Prognostic implication of thyroglobulin and quantified whole body scan after initial radioiodine therapy on early prediction of ablation and clinical response for the patients with differentiated thyroid cancer

A