Validation of the QTNM staging system for cancer-specific survival in patients with differentiated thyroid cancer

The impact of lymph node ratio on disease recurrence in papillary thyroid microcarcinoma

INTRODUCTION

Lymph node (LN) metastases in papillary thyroid microcarcinomas (microPTCs) are common. The lymph node ratio (LNR) has been proposed as a risk factor for recurrence in papillary thyroid cancer. However, its relevance in microPTC is undetermined.

METHODS

Patients who underwent resection of their microPTC with concomitant LN clearance between 2005 and 2018 were identified. The LNR was calculated as the ratio of positive LNs to the total number of LNs.

RESULTS

Data on 50 patients (36 female [72%]; median age 47 years [range: 19-84]) who underwent LN clearance (28 central [56%] vs 22 central + lateral [44%]) were analysed. Positive LNs were found in over two-thirds of the patients (n = 34; 68%). After a median follow-up of 61 months, 14 patients (28%) had developed recurrence. Positive LNs were not found to impact recurrence-free survival; extranodal extension and an LNR ≥ 0.26 were found to significantly increase the risk of recurrence on unadjusted analyses (p < 0.05).

CONCLUSIONS

LN metastases are frequent among patients with microPTC. A higher LNR seems to be associated with recurrence. Additional studies are needed to further clarify these findings and to assess the possible role of LNR in treatment and surveillance.

Hemithyroidectomy in Papillary Thyroid Cancers: A Prospective, Single Institutional Surgical Audit and Contemplating on the Clinical Implications of 2015 American Thyroid Association Guidelines

Papillary thyroid carcinoma (PTC) contributes to 88% of thyroid malignancies and its extent of surgical management has been a topic of debate in the past 2 decades. American thyroid association (ATA) recommendations have been periodically updated for its robust and evidence-based management. We present our experience in implementing 2015 ATA guidelines, assessment of surgical outcomes of hemithyroidectomy in PTC ≤ 4 cm and contemplating on the potential clinical implications of 2015 ATA guidelines. A prospective study in a cohort of Bethesda class V and VI PTC with nodule ≤ 4 cm who underwent Hemithyroidectomy between 2012 and 2020. Data on thyroid nodule evaluation, management, histopathology and follow up were used for risk stratification. Of 37 patients, 27 (72.9%) were low risk and 10 (37%) were intermediate risk ATA group. 4 (40%) intermediate risk patients had structural incomplete response and underwent completion thyroidectomy. 1 (2.7%) out of 4 completion surgery patients required adjuvant radio-ablation iodine (RAI) and 3 patients were under surveillance. Overall, 2 (5.4%) of 37 patients, 1 each from low and intermediate groups were given remnant RAI in view of aggressive histology, old age and unwillingness for a completion surgery. During follow up of 4.94 ± 2.4 years, 35 (94.5%) showed excellent response and 2 (5.4%) showed biochemical incomplete response. The difference in RFS between two groups was statistically significant with p < 0.001. Thyroid preserving surgery combined with real time risk stratification seems appropriate for low and intermediate risk PTC ≤ 4 cm.

BRAF V600E Status Sharply Differentiates Lymph Node Metastasis-associated Mortality Risk in Papillary Thyroid Cancer

CONTEXT

How lymph node metastasis (LNM)-associated mortality risk is affected by BRAF V600E in papillary thyroid cancer (PTC) remains undefined.

OBJECTIVE

To study whether BRAF V600E affected LNM-associated mortality in PTC.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively analyzed the effect of LNM on PTC-specific mortality with respect to BRAF status in 2638 patients (2015 females and 623 males) from 11 centers in 6 countries, with median age of 46 [interquartile range (IQR) 35-58] years and median follow-up time of 58 (IQR 26-107) months.

