Tae-Yon Sung

Long-term clinical outcome of differentiated thyroid cancer patients with undetectable stimulated thyroglobulin level one year after initial treatment.

BACKGROUND Measurement of the serum thyroglobulin (Tg) level with TSH stimulation (sTg) is the cornerstone of monitoring for the recurrence or persistence of differentiated thyroid cancer (DTC) in patients who have undergone surgery and remnant ablation. However, there have been several reports that an undetectable sTg could not predict the absence of future recurrence. The aim of this study was to evaluate the long-term outcome of DTC patients who achieved biochemical remission (BR, defined as sTg<1 ng/mL) after initial treatment, and to determine the role of repeated sTg measurement in detecting a clinical recurrence. METHODS This is a retrospective observational cohort study in a tertiary referral hospital. There were 1010 DTC patients who achieved BR at 12 months after the initial treatment (surgery and ablation), and they were eligible for analysis. Among them, 787 patients had values of repeated sTg. RESULTS Thirteen out of 1010 (1.3%) patients had clinical recurrences during a median 84 months of follow-up. All of the clinical recurrences were limited to the cervical lymph nodes without clinical evidence of distant metastasis. Among 787 patients with available repeated sTg, 10 had clinical recurrences (5 out of 750 patients with repeated sTg<1 ng/mL and 5 out of 37 patients with repeated sTg ≥ 1 ng/mL). Patients with repeated sTg ≥ 1 ng/mL had a much greater chance of disease recurrence (log-rank statistics=43.7, df=1, p<0.001). CONCLUSIONS About 1% of DTC patients who had sTg<1 ng/mL 12 months after initial treatment had a clinical recurrence. All of clinical recurrences were loco-regional recurrences. Although repeated sTg measurement can be helpful to predict recurrence, we could not recommend it for surveillance in patients with BR due to its very low yield.

Familial history of non‐medullary thyroid cancer is an independent prognostic factor for tumor recurrence in younger patients with conventional papillary thyroid carcinoma

It is not clear whether familial non‐medullary thyroid cancer (FNMTC) is more aggressive and has a poorer prognosis, than sporadic carcinoma. Therefore, the optimal clinical approach for FNMTC is yet to be established. In this study, we investigated the biological behavior and prognosis of FNMTC compared with its sporadic counterpart.

The Role of Core-Needle Biopsy as a First-Line Diagnostic Tool for Initially Detected Thyroid Nodules

BACKGROUND The aim of this study was to evaluate the role of core-needle biopsy (CNB) as a first-line diagnostic tool for initially detected thyroid nodules. METHODS This observational study evaluated 632 initially detected thyroid nodules in 632 consecutive patients who underwent CNB between October 2008 and December 2011. CNB results were categorized into the six categories of the Bethesda System. A final diagnosis of malignancy was based on surgery or CNB, whereas a final diagnosis of benign nodules was based on surgery, two benign biopsy results, or benign cytology of stable size after one year. The rates of Bethesda category 1 and inconclusive results, diagnostic performance, unnecessary surgery, and complications were evaluated. Subgroup analysis based on nodule size was performed. Risk factors for inconclusive results were evaluated by multivariate logistic regression analysis. RESULTS The rates of Bethesda category 1 and inconclusive results by CNB were 1.3% and 5.9%, respectively. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of malignancy were 97.6%, 90.0%, 100%, 100%, and 92.3%, respectively. The rate of unnecessary surgery was 0.5%, and the complications rate was 0.2%. Based on subgroup analysis, the diagnostic performance was not significantly associated with nodule size. There were no independent risk factors associated with inconclusive results. CONCLUSION CNB showed low rates of Bethesda category 1 and inconclusive results and a high diagnostic accuracy. CNB also minimized unnecessary surgery. CNB seems to be a promising diagnostic tool for patients with initially detected thyroid nodules.

