Prognostic significance of extrathyroid extension of papillary thyroid carcinoma: massive but not minimal extension affects the relapse-free survival

Single Institution Experience in the Management of Locally Advanced (pT4) Differentiated Thyroid Carcinomas

BACKGROUND

Locally infiltrating (T4) differentiated thyroid carcinomas (DTC) represent a challenge. Surgical strategy and adjuvant therapy should be planned balancing morbidity and oncologic outcome. A series of patients with T4 DTC who underwent multidisciplinary evaluation and treatment is reported. The main study endpoints were the oncologic outcome, complication rates, and risk factors for tumor recurrence.

PATIENTS AND METHODS

All DTC cases operated between 2009 and 2021 were reviewed and T4 DTC cases were identified. En bloc resection of inferior laryngeal nerve (ILN), tracheal, and/or internal jugular vein (IJV) was performed in cases of massive infiltration. In cases of pharyngoesophageal junction (PEJ) invasion, the shaving technique was always applied.

RESULTS

Among 4775 DTC cases, 60 were T4. ILN infiltration was documented in 45 cases (en bloc resection in 9), tracheal infiltration in 14 (tracheal resection in 2), PEJ invasion in 11 (R0 resection in 7 cases and < 1 cm residual tissue in 4 cases), IJV resection in 6, and laryngeal in 2. In total, 11 postoperative ILN palsy, 23 transient hypoparathyroidisms, and 2 hematomas requiring reoperation were registered. Final histology showed 7 pN0, 22 pN1a, and 31 pN1b tumors. Aggressive variants were observed in 47 patients. All but 1 patient underwent radioiodine treatment, 12 underwent adjuvant external beam radiation therapy (EBRT), and 2 underwent chemotherapy. At a median follow-up of 58 months, no tumor-related death was registered, and seven patients required reoperation for recurrence. Tracheal invasion was the only significant factor negatively impacting recurrence (p = 0.045).

CONCLUSIONS

A multidisciplinary approach is essential for the management of T4 DTC. Individualized and balanced surgical strategy and adjuvant treatments, in particular EBRT, ensure control of locally advanced disease with acceptable morbidity.

Ultrasound Imaging in Active Surveillance of Small, Low-Risk Papillary Thyroid Cancer

The recent surge in the incidence of small papillary thyroid cancers (PTCs) has been linked to the widespread use of ultrasonography, thereby prompting concerns regarding overdiagnosis. Active surveillance (AS) has emerged as a less invasive alternative management strategy for low-risk PTCs, especially for PTCs measuring ≤1 cm in maximal diameter. Recent studies report low disease progression rates of low-risk PTCs ≤1 cm under AS. Ongoing research is currently exploring the feasibility of AS for larger PTCs (<20 mm). AS protocols include meticulous ultrasound assessment, emphasis on standardized techniques, and a multidisciplinary approach; they involve monitoring the nodules for size, growth, potential extrathyroidal extension, proximity to the trachea and recurrent laryngeal nerve, and potential cervical nodal metastases. The criteria for progression, often defined as an increase in the maximum diameter of the PTC, warrant a review of precision and ongoing examinations. Challenges exist regarding the reliability of volume measurements for defining PTC disease progression. Although ultrasonography plays a pivotal role, challenges in assessing progression and minor extrathyroidal extension underscore the importance of a multidisciplinary approach in disease management. This comprehensive overview highlights the evolving landscape of AS for PTCs, emphasizing the need for standardized protocols, meticulous assessments, and ongoing research to inform decision-making.

Impact of Tumor Size on Prognosis in Differentiated Thyroid Cancer with Gross Extrathyroidal Extension to Strap Muscles: Redefining T3b

The prognostic significance of tumor size in T3b differentiated thyroid cancer (DTC) remains debated and underexplored. This study aimed to examine the varying impact of T3b based on tumor size, analyzing disease-specific survival, disease-free survival, and overall survival. A retrospective review of 6282 DTC patients who underwent thyroid surgery at Seoul St. Mary's Hospital from September 2000 to December 2017 was conducted. T3b was classified into three subcategories, T3b-1 (≤2 cm), T3b-2 (2-4 cm), and T3b-3 (>4 cm), using the same size criteria for T1, T2, and T3a. T3b-1 showed no significant difference in disease specific survival compared to T1, and both disease-free and disease-specific survival curves were sequentially ranked as T1, T3b-1, T2, T3a, T3b-2, and T3b-3. The modified T category, reclassifying T3b-1 as T1, demonstrated superior staging performance compared to the classic T category (c-index: 0.8961 vs. 0.8959 and AUC: 0.8573 vs. 0.8518). Tumors measuring 2 cm or less within the T3b category may require downstaging, and a modified T category could improve the precision of prognostic staging compared to the current T category.

A Case on Papillary Thyroid Carcinoma With Intraluminal Tracheal Extension: A Malaysian Experience and Literature Review

Papillary thyroid carcinoma (PTC) is a common malignancy originating from the thyroid gland. In rare cases, it can invade the trachea, resulting in airway obstruction. Subsequent surgical planning may be complicated as the technique selected depends on a case-by-case basis. Here, we report a case of PTC with tracheal involvement and a literature review on the latest surgical options. A 56-year-old gentleman presented with an anterior neck swelling of 3 x 3 cm for 3 months. Flexible endoscopy showed irregular mass in the subglottic region. Subsequent aspiration for cytology confirmed a diagnosis of PTC. Neck contrast enhanced computed tomography showed an ill-defined lesion in the right thyroid (3.1 x 3.8 x 2.9 cm) with a subtle irregularity of the adjacent tracheal wall suggestive of infiltration. The findings indicated a clinical staging of cT4aN0M0 (Stage III) with Shin's staging of Stage IV. The patient underwent a total thyroidectomy and a single-stage partial cricoid-tracheal resection with anastomosis. There were no immediate post-operative complications reported. Unfortunately, the patient suffered from pulmonary embolism, which eventually resulted in his demise. A subsequent histopathology report confirmed the diagnosis of PTC. Surgical planning for such cases may be complicated. The risk of recurrent laryngeal nerve injury is increased as the site of resection is close to the nerve. Multiple intraoperative nerve monitoring systems may be required. Meticulous planning of intraoperative airway management is needed as a large intraluminal tumor may interfere with intubation. Generally, extensive tracheal invasion would require radical surgical approaches such as circumferential resection and total laryngectomy. Less extensive cases can be treated with shave excision or window resection. PTC with tracheal invasion is an uncommon condition, and surgical excision is indicated for cases with high Shin's staging.

The impact of microscopic extrathyroidal extension on the clinical outcome of classic subtype papillary thyroid microcarcinoma: a multicenter study

OBJECTIVES

Despite the presumed overdiagnosis of papillary thyroid microcarcinoma (PTMC) which has resulted in a new trend toward less-extensive surgery and a preference for active surveillance, the impact of microscopic extrathyroidal extension (mETE) on the clinical outcomes of PTMC is still controversial. This study assessed the impact of mETE on the clinical outcomes of patients with classic subtype PTMC.

METHODS

The data of consecutive patients who underwent thyroidectomy and were histopathologically diagnosed as classic subtype PTMC were analyzed. Cox's proportional hazards model was used to assess the impact of contributing variables on persistent/recurrent disease. Disease-free survival was estimated using the Kaplan-Meier method.

RESULTS

This study included 1013 patients (84% females), with a mean follow-up period of 62.5 ± 35.3 months. Patients with mETE had a significantly higher rate of locoregional persistent/recurrent disease than patients without mETE (9.8% vs 2.1%, p < 0.001). The disease-free survival rate was significantly lower in patients with mETE than in those without (90.2% vs 97%, Log-Rank p < 0.001). Furthermore, mETE and neck lymph node involvement were independent predictors of persistent/recurrent disease in multivariate analysis (HR: 2.43, 95% CI:1.02-5.81, p = 0.043; HR: 4.38, 95% CI: 1.7-11.2, p = 0.002, respectively).

CONCLUSIONS

In patients with the classic subtype of PTMC, mETE is an independent predictor of persistent/recurrent disease and is associated with a lower DFS rate. However, neck lymph node involvement is the strongest predictor of persistent/recurrent disease. Therefore, PTMCs with mETE and neck lymph node involvement are at a higher risk of persistent/recurrent disease than individuals lacking both characteristics.

Papillary thyroid carcinoma: the impact of histologic vascular invasion

BACKGROUND

The American Thyroid Association (ATA) recurrence risk prediction system considers vascular invasion (VI) as a relative indicator for adjuvant radioactive iodine (RAI) treatment, nevertheless VI final role in PTC management is yet to be defined. This study aims to assess the impact of histologic VI in papillary thyroid carcinoma (PTC).

METHODS

A retrospective study with PTC patients admitted in our Thyroid Cancer Unit, between January 1960 and December 2016 was performed. We reviewed 905 patient records with 275 having full information about VI on their pathological reports. Demographic and clinical variables were obtained, and univariate/multivariate analysis was performed in order to obtain potential predictive prognostic factors.

RESULTS

Fifty-one out 275 patients presented VI (18.5%; 95% CI 14.4-23.6%), these individuals had larger tumors (median 19 mm vs. 12 mm, P<0.001) with more frequent extraglandular invasion (54.0% vs. 17.1%, P<0.001), regional lymph nodes involvement (29.8% vs. 12.6%, P=0.003)and distant metastasis (10.9% vs. 1.9%, P=0.003) at diagnosis. VI was an independent predictor for regional lymph node and/or distant metastasis at diagnosis (OR 2.93 [IC 95% 1.16-7.41, P=0.008]). After a median follow-up time was 68.5 months patients with VI presented higher rates of local recurrence and lymph node metastasis recurrence.

