Current Management of Low Risk Differentiated Thyroid Cancer and Papillary Microcarcinoma

Ablation techniques or active surveillance compared to surgical resection in patients with low-risk papillary thyroid cancer: a systematic review and meta-analysis

BACKGROUND

The global prevalence of thyroid cancer is on the rise. About one-third of newly diagnosed thyroid cancer cases comprise low-risk papillary thyroid cancer (1.5 cm or more minor). While surgical removal remains the prevailing approach for managing low-risk papillary thyroid cancer (LPTC) in patients, other options such as active surveillance (AS), radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) are also being considered as viable alternatives. This study evaluated and compared surgical thyroid resection (TSR) versus non-surgical (NS) methods for treating patients with LPTC.

METHODS

The study encompassed an analysis of comparisons between surgical thyroid resection (TSR) and alternative approaches, including active surveillance (AS), radiofrequency ablation (RFA), microwave ablation (MWA), or laser ablation (LA). The focus was on patients with biopsy-confirmed low-risk papillary thyroid cancer (LPTC) of less than 1.5 cm without preoperative indications of local or distant metastasis. The primary outcomes assessed were recurrence rates, disease-specific mortality, and quality of life (QoL). Data were collected from prominent databases, including Cochrane Database, Embase, MEDLINE, and Scopus, from inception to June 3rd, 2020. The CLARITY tool was utilized to evaluate bias risk. The analysis involved odds ratios (OR) with 95% confidence intervals (CI) for dichotomous outcomes, as well as mean differences (MD) and standardized mean differences (SMD) for continuous outcomes. The study is registered on PROSPERO under the identifier CRD42021235657.

RESULTS

The study incorporated 13 retrospective cohort studies involving 4034 patients. Surgical thyroid resection (TSR), active surveillance (AS), and minimally invasive techniques like radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) were performed in varying proportions of cases. The analysis indicated that specific disease mortality rates were comparable among AS, MWA, and TSR groups. The risk of recurrence, evaluated over different follow-up periods, showed no significant differences when comparing AS, RFA, MWA, or LA against TSR. Patients undergoing AS demonstrated better physical health-related quality of life (QoL) than those undergoing TSR. However, no substantial differences were observed in the overall mental health domain of QoL when comparing AS or RFA with TSR. The risk of bias was moderate in nine studies and high in four.

CONCLUSION

Low-quality evidence indicates comparable recurrence and disease-specific mortality risks among patients with LPTC who underwent ablation techniques or active surveillance (AS) compared to surgery. Nevertheless, individuals who opted for AS exhibited enhanced physical quality of life (QoL). Subsequent investigations are warranted to validate these findings.

A study of variation in therapeutic approach to low-risk differentiated thyroid cancer in the UK

BACKGROUND

The British Thyroid Association and American Thyroid Association guideline definitions for low-risk differentiated thyroid cancers are susceptible to differing interpretations, resulting in different clinical management in the UK.

OBJECTIVE

To explore the national effect of these guidelines on the management of low-risk differentiated thyroid cancers.

METHODS

Anonymised questionnaires were sent to multidisciplinary teams performing thyroidectomies in the UK. Risk factors that multidisciplinary teams considered important when managing low-risk differentiated thyroid cancers were established.

RESULTS

Most surgeons (71 out of 75; 94.7 per cent) confirmed they were core multidisciplinary team members. More than 80 per cent of respondents performed at least 30 hemi- and/or total thyroidectomies per annum. A majority of multidisciplinary teams (50 out of 75; 66.7 per cent) followed British Thyroid Association guidelines. Risk factors considered important when managing low-risk differentiated thyroid cancers included: type of tumour histology findings (87.8 per cent), tumour size of greater than 4 cm (86.5 per cent), tumour stage T3b (85.1 per cent) and central neck node involvement (85.1 per cent). Extent of thyroid surgery (e.g. hemi- or total thyroidectomy) was highly variable for low-risk differentiated thyroid cancers.

CONCLUSION

Management of low-risk differentiated thyroid cancers is highly variable, leading to a heterogeneous patient experience.

Risk factors for recurrent disease in small papillary thyroid cancers - a Swedish register-based study

AIMS

To study the correlation between clinicopathological risk factors and the risk for intervention-requiring cancer recurrence in patients with small papillary thyroid cancers (sPTCs).

