big public health problem, particularly where resources are scarce. This article aims to describe and evaluate the procedures related to investigation of thyroid nodules and treatment and follow-up of thyroid cancer and the costs for the Brazilian public health system between 2008 and 2015.

MATERIALS AND METHODS

Data on procedures related to investigation of thyroid nodules and treatment/follow-up of thyroid cancer between 2008 and 2015 in Brazil were collected from the Department of Informatics of the Brazilian Unified Health System (Datasus) website.

RESULTS

A statistically significant increase in the use of procedures related to thyroid nodules investigation and thyroid cancer treatment and follow-up was observed in Brazil, though a reduction was noted for procedures related to the treatment of more aggressive thyroid cancer, such as total thyroidectomy with neck dissection and higher radioiodine activities such as 200 and 250 milicuries (mCi). The procedures related to thyroid nodules investigation costs increased by 91% for thyroid ultrasound (p = 0.0003) and 128% in thyroid nodule biopsy (p < 0.001). Costs related to treatment and follow-up related-procedures increased by 120%.

CONCLUSION

The increase in the incidence of thyroid cancer in Brazil is directly associated with an increased use of diagnostic tools for thyroid nodules, which leads to an upsurge in thyroid cancer treatment and followup-related procedures. These data suggest that substantial resources are being used for diagnosis, treatment and follow-up of a potentially indolent condition.

Impact of Patient Age and Histological Type on Radioactive Iodine Avidity of Recurrent Lesions of Differentiated Thyroid Carcinoma

BACKGROUND

Age is a prognostic factor for recurrent differentiated thyroid carcinoma (DTC) and may be related to radioactive iodine (RAI) nonavidity. Indications for molecular-targeted drugs (MTDs) are currently limited to RAI-refractory DTC. Demonstrating refractoriness to RAI, mainly indicated by RAI nonavidity, may be a barrier to the introduction of MTDs for elderly patients. The present study was conducted to evaluate the impact of age and histological type on the RAI avidity of recurrent lesions of DTC.

METHODS

Two hundred fifty-eight patients (189 patients with classic papillary thyroid carcinoma [cPTC], 8 patients with follicular variant of papillary thyroid carcinoma, and 61 patients with follicular thyroid carcinoma), who underwent their first RAI whole-body scanning for recurrent DTC at our institution between 2004 and 2013, were retrospectively studied. Radioactive iodine uptake was determined by visible uptake by metastatic lesion(s) in a diagnostic RAI-whole-body scan.

RESULTS

The prevalence of RAI-avid lung metastases in cPTC indicated a significant, inverse correlation with age (<55 years, 36.2%; ≥55 years, 3%; P < 0.001). By contrast, for follicular thyroid carcinoma, the prevalence of RAI avidity was not influenced by age. Similar tendencies were observed for lymph node metastases.

CONCLUSIONS

Radioactive iodine avidity by metastatic lesions of cPTC in elderly patients, especially those older than 55 years, was seldom demonstrated. Adherence to a strategy of restricting MTD administration after confirmation of RAI refractoriness should be revisited for elderly patients. A strategy of omitting RAI treatment should be taken into account when considering age and histological type.

Research ethics dilemmas in thyroid disease

PURPOSE OF REVIEW

Since research ethics dilemmas frequently fall outside the purview of the Institutional Review Board (IRB), we present three unique recent research ethics cases in thyroidology that demonstrate research ethics dilemmas.

RECENT FINDINGS

The cases presented raise questions surrounding epistemic/scientific integrity, publication ethics, and professional, and personal integrity.

SUMMARY

Research ethics dilemmas that fall outside the purview of the IRB are appropriate for a Research Ethics Consultation, a common service in many large academic medical centers.

Study Protocol of Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro)

BACKGROUND

The ongoing Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) aims to observe the natural course of papillary thyroid microcarcinoma (PTMC), develop a protocol for active surveillance (AS), and compare the long-term prognosis, quality of life, and medical costs between the AS and immediate surgery groups.