CONCLUSIONS

In this study, the presence of VI in PTC is associated to higher rate of lymph node and distant metastasis at diagnosis. Its presence should be probably considered an adverse prognostic factor in PTC, perhaps justifying more aggressive therapeutic and follow-up approaches in such cases.

Minimal Extrathyroid Extension (mETE) as the Only Risk Factor in Patients with Papillary Thyroid Carcinoma (PC): Its Clinical Impact on Recurrence and Outcome during Long-Term Follow-Up

Minimal extrathyroid extension (mETE) effect on papillary thyroid carcinoma (PC) prognosis is still debated even more so now that this factor has been removed in the 8th AJCC Edition, supporting the hypothesis that mETE is not associated with aggressive tumors. We retrospectively enrolled 91 PC patients (Group 1) submitted to total thyroidectomy and radioiodine ablation. At the time of the primary tumor surgery, mETE was ascertained in all patients with no other risk factors, such as multifocality, vascular invasion, neck and distant metastases, and aggressive histological variants. As controls, 205 consecutive matched PC patients (Group 2) without mETE and the aforementioned risk factors were enrolled. During the follow-up (average 8 years), 16/91 (17.58%) Group 1 patients and 15/205 (7.32%) Group 2 patients developed metastases (p = 0.0078). Cox regression analysis showed an increased risk of metastases in patients with mETE (HR: 2.58 (95% CI 1.28-5.22) p = 0.008). Disease-free survival (DFS) was significantly lower in patients with mETE than in controls (p = 0.0059). The present study seems to demonstrate that mETE can be associated with an aggressive PC and can be considered, even alone without other risk factors, an independent factor of unfavorable DFS. Thus, by excluding mETE in the 8th AJCC Edition, patient care and management could be compromised.

Radio-iodine refractory thyroid cancer patients: a tailored follow-up based on clinicopathological features

OBJECTIVE

To report the experience of a single center for the selection of radioiodine-refractory (RAIR) thyroid cancer patients (RAIR-TC) who needed tyrosine kinase inhibitor (TKIs) treatment.

PATIENTS AND METHODS

We evaluated all features of 279 RAIR-TC patients both at the time of diagnosis and at the RAIR diagnosis.

RESULTS

Ninety-nine patients received indication to TKIs (Group A), while 180 remained under active surveillance (Group B). Group A had greater tumor size, more aggressive histotype, more frequent macroscopic extrathyroidal extension, distant metastases, advanced AJCC stage, and higher ATA risk of recurrence. After RAIR diagnosis, 93.9% of Group A had progression of disease (PD) after which TKIs' therapy was started. The remaining 6.1% of patients had a so severe disease at the time of RAIR diagnosis that TKIs' therapy was immediately started. Among Group B, 42.7% had up to 5 PD, but the majority underwent local treatments. The mean time from RAIR diagnosis to the first PD was shorter in Group A, and the evidence of PD within 25 months from RAIR diagnosis was associated with the decision to start TKIs.

CONCLUSIONS

According to our results, a more tailored follow-up should be applied to RAIR-TC patients. A too strict monitoring and too many imaging evaluations might be avoided in those with less-aggressive features and low rate of progression. Conversely, RAIR-TC with an advanced stage at diagnosis and a first PD occurring within 25 months from RAIR diagnosis would require a more stringent follow-up to avoid a late start of TKIs.

Impact of microscopic extrathyroidal extension on differentiated thyroid cancer post-surgical risk of recurrence: a retrospective analysis

PURPOSE

In the last edition of the American Joint Committee on Cancer (AJCC) staging system, differentiated thyroid cancers (DTC) showing microscopic extrathyroidal extension (mETE) are considered comparable to intrathyroidal cancers for their clinical behavior and prognosis. The aim of the study is to evaluate the impact of this updated assessment of T, when applied to the postoperative recurrence risk stratification, according to the American Thyroid Association Guidelines (ATA-RR).

METHODS

One-hundred DTC patients who underwent total thyroidectomy were retrospectively evaluated. The downstaging of mETE was introduced in the definition of T, and the updated classification defined as modified ATA-RR (ATAm-RR). For each patient, post-surgical basal and stimulated thyroglobulin (Tg) levels, neck ultrasound (US) and post-ablative 131-I whole body scan (WBS) reports were considered. The predictive performance (PP) of disease recurrence was calculated both for each single parameter, as well as for all of them.

RESULTS

According to ATAm-RR classification, 19/100 patients (19%) were downstaged. ATA-RR proved a significant PP for disease recurrence (DR) (sensitivity 75.0%, specificity 63.0%, p = 0.023). However, ATAm-RR performed slightly better due to an increased specificity (sensitivity 75.0%, specificity 83.7%, p < 0.001). For both classifications, the PP was optimal when all the above-mentioned predictive parameters were considered.

CONCLUSION

Our results suggest that the new assessment of T considering mETE resulted in a downgrading of ATA-RR class in a significant number of patients. This provides a better PP for disease recurrence, and the best PP was obtained when considering the whole predictive variables together.

Comparison of staging and recurrence predictors in patients with differentiated thyroid cancer between the 7th and 8th editions of the American Joint Committee on Cancer staging systems

BACKGROUND

The predictive value of American Joint Committee on Cancer (AJCC) 8 for recurrence in differentiated thyroid cancer (DTC) is not known. We aimed to compare AJCC 7 and 8 regarding the differences in staging and recurrence predictors in DTC.

METHODS

Demographic, clinical (duration of disease and follow-up, the extent of surgery), laboratory (TSH, fT4, thyroglobulin, and antithyroglobulin), pathological (type of thyroid cancer, localization, multifocality, diameter, extrathyroidal extension [ETE], and lymph node [LN] metastasis), and imaging findings (sonography, and whole-body scan), and follow-up features (metastases, recurrence and/or persistence, and RAI need) were retrospectively analyzed in adult patients with DTC followed-up for at least six months. Staging was determined in accordance with AJCC 7 and AJCC 8, prediction of recurrence and persistence by ATA risk stratification, and death risk by AMES systems. The alterations in staging and recurrence predictors were analyzed.

RESULTS

A majority of study patients (N.=524) were female (N.=424) and diagnosed with papillary cancer (N.=511), the median age at diagnosis was 44. 97.89% (N.=93) of stage 2-4 patients (N.=95) in AJCC 7 were down-staged in AJCC 8. We down-staged 41 patients of 45-55 years of age into stage 1 in AJCC 8 independent of LN status. A percentage of 26.71% of patients (N.=140) did have persistence, 9.54% (N.=50) persistence at the last follow-up, and 9.54% (N.=50) had recurrence. According to AJCC 8, T4 and AMES high risk were predictors for recurrence (hazard ratio: 3.053, P=0.023; hazard ratio:2.465, and P=0.005; respectively). Both AJCC 7 and 8 were associated with recurrence (P=0.008 and P<0.001, respectively). Stage 4 in AJCC 7, and stages 3 and 4 in AJCC 8 better predicted the probability of recurrence.

CONCLUSIONS

Our findings suggest that AJCC 8 better predicted the recurrence in DTC than AJCC 7. In AJCC 8, T4 tumor, AMES high risk, stages 3 and 4 predicted recurrence. The vast majority of patients with stages 2-4 in AJCC 7 were down-staged in AJCC 8.

Causal inference between aggressive extrathyroidal extension and survival in papillary thyroid cancer: a propensity score matching and weighting analysis

Background

Extrathyroidal extension is a major risk factor for poor prognosis in papillary thyroid cancer. However, the effect of different degrees of extrathyroidal extension on prognosis remains controversial. We performed a retrospective study to elucidate how the extent of extrathyroidal extension in papillary thyroid cancer affected the clinical prognosis of patients and its covariates.

Methods

The study included 108,426 patients with papillary thyroid cancer. We categorized the extent of extension into none, capsule, strap muscles, and other organs. Three causal inference methods for retrospective studies, namely, inverse probability of treatment weighting, standardized mortality ratio weighting, and propensity score matching analysis, were used to minimize potential selection bias. Kaplan-Meier analysis and univariate Cox regression analyses were applied to analyze the precise effect of ETE on survival in papillary thyroid cancer patients.

Results

In the Kaplan-Meier survival analysis, only extrathyroidal extension into or beyond the strap muscles was statistically significant for both overall survival (OS) and thyroid cancer-specific survival (TCSS). In univariate Cox regression analyses before and after matching or weighting based on causal inference, extrathyroidal extension into soft tissues or other organs is a high-risk factor for both overall survival and thyroid cancer-specific survival. Sensitivity analysis revealed that lower overall survival was observed in patients with older age (≥55) and larger tumor size (>2 cm) of papillary thyroid cancer with extrathyroidal extension into or beyond the strap muscles.

Conclusions

Our study indicates that extrathyroidal extension into soft tissues or other organs is a high-risk factor in all papillary thyroid cancer. Even though invasion into the strap muscles did not seem to be a marker for poor prognosis, it still impaired the overall survival of patients with older age (≥55 years old) or larger tumor size (>2 cm). Further investigation is needed to confirm our results and to clarify further risk factors independent of extrathyroidal extension.

Surgical management of T1/T2 node-negative papillary thyroid cancer with tall cell histology: Is lobectomy enough?

BACKGROUND

The tall cell variant of papillary thyroid carcinoma has traditionally been treated more aggressively than classic papillary thyroid carcinoma. However, this may not be justified in patients with T1/T2 tall cell variant node-negative tumors.

METHODS

We evaluated well-differentiated thyroid cancers treated surgically between 1985 and 2015 at our institution. We compared patients undergoing lobectomy for node-negative T1/T2 tall cell variant tumors with the same cohort with classic papillary thyroid carcinoma. Patients who underwent early planned completion thyroidectomy were excluded. Tall cell variant tumors were defined as those with ≥30% tall cells. Survival and recurrence outcomes were determined by the Kaplan-Meier method and groups compared using the log-rank test.