RESULTS

Overall, LNM showed a modest mortality risk in wild-type BRAF patients but a strong one in BRAF V600E patients. In conventional PTC (CPTC), LNM showed no increased mortality risk in wild-type BRAF patients but a robustly increased one in BRAF V600E patients; mortality rates were 2/659 (0.3%) vs 4/321 (1.2%) in non-LNM vs LNM patients (P = 0.094) with wild-type BRAF, corresponding to a hazard ratio (HR) (95% CI) of 4.37 (0.80-23.89), which remained insignificant at 3.32 (0.52-21.14) after multivariate adjustment. In BRAF V600E CPTC, morality rates were 7/515 (1.4%) vs 28/363 (7.7%) in non-LNM vs LNM patients (P < 0.001), corresponding to an HR of 4.90 (2.12-11.29) or, after multivariate adjustment, 5.76 (2.19-15.11). Adjusted mortality HR of coexisting LNM and BRAF V600E vs absence of both was 27.39 (5.15-145.80), with Kaplan-Meier analyses showing a similar synergism.

CONCLUSIONS

LNM-associated mortality risk is sharply differentiated by the BRAF status in PTC; in CPTC, LNM showed no increased mortality risk with wild-type BRAF but a robust one with BRAF mutation. These results have strong clinical relevance.

Emerging systemic antitarget treatment for differentiated thyroid carcinoma

PURPOSE OF REVIEW

We review the new systemic treatment strategies for differentiated thyroid carcinoma, as well as the acquaintance of its molecular biology.

RECENT FINDINGS

Multiple kinase inhibitor drugs have become the standard therapy for thyroid cancer, albeit several adverse effects. In the last few years, new molecules have raised with an overall safety profile. Most of them, are considered targeted therapies directed toward driven-molecules alterations, such as neurotrophic tyrosine kinase receptor (NTRK) inhibitors for NTRK-fusion thyroid cancer and rearranged during transfection (RET) inhibitors for RET-fusion thyroid cancer. Recently, promising outcomes and safety data have been presented. Furthermore, other novel strategies for advanced thyroid carcinoma are currently investigated in clinical trials.The ability to provide precision medicine to patients in routine clinical settings depends on the availability of molecular profiling test at their cancer centers. The impossibility to perform molecular characterization could turn out to be a diagnostic and treatment limitation for some patients.

SUMMARY

The treatment of advanced differentiated thyroid carcinoma has undergone rapid evolution in the last decade. An emerging treatment era is coming. From now to then, we will need to face the different types of diagnostic tools for molecular characterization, their interpretation and, finally the access to targeted therapies.

Is a simplified TNM staging system more clinically relevant than the American Joint Committee on Cancer system for the follicular variant of papillary thyroid cancer?

BACKGROUND

Despite the recent release of the 8th edition of the American Joint Committee on Cancer (AJCC) staging manual, risk stratification for the follicular variant of papillary thyroid cancer (FVPTC), which is the second common variant of papillary thyroid carcinoma (PTC) after classical PTC, remains controversial. This study aimed to develop a more accurate and relevant staging system specifically for FVPTC.

METHODS

Patients with FVPTC who were included in the Surveillance, Epidemiology, and End Results (SEER) open database between 2010 and 2015 were divided into 47 groups according to their TNM classifications and age. Subsequently, these 47 groups were categorized into appropriate stages based on Kaplan-Meier survival curves, mortality analyses, a Cox proportional hazards model, and clinical considerations.

RESULTS

Our retrospective analysis of 17,628 cases yielded the following new staging classification: stage I, defined as age <55 years and any T/N/M or age ≥55 years and T1-3/any N/M0 (n=17,427, 98.85%); stage II, age ≥55 and T4/any N/M0 or age ≥55 and any T/N0/M1 (n=173, 0.99%); and stage III, age ≥55 and any T/N1/M1 (n=28, 0.16%). The overall mortality rates per 1,000-person-years were 4.135 [95% confidence interval (CI): 3.653-4.681], 71.193 (95% CI: 51.354-98.697), and 199.744 (95% CI: 115.983-343.997) for our new stages I, II, and III, respectively. The hazard ratios for the new stages II and III (reference: stage I) were 5.081 (95% CI: 3.110-8.301) and 21.690 (95% CI: 11.402-41.258), respectively.