METHODS

This multicenter prospective cohort study of PTMC started in June 2016. The inclusion criteria were suspicious of malignancy or malignancy based on fine needle aspiration or core needle biopsy, age of ≥18 years, and a maximum diameter of ≤1 cm. If there was no major organ involvement, no lymph node/distant metastasis, and no variants with poor prognosis, the patients were explained of the pros and cons of immediate surgery and AS before selecting AS or immediate surgery. Follow-up visits (physical examination, ultrasonography, thyroid function, and questionnaires) are scheduled every 6 months during the first 2 years, and then every 1 year thereafter. Progression was defined as a maximum diameter increase of ≥3, ≥2 mm in two dimensions, suspected organ involvement, or lymph node/distant metastasis.

RESULTS

Among 439 enrolled patients, 290 patients (66.1%) chose AS and 149 patients (33.9%) chose immediate surgery. The median follow-up was 6.7 months (range, 0.2 to 11.9). The immediate surgery group had a larger maximum tumor diameter, compared to the AS group (7.1±1.9 mm vs. 6.6±2.0 mm, respectively; P=0.014).

CONCLUSION

The results will be useful for developing an appropriate PTMC treatment policy based on its natural course and risk factors for progression.

Determining patient selection tool and response predictor for outpatient 30 mCi radioiodine ablation dose in non-metastatic differentiated thyroid carcinoma: a Japanese perspective

The lack of isolation ward throughout Japan has long been limiting the ¹³¹I radioactive iodine (RAI) ablation for differentiated thyroid cancer (DTC) cases. The 30 mCi RAI ablation was only recently permitted for outpatient basis. However, no patient selection tool nor response predictor has been proposed. This study evaluated factors to find response predictor and determinant for the suitable patients. The retrospective study reviewed 47 eligible non-metastatic papillary DTC patients whose had first 30 mCi RAI ablation after total thyroidectomy. Age, gender, clinical stage, risk category, and pre-ablation serum thyroglobulin (Tg) level were among covariates analyzed to determine the patient selection factors; while the thyroid bed uptake on initial whole body scan (WBS) was later also included in determining RAI ablation response. Thirteen (28%) patients had a low risk (T1-2) while 23 (49%) and 11 (23%) had an intermediate (T3) or high risk (T4), respectively. Twenty-five patients were responders, and 22 were non-responders. All factors were similar between responders and non-responders except pre-ablation serum Tg level (p < 0.001). In multivariate analysis, pre-ablation serum Tg level was the only significant factor for both patient selection (odd ratio (OR) = 1.52, 95% confidence interval (CI) = 1.13-2.06) and response predictor (OR = 1.48; 95% CI = 1.12-1.95). With the cut-off of 5.4 ng/mL, pre-ablation serum Tg level predicts RAI ablation response with 92% specificity and 73% sensitivity. Pre-ablation serum Tg level may help patient selection and predict the response to outpatient 30 mCi RAI ablation among post total thyroidectomy non-metastatic DTC patients.

Thyroid cancer surgery guidelines in an era of de-escalation

Well-differentiated thyroid carcinoma has seen a tremendous rise in global incidence over the past three decades, largely owing to widespread screening and identification of small, incidentally detected tumors. With this increased incidence has emerged a movement questioning whether all cases of thyroid cancer merit a treatment approach focused on oncologic completeness. Such trends towards thoughtful, evidence-based treatment de-escalation paradigms reflect better risk stratification of thyroid cancers, and recognition that not all detected disease poses a threat to health or survival. Thus, national and professional guidelines are evolving to incorporate higher thresholds for surgery, acceptance of less than total thyroidectomy in specific circumstances, higher thresholds for adjuvant therapy, and introduction of the role of active surveillance for selected cases of low risk disease. Despite these common themes, there are significant differences among guidelines. This lack of consensus in guidelines persists due to variation in clinical practice patterns, differences in consideration and interpretation of existing evidence, cultural and geographical considerations, and resources available for both diagnosis and treatment.