Recent Changes in the Clinical Outcome of Papillary Thyroid Carcinoma With Cervical Lymph Node Metastasis

CONTEXT The prognosis of papillary thyroid cancer (PTC) with cervical lymph node (LN) metastasis has changed with increased detection of subclinical metastatic LNs. The number and size of metastatic LNs were proposed as new prognostic factors in PTC with cervical LN metastasis (N1). OBJECTIVE The objective of the study was to evaluate changes in N1 PTC characteristics and clinical outcome over time and to confirm the prognostic value of the number and size of metastatic LNs. DESIGN AND PATIENTS This study included 1815 N1 PTC patients diagnosed between 1997 and 2011. Patients were classified into three risk groups according to the number and size of metastatic LNs: very low risk, five or fewer and 0.2 cm or less; low risk, five or fewer and 0.2 cm or greater; and high risk, more than five. MAIN OUTCOME MEASURES Response to initial therapy and disease-free survival (DFS) was measured. RESULTS Metastatic LNs became smaller, and the ratio of metastatic LNs, which represents the extent of LN involvement and the completeness of surgery, decreased significantly over time. The proportion of patients with excellent response significantly increased from 33% to 67% over time (P < .001). These improvements were more evident in the low- and high-risk groups than in the very low-risk group. The DFS 5 years after initial surgery was also significantly increased from 73% to 91% over time (P < .001). The new LN classification was strongly associated with outcome. Patients in the very low-risk group had longer DFS than those in the low- and high-risk groups during the study period. CONCLUSIONS The clinical outcome of N1 PTC has significantly changed over time with the earlier detection of thyroid cancers with less extensive LN involvement. More complete surgical neck dissection also might be responsible for these changes. The number and size of metastatic LNs are important prognostic factors of recurrence in N1 PTC.

Adjuvant Radioactive Therapy after Reoperation for Locoregionally Recurrent Papillary Thyroid Cancer in Patients Who Initially Underwent Total Thyroidectomy and High-Dose Remnant Ablation

CONTEXT Some patients have elevated stimulated thyroglobulin (sTg) concentrations after reoperation for locoregionally recurrent/persistent papillary thyroid cancer (PTC). Little is known, however, about the efficacy of adjuvant radioactive iodine (RAI) therapy in these patients. OBJECTIVE The objective of the study was to evaluate the efficacy of adjuvant RAI therapy in patients with elevated sTg after reoperation for locally recurrent/persistent PTC. DESIGN AND SETTINGS This was a retrospective observational cohort study in a tertiary referral hospital. PATIENTS We evaluated 45 consecutive patients with sTg greater than 2 ng/ml after reoperation for locoregionally recurrent PTC, all of whom had previously undergone initial total thyroidectomy followed by high-dose RAI remnant ablation. Of these 45 patients, 23 received adjuvant RAI therapy (adjuvant group) and 22 did not (control group). MAIN OUTCOME MEASURES Main outcome measures included changes in sTg concentration after reoperation and disease-free survival. RESULTS Over time, there were no significant differences in mean sTg concentration in the adjuvant (P = 0.35) and control (P = 0.74) groups. Only 15% of patients in the adjuvant group and 33% in the control group showed a greater than 50% decrease in sTg level from baseline. There were no between-group differences in changes (P = 0.83) or percent decrease (P = 0.97) in sTg concentration and no difference in clinical recurrence-free survival (P = 0.20). CONCLUSION In patients who still have elevated sTg after reoperation for locally recurrent/persistent PTC, adjuvant RAI therapy compared with no additional RAI therapy resulted in no significant differences in the subsequent sTg changes or the recurrence-free survival.

Thyroglobulin level in fine-needle aspirates for preoperative diagnosis of cervical lymph node metastasis in patients with papillary thyroid carcinoma: two different cutoff values according to serum thyroglobulin level.