MATERIALS AND METHODS

Records for 397 patients with sPTC (T1 ≤ 20mm) were obtained from the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal Surgery (SQRTPA) between 2010 and 2016. Follow-up time was at least 5 years. Data regarding intervention-requiring cancer recurrence were obtained from patient medical records and analysed regarding lymph node (LN) status (N0, N1a and N1b) and recurrence.

RESULTS

Age was significantly lower in the N1a and N1b groups compared to N0 (45 vs. 40.5 vs. 49 years, respectively; p = 0.002). Tumour size was smaller in the N1a group compared to N1b group (9 vs. 11.8 mm; p <0.01). The mean number of metastatic LNs at initial surgery was higher in the N1b compared to N1a group (6.6 vs. 3; p = 0.001), and in the recurrent compared to the non-recurrent group (7 versus 3.9; p <0.01). The recurrence rate was higher in the N1b group than the N1a and N0 groups (25% vs. 2.4% vs. 1.4%, respectively; p = 0.001).

CONCLUSIONS

Lymph node stage N1b at diagnosis, and having five or more metastatic nodes, are strong risk factors for cancer recurrence and decreased disease-free survival in sPTC. The management of patients with sPTC should include thorough lymph node mapping for optimal treatment and individual risk stratification.

The role of surgery in small differentiated thyroid cancer

INTRODUCTION

The incidence of small, differentiated thyroid cancer (DTC) cases has been increasing in the United States and the world mainly due to incidental detection because of widespread use of diagnostic modalities. While the option of active surveillance instead of surgical resection is getting more popular, there is still an open discussion about the best approach in these cases.

MATERIALS AND METHODS

The National Cancer Database was queried for patients diagnosed with non-metastatic small T1/N0 DTC between 2004 and 2016, who have known surgical status and Charlson comorbidity index of two or less. We evaluated the overall survival (OS) based on the surgery status using Kaplan-Meier estimates and multivariable cox regression analyses.

RESULTS

A total of 98,501 patients with non-metastatic small DTC were included, within which 96,612 (98.1%) were treated with surgery, and 1889 (1.9%) were not treated with surgery or other ablative modalities. We found that patients who were treated with surgery had better OS compared to patients who were not treated with surgery (mean OS 171 months vs 134.1 months, P < 0.001, median OS was not reached). This difference was still statistically significant even after we used propensity score matching for age, gender, race, Charlson-Deyo score, tumor size, and histology. On multivariate analysis, surgery was associated with better OS (HR 0.218; 95% CI: 0.196-0.244; P < 0.001). Same trend was found in subgroup analysis when we split the cohort according to tumor size (<1 and ≥1 cm), histology (follicular, papillary and Hurthle cell carcinoma), and age (<55 years vs ≥55 years).

CONCLUSION

Patients with non-metastatic small DTC who were treated with surgery had significant improvement in OS compared to patients who were not treated with surgery. Notwithstanding the limitations of the current analysis, these results call for caution prior to recommending routine surveillance for all patients with small DTC.

What's in a Name? A Cost-Effectiveness Analysis of the Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features' Nomenclature Revision

Background: The noninvasive subtype of encapsulated follicular variant of papillary thyroid carcinoma (eFVPTC) has been reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in 2016 to reflect the indolent behavior and favorable prognosis of this type of tumor. This terminology change has also de-escalated its management approach from cancer treatment to a more conservative treatment strategy befitting a benign thyroid neoplasm. Objective: To characterize the reduced health care costs and improved quality of life (QOL) from management of NIFTP as a nonmalignant tumor compared with the previous management as eFVPTC. Methods: A cost-effectiveness analysis was performed by creating Markov models to simulate two management strategies for NIFTP: (i) de-escalated management of the tumor as NIFTP involving lobectomy with reduced follow-up, (ii) management of the tumor as eFVPTC involving completion thyroidectomy/radioactive iodine ablation for some patients, and follow-up recommended for carcinoma. The model was simulated for 5 and 20 years following diagnosis of NIFTP. Aggregate costs and quality-life years were measured. One-way sensitivity analysis was performed for all variables. Results: Over a five-year simulation period, de-escalated management of NIFTP had a total cost of $12,380.99 per patient while the more aggressive management of the tumor as eFVPTC had a total cost of $16,264.03 per patient (saving $3883.05 over five years). Management of NIFTP provided 5.00 quality-adjusted life years, whereas management as eFVPTC provided 4.97 quality-adjusted life years. Sensitivity analyses showed that management of NIFTP always resulted in lower costs and greater quality-adjusted life years (QALYs) over the sensitivity ranges for individual variables. De-escalated management for NIFTP is expected to produce ∼$6-42 million in cost savings over a five-year period for these patients, and incremental 54-370 QALYs of increased utility in the United States. Conclusion: The degree of cost savings and improved patient utility of de-escalated NIFTP management compared with traditional management was estimated to be $3883.05 and 0.03 QALYs per patient. We demonstrate that these findings persisted in sensitivity analysis to account for variability in recurrence rate, surveillance approaches, and other model inputs. These findings allow for greater understanding of the economic and QOL impact of the NIFTP reclassification.