Editorial: Risk of disease progression during active surveillance of papillary thyroid cancer

With the rapid rise in incidence of micropapillary carcinoma, there is considerable interest in active surveillance or deferred intervention in patients with incidental micropapillary carcinoma. The risk of disease progression is different based on the age of the patient. It is high in third and fourth decade, while very low in sixth and seventh decade. Appropriate selection and close surveillance is very critical, with active involvement of the multidisciplinary team.

Experience of US Patients Who Self-identify as Having an Overdiagnosed Thyroid Cancer: A Qualitative Analysis

Importance

Overdiagnosis of cancer-the identification of cancers that are unlikely to progress-is a source of discomfort and challenge for patients, physicians, and health care systems. A major cause of this discomfort is the inability to know prospectively with certainty which cancers are overdiagnosed. In thyroid cancer, as patients have begun to understand this concept, some individuals are independently deciding not to intervene, despite this practice not yet being widely accepted.

Objective

To describe the current experience of people who independently self-identify as having an overdiagnosed cancer and elect not to intervene.

Design, Setting, and Participants

In this qualitative study, semistructured interviews were conducted between July 1 and December 31, 2015, with 22 community-dwelling adults aged 21 to 75 years who had an incidentally identified thyroid finding that was known or suspected to be malignant and who questioned the intervention recommended by their physicians. Verbatim transcripts were analyzed using constant comparative analysis.

Main Outcomes and Measures

The experience of individuals who self-identify as having an overdiagnosed cancer and elect not to intervene.

Results

Of the 22 people interviewed (16 females and 6 males; mean age, 48.5 years), 18 had elected not to intervene on their thyroid finding and had been living with the decision for a mean of 39 months (median, 40 months; range, 1-88 months). Twelve of the 18 participants reported that they experienced significant anxiety about cancer progression, but had considered reasons for choosing nonintervention: understanding issues of precision in diagnostic testing and the varied behavior of cancer, surgical risks, medication use, and low risk of death from the cancer. Twelve participants described their decisions as met with nonreassuring, unsupportive responses. Medical professionals, friends, and internet discussion groups told them they were "being stupid," "were wrong," or were "crazy" to not intervene. Although 14 individuals said they wished to connect with others about their experiences, only 3 reported success in doing so. Fifteen participants reported that they managed their overall experience through secret keeping. By the time of this study, 5 of the 18 individuals had discontinued surveillance, the recommended alternative to intervention. Despite this, only 7 participants "wished they did not know" about their thyroid finding.

Conclusions and Relevance

Isolation and anxiety characterize the current experience of patients with thyroid cancer who are living with the decision to not intervene. These patients are at risk of disengaging from health care. Successful de-escalation of intervention for patients who self-identify as having overdiagnosed cancers requires explicit social and health system support and education. We hypothesize that improved support would also promote quality of care by increasing the likelihood that patients could be kept engaged for recommended surveillance.

Problematic clinical trials in thyroid cancer: the issue of papillary carcinoma and observational approaches

We describe the clinical ethics problem of American thyroid cancer patients being offered ‘observation’ instead of the USA standard of care with questionable informed consent. This problem arose because some American practitioners misinterpreted 1990s Japanese studies. American proponents of these studies failed to recognize major differences in ethical oversight between Japanese and US clinical research, misrepresenting these studies as justifying clinical practices for higher risk patients that were not supported by data. The current professional environment in American thyroid cancer management is sufficiently problematic that consideration should be made, for patients who have inadvertently consented to nonevidence-based treatments, to be recontacted and provided an opportunity to revisit their care plans or seek second opinions regarding an observational approach.