BACKGROUND Measurement of thyroglobulin (Tg) in the washout fluid of fine-needle aspirates (FNA-Tg) is useful for diagnosis of lymph node (LN) metastasis in papillary thyroid carcinoma (PTC). However, the cutoff value of FNA-Tg in the preoperative state is not defined clearly. This study aimed to evaluate the optimal cutoff value of preoperative FNA-Tg according to serum Tg level. METHODS FNA-Tg was measured in 135 PTC patients (160 LNs) for preoperative diagnosis of cervical LN metastasis. RESULTS Of the 160 LNs, 119 (74%) were surgically removed and 110 (69%) were diagnosed as malignant. When we adopted a FNA-Tg of 1.0 μg/L as the cutoff value, the sensitivity and specificity were 99% and 76%, respectively. FNA-Tg levels were correlated with serum Tg levels (Pearsons coefficient 0.42, p=0.002) and the FNA-Tg levels of 12 of the 50 benign LNs were above 1.0 μg/L. We classified the LNs into two groups according to serum Tg level regardless of anti-Tg antibody status: a low Tg group (≤1.0 μg/L, n=22, 14%) and a high Tg group (>1.0 μg/L, n=138, 86%). In the low Tg group, the sensitivity and specificity of the FNA-Tg cutoff value of 1.0 μg/L were 93% and 100%, respectively. In the high Tg group, the sensitivity and specificity of the FNA-Tg cutoff value of 19.0 μg/L were 93% and 100%, respectively. A Tg ratio (FNA-Tg level divided by serum Tg level) of 0.5 gave an improved diagnostic performance (sensitivity, 98%; specificity, 98%) in the high Tg group. CONCLUSIONS FNA-Tg levels in the preoperative state are affected by serum Tg levels when they exceeded 1.0 μg/L. For the preoperative diagnosis of metastatic cervical LNs, it seems reasonable to employ different cutoff values of FNA-Tg depending on serum Tg levels. We propose the use of an optimal cutoff value of FNA-Tg of 1.0 μg/L in patients with low serum Tg levels and a Tg ratio of 0.5 in those with high serum Tg levels irrespective of thyroglobulin antibody status.

Surgical outcomes of robotic thyroid surgery using a double incision gasless transaxillary approach: Analysis of 400 cases treated by the same surgeon

The purpose of this study was to evaluate the surgical outcomes of 400 cases of robotic thyroid surgery using a double incision gasless transaxillary approach.

Impact of Reclassification on Thyroid Nodules with Architectural Atypia: From Non-Invasive Encapsulated Follicular Variant Papillary Thyroid Carcinomas to Non-Invasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features

Background The follicular variant of papillary thyroid cancer (FVPTC), especially the encapsulated non-invasive subtype, is a controversial entity. Recent study suggested using ‘non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)’ for these indolent carcinomas. We evaluated the impact of reclassification from non-invasive encapsulated FVPTCs (EFVPTCs) to NIFTPs in the diagnosis of thyroid nodules with architectural atypia. Methods We reviewed 1301 thyroid nodules with architectural atypia in core needle biopsy (CNB) specimens obtained from March 2012 to February 2013. Nodules were classified into atypia of undetermined significance with architectural atypia (AUS-A, 984, 76%) or follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN, 317, 24%). Among them, diagnostic surgery was performed in 384 nodules (30%). Results In total, 160 nodules (42%) presented final malignant diagnoses including 39 non-invasive encapsulated FVPTCs (10%). The malignancy rate was estimated to be 7–35% in AUS-A nodules and 28–49% in FN/SFN nodules. After reclassification, the malignancy rate was much decreased and estimated to be 5–24% in AUS-A nodules, and 23–39% in FN/SFN nodules. Thyroid nodules with final malignant diagnoses were significantly more likely to have a FN/SFN CNB diagnosis, malignant US features and concomitant nuclear atypia in CNB specimens. However, these factors could not differentiate NIFTPs from other malignancies. Conclusions After reclassification of non-invasive EFVPTCs to NIFTPs, the malignancy rate of thyroid nodules with architectural atypia in CNB specimens was decreased. However, there were no preoperative factors differentiating other malignancies from NIFTPs. The presence of malignant US features or concomitant nuclear atypia might help clinicians deciding diagnostic surgery but, these features also might indicate NIFTPs.

Changing trends in the clinicopathological features and clinical outcomes of medullary thyroid carcinoma.

The early detection of papillary thyroid cancer has contributed to the increase in the incidence and improved clinical outcomes. However, recent changes of medullary thyroid carcinoma (MTC) over time remain unclear. We evaluated changes of the clinicopathological characteristics and clinical outcomes in patients with MTC in recent years.

Risk factors for recurrence in patients with papillary thyroid carcinoma undergoing modified radical neck dissection

This study evaluated the impact of lymph node‐related factors on the risk of and site of recurrence in patients who had papillary thyroid carcinoma with lymph node metastasis in the lateral compartment (classified as pN1b).