Preoperative prognostic risk stratification model for papillary thyroid carcinoma based on clinical and ultrasound characteristics

BACKGROUND

The preoperative risk stratification for patients with papillary thyroid carcinoma (PTC) plays a crucial role in guiding individualized treatment. We aim to construct a predictive model that aids in distinguishing between patients with low-risk and high-risk PTC based on preoperative clinical and ultrasound characteristics.

MATERIALS AND METHODS

Patients who underwent open surgery and were diagnosed with PTC via a postoperative pathological report between January 2020 and December 2020 were retrospectively reviewed. Data including basic information, preoperative ultrasound characteristics, thyroid function, and postoperative pathology characteristics were obtained. Univariate logistic regression analysis and least absolute shrinkage and selection operator regression analysis were performed to screen candidate variables. Finally, the preoperative predictive model for PTC was established based on the results of the multivariate logistic regression analysis.

RESULTS

A total of 1,875 patients with PTC were enrolled. Eight variables (sex, age, number of foci, maximum tumor diameter on ultrasound, calcification, capsule, lymph node status on ultrasound, and thyroid peroxidase (TPO) antibody level) significantly associated with risk stratification were included in the predictive model. A nomogram was constructed for clinical utility. The model showed good discrimination, and the area under the curve was 0.777 [95% confidence interval (CI): 0.752-0.803] and 0.769 (95% CI: 0.729-0.809) in the training set and validation set, respectively. The calibration curve exhibited a rather good consistency with the perfect prediction. Furthermore, decision curve analysis and clinical impact curve showed that the model had good efficacy in predicting the prognostic risk of PTC.

CONCLUSIONS

The nomogram model based on preoperative indicators for predicting the prognostic stratification of PTC showed a good predictive value. This could aid surgeons in deciding on individualized precision treatments.

Incidence and predictive factors of postoperative hypocalcaemia according to type of thyroid surgery in older adults

PURPOSE

Transient hypocalcaemia after thyroid surgery and its possible predictors have not been extensively described in the elderly. This study aimed to establish the frequency of postsurgical transient hypocalcaemia according to the extent of thyroid surgery in older adults and to assess mineral metabolism biochemical parameters as its predictors.

METHODS

All patients ≥60 years undergoing thyroid surgery were prospectively included. Type of surgery (hemithyroidectomy(HT) or total thyroidectomy(TT)); and preoperative 25OH Vitamin D (25OHD) and pre and 6 (only TT), 24 h and 6 months postsurgical serum levels of calcium, magnesium, phosphate and parathormone (PTH) were considered. Postsurgical hypoparathyroidism (hPTpost) was defined at PTH levels ≤11 pg/mL.

RESULTS

Out of 46 patients (87% female), age (mean ± SD) 70.1 ± 6.2 years, 24 h postsurgical hypocalcaemia was found in ten patients (22%). In 25 (54%) TT patients, 36% and 16% had postsurgical hypocalcaemia at 6 and 24 h respectively; 28% hPTpost but no definitive hPT was recorded and 44% had 25OHD deficiency. Lower 24 h magnesium levels were found in those TT patients with 24 h hypocalcaemia (1.6 ± 0.1 vs 1.9 ± 0.1 mg/dL (p = 0.005)). Among 21 (46%) HT patients, 28.6% had 24 h postsurgical hypocalcaemia; 9.5% had hPTpost. A positive correlation was observed between preoperative 25OHD and 24 h calcaemia (r:0.51,p = 0.02). 43% of the patients were 25OHD deficient, in whom 55% had 24 h hypocalcaemia vs only 9% in the 25OHD sufficient group (p = 0.049).