Current Management of Low Risk Differentiated Thyroid Cancer and Papillary Microcarcinoma

Each year, the proportion of thyroid cancer patients presenting with low risk disease is increasing. Moreover, the definition of low risk thyroid cancer is expanding and several histological subtypes beyond papillary microcarcinomas are now classified as low risk disease. This shift in the landscape of thyroid cancer presentation is forcing clinicians to critically re-evaluate whether or not traditional management paradigms that were effective in treating intermediate and high risk disease are applicable to these low risk patients. Here we review the definition of low risk disease, examine the various histological subtypes that are considered low risk in the 2015 American Thyroid Association guidelines for the management of thyroid nodules and thyroid cancer, and review our current approach to the management of these low risk tumours.

Development of prognostic signatures for intermediate-risk papillary thyroid cancer

Background

The incidence of Papillary thyroid carcinoma (PTC), the most common type of thyroid malignancy, has risen rapidly worldwide. PTC usually has an excellent prognosis. However, the rising incidence of PTC, due at least partially to widespread use of neck imaging studies with increased detection of small cancers, has created a clinical issue of overdiagnosis, and consequential overtreatment. We investigated how molecular data can be used to develop a prognostics signature for PTC.

Methods

The Cancer Genome Atlas (TCGA) recently reported on the genomic landscape of a large cohort of PTC cases. In order to decrease unnecessary morbidity associated with over diagnosing PTC patient with good prognosis, we used TCGA data to develop a gene expression signature to distinguish between patients with good and poor prognosis. We selected a set of clinical phenotypes to define an ‘extreme poor’ prognosis group and an ‘extreme good’ prognosis group and developed a gene signature that characterized these.

Results

We discovered a gene expression signature that distinguished the extreme good from extreme poor prognosis patients. Next, we applied this signature to the remaining intermediate risk patients, and show that they can be classified in clinically meaningful risk groups, characterized by established prognostic disease phenotypes. Analysis of the genes in the signature shows many known and novel genes involved in PTC prognosis.

Conclusions

This work demonstrates that using a selection of clinical phenotypes and treatment variables, it is possible to develop a statistically useful and biologically meaningful gene signature of PTC prognosis, which may be developed as a biomarker to help prevent overdiagnosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2771-6) contains supplementary material, which is available to authorized users.

Therapeutic Strategies and Clinical Outcome in Papillary Thyroid Microcarcinoma: A Multicenter Observational Study

PURPOSE

Papillary thyroid microcarcinoma (MPTC) has an excellent prognosis. We aimed to evaluate the evolution of therapeutic strategies over time and the clinical outcome of MPTC.

METHODS

In this retrospective multicenter observational study in a northwest Italian region, patients with intrathyroidal, unifocal tumor ≤1 cm in size, incidentally found at histology or preoperative cytology diagnosis, were included. Exclusion criteria were a previous head-and-neck irradiation and/or node metastases.

RESULTS

From 1985 to 2012, 437 patients had an MPTC diagnosis, which was incidental in 85% and preoperative in 15%. Patients with a preoperative diagnosis were younger at the time of diagnosis (47.6 ± 12.7 years, p < 0.01) and had a larger tumor (7.0 ± 2.5 mm, p < 0.0001) than patients with an incidental diagnosis (age 52 ± 13.5 years, size 4.4 ± 2.8 mm), but there were no differences in clinical outcome between both groups. We observed a significant (p < 0.001) reduction in radioiodine remnant ablation during the years. TSH levels were: <0.1 mIU/l in 27.5%, 0.1-0.5 mlU/l in 33.7%, 0.5-2.5 mlU/l in 32.6%, 2.5-4.2 mlU/l in 3.9%, and >4.2 mlU/l in 2.3% of patients. Six patients (1.37%) had nodal recurrence; 5 of them were cured after therapy. MPTC-linked mortality was null.

CONCLUSIONS

We confirmed the favorable clinical outcome of MPTC. Despite the reduction in radioiodine ablation, overtreatment of MPTC is still observed.