RESULTS

Thyroid lobectomy was performed for T1/T2 N0X disease in 70 (15%) tall cell cases and 429 (23%) classic papillary thyroid carcinoma cases. There was no significant difference in 10-year overall survival (P = .56) or locoregional recurrence-free probability (P = .52). Disease-specific survival and local or central nodal recurrence-free probability were 100% in both groups. In 9 papillary thyroid carcinoma cases, subsequent contralateral lobe tumors developed, and in 5, lateral neck metastases developed. No recurrences were seen in the tall cell group.

CONCLUSION

T1 node-negative tumors with tall cell histology can be satisfactorily managed with thyroid lobectomy, with equivalent oncological outcomes to classic papillary thyroid carcinoma.

Clinical significance of extrathyroidal extension to major vessels in papillary thyroid carcinoma

PURPOSE

Gross extrathyroidal extension (gETE) into major vessel is considered the most advanced stage of the locally advanced papillary thyroid cancer (PTC). Surgical intervention may not benefit some patients at this disease stage or even result in intraoperative death due to massive hemorrhage; however, it is still considered an effective strategy for most cases. The lack of description for this challenging invasion in PTC warrants detailed characterization of its pattern, risk factors, optimal surgical method, and prognostic value.

METHODS

In total, 3127 patients diagnosed as having PTC were enrolled and categorized into two the following groups, namely the major vessel invasion (MVI) group (n = 30) and the control group (n = 3097). Data regarding clinicopathological and demographic characteristics, vascular invasion sites, postoperative complications, locoregional recurrence, distant metastasis, and surgical strategies were collected. Predictive disease-free survival (DFS) was also compared between the two groups.

RESULTS

MVI was independently associated with invasion of the esophageal extension, age < 55 years, tumor size > 1 cm, lateral lymph node metastasis, and distant metastasis (P = 0.00; P = 0.01; 0.05; P = 0.00; P = 0.00, respectively). The difference in the predictive DFS between the two groups was significant (P = 0.00), and the difference remained significant even in patients with ETE when compared with patients without ETE (P = 0.00). Additionally, predictive DFS did not differ significantly between patients who received vessel repairment and those who received vessel resection (P = 0.28).

CONCLUSIONS

This study first characterized the gross MVI pattern exhibited by PTC and the risk factors for MVI. Additionally, it demonstrated the DFS of patients with PTC. Extensive gross MVI significantly worsened the biological characteristics of PTC. Regardless of the high risk and difficulty of the operation, patients still benefited from the surgical intervention, and vessel repairment may be the optimal surgical strategy.

Observational management of papillary microcarcinoma appearing in the remnant thyroid after hemithyroidectomy

Active surveillance for papillary thyroid microcarcinomas (PTMCs) initiated in Japan is becoming adopted worldwide as a management option. However, it remains unclear how to manage newly appearing PTMCs in the remnant thyroid after hemithyroidectomy. We investigated the outcomes of similar observational management (OM) for PTMCs appearing in the remnant thyroid after hemithyroidectomy for papillary thyroid carcinoma (PTC) and benign thyroid nodules. Eighty-three patients were newly diagnosed with PTMC in the remnant thyroid between January 1998 and March 2017. Of these, 42 patients underwent OM with >3 times ultrasound examinations. Their initial diagnoses were PTC (initially malignant group) in 37 patients and benign nodule (initially benign group) in 5 patients. We calculated the tumor volume doubling rate (TV-DR) during OM for each PTMC. The TV-DR (/year) was <-0.1, -0.1-0.1, 0.1-0.5, and >0.5 in 12, 19, 5, and 6 patients, respectively. The TV-DRs in both groups did not statistically differ, but six patients (16%) in the initially malignant group showed moderate growth (TV-DR >0.5/year). They underwent conversion surgery and none of them had further recurrence. The remaining 36 patients retained OM without disease progression. The TV-DR in the initially malignant group was not significantly associated with patients' backgrounds or their initial clinicopathological features. None of the patients in this study showed distant metastases/recurrences or died of thyroid carcinoma. Although a portion of PTMCs appearing after hemithyroidectomy for thyroid malignancy are moderately progressive, OM may be acceptable as a management option for PTMCs appearing in the remnant thyroid after hemithyroidectomy.

Comparison of the prognostic value of AJCC cancer staging system 7th and 8th editions for differentiated thyroid cancer

BACKGROUND

In the last American Joint Committee on Cancer/Tumor, Node, Metastasis (AJCC/TNM) 8th edition (TNM8), several changes were introduced to this risk stratification system to improve the prognosis of differentiated thyroid cancer (DTC).

AIM

To validate the impact of TNM8 vs. TNM 7th edition (TNM7) in DTC in terms of predictive value in two hospitals from Buenos Aires, Argentina.

METHODS

Retrospective study of DTC patients from two institutions. Reclassification from TNM7 to TNM8, disease-specific survival (DSS), and final clinical outcomes at the end of follow-up (recurrent/persistent structural disease) (median 5 years) were analyzed. The proportion of variation explained (PVE) was used to compare the predictive capability of DSS of both classification systems.

RESULTS

Reclassification of 245 patients, aged (mean ± SD) 55 ± 15.36 years, 91% women, to TNM8 from TNM7 showed: 82% vs 57% stage I (SI), 10% vs 8.5% SII, 5% vs 22% SIII, 3% vs 12% SIV (p < 0.01). Forty percent of the population was downstaged with TNM8. Ten-year DSS rates for SI, SII, SIII and SIV in TNM7 were 100, 100, 100 and 74%, respectively and in TNM8: 97.6, 100, 100 and 37.5%, respectively. Out of 4 disease-specific deaths in SIV TNM7, one was subclassified to SI TNM8, corresponding to a 53-year-old patient with structural persistence. PVE for TNM8 (29%) was more than twice that of TNM7 (13%).

CONCLUSION

In this Argentinian DTC patients sample, it was confirmed that the new TNM8 classification is more accurate in predicting survival attributable to cancer than its previous version.

Minimal extrathyroidal extension is associated with lymph node metastasis in single papillary thyroid microcarcinoma: a retrospective analysis of 814 patients

Background

Extrathyroidal extension (ETE) is considered a major prognostic factor in papillary thyroid carcinoma (PTC). Patients with gross ETE are at increased risk of recurrence and mortality. The importance of minimal ETE still remains controversial, especially in patients with papillary thyroid microcarcinoma (PTMC). The purpose of this study was to evaluate the association between ETE and lymph node (LN) metastasis in single PTMC.

Methods

A retrospective analysis was performed of 1994 patients underwent thyroidectomy for PTC between 2012 and 2016 in a single institution. Patients with combined thyroid carcinoma of other types and those who underwent completion thyroidectomy were excluded. After further exclusion of PTC larger than 1 cm and multifocal tumors, 814 patients with single PTMC were included in the study.

Results

72.9% patients had no ETE, 25.1% minimal ETE, and 2.1% gross ETE. ETE was associated with lymphatic invasion, perineural invasion, and vascular invasion. Patients with minimal and gross ETE were also more likely to have LN metastasis, including lateral neck metastasis, compared to those without ETE. In univariate analysis, LN metastasis was associated with male gender, conventional PTC, lymphatic invasion, perineural invasion, and ETE. In multivariate analysis, male gender (OR = 1.987; 95% CI 1.369–2.884), lymphatic invasion (OR = 4.389; 95% CI 1.522–12.658), perineural invasion (OR = 6.545; 95% CI 1.262–33.948), and minimal ETE (OR = 1.852; 95% CI 1.298–2.643) were found to be independent risk factors of LN metastasis.

Conclusions

Minimal ETE is associated with LN metastasis in single PTMC, compared to no ETE. Minimal ETE should be considered in the management of patients with single PTMC, whether surgical or during active surveillance.

Prognostic Impact of Microscopic Extra-Thyroidal Extension (mETE) on Disease Free Survival in Patients with Papillary Thyroid Carcinoma (PTC)

Background: This study assessed the risk of reduced disease-free survival (DFS) and poor clinical outcome in patients with papillary thyroid carcinomas (PTC) with microscopic extra-thyroidal extension (mETE), as compared to PTC patients without mETE. Methods: Retrospective analysis of a prospective database of patients treated by total thyroidectomy and radioactive iodine (RAI) with a five-year follow-up and tumors < 40 mm. In total, 303 patients were analyzed: 30.7% presented tumors with mETE, and 69.3% without. mETE was defined as extra-thyroidal invasion without skeletal muscle involvement. The primary outcome, DFS, was defined as the interval between initial treatment and any subsequent PTC-related treatment. The second outcome was the clinical status at five years. Results: In univariate analyses, the five-year DFS was significantly lower for tumors with mETE (62.4% versus 88.1%, p < 0.001). In multivariate analysis, mETE and massive lymph node involvement (LNI) were independent prognostic factors, associated respectively with a hazard ratio of 2.55 (95% CI 1.48−4.40) and 8.94 (95% CI 4.92−16.26). mETE was significantly associated with a pejorative clinical outcome at five years, i.e., biochemical/indeterminate response and structural persistence (Respectively OR 1.83 (95% CI 0.83; 4.06) and OR 4.92 (95% CI 1.87; 12.97)). Conclusion: Our results suggest that mETE is an independent poor prognosis factor of reduced DFS and predictive of poor clinical outcome.