CONCLUSIONS

Compared to the 8th edition of the AJCC staging system, our newly proposed system provided more accurate risk stratification for patients with FVPTC, as demonstrated by actual survival and mortality outcomes. This new model may thus help guide more personalized treatment for these patients.

BRAF V600E Confers Male Sex Disease-Specific Mortality Risk in Patients With Papillary Thyroid Cancer

Purpose To test whether the prognostic risk of male sex in papillary thyroid cancer (PTC) is determined by BRAF V600E and can thus be stratified by BRAF status. Patients and Methods We retrospectively investigated the relationship between male sex and clinicopathologic outcomes in PTC, particularly mortality, with respect to BRAF status in 2,638 patients (male, n = 623; female, n = 2,015) from 11 centers in six countries, with median age of 46 years (interquartile range, 35-58 years) at diagnosis and median follow-up time of 58 months (interquartile range, 26-107 months). Results Distant metastasis rates in men and women were not different in wild-type BRAF PTC but were different in BRAF V600E PTC: 8.9% (24 of 270) and 3.7% (30 of 817; P = .001), respectively. In wild-type BRAF PTC, mortality rates were 1.4% (five of 349) versus 0.9% (11 of 1175) in men versus women ( P = .384), with a hazard ratio (HR) of 1.59 (95% CI, 0.55 to 4.57), which remained insignificant at 0.70 (95% CI, 0.23 to 2.09) after clinicopathologic multivariable adjustment. In BRAF V600E PTC, mortality rates were 6.6% (18 of 272) versus 2.9% (24 of 822) in men versus women ( P = .006), with an HR of 2.43 (95% CI, 1.30 to 4.53), which remained significant at 2.74 (95% CI, 1.38 to 5.43) after multivariable adjustment. In conventional-variant PTC, male sex similarly had no effect in wild-type BRAF patients; mortality rates in BRAF V600E patients were 7.2% (16 of 221) versus 2.9% (19 of 662) in men versus women ( P = .004), with an HR of 2.86 (95% CI, 1.45 to 5.67), which remained significant at 3.51 (95% CI, 1.62 to 7.63) after multivariable adjustment. Conclusion Male sex is a robust independent risk factor for PTC-specific mortality in BRAF V600E patients but not in wild-type BRAF patients. The prognostic risk of male sex in PTC can thus be stratified by BRAF status in clinical application.

Differentiated thyroid cancer: millions spent with no tangible gain?

The incidence of differentiated thyroid cancer (DTC) has rapidly increased worldwide over the last decades. It is unknown if the increase in diagnosis has been mirrored by an increase in thyroidectomy rates with the concomitant economic impact that this would have on the health care system. DTC and thyroidectomy incidence as well as DTC-specific mortality were modeled using Poisson regression in New South Wales (NSW), Australia per year and by sex. The incidence of 2002 was the point from which the increase in rates was assessed cumulatively over the subsequent decade. The economic burden of potentially avoidable thyroidectomies due to the increase in diagnosis was estimated as the product of the additional thyroidectomy procedures during a decade attributable to rates beyond those reported for 2002 and the national average hospital cost of an uncomplicated thyroidectomy in Australia. The following results were obtained. The incidence of both DTC and thyroidectomy doubled in NSW between 2003 and 2012, while the DTC-specific mortality rate remained unchanged over the same period. Based on the 2002 incidence, the projected increase over 10 years (2003-2012) in thyroidectomy procedures was 2196. This translates to an extra cost burden of over AUD$ 18,600,000 in surgery-related health care expenditure over one decade in NSW. Our findings suggest that, if this rise is solely attributable to overdetection, then the rising expenditure serves no additional purpose. Reducing unnecessary detection and a conservative approach to managing DTC are sensible and would lead to millions of dollars in savings and reduced harms to patients.