ACTIVE SURVEILLANCE FOR PAPILLARY THYROID MICROCARCINOMA: NEW CHALLENGES AND OPPORTUNITIES FOR THE HEALTH CARE SYSTEM

OBJECTIVE

The dramatic increase in papillary thyroid carcinoma (PTC) is primarily a result of early diagnosis of small cancers. Active surveillance is a promising management strategy for papillary thyroid microcarcinomas (PTMCs). However, as this management strategy gains traction in the U.S., it is imperative that patients and clinicians be properly educated, patients be followed for life, and appropriate tools be identified to implement the strategy.

METHODS

We review previous active surveillance studies and the parameters used to identify patients who are good candidates for active surveillance. We also review some of the challenges to implementing active surveillance protocols in the U.S. and discuss how these might be addressed.

RESULTS

Trials of active surveillance support nonsurgical management as a viable and safe management strategy. However, numerous challenges exist, including the need for adherence to protocols, education of patients and physicians, and awareness of the impact of this strategy on patient psychology and quality of life. The Thyroid Cancer Care Collaborative (TCCC) is a portable record keeping system that can manage a mobile patient population undergoing active surveillance.

CONCLUSION

With proper patient selection, organization, and patient support, active surveillance has the potential to be a long-term management strategy for select patients with PTMC. In order to address the challenges and opportunities for this approach to be successfully implemented in the U.S., it will be necessary to consider psychological and quality of life, cultural differences, and the patient's clinical status.

Recurrence pattern after conservative surgery for papillary thyroid carcinoma

OBJECTIVE

Risk-based treatment represents the optimal management strategy for papillary thyroid carcinoma; however, the optimal extent of thyroidectomy and neck dissection remains controversial. This study aims to clarify the pattern of recurrence after conservative surgery in patients with papillary thyroid carcinoma.

METHODS

We retrospectively reviewed 93 patients with papillary thyroid carcinoma treated with conservative surgery. We analyzed recurrence rate, recurrence pattern, risk factors for recurrence, salvage treatment, and disease-free survival (DFS) in patients stratified according to risk.

RESULTS

The recurrence rate was significantly lower in the low-risk group compared with the high-risk group (14% vs 34%; p<0.01). The recurrence pattern also differed between the two groups, with ipsilateral lateral neck recurrence being more common in the low-risk group (9%), while contralateral lateral neck recurrence was more common in the high-risk group (18%). Patients with contralateral thyroid lobe metastasis and/or direct contralateral thyroid lobe invasion showed a significantly higher rate of contralateral lateral neck metastasis than patients negative for both these features. The overall 5-year DFS was 81% in all patients. Advanced T and N classification, large primary tumor (≥4cm), extrathyroidal invasion, and high-risk group were significantly associated with poorer 5-year DFS in univariate analysis.

CONCLUSION

Conservative surgery may represent a good treatment option for patients with low-risk papillary thyroid carcinoma. Tumor recurrence patterns differ between risk groups, with contralateral thyroid lobe lesions and direct contralateral lobe invasion being risk factors for contralateral lateral neck recurrence.

Therapeutic strategy for low-risk thyroid cancer in Kanaji Thyroid Hospital

It is well-known that differentiated thyroid carcinoma (DTC) has a generally indolent character and shows a favorable prognosis in comparison with many other carcinomas. The therapeutic strategy for patients with DTC in Japan has differed from that in Western countries. Total thyroidectomy followed by radioactive iodine (RAI) ablation has been standard in Western countries, whereas limited hemi-thyroidectomy and subtotal thyroidectomy has been extensively accepted in Japan. Papillary thyroid carcinoma (PTC) accounts for over 90% of all thyroid cancers in Japan. The majority of patients with PTC are categorized into a low-risk group on the basis of the recent risk-group classification schemes, and they show excellent outcomes. Several management guidelines for thyroid cancers have been published in Western countries. However, the optimal therapeutic options for PTC remain controversial, and high-level clinical evidence aimed at resolving these issues is lacking. Moreover, as socioeconomic differences in medical care exist, conventional policies for the treatment of PTC have differed between Japan and other countries. This review focuses on the special features of treatment in Japan for patients with low-risk DTC involving subtotal thyroidectomy without adjuvant therapies, rather than total thyroidectomy with RAI, with the aim of preserving quality of life. At our institution in Japan, we have had extensive experience with RAI treatment for high-risk DTC patients, and this represents a very rare situation. Here we introduce the therapeutic strategy for low-risk thyroid cancer in Japan, including the measures adopted at our institution.