Is Gross Extrathyroidal Extension to Strap Muscles (T3b) Only a Risk Factor for Recurrence in Papillary Thyroid Carcinoma? A Propensity Score Matching Study

Simple Summary

In papillary thyroid carcinoma (PTC), staging classification of gross and minimal extrathyroidal extension (ETE) has been recently modified in the eighth edition of the American Joint Commission on Cancer/Union for International Cancer Control (AJCC/UICC) TNM staging system. In this study, we compared the clinicopathological characteristics and recurrence rates between minimal and gross ETE. No significant differences in the recurrence and disease-free survival rates were found between the two groups. Whether gross ETE invading strap muscles (T3b) only could be a risk factor for recurrence in PTC remains questionable.

Abstract

The presence of extrathyroidal extension (ETE) is associated with locoregional recurrence and distant metastases in papillary thyroid carcinoma (PTC). This study was designed to compare the recurrence risk between minimal ETE (mETE) and gross ETE (gETE) in patients with PTC using propensity score matching. In this study, 4452 patients with PTC who underwent thyroid surgery in a single center were retrospectively analyzed, and clinicopathological characteristics were compared according to the ETE status. Disease-free survival (DFS) and recurrence risk were compared between mETE and gETE after propensity score matching. The mean follow-up duration was 122.7 ± 22.5 months. In multivariate analysis, both mETE and gETE were not associated with recurrence risk before propensity score matching (p = 0.154 and p = 0.072, respectively). After propensity score matching, no significant difference in recurrence rates was observed between the two groups (p = 0.668). DFS of the gETE group did not significantly differ from that of the mETE group (log-rank p = 0.531). This study revealed that both mETE and gETE are not independent risk factors for the risk of recurrence in PTC. Our findings suggest that gETE invading strap muscles only might not be associated with worse oncological outcomes in PTC.

Preoperative voice analysis and survival outcomes in papillary thyroid cancer with recurrent laryngeal nerve invasion

OBJECTIVE

To investigate the clinicopathological characteristics of papillary thyroid cancer (PTC) and identify risk factors for postoperative recurrence of PTC with recurrent laryngeal nerve (RLN) involvement.

METHODS

In total, 171 patients (112 women and 59 men, age: 18-80 years, and 65 patients aged ≥ 55) with T4a PTC with RLN involvement, treated at Beijing Tongren Hospital, Capital Medical University, from January 2006 to December 2020, were retrospectively examined. Clinicopathological characteristics, including voice analysis results, and survival outcomes were assessed. The Mann-Whitney U and Kruskal-Wallis H tests were used to analyze differences in acoustic parameters. The Kaplan-Meier method was used to calculate the overall survival (OS) and recurrence-free (RFS) rates. Univariate and multivariate Cox regression analyses were performed of the clinical data.

RESULTS

The postoperative follow-up period ranged from 12 to 196 months (mean: 66.18 months). Of the 171 patients, 16 had recurrence and 8 died of thyroid-related diseases. The 5-year OS rate was 95.22%. The 5-year RFS rate was 89.38%. Jitter and shimmer were higher and maximum phonation time was shorter in patients with preoperative vocal cord paralysis (VCP) than in those without RLN involvement, and in those with RLN involvement but without preoperative VCP. Acoustic parameters were similar in patients with no preoperative VCP and those without RLN involvement. Voice analysis results did not differ between cases with RLN adhesion and RLN invasion. Univariate analysis showed that age at onset ≥ 55 years, preoperative RLN palsy, and esophageal invasion were risk factors for postoperative recurrence of PTC with RLN involvement. Multivariate analysis showed that onset age ≥ 55 years (OR 4.52, 95% confidence interval: 1.44-14.19, P = 0.010) was an independent risk factor for recurrence.

CONCLUSIONS

PTC patients with RLN invasion can achieve good outcomes. Preoperative voice analysis may offer insights into RLN function. Age of onset ≥ 55 years is an independent risk factor for postoperative recurrence in T4a PTC patients.

A critical analysis of the current TNM classification for differentiated thyroid carcinoma in young patients: Time for a change?

BACKGROUND

The current TNM classification that simply classifies differentiated thyroid carcinoma (DTC) patients younger than 55 years into stage I and stage II based on the presence or absence of distant metastases has been questioned. In this study, we reexamined the impact of T status and N status on prognosis and then developed a new prediction model to improve the predictability of cancer-specific survival (CSS) in young patients.

MATERIALS AND METHODS

Kaplan-Meier method was applied to calculate the CSS. Multivariable Cox proportional hazards models were used to assess the impact of T status and N status on CSS after adjustment for known covariates. The area under the receiver operating characteristic curve (AUC), C-index, Bayesian information criterion (BIC), and Akaike information criterion (AIC) were calculated to compare model performance.

RESULTS

A total of 9,242 DTC patients younger than 55 years were enrolled in the study. After adjusting for gender, age at diagnosis, race, pathology subtype, N stage, and M stage, T3 disease [hazard ratio (HR): 3.78, P = 0.006] and T4 disease (HR: 7.96, P < 0.001) remain independent predictors of CSS. Similarly, the 10-year CSS rate of N1b disease (HR: 3.78, P < 0.001) was significantly higher than that of N0 disease after adjustment. Moreover, Kaplan-Meier survival analysis showed that the 10-year CSS of stage II disease in younger patients with DTC showed a sharp decrease compared with that in older patients with DTC (74.47% vs. 98.43%, P < 0.001). Furthermore, a modified TNM staging system based on significantly prognostic T stage and N stage was established, which showed better performance than the current TNM staging system (P < 0.05). The new prediction model is also applicable to papillary thyroid carcinoma patients and follicular thyroid carcinoma patients.

CONCLUSIONS

This is the first study to question the rationality of the current TNM staging system for patients younger than 55 years and successfully develop a new prognostic model, which improves prognostic stratification and guides individualized management.

Minimal Extrathyroidal Extension in Predicting 1-Year Outcomes: A Longitudinal Multicenter Study of Low-to-Intermediate-Risk Papillary Thyroid Carcinoma (ITCO#4)

Background: The role of minimal extrathyroidal extension (mETE) as a risk factor for persistent papillary thyroid carcinoma (PTC) is still debated. The aims of this study were to assess the clinical impact of mETE as a predictor of worse initial treatment response in PTC patients and to verify the impact of radioiodine therapy after surgery in patients with mETE. Methods: We reviewed all records in the Italian Thyroid Cancer Observatory database and selected 2237 consecutive patients with PTC who satisfied the inclusion criteria (PTC with no lymph node metastases and at least 1 year of follow-up). For each case, we considered initial surgery, histological variant of PTC, tumor diameter, recurrence risk class according to the American Thyroid Association (ATA) risk stratification system, use of radioiodine therapy, and initial therapy response, as suggested by ATA guidelines. Results: At 1-year follow-up, 1831 patients (81.8%) had an excellent response, 296 (13.2%) had an indeterminate response, 55 (2.5%) had a biochemical incomplete response, and 55 (2.5%) had a structural incomplete response. Statistical analysis suggested that mETE (odds ratio [OR] 1.16, p = 0.65), tumor size >2 cm (OR 1.45, p = 0.34), aggressive PTC histology (OR 0.55, p = 0.15), and age at diagnosis (OR 0.90, p = 0.32) were not significant risk factors for a worse initial therapy response. When evaluating the combination of mETE, tumor size, and aggressive PTC histology, the presence of mETE with a >2 cm tumor was significantly associated with a worse outcome (OR 5.27 [95% confidence interval], p = 0.014). The role of radioiodine ablation in patients with mETE was also evaluated. When considering radioiodine treatment, propensity score-based matching was performed, and no significant differences were found between treated and nontreated patients (p = 0.24). Conclusions: This study failed to show the prognostic value of mETE in predicting initial therapy response in a large cohort of PTC patients without lymph node metastases. The study suggests that the combination of tumor diameter and mETE can be used as a reliable prognostic factor for persistence and could be easily applied in clinical practice to manage PTC patients with low-to-intermediate risk of recurrent/persistent disease.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Does macroscopic extrathyroidal extension to the strap muscles alone affect survival in papillary thyroid carcinoma?

BACKGROUND

Macroscopic extrathyroidal extension to structures adjacent to the thyroid gland is one of the most important predictors of survival in papillary thyroid carcinoma. However, the prognostic significance of macroscopic extrathyroidal extension to strap muscles alone is unknown. The aim of this study is to determine the impact on survival in patients with macroscopic extrathyroidal extension to strap muscles alone compared to those with no macroscopic extrathyroidal extension and macroscopic extrathyroidal extension involving other adjacent structures.

METHODS

After institutional review board approval, adult papillary thyroid carcinoma patients were identified from an institutional database of 6,259 patients undergoing initial surgery for well-differentiated thyroid carcinoma from 1986 to 2015. Patients were classified as having no macroscopic extrathyroidal extension, macroscopic extrathyroidal extension to strap muscles alone, or macroscopic extrathyroidal extension to other adjacent structures. Disease-specific survival was calculated using the Kaplan-Meier method and groups were compared using the log-rank test. A P value < .05 was considered statistically significant and significant factors were used in a Cox proportional hazard model to predict disease-specific survival.

RESULTS

There were 5,880 patients included in the analysis; 5,485 patients (93.3%) in the no macroscopic extrathyroidal extension group, 179 (3.0%) in the macroscopic extrathyroidal extension to strap muscles alone group and 216 (3.7%) in the macroscopic extrathyroidal extension involving other adjacent structures group. With a median follow-up of 64 months, the estimated 10-year disease-specific survival for patients with no macroscopic extrathyroidal extension, macroscopic extrathyroidal extension to strap muscles alone, and macroscopic extrathyroidal extension involving other adjacent structures were 98.9%, 95.7%, and 83.7%, respectively (P < .0001). In the ≥55-year-old cohort, the estimated 10-year disease-specific survival for patients with no macroscopic extrathyroidal extension, macroscopic extrathyroidal extension to strap muscles alone, and macroscopic extrathyroidal extension involving other adjacent structures were 97.6%, 89.3%, and 68.1%, respectively (P <.0001). After controlling for pathological nodal stage and distant metastasis stage, extent of extrathyroidal extension remained an independent predictor of disease-specific survival; patients with macroscopic extrathyroidal extension to strap muscles alone had a 3.3-fold increased likelihood of a disease-specific death compared to no macroscopic extrathyroidal extension patients (hazard ratio 3.294; 95% confidence interval 1.076-10.086, P < .0368).