Optimal Cut-Off Values of Lymph Node Ratio Predicting Recurrence in Papillary Thyroid Cancer

Regional lymph node (LN) metastasis has a significant impact for prediction of recurrence in patients with papillary thyroid cancers (PTC); however, the prognostic value of the lymph node ratio (LNR), which is defined as the ratio of the number of metastatic LNs to the total number of investigated LNs, is controversial. In this study, we determined the optimal cut-off values of LNRs for the prediction of recurrence in PTC patients.This large cohort study retrospectively evaluated 2294 patients who had undergone total thyroidectomy for PTC at a single institution from October 1985 to June 2009. The prediction probability of central LNR (cLNR, level VI) and total LNR (tLNR, levels II-VI) were estimated by binominal logistic regression analysis. Hazard ratios of the cut-off LNR values for cancer recurrence were calculated for relevant covariates using multivariate Cox regression analyses. Kaplan-Meier analyses were also utilized to assess the effects of estimated LNR cut-off values on recurrence-free survival (RFS).Of the 2294 patients, 138 (6.0%) presented cancer recurrence during the follow-up period (median duration = 107.1 months). The prediction probability indicated that LNRs of 0.4 and 0.5 for central LN and total LN, respectively, are optimal cut-off values for precise prediction with minimization of outliers. Multivariate Cox regression analyses revealed that cLNR ≥0.4 was independently predictive of recurrence in patients with N0 and N1a PTCs (hazard ratio [HR]: 7.016, 95% confidence interval [CI]: 3.72-12.986, P < 0.001) and that tLNR ≥0.5 indicated a significantly increased risk of recurrence in patients with N1b PTCs (HR: 2.372, 95% CI: 1.458-3.860, P < 0.001). In addition, Kaplan-Meier analyses clearly demonstrated that these LNR cut-off values are precisely operational in RFS estimation.The cut-off LNR values of 0.4 and 0.5 for cLNR and tLNR, respectively, were identified. Risk stratification combined with these LNR cut-off values may prove useful to determine treatment and follow-up strategies for PTC patients.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Association between TNM staging system and histopathological features in patients with papillary thyroid carcinoma

We aimed to assess the validity of the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging system in patients with papillary thyroid carcinoma (PTC) by evaluating the relationships between clinicopathologic factors and TNM stage using histopathological specimens and electronic medical records. We enrolled 733 consecutive patients who had undergone thyroid surgery for PTC between 2010 and 2013. Clinical data were obtained from electronic medical records. TNM stages, multifocality, and bilaterality were analyzed after review of histopathological specimens by applying the AJCC TNM staging system. Multiple statistical analyses were performed to evaluate the correlation between the AJCC TNM staging system and the clinicopathologic factors. Of the 733 patients, there were T stage including T1a (46.9 %, 344/733), T1b (12.6 %, 92/733), T2 (2.0 %, 15/733), T3 (38.1 %, 279/733), T4a (0.4 %, 3/733), and T4b (0 %, 0/733), N stage including N0 (58.9 %, 432/733), N1a (24.3 %, 178/733), and N1b (16.8 %, 123/733), and multiplicity including multifocality (31.1 %, 228/733) and bilaterality (23.7 %, 174/733). There was a significant association between the PTC primary tumor size and T stage, N stage, multifocality, and bilaterality (p < 0.0001). Multifocality, bilaterality, and the presence of nodal metastasis were most frequently seen in patients with T3 stage (p < 0.0001). In multivariate logistic regression analyses, T and N stages were independent predictors of multiple PTCs. The PTC primary tumor size had a significant association with the T and N stages of the AJCC TNM staging system, and these factors were independent predictors of multifocality and bilaterality.