E-cadherin expression and cell proliferation in the primary tumor and metastatic lymph nodes of papillary thyroid microcarcinoma

Although papillary thyroid microcarcinoma (PTMC) has an excellent prognosis, certain cases exhibit aggressive clinical manifestations. In this study, we assessed the expression of E-cadherin and Ki-67 in primary PTMC tumors and metastatic lymph nodes, in order to investigate the mechanism underlying the mainly indolent but potentially malignant nature of PTMC. A total of 93 PTMC patients treated in our institute were included in this study. All primary tumors and 57 metastatic lymph nodes were immunohistochemically stained and a total of 73 tumors (78.5%) were positive for E-cadherin. E-cadherin expression was significantly less common at the invasive front (58.1%, P<0.01) compared to that at the center of the tumor. Tumors that had lost E-cadherin expression at the invasive front frequently presented with lymph node metastasis (70.6%). Small tumors (≤5 mm diameter) expressed E-cadherin significantly more frequently compared with larger tumors (P=0.04); however, no other particular characteristic was found to correlate with the status of E-cadherin expression in the primary tumors. E-cadherin expression was detected in 49 (86.0%) of the 57 metastatic foci and correlated significantly with the expression status at the invasive front of the tumor (P=0.02). The Ki-67 index was universally low and was not correlated with the clinicopathological characteristics or the E-cadherin expression of the tumors. These results suggested that cancer cells in the metastatic lymph nodes exhibit indolent characteristics, similar to those of the primary PTMC. However, the metastatic cancer cells may have already completed the process of epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET), suggesting an innate malignant potential.

Total thyroidectomy as the single surgical option for benign and malignant thyroid disease: a surgical challenge

INTRODUCTION

Total thyroidectomy has been the treatment of choice for patients with malignant thyroid disease. However, the efficacy and safety of this procedure for patients with benign disease is still a matter of debate. The aim of this study is to show that total thyroidectomy can be safely performed for both malignant and benign disease.

MATERIAL AND METHODS

A retrospective study on 216 patients was conducted. Once an indication for surgery was established, our single surgical treatment was total thyroidectomy. Age, sex, nature of thyroid disease, final pathology and postoperative complications were recorded.

RESULTS

For both benign and malignant disease, total thyroidectomy resulted in no permanent laryngeal nerve injury and no permanent hypoparathyroidism. Temporary laryngeal nerve palsy occurred in 0.9% and 3% of patients with benign and malignant disease respectively (p = 0.245). Six percent of patients with benign and 10.0% of patients with malignant thyroid disease suffered temporary hypoparathyroidism (p = 0.280). Immediate reoperation for postoperative hemorrhage was performed in 1.7% of patients with benign disease and in 1.0% of patients with malignancy with an uneventful outcome (p = 0.650).

CONCLUSIONS

When performed by surgeons experienced in endocrine surgery, total thyroidectomy may be considered as the treatment of choice for both malignant and benign thyroid disease requiring surgical treatment. Total thyroidectomy virtually eliminates the requirement of completion thyroidectomy for incidentally diagnosed thyroid carcinoma and significantly reduces the rate of reoperation for recurrent disease, as it provides an immediate and permanent cure for all benign thyroid diseases, with a low incidence of postoperative complications.

Pattern of initial metastasis in the cervical lymph node from papillary thyroid carcinoma

PURPOSES

This study attempted to reveal the pattern of initial lymphatic spread in order to investigate the clinical significances of lymph node metastasis in papillary thyroid carcinoma (PTC) since such information has yet to be elucidated in previous studies.