CONCLUSION

In our study, patients aged ≥55 years with papillary thyroid carcinoma and macroscopic extrathyroidal extension to strap muscles alone appear to have an increased likelihood of a disease-specific death compared to patients with no macroscopic extrathyroidal extension.

Ultrasound in active surveillance for low-risk papillary thyroid cancer: imaging considerations in case selection and disease surveillance

Active surveillance (AS) of small, low-risk papillary thyroid cancers (PTCs) is increasingly studied in prospective observational studies. Ultrasound is the primary imaging modality for case selection. While researchers have put forward selection criteria for PTCs based on size, absence of suspicious lymph nodes and tumor location, there are limited reported data highlighting inherent ultrasound limitations and guidelines for case selection and follow-up. We report our experience including imaging limitations encountered in the ongoing AS prospective observational study for PTCs measuring < 2 cm at our institute. We define disease progression as an increase in size of > 3 mm in the largest dimension of nodule or evidence of metastatic disease or extrathyroidal extension. Accurate, consistent and reproducible measurements of PTCs are essential in risk stratifying patients for the option of AS or disease progression. Interobserver discrepancy, shadowing from coarse calcification and background parenchyma heterogeneity or thyroiditis can limit accurate PTC size assessment and therefore hinder patient eligibility evaluation or AS follow-up. Following the ACR Thyroid Imaging, Reporting and Data System (TI-RADS) protocol of three-axes technique to measure a thyroid nodule enables reproducibility of measurements. In patients with multi-nodular goiter, accurate identification and labeling of the PTC is important to avoid mistaking with adjacent benign nodules at follow-up. Ultrasound assessment for extrathyroid extension of PTC, and relationship of PTC to trachea and the anatomic course of the recurrent laryngeal nerve are important considerations in evaluation for AS eligibility.

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

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

The Diagnostic Usefulness of 131I-SPECT/CT at Both Radioiodine Ablation and during Long-Term Follow-Up in Patients Thyroidectomized for Differentiated Thyroid Carcinoma: Analysis of Tissue Risk Factors Ascertained at Surgery and Correlated with Metastasis Appearance

¹³¹I Single-photon emission computerized tomography/computerized tomography (SPECT/CT) in the management of patients thyroidectomized for differentiated thyroid carcinoma (DTC) was further investigated. Retrospectively, 106 consecutive DTC patients were enrolled at the first radioiodine ablation, 24 at high risk (H), 61 at low risk (L) and 21 at very low risk (VL). ¹³¹I whole-body scan (WBS) and SPECT/CT were performed after therapeutic doses using a hybrid dual-head gamma camera. At ablation, SPECT/CT correctly classified 49 metastases in 17/106 patients with a significantly (p < 0.001) more elevated number than WBS which evidenced 32/49 foci in 13/17 cases. In this case, 86/106 patients could be monitored in the follow-up including 13/17 cases with metastases already at post-therapeutic scans. SPECT/CT after radioiodine diagnostic doses more correctly than WBS ascertained disease progression in 4/13 patients, stable disease in other 4/13 cases and disease improvement in the remaining 5/13 cases. Further 13/86 patients with only residues at post-therapeutic scans showed at SPECT/CT 16 neck lymph node (LN) metastases, three unclear and 13 occult at WBS. Significant involvement of some tissue risk factors with metastasis appearance was observed, such as minimal extrathyroid tumor extension and neck LN metastases. These risk factors should be carefully considered in DTC patient follow-up where ¹³¹I-SPECT/CT routinely use is suggested as a support tool of WBS.

Analysis of risk factors and prognosis in differentiated thyroid cancer with focus on minimal extrathyroidal extension

AIMS

In contrast to all prior AJCC/TNM classifications for differentiated thyroid cancer (DTC) the 8th edition does not take minimal extrathyroidal extension (M-ETE) into consideration for local tumor staging. We therefore aimed to retrospectively assess the specific impact of M-ETE on the outcome of M-ETE patients treated in our clinic.

METHODS

DTC patients with M-ETE and a follow-up time of ≥ 5 years were included and matched with an identical number of patients without M-ETE, but with equal histopathological tumor subtype and size. The frequency of initially metastatic disease among groups was compared using Fisher's exact test, the recurrence rate by virtue of log-rank test. Fisher's exact test and multivariate analysis were used to account for the presence of confounding risk factors.

RESULTS

One hundred sixty patients (80 matching pairs) were eligible. With other confounding risk factors being equal, the prevalence of N1-/M1-disease at initial diagnosis was comparable among groups (M-ETE: 42.5 %; no M-ETE: 32.5 %; p = 0.25). No differences with regard to the recurrence rate were shown. However, M-ETE patients were treated with external beam radiation therapy more often (16.3 % vs. 1.3 %; p = 0.004) and received higher median cumulative activities of ¹³¹I (10.0 vs. 8.0 GBq; p < 0.001).

DISCUSSION

Although having played a pivotal role for local tumor staging of DTC for decades M-ETE did not increase the risk for metastases at initial diagnosis and the recurrence rate in our cohort. Patients with M-ETE had undergone intensified treatment, which entails a possible confounding factor that warrants further investigation in randomized controlled trials.

Long-term outcomes of lobectomy for papillary thyroid carcinoma with high-risk features

BACKGROUND

Lobectomy is not advocated for papillary thyroid carcinoma (PTC) with high-risk features, although there is no high-level evidence showing that this is an inferior strategy. This study aimed to examine the association between the extent of surgery and survival of patients with PTC and high-risk features.

METHODS

Consecutive patients with PTC and at least one high-risk feature treated in 2000-2012 were included in the study. High-risk features were defined as: primary tumour larger than 4 cm, gross extrathyroidal extension, macroscopic multifocality, and confirmed nodal metastasis including pathological lateral neck metastasis (pN1b) or more than five central lymph node metastases. Cox proportional hazards models were employed to measure the association between the extent of surgery and disease-specific survival (DSS) in the whole cohort and in a matched-pair analysis.

RESULTS

Among a total of 2059 patients with high-risk features, 1224 underwent lobectomy and 835 had total thyroidectomy. Patients who underwent total thyroidectomy had significantly higher rates of bilateral cancer than those who had a lobectomy (79.4 versus 2.7 per cent respectively), macroscopic multifocality (80.8 versus 32.8 per cent) and bilateral neck metastasis (30.9 versus 3.3 per cent) (all P < 0.001). With a median follow-up of 93 months, multivariable analysis showed that the extent of surgery was not associated with DSS in the whole cohort (hazard ratio 1.36, 95 per cent c.i. 0.75 to 2.48; P = 0.310). After 1 : 1 case-control matching of 528 patients, no significant difference between lobectomy and total thyroidectomy groups was observed with respect to the 10-year DSS rate (94.3 versus 95.2 per cent respectively; P = 0.323) or 10-year recurrence-free survival rate (75.8 versus 79.2 per cent; P = 0.784).

CONCLUSION

Lobectomy was not associated with significantly worse outcomes for patients with PTC and high-risk features.

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

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

Prognostic Assessment of BRAF Mutation in Preoperative Thyroid Fine-Needle Aspiration Specimens

OBJECTIVES

We investigate the potential role of BRAF testing in guiding surgical intervention in papillary thyroid carcinoma (PTC).

METHODS

Thyroid fine-needle aspiration (FNA) cases with available BRAF result and follow-up thyroidectomy for PTC were included in the study. Cytology and surgical diagnoses were correlated with BRAF status.

RESULTS

There were 151 cases of thyroid FNA specimens with BRAF testing (70 mutant and 81 wild-type BRAF) and histologically confirmed unilateral, unifocal PTCs. There were no differences in age, sex, tumor size, or lymphovascular invasion on thyroidectomy specimens between mutant and wild-type BRAF cases. BRAF mutation was significantly associated with cytology diagnosis (P < .001), PTC subtype (P < .001), extrathyroidal extension (ETE) (P = .006), and higher tumor (T) stage (P = .04). However, an analysis within the histologic subtypes of PTC revealed no significant association between BRAF mutation and ETE or higher T stage. There was also no difference in central (P = .847) or lateral (p = 1) neck lymph node (LN) metastasis.

CONCLUSIONS

BRAF mutation identified in thyroid FNA specimens correlates with histologic subtypes but is not an independent factor for predicting PTC biological behavior and should not be used to guide the extent of LN dissection.

Data set for reporting carcinoma of the thyroid: recommendations from the International Collaboration on Cancer Reporting

Thyroid cancer therapy is increasingly tailored to patients' risk of recurrence and death, placing renewed importance on pathologic parameters. The International Collaboration on Cancer Reporting (ICCR), an organization promoting evidence-based, internationally agreed-upon standardized pathology data sets, is the ideal conduit for the development of a pathology reporting protocol aimed at improving the care of patients with thyroid carcinomas. An international expert panel reviewed each element of thyroid pathology reporting. Recommendations were made based on the most recent literature and expert opinion.The data set uses the most recent World Health Organization (WHO) classification for the purpose of a more clinically and prognostically relevant nomenclature. One example is the restriction of the term minimally invasive follicular carcinoma to tumors with capsular invasion only. It reinforces the already established criteria for blood vessel invasion adopted by the most recent WHO classification and Armed Forces Institute of Pathology fascicle. It emphasizes the importance of the extent of blood vessel invasion and extrathyroid extension to better stratify patients for appropriate therapy. It is the first data set that requires pathologists to use the more recently recognized prognostically powerful parameters of mitotic activity and tumor necrosis. It highlights the importance of assessing nodal disease volume in predicting the risk of recurrence.The ICCR thyroid data set provides the tools to generate a report that will guide patient treatment in a more rational manner aiming to prevent the undertreatment of threatening malignancies and spare patients with indolent tumors the morbidity of unnecessary therapy. We recommend its routine use internationally for reporting thyroid carcinoma histology.