CONCLUSION

Postsurgical hypocalcaemia was common in elderly thyroidectomized patients. After TT, lower magnesium levels were found in those patients with 24 h hypocalcaemia. In the HT group, preoperative 25OHD deficiency predicted lower postsurgical calcium levels.

Controversy: For or against thyroid lobectomy in>1cm differentiated thyroid cancer?

In this controversy article, the respective advantages of lobectomy vs. total thyroidectomy in differentiated thyroid cancers are argued. The authors conclude that lobectomy has the same oncological prognosis as thyroidectomy in terms of specific survival or recurrence, in case of low risk of recurrence (T1-2N0). However, as a precaution, and taking into account current data, thyroidectomy is recommended in N0 thyroid papillary cancers with aggressive subtype, with even minimal infiltration of perithyroid tissue and/or vascular invasion, and in N1 cancers with more than 5 lymphadenopathies or lymphadenopathies with a major axis greater than or equal to 0.2cm. Other forms of papillary cancer should be treated with lobectomy, as risk of morbidity is low and hospital stay is short. Lobectomy allows reliable monitoring, especially by ultrasound. On the other hand, total thyroidectomy, despite a higher rate of surgical complications due to the risk of recurrent paralysis and permanent hypoparathyroidism, is nevertheless preferable to lobectomy. Indeed lobectomy is not always avoiding hormone replacement therapy, for more precise monitoring by thyroglobulin assay, which is an uninterpretable tool after lobectomy but allows early diagnosis of local or metastatic recurrence with reducing mortality. Thus, in situations where the diagnostic criteria for high-risk cancer are not rigorously determined or taken into account, thyroidectomy is recommended. In addition, it will remain preferable as long as the recommendations for administration of radioactive iodine do not change in favor of use reserved for high-risk cancers as in US guidelines.

A comparison between unifocal papillary thyroid microcarcinoma with noninvasive follicular thyroid neoplasm with papillary-like nuclear features and other patterns: A retrospective clinicopathological study

Background

Papillary thyroid microcarcinoma (mPTC) is defined as a tumor with low malignancy potential. Different treatment protocols have been used at different centers for analyzing this tumor which has common recurrence and metastasis rates. Consequently, in 2016, the definition of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was accepted which included the lesions > cm. It is important to explain the clinical course and appropriate treatment options for mPTC and its subtypes.

Aims

In this study, we aimed to describe the clinical course of mPTC with and without NIFTP and to determine different risk groups among these subtypes.

Material and Methods

We performed microscopic reexamination of about 280 unifocal mPTCs retrieved from our archives between 2007-2018 and analyzed the results of morphological and clinical comparison among these cases that had 0-11-years of clinical follow-up.

Results

Among 280 unifocal mPTCs, 127 cases (45.4%) had classical morphology, 58 (20.7%) had NIFTP, 53 (18.9%) had infiltrative pattern, 27 (9.6%) had oncocytic pattern, 12 (4.3%) showed capsular invasion, and 3 (1.1%) showed other morphologies. Seven patients were detected with lymph node metastasis and one with distant metastasis at diagnosis. Lymph node metastasis (recurrence) was postoperatively detected in five patients. All patients with recurrence were women. Moreover, three of these patients were in their 30s and two in 70s. The median diameter of the tumor was 3 mm. Both invasive and noninvasive cases have recurred.

Conclusion

Contrary to the results of the previous studies, the results of our study did not confirm the indolent course of mPTC with NIFTP. However, metastasis was detected both at the time of diagnosis and during the postoperative period. The malignancy potential of these tumors may not be low. Therefore, more clinicopathological and molecular studies are needed to determine the biological behavior of mPTC cases with different histology.

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.

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.

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.

New paradigms in the treatment of low-risk thyroid cancer

INTRODUCTION

Thyroid cancer is the most common endocrine malignancy. Multiple different staging systems have been introduced and used for differentiated thyroid carcinoma (DTC).

AREAS COVERED

In this literature review we provide an overview of the standard options for management of patients with low risk differentiated thyroid cancer.

EXPERT OPINION

Surgery is considered the first and most important step in managing DTC with goal to remove all the malignant foci in order to achieve cure and increase the survival with least chance of recurrence. Many studies have been conducted to determine the best surgical approaches and how aggressive surgeries should be in order to achieve the best outcomes regarding efficacy as well as safety. Radioactive iodine (RAI) therapy has also been a part of the treatment regimen and is used for different purposes with three main goals: post-surgical ablation, adjuvant therapy and persisted/recurrent disease treatment. Radiation therapy, on the other hand, is still not recommended to be used routinely in DTC because of the conflicting data of its benefit.