METHODS

This study reviewed 501 consecutive patients with PTC who had been surgically treated, accompanied by routine node dissection of the central, and lateral compartments. Thirty-eight cases were found to have only one metastatic node, and 62 cases were found to have 2 or 3 metastatic nodes. The locations of these metastatic nodes were mapped, and evaluated.

RESULTS

The initial lymph node metastasis occurred equally in the lateral and central compartments (19 vs. 19 nodes). Metastatic nodes were more frequently found in the central compartment (60 and 65 %) in cases with 2- and 3-node involvements. Twenty-two (60 %) and 33 (65 %) cases had at least one instance of lateral node involvement in those cases, respectively.

CONCLUSIONS

The current results demonstrated the pattern of initial lymphatic spread in PTC cases, and indicated the importance of evaluating the lateral nodes of at least compartments III and IV for accurate pathological staging, as well as for investigating the nature of the disease.

Computerized detection and quantification of microcalcifications in thyroid nodules

To improve the ultrasonographic detection rates of thyroid cancers with microcalcifications, we propose to enhance the sensitivity of sonographic calcifications detection and to avoid interobserver variation by a computerized quantification method in a prospective setting. A total of 227 participants with 258 nodules were evaluated. Among them, two nodules were excluded for suspicious aspiration cytology results without pathologic proof. Among the remaining 256 nodules, the diagnosis of 181 nodules was verified by surgical pathology and the diagnosis of 75 was based on fine needle aspiration (FNA) biopsy results. There were 173 benign thyroid nodules and 83 malignant thyroid nodules, which included 74 papillary carcinomas. Patient clinical data were collected and the presence of calcifications on conventional gray-scale ultrasound images was retrospectively reviewed by a thyroid specialist. Quantification of cystic components and calcifications was automatically performed by a proprietary program (AmCAD-UT) implemented with methods proposed in this article. The calcification index (CI) was calculated after the cystic component was excluded. The CI between benign and malignant nodules diagnosed by combined FNA biopsy and surgical pathology results (total number, 256) showed a significant difference (p < 0.0001, AUC = 0.746). Furthermore, we excluded patients without surgical pathology results for further validation and the CI between benign and malignant nodules confirmed by pathology results (total number, 181) showed a significant difference (p < 0.0001, AUC = 0.763). To learn whether our computer program increased our diagnostic capabilities, we analyzed human investigators and their abilities to detect and evaluate. In this study, calcifications were noted in 48.19% (40 of 83) of malignant thyroid nodules and in 10.98% (19 of 173) of benign nodules. This new computer-aided diagnosis method to evaluate the sonographic calcifications of thyroid nodules is a more sensitive and more objective method. It can provide better sensitivity than conventional methods in the diagnosis of thyroid malignancies containing microcalcifications.

Three distinctly different kinds of papillary thyroid microcarcinoma should be recognized: our treatment strategies and outcomes

BACKGROUND

Papillary microcarcinoma (PMC) of the thyroid generally follows a benign clinical course. However, treatment strategies remain controversial. According to our previous retrospective review of 178 patients with PMC who underwent surgery between 1976 and 1993, the most significant risk factors affecting cancer-specific survival were clinical symptoms at presentation due to invasion or metastasis. Distant metastasis and cancer-specific death were never seen postoperatively for 148 cases (83%) of asymptomatic PMC without clinically apparent (>or=1 cm) lymph node metastasis or recurrent nerve palsy. Based on these results, we identified three biologically different types of PMC that should be treated differently. Type I comprises incidentally detected PMC without any symptoms, which is harmless and the lowest-risk cancer. Conservative follow-up with ultrasonography every 6 or 12 months is feasible. Type II involves the early stage of the usual low-risk papillary carcinoma. This can be treated by lobectomy when increasing size is noted during conservative follow-up. Type III comprises clinically symptomatic PMC, representing a high-risk cancer. Immediate wider resection followed by radioiodine treatment and suppression of thyroid-stimulating hormone is recommended.