Minimal extrathyroid extension in papillary micro carcinoma of the thyroid is an independent risk factor for relapse through lymph node and distant metastases

Aims: Minimal extrathyroid extension (mETE) is no longer considered in the new 8th edition of the AJCC/UICC staging system. Therefore, papillary thyroid microcarcinoma with mETE previously staged as pT3 will now be staged as pT1a and most likely not receive adjuvant radioiodine therapy. However, it remains unclear if mETE is associated with higher aggressiveness in papillary thyroid microcarcinoma. Therefore, the aim of this study was to investigate if mETE is associated with higher risk of lymph node or distant metastases. Methods: 721 patients with thyroid papillary microcarcinoma presenting at our department for postoperative counseling from 05/1983 to 8/2012 were included in this retrospective analysis (median follow-up time 9.30 years). The impact of mETE on the presence of lymph node metastases at thyroidectomy and relapse through lymph node and distant metastases was assessed by logistic regression and Fine-Gray model analyses. Results: 10.7% (n = 77) of patients had mETE. mETE was an independent risk factor for lymph node metastases at thyroidectomy with an adjusted odds ratio of 4.33 (95%CI: 2.02-9.60, p<0.001) in multivariable analysis. Patients with mETE had significantly more relapses through lymph node (over 5 years: 13.1% vs. 1.25%; P < 0.001) and distant metastases (over 5 years: 7.8% vs. 1.1%; P < 0.001) compared to patients without mETE. mETE was an independent risk factor for relapse through lymph node and distant metastases in multivariable analysis (hazard ratio: 7.78, 95%CI: 2.87-21.16, p< 0.001 and 4.09, 95%CI: 1.25-13.36, P = 0.020). Conclusion: mETE is a statistically significant and independent risk factor for relapse through lymph node and distant metastases in papillary microcarcinoma. Therefore, future studies should evaluate, if patients with mETE and microcarcinoma might benefit from intensified surveillance and therapy.

The new T3b category has clinical significance? SEER-based study

OBJECTIVE

As per the eighth edition of the American Joint Committee on Cancer (AJCC) staging system for differentiated thyroid carcinoma (DTC), minimal extrathyroidal extension (mETE) has been removed. Instead, gross ETE (gETE) invading only strap muscles has been designated as a new T3b category. Our objective was to investigate the impact of the T3b category on survival in order to establish its prognostic value in DTC.

DESIGN

In this retrospective study, we included patients who had undergone thyroidectomy between 2004 and 2012. Data from the Surveillance, Epidemiology and End Results (SEER) database were examined.

METHODS

We used the Kaplan-Meier method and log-rank test to analyse overall survival (OS) and cancer-specific survival (CSS). The effect of potential predictors associated with survival were estimated using the Cox regression model. To minimize selection bias, propensity-score matching (PSM) was performed.

RESULTS

A total of 63 315 patients were included in our study. During the average follow-up duration of nearly 78 months, significant differences were observed in cancer-specific survival among patients with no ETE, mETE, gETE invading only strap muscles (T3b) and gETE invading perithyroidal structures other than strap muscles (T4) (P < .05). In univariable and multivariate analysis, both mETE and T3b exhibited significant poorer CSS compared with no ETE. After adjusting for patient features with PSM, it was confirmed that T3b was associated with worse CSS compared with no ETE and mETE.

CONCLUSIONS

Both mETE and gETE are independent factors for DTC, implying that the new T3b category is worthy of reference for medical workers. Furthermore, mETE was significantly associated with poorer outcome. Our conclusion may provide support for the modification of the TNM staging system in the future.

Papillary thyroid microcarcinoma with minimal extrathyroidal extension. Is its course so indolent that it requires a less aggressive treatment?

BACKGROUND

Although the incidence of papillary thyroid microcarcinoma (PTMC) has increased in recent decades, the role played by minimal extrathyroidal extension (mETE) in the prognosis of PTMC is still unclear. The aim of this study is to analyze the factors associated with PTMC with mETE and its long-term prognosis.

MATERIAL AND METHODS

We conducted a retrospective study on patients with a histological diagnosis of PTMC. We excluded patients who had previously undergone thyroid surgery, those who had other synchronous malignancies, those with an ectopic location of the PTMC, and those lost to follow-up within 2years. We compared group 1 (PTMC without extrathyroidal extension) to group 2 (PTMC with mETE) and performed a multivariate analysis.

RESULTS

We observed PTMC with mETE in 11.2% (n=18) of patients. On the multivariate analysis, mETE was associated with age ≥45 years (OR: 4.383; 95% CI: 1.051-18.283, p = .043), tumor size ≥8mm (OR: 5.913; 95% CL: 1.795-19.481; p = .003), bilaterality (OR: 4.430; 95% CI: 1.294-15.173; p = .018) and metastatic lymph nodes (OR: 12.588; 95% CI: 2.919-54.280; p = .001). During a mean follow-up of 119.8±65 months, one recurrence was detected in group 2 (0% vs. 5.6%; p = .112). No patients died of the disease. Disease-free survival was lower in group 2 (124.9±5.6 vs. 97.4±10.3 months; p = .034).

CONCLUSIONS

The mETE of PTMC is a factor of worse prognosis associated with the presence of metastatic lymph nodes and a lower rate of disease-free survival.

Papillary thyroid microcarcinoma with minimal extrathyroidal extension. Is its course so indolent that it requires a less aggressive treatment?

BACKGROUND

Although the incidence of papillary thyroid microcarcinoma (PTMC) has increased in recent decades, the role played by minimal extrathyroidal extension (mETE) in the prognosis of PTMC is still unclear. The aim of this study is to analyze the factors associated with PTMC with mETE and its long-term prognosis.

MATERIAL AND METHODS

We conducted a retrospective study on patients with a histological diagnosis of PTMC. We excluded patients who had previously undergone thyroid surgery, those who had other synchronous malignancies, those with an ectopic location of the PTMC, and those lost to follow-up within two years. We compared group 1 (PTMC without extrathyroidal extension) to group 2 (PTMC with mETE) and performed a multivariate analysis.

RESULTS

We observed PTMC with mETE in 11.2% (n = 18) of patients. On the multivariate analysis, mETE was associated with an age ≥45 years (OR: 4.383; 95% CI: 1.051-18.283, p = .043), tumor size ≥8 mm (OR: 5.913; 95% CI: 1.795-19.481; p = .003), bilaterality (OR: 4.430; 95% CI: 1.294-15.173; p = .018) and metastatic lymph nodes (OR: 12.588; 95% CI: 2.919-54.280; p = .001). Over the mean follow-up period of 119.8 ± 65 months, one case of recurrence was detected in group 2 (0% vs. 5.6%; p = .112). No patients died of the disease. Disease-free survival was lower in group 2 (124.9 ± 5.6 vs. 97.4 ± 10.3 months; p = .034).

CONCLUSIONS

The mETE of PTMC is a factor of worse prognosis associated with the presence of metastatic lymph nodes and a lower rate of disease-free survival.

Surgical Management of Tracheal Invasion by Well-Differentiated Thyroid Cancer

Simple Summary

Tracheal invasion is a poor prognostic factor in well-differentiated thyroid cancer. Appropriate resection can improve the prognosis and maintain the patient’s quality of life. Shaving resection for superficial tracheal invasion is minimally invasive because it does not involve the tracheal lumen, despite the problematic risk of local recurrence. Window resection for tracheal mucosal and luminal invasion provides good tumor control and does not cause postoperative airway obstruction; however, the need for surgical closure of the tracheocutaneous fistula is a disadvantage of this method. Circumferential (sleeve) resection and end-to-end anastomosis are highly curative, but the risk of fatal complications, such as anastomosis dehiscence, is a concern.

Abstract

Well-differentiated thyroid carcinoma (WDTC) is a slow-growing cancer with a good prognosis, but may show extraglandular progression involving the invasion of tumor-adjacent tissues, such as the trachea, esophagus, and recurrent laryngeal nerve. Tracheal invasion by WDTC is infrequent. Since this condition is rare, relevant high-level evidence about it is lacking. Tracheal invasion by a WDTC has a negative impact on survival, with intraluminal tumor development constituting a worse prognostic factor than superficial tracheal invasion. In WDTC, curative resection is often feasible with a small safety margin, and complete resection can ensure a good prognosis. Despite its resectability, accurate knowledge of the tracheal and peritracheal anatomy and proper selection of surgical techniques are essential for complete resection. However, there is no standard guideline on surgical indications and the recommended procedure in trachea-invading WDTC. This review discusses the indications for radical resection and the three currently available major resection methods: shaving, window resection, and sleeve resection with end-to-end anastomosis. The review shows that the decision for radical resection should be based on the patient’s general condition, tumor status, expected survival duration, and the treating facility’s strengths and weaknesses.