Papillary microcarcinoma of the thyroid gland: current controversies and management

PURPOSE OF REVIEW

To highlight recent advances in our understanding of the nature of micropapillary thyroid carcinoma (mPTC), its evaluation and options of management based on risk.

RECENT FINDINGS

A dramatic increase of the incidence of papillary thyroid carcinoma has been reported worldwide during recent decades, specifically those smaller than 10 mm (mPTC). Although not taking into consideration other risk factors for aggressiveness when describing tumours by their size, most of these newly diagnosed mPTC are indolent and active surveillance can be considered as valid option for their management.

SUMMARY

An increasing number of patients with mPTC will be encountered in clinical practice. Although it is difficult to assess the aggressiveness of a tumour on size criteria, less than a total thyroidectomy and active surveillance can be considered for the majority of patients with mPTC. Further trials should be performed to prove this as a valid option of management in the majority of these patients.

Comparative study on operative trauma between microwave ablation and surgical treatment for papillary thyroid microcarcinoma

AIM

To compare the effect and postoperative trauma of ultrasound-guided percutaneous microwave ablation and surgical resection in the treatment of papillary thyroid microcarcinoma (PTMC).

METHODS

Eighty-seven patients with PTMC treated at Fudan University affiliated Shanghai Fifth People’s Hospital were enrolled as subjects. The patients were divided into a microwave ablation group (41 cases) and a surgical group (46 cases). The operative time, intraoperative blood loss, length of hospital stay, serum C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), thyroid-related hormonal changes, and complications 7 d and 30 d after surgery were observed.

RESULTS

The operative time, intraoperative blood loss, and length of hospital stay in the surgical group were significantly higher than those in the microwave ablation group (P < 0.05). The levels of CRP, IL-6, and TNF-α in the surgical group were significantly higher than those in the microwave ablation group (P < 0.05). The free triiodothyronine (FT3) and free thyroxin (FT4) levels in the surgical group were significantly lower than those in the microwave ablation group (P < 0.05). However, the postoperative thyroid stimulating hormone (TSH) level was significantly higher than that in the microwave ablation group (P < 0.05). There were significant interactions between the FT3, FT4, and TSH 7 d and 30 d after operation and the treatment methods (P < 0.05). There was no significant difference in the complications between the two groups (P > 0.05).

CONCLUSION

Microwave ablation for papillary microcarcinoma of the thyroid gland has less trauma to the body, quicker recovery, and no scars. It can effectively shorten the length of hospital stay and improve the quality of life of patients.

Management of Low-Risk Papillary Thyroid Cancer

The incidence of thyroid cancer has increased, mainly due to the incidental finding of low-risk papillary thyroid cancers (PTC). These malignancies grow slowly, and are unlikely to cause morbidity and mortality. New understanding about the prognosis of tumor features has led to reclassification of many tumors within the low-risk thyroid category, and to the development of a new one "very low-risk tumors." Alternative less aggressive approaches to therapy are now available including active surveillance and minimally invasive interventions. In this narrative review, we have summarized the available evidence for the management of low-risk PTC.

Papillary thyroid microcarcinoma: characteristics at presentation, and evaluation of clinical and histological features associated with a worse prognosis in a Latin American cohort

Objective We aimed to describe the presentation of papillary microcarcinoma (PTMC) and identify the clinical and histological features associated with persistence/recurrence in a Latin American cohort. Subjects and methods Retrospective study of PTMC patients who underwent total thyroidectomy, with or without radioactive iodine (RAI), and who were followed for at least 2 years. Risk of recurrence was estimated with ATA 2009 and 2015 classifications, and risk of mortality with 7th and 8th AJCC/TNM systems. Clinical data obtained during follow-up were used to detect structural and biochemical persistence/recurrence. Results We included 209 patients, predominantly female (90%), 44.5 ± 12.6 years old, 183 (88%) received RAI (90.4 ± 44.2 mCi), followed-up for a median of 4.4 years (range 2.0-7.8). The 7th and 8th AJCC/TNM system classified 89% and 95.2% of the patients as stage I, respectively. ATA 2009 and ATA 2015 classified 70.8% and 78.5% of the patients as low risk, respectively. Fifteen (7%) patients had persistence/recurrence during follow-up. In multivariate analysis, only lymph node metastasis was associated with persistence/recurrence (coefficient beta 4.0, p = 0.016; 95% CI 1.3-12.9). There were no PTMC related deaths. Conclusions Our series found no mortality and low rate of persistence/recurrence associated with PTMC. Lymph node metastasis was the only feature associated with recurrence in multivariate analysis. The updated ATA 2015 and 8th AJCC/TNM systems classified more PTMCs than previous classifications as low risk of recurrence and mortality, respectively.