METHODS

Since 1995, we have been conducting a prospective clinical trial of nonsurgical observation for asymptomatic PMC. As of 2008, 230 of 244 candidates (94%) have decided to accept this policy, whereas 56 patients underwent surgery for symptomatic PMC between 1976 and 2006.

RESULTS

Nonsurgical observation for a mean of 5 (range, 1-17) years for 300 lesions of asymptomatic PMC revealed that 22 (7%) had increased in size, 269 (90%) were unchanged, and 9 (3%) had decreased. No patients developed extrathyroidal invasion or distant metastasis. Three patients (1%) who developed apparent lymph node metastasis and nine patients (4%) in whom tumor increased in size eventually received surgery after 1-12 years of follow-up. No recurrences have been identified postoperatively. Conversely, 10-year cause-specific survival for symptomatic PMC was 80%. Multivariate analysis identified extrathyroidal invasion, large lymph node metastasis (>or=2 cm), and poorly differentiated component as significantly related to adverse outcomes.

CONCLUSIONS

Nonsurgical observation seems to represent an attractive alternative to surgery for asymptomatic PMC. Almost 95% of asymptomatic PMC patients are type I, and another 5% are type II and can be treated with conservative surgery. A small number of PMCs with bulky lymph node metastasis or extrathyroidal invasion are high-risk type III and require aggressive treatment.

Re-evaluation of histopathological factors affecting prognosis of differentiated thyroid carcinoma in an iodine-sufficient country

BACKGROUND

Poorly differentiated thyroid carcinoma (PDTC) was recognized as an independent clinicohistological entity of thyroid cancer in the 2004 World Health Organization (WHO) classifications, separated from papillary (PTC) and follicular carcinoma (FTC). The Turin proposal provides more specific criteria for the diagnosis of PDTC. However, in an iodine-sufficient country such as Japan, PDTC comprises <1% of all thyroid cancers. In 1983, Sakamoto analyzed pathological characteristics of PTC and FTC that recurred within 5 years after initial surgery and identified solid, trabecular, insular (STI) and scirrhous growth patterns as important predictors of poor prognosis. We re-evaluated the impact of histopathological findings on the clinical course of PTC and FTC.

MATERIALS AND METHODS

Specimens from 376 consecutive cases diagnosed as PTC (n = 351) or FTC (n = 25) between 1994 and 2001 were reviewed.

RESULTS

Nine (2%) patients were diagnosed with PDTC according to WHO criteria. Only 1 case (0.3%) met the Turin criteria. In addition, STI components were seen in various specimens as follows: >or=50%, >or=10% but <50%, >0% but <10%, and 0% of specimens for 9 (2%), 31 (8%), 19 (5%), and 317 cases (85%), respectively. As for cause-specific survival, a significant difference was apparent between the >or=50% and >or=10% but <50% groups. Disease-free survival was identical between these groups and was significantly worse than in the >0% but <10% and 0% groups. According to multivariate analysis, histological features of STI >or=10% and squamous metaplasia were significantly related to cause-specific survival, but scirrhous infiltration, necrosis, nuclear atypia, and vascular invasion were not. The presence of STI at a level >or=10% was also a significant risk factor, together with clinical risk factors including large tumor size, large nodal metastasis, and distant metastasis. According to AMES risk-group definition, clinically high-risk patients with STI >or=10% showed the worst 10-year cause-specific survival, at 57%, irrespective of total thyroidectomy with radioactive iodine (RAI) treatment. Ten of 25 PTC patients (40%) with STI >or=10% developed cervical recurrence, whereas 9 of 15 FTC patients (60%) with STI >or=10% showed distant metastasis.

CONCLUSIONS

The measurement of STI >or=10% represents a distinctly important risk factor for patient survival. In particular, clinically high-risk patients with STI >or=10% need further therapy beyond RAI. Original histological pattern, as papillary or follicular, affects the site of recurrence.