Changes in Stage Distribution and Disease-Specific Survival in Differentiated Thyroid Cancer with Transition to American Joint Committee on Cancer 8th Edition: A Systematic Review and Meta-Analysis

BACKGROUND

Recent revision significantly changed the American Joint Committee on Cancer (AJCC) staging criteria for differentiated thyroid cancer (DTC). To quantitatively evaluate resulting changes in patient stage distribution and the associated disease-specific survival (DSS) incorporating diverse populations, we performed a meta-analysis of studies comparing the AJCC 7th edition (AJCC-7) with 8th edition (AJCC-8) staging for DTC.

MATERIALS AND METHODS

After PROSPERO registration (#CRD42019123657), publications in English reporting DSS of DTC with AJCC-7 and AJCC-8 from inception to June 2019 were identified by search of MEDLINE and PubMed. Random-effects meta-analyses were conducted to compare differences in survival between AJCC-7 and AJCC-8. Pooled hazard ratios, 10-year DSS, and corresponding interval estimates were calculated for AJCC subgroups. Differences in survival between editions were assessed using subgroup analysis with nonoverlapping confidence intervals indicating statistical significance.

RESULTS

Final analysis included six studies with 10,850 subjects and median follow-up from 55 to 148 months. Use of AJCC-8 shifted classification to earlier stages: stage I, from 60% to 81%; stage II, from 5% to 13%; stage III, from 21% to 2%; stage IV, from 10% to 3%. Ten-year DSS was significantly lower in AJCC-8 versus AJCC-7 in patients with stage II (88.6%, 95% confidence interval [CI] 82.7-94.6% vs. 98.1%, 95% CI 96.6-99.6%, respectively) and stage III disease (70.5%, 95% CI 59.1-83.9% vs. 96.8%, 95% CI 94.1-99.64%, respectively).

CONCLUSION

Meta-analysis of revised AJCC staging for DTC, incorporating diverse populations, demonstrates redistribution of patients toward earlier clinical stages and better stratification of disease-specific mortality risk, specifically among patients now classified with stage II and III disease.

IMPLICATIONS FOR PRACTICE

This study provides updated estimates of disease-specific survival for patients with differentiated thyroid cancer determined by the American Joint Committee on Cancer staging system that are generalizable to broader populations and support improved stratification using the recently revised criteria.

Current surgical treatment of intermediate risk differentiated thyroid cancer: a systematic review

Introduction: Surgical treatment of thyroid cancer has become less aggressive but for many patients, the threshold for performing total thyroidectomy (TT), as opposed to thyroid lobectomy (TL), has remained unclear. Current American Thyroid Association (ATA) guidelines encourage more individualization of treatment options, which necessitates explicit review of the pros and cons of the different options with patients.Areas covered: This review focuses on the extent of surgery for treatment of intermediate-risk differentiated thyroid cancer, restricted to relevant literature available after publication of the 2015 ATA guidelines.Expert opinion: Dynamic risk-stratification facilitates a tailored approach when deciding on the extent of surgery for thyroid cancer. Treatment with TT allows for a lower recurrence risk, a simpler follow-up regimen, and treatment with adjuvant post-operative radioactive iodine. Treatment with TL has a lower associated risk of complications and avoidance of lifelong thyroid hormone replacement but has a significant risk of requiring a completion thyroid lobectomy (CT). Overall, treatment with TL and TT have comparable survival outcomes, but TL is the more cost-effective option. Larger cancer size is correlated with worse clinical outcomes, and numerous subgroup analyses have shown poorer outcomes for cancers with a diameter that is 2-4 cm compared to 1-2 cm.

How Does The AJCC/TNM Staging System Eighth Edition Perform in Thyroid Cancer at A Major Middle Eastern Medical Center?

OBJECTIVE

The American Joint Committee on Cancer tumor node metastasis (TNM) staging system eighth edition (TNM-8) for differentiated thyroid cancer (DTC) has been introduced as a replacement for tumor node metastasis staging system seventh edition (TNM-7). We present the first study from a Middle Eastern population comparing these 2 versions of the TNM staging system.

METHODS

We compared TNM-8 with TNM-7 in 701 patients with DTC seen during a 3-year period with a median age of 37 years (6-83) and a female-to-male ratio of 558 (79.6%) to 143 (20.4%).

RESULTS

The number (%) of patients within each stage in TNM-7 and TNM-8, respectively, are as follows: stage I = 503 (71.6%) and 583 (83.2%), stage II = 52 (7.4%) and 81 (11.4%), stage III = 53 (7.6%) and 6 (0.9%), and stage IV = 93 (13.2%) and 31 (4.6%). Overall, 172 patients (24.5%) were downstaged in TNM-8 compared to that in TNM-7, as follows: 26, 30, and 24 patients from stages II, III, and IV in TNM-7 to stage I in TNM-8; 23 and 32 patients from TNM-7 stages III and IV to TNM-8 stage II; 6 patients from stage IVa in TNM-7 to stage III in TNM-8; and 31 patients from stage IVc in TNM-7 to stage IVb in TNM-8. TNM-7 and TNM-8 predicted the long-term outcome well (median follow-up, 7.9 years), but Kaplan-Meier analysis showed better separation of cancer-specific survival in TNM-8 compared to TNM-7.

CONCLUSIONS

Compared with TNM-7, TNM-8 approximately downstaged a quarter of DTC patients and was more robust in separating the outcome of different stages over time.

Effects of the Minimal Extrathyroidal Extension on Early Response Rates after (Adjuvant) Initial Radioactive Iodine Therapy in PTC Patients

Simple Summary

The aim of our retrospective study was to evaluate the impact of minimal extrathyroidal extension on early response rate after (adjuvant) initial radioactive iodine therapy in patients with papillary thyroid cancer (PTC). We found that response rates after radioactive iodine (RAI) therapy in PTC patients were achieved irrespective of minimal extrathyroidal extension (mETE). Nonetheless, the risk of lymph node metastases involvement was significantly higher in the mETE patient group.

Abstract

Background: Extrathyroidal extension of differentiated thyroid cancer is a poor outcome factor but seems to be less significant in minimal extrathyroidal extension (mETE). However, the impact of mETE on response rate after (adjuvant) initial radioactive iodine (RAI) therapy remains unclear. We therefore compared response rates of patients with classical and follicular variants of papillary thyroid cancer (PTC) according to the updated eighth tumor-node-metastasis (TNM) classification to a control group. Methods: 455 patients with T3 (primary tumor > 4 cm) PTC according to the seventh classification who underwent total thyroidectomy followed by RAI therapy were screened. Patients formerly classified as T3 PTC solely due to mETE were reclassified into patients with T1 (primary tumor ≤ 2 cm) or T2 (primary tumor > 2 cm but ≤ 4 cm) +mETE and compared to a control group of T1/T2 −mETE PTC patients. Results: 138/455 patients were reclassified as T1/2 +mETE and compared to 317/455 T1/T2 −mETE control patients. At initial presentation, +mETE patients showed significantly higher rates of cervical lymph node metastases (p-value 0.001). Response rates were comparable in both groups (p-value n.s.). N1a/N1b-stage (Hazard ratio, HR 0.716; 95% CI 0.536–0.956, p-value 0.024) was identified as an independent prognostic factor for lower response rates. Conclusion: Response rates after RAI therapy were comparable in PTC patients irrespective of mETE but with higher rates of lymph node metastases.

Dynamic Risk Stratification for Predicting Treatment Response in Differentiated Thyroid Cancer

Prognosis in Differentiated Thyroid Cancer (DTC) patients is excellent, but a significant degree of overtreatment still exists because of the inability to accurately identify small patient cohorts who experience a more aggressive form of the disease, often associated with certain poor prognostic factors. Identifying these cohorts at an early stage would allow patients at high risk to receive more aggressive treatment while avoiding unnecessary and invasive treatments in those at low risk. Most risk stratification systems include age, tumor size, grade, presence of local invasion, and regional or distant metastases. Here we discuss these common factors as well as their association with treatment response, but also other upcoming markers including histology and multifocality of primary tumor, dose administered and preparation method for Radioiodine Therapy (RAI), Thyroglobulin (Tg), Anti-thyroglobulin Antibodies (Tg-Ab) levels both at initial management and during follow-up, and the presence of previously existing benign thyroid disease. In addition, we examine the role of remnant size and avidity as well as surgeons' experience in performing thyroidectomies with recurrence rate, discussing its impact on disease prognosis. Our results reveal that treatment response has a statistically significant association with histology, T and M stages, surgeons' experience, Tg levels and remnant score both during RAI and follow up and Tg-Ab levels during follow-up whole body scan (WBS).

Sonographic Assessment of the Extent of Extrathyroidal Extension in Thyroid Cancer

Objective

This study aimed to determine the sonographic features suggestive of extrathyroidal extension (ETE) of thyroid cancers.

Materials and Methods

We retrospectively reviewed the sonographic images of 1656 consecutive patients who had undergone thyroidectomy in 2017. The diagnostic performance of sonographic features suggestive of ETE was evaluated using operation and histopathologic reports. Sonographic features for gross ETE to the strap muscle and minor ETE were assessed for thyroid cancer abutting the anterolateral thyroid capsule. Sonographic features for tracheal invasion were assessed according to whether the angle between the tumor and the trachea was an acute, right, or obtuse angle. Sonographic features for recurrent laryngeal nerve (RLN) invasion were assessed based on the association between the tumor and tracheoesophageal groove (TEG) as preserved normal tissue, abutting or protruding into the TEG.

Results

ETE was observed in 783 patients (47.3%), including 123 patients with gross ETE (7.4% [strap muscle, n = 97; RLN, n = 24; and trachea, n = 14]) and 660 patients with minor ETE (39.9%). Regarding the diagnosis of gross and minor ETE to the strap muscle, sonographic features of replacement of the strap muscle and capsular disruption showed the highest positive predictive value (75.9% and 58.5%, respectively). Thyroid cancer forming an obtuse angle with the trachea had the highest sensitivity for the diagnosis of tracheal invasion (85.7%), and thyroid cancer protrusion into the TEG showed the highest sensitivity for the diagnosis of RLN (83.3%).