Risk factors associated with intrathyroid extension of thyroid microcarcinomas

PURPOSE

The aims of this study were to investigate the rate of intrathyroid extension of papillary thyroid microcarcinoma (PTMC) in patients operated for benign thyroid disease and to identify independent risk factors associated with it.

METHODS

A retrospective study of 301 patients operated for benign thyroid diseases (hyperthyroid diseases, multinodular goitre, Hashimoto thyroiditis and benign thyroid tumours) was performed at a high-volume endocrine surgery unit of a tertiary referral academic hospital, in a 5-year period. These patients had a PTMC incidentally discovered on definite histopathological findings following total or near-total thyroidectomy. Since distinguishing between intrathyroid extension of PTMC as the result of intrathyroid dissemination or as the result of multicentricity is challenging, we observed them together as multifocality. In statistical analysis, we used standard descriptive statistics and univariate and multivariate logistic regression analysis to determine independent risk factors associated with multifocality.

RESULTS

In our study, there were 85.4% females and 14.6% males with a median age of 54 years. A multinodular goitre (32.5%) was the most common indication for an operation. Most patients (68.4%) had a PTMC that was 5 mm or smaller. The most frequent histological variants of PTMC were the follicular variant (52.8%), followed by the papillary variant (22.6%) and the mixed follicular-papillary variant (18.6%). A multifocal PTMC was present in 26.6% of cases. An independent protective factor for multifocality of PTMC was a thyroid gland that weighed more than 38 g (OR 0.55, 95% CI 0.31-0.97, p = 0.039). Size of PTMC greater than 5 mm was an independent risk factor for a multifocal PTMC (OR 3.26, 95% CI 1.85-5.75, p = 0.000). Finally, the mixed follicular-papillary variant of PTMC represents an independent risk factor for a multifocal PTMC (OR 2.42, 95% CI 1.09-5.36, p = 0.030).

CONCLUSIONS

Intrathyroid extension is present in more than a quarter of PTMCs found in patients operated for benign thyroid disease. Independent risk factors for intrathyroid extension are size of PTMC greater than 5 mm and the mixed follicular-papillary variant of PTMC, while a large thyroid gland is an independent protective factor.

Surgical management for follicular variant of papillary thyroid carcinoma

Background and Aims

For most patients with follicular variant of papillary thyroid carcinoma (FVPTC), surgery is required, while the surgical management remains controversial. We aim to further understanding of treatment of FVPTC and to determine whether specific features could be identified for the decision of surgical strategy.

Materials and Methods

Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) Program database during 2003 and 2013. 26700 patients were eligible and stratified by tumor size or extension. Survival rates were compared using multivariate Cox proportional hazard regressions.

Results

Of the total death of 1041, 136 patients died from thyroid cancer. Most patients (79.1%) underwent total thyroidectomy while only a little part of patients (8.2%) underwent lobectomy. Patients receiving radioisotopes had significantly better overall survival (OS) (HR = 0.659, P < 0.001), but showed no differences on disease-specific survival (DSS). No statistical difference was found between total thyroidectomy and lobectomy in multivariate analysis when controlling for tumor size. While for tumor > 2 cm with extrathyroidal extension, lobectomy had significantly worse OS (aHR = 3.364, P = 0.010) and DSS (aHR = 5.494, P = 0.032) compared to total thyroidectomy. Multivariate analysis demonstrated that advanced age, male, higher grade, extrathyroidal extension, lymph nodes metastases and distant metastases had negative effects on OS and DSS controlling for the remaining variables (each P < 0.05).

Conclusions

The results of our study revealed total thyroidectomy could benefit the survival for patients whose tumors > 2 cm with extrathyroidal extension, total thyroidectomy should be recommended for those patients. Lots of factors should be taken into consideration on the decision of surgical treatment.