Conclusion

Sonography is considered beneficial in the diagnosis of ETE to the strap muscle, trachea, and RLN. Assessment of ETE is important for the accurate staging of thyroid cancer, which in turn determines the extent of surgery or whether active surveillance is appropriate or not.

Extrathyroidal extension predicts negative clinical outcomes in papillary thyroid cancer

BACKGROUND

The eighth edition American Joint Committee on Cancer tumor-node-metastasis staging for well-differentiated thyroid cancers, no longer considers "minimal" extrathyroidal extension for tumor staging. This change prompted us to examine the effect of extrathyroidal extension on patient outcomes.

METHODS

Patients (n = 177,497) in the 2016 National Cancer Database with classic papillary thyroid cancer were evaluated to determine the effect of extrathyroidal extension on overall survival and risk for nodal and distant metastases. Kaplan-Meier curves with the log-rank test were used to evaluate survival differences. Multivariable Cox and logistic regression analyses included relevant clinicopathologic variables (e.g. age, sex, race, and Charlson Comorbidity Index).

RESULTS

Patients with "minimal" extrathyroidal extension had worse survival versus patients with no extrathyroidal extension (10-year survival 89.3% vs 93.1%, hazard ratio 1.23; 95% confidence interval, 1.13-1.35; P < .001). Any extrathyroidal extension was associated with higher risks for lymph node (odds ratio 2.78; 95% confidence interval, 2.69-2.87) and distant metastasis (odds ratio 3.5; 95% confidence interval, 3.05-4.04). These associations persisted when comparing "micro" (extension into the thyroid capsule) versus none for nodal risk (odds ratio 1.25; 95% confidence interval, 1.18-1.33) and distant metastasis (OR 1.52; 95% confidence interval, 1.11-2.09).

CONCLUSION

All levels of extrathyroidal extension, including microscopic, were associated with increased risk for nodal and distant metastasis. Both minimal and macroscopic extrathyroidal extension were also associated with decreased overall survival. Such findings have the potential to affect the clinical decision making for patients diagnosed with papillary thyroid cancer.

Is There a Difference Between Minimal and Gross Extension into the Strap Muscles for the Risk of Recurrence in Papillary Thyroid Carcinomas?

Background: The morbidity of papillary thyroid carcinoma (PTC) is primarily related to locoregional recurrences and distant metastases. The definition of minimal extrathyroidal extension (mETE) has been recently revised. The presence of mETE does not impact mortality and is generally not considered to be a predictor for the risk of recurrence. This study aimed at comparing the risk of recurrence and the response to therapy of PTC with mETE and gross extrathyroidal extension (ETE) into the strap muscles (gETE) with low- and intermediate-risk PTC without ETE (low risk w/o ETE and intermediate risk w/o ETE, respectively) to further characterize the impact of ETE on outcomes. Methods: A total of 596 PTCs were analyzed according to the degree of ETE as well as other predictors of recurrence. Four groups of patients were compared, low risk w/o ETE (n = 251), intermediate risk w/o ETE (n = 89), mETE (n = 191), and gETE (n = 65), to determine the risk of recurrence and the response to treatment. Cox proportional hazards models were used to investigate associations between groups and disease-free survival (DFS). Results: The risk of recurrence was 3% in low risk w/o ETE PTC, 14% in intermediate risk w/o ETE, 14% in mETE, and 25% in gETE. The recurrence risk was increased by the presence of ETE (odds ratio [OR] = 2.86, 95% confidence interval [CI] 1.36-5.85, p = 0.005) and lymph node metastases (OR = 2.44 [95% CI 1.25-4.76], p = 0.009). Patients with low-risk carcinomas w/o ETE experienced longer DFS than those with mETE (hazard ratio = 0.08 [95% CI 0.02-0.28], p < 0.001), but no significant difference was observed between intermediate risk w/o ETE, mETE, and gETE. In terms of the response to therapy, patients with gETE had higher rates of biochemical and/or structural incomplete responses within the first year of treatment (OR = 2.68 [95% CI 1.31-5.45], p = 0.007) and at the final follow-up evaluation (OR = 4.35 [95% CI 1.99-9.51], p < 0.001) compared with those with mETE. An analysis of the subgroups of microcarcinomas without lymph node metastases revealed no significant difference in DFS or the response to therapy between the low risk w/o ETE and mETE PTC groups. Conclusions: The results of this study suggest that both mETE and gETE are independent risk factors for the risk of recurrence in PTC. Although gETE has a more pronounced impact on the recurrence risk and is associated with a worse response to therapy, mETE may not be associated with a low risk of recurrence. This observation suggests that patients with PTC and mETE may, in part, have an intermediate risk of recurrence and need to be followed accordingly.

Locally unresectable differentiated thyroid cancer: outcomes and perspectives

PURPOSE

Differentiated thyroid cancer (DTC) patients with an unresectable primary tumor cannot benefit from curative surgery, and radioiodine treatment for locoregional and distant disease is not possible with the thyroid gland still in place. Due to local invasion, these patients cannot be included in clinical trials, so that treatment options are limited. The aim of this study was to describe the characteristics and the prognosis of patients with these locally unresectable DTC.

PATIENTS AND METHODS

A retrospective and multicentric analysis of consecutive cases of unresectable DTC diagnosed between 2000 and 2015 was performed.

RESULTS

The study population consisted in 22 patients, 13 females (59%); median age: 77 years (range: 52-91). Thyroid tumors were papillary in six, follicular in seven, Hürthle cell in one and poorly differentiated in eight patients. Patients were treated with external beam radiation therapy (EBRT) (57%), locoregional therapy of distant metastases (41%), cytotoxic chemotherapy (38%) and tyrosine kinase inhibitors (TKIs) (33%). TKI treatment resulted in median disease control duration of 7 months with a grade 3-4 toxicity rate of 44%. Only one patient had a total thyroidectomy after neo-adjuvant EBRT. The 1, 3 and 5-year cumulative survival rate was 81%, 27.7% and 21.5%, respectively. The cause of death was DTC in 11 cases (local progression in 7), and to other causes in 7 cases; no patient died from treatment toxicity.

CONCLUSIONS

Clinical trials and approved treatments are lacking for unresectable DTC. TKI treatment may allow prolonged disease control with acceptable toxicity.

Comparison of long-term prognosis for differentiated thyroid cancer according to the 7th and 8th editions of the AJCC/UICC TNM staging system

BACKGROUND

The 8th edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumor-node-metastasis (TNM) staging system was released with major revisions. The purpose of this retrospective study was to investigate differences between the 7th and 8th editions of the AJCC/UICC TNM staging system and to compare the predictability of prognosis between the two staging systems with patients who underwent thyroidectomy for differentiated thyroid cancer (DTC) at a single institution.

METHODS

A total of 3238 patients underwent thyroid operation from January 2002 to December 2006 at Yonsei University Hospital (Seoul, Korea), of which 2294 with complete clinical data and sustained follow up were enrolled. Clinicopathologic features and TNM staging by applying the 7th and 8th editions of the AJCC/UICC were analyzed retrospectively by the complete review of medical charts and pathology reports of patients. Mean follow-up duration was 132.9 ± 27.9 months.

RESULTS

A significant number of T3 patients were downstaged to T1 (838, 36.5%) and T2 (122, 5.3%). After applying the 8th edition of the AJCC/UICC TNM staging system, the number of stage I patients increased significantly from 1434 (62.5%) to 2058 (89.7%), whereas numbers of stage III and IV patients decreased significantly from 644 (28.1%) to 33 (1.4%) and from 199 (8.7%) to 17 (0.7%), respectively. According to Kaplan-Meier survival analyses and values of the Harrell's c-index and integrated area under the curve (iAUC), the 8th edition has significantly better predictive performance for disease-free survival (DFS) and disease-specific survival (DSS) than the 7th edition.

CONCLUSIONS

A significant population was downstaged after applying the 8th edition of the AJCC/UICC TNM staging system, and the 8th edition provided significantly better accuracy in predicting DFS and DSS in patients with DTC.

The impact of minimal extrathyroidal extension in the recurrence of papillary thyroid cancer patients

OBJECTIVE

We aimed to evaluate the impact of minimal extrathyroidal extension (mETE) alone on the risk of recurrence of papillary thyroid carcinoma (PTC). The impact of other factors, including multifocality, age, tumor size, and stimulated thyroglobulin (sTg) values was also assessed.

SUBJECTS AND METHODS

We retrospectively analyzed 1,108 PTC patients from a medical institution, who presented tumors ≤ 4 cm without any adverse characteristics other than mETE. Patients were classified according to their response to initial treatment 12 to 24 months after surgery as proposed by the 2015 American Thyroid Association (ATA) guideline. Statistical analysis was performed using multivariate logistic regression and receiver operating characteristic (ROC) curve.

RESULTS

In the multivariate logistic regression analysis, mETE did not have an impact on the response to initial treatment (p = 0.44), similar to multifocality, age, and tumor size. Initial Tg value was the only variable associated with a poor response (p < 0.01, odds ratio = 1.303, 95% confidence interval 1.25-1.36). The ROC analysis revealed that Tg was significant (area under curve = 0.8750); the cutoff value of sTg as a predictor of poor response was 10 ng/mL (sensitivity = 72.2%, specificity = 98.5%).

CONCLUSION

For low-risk PTC presenting mETE as the only aggressive feature, the initial sTg value is essential to identify patients who may have a poor response after initial treatment and benefit from further treatment. Arch Endocrinol Metab. 2020;64(3):251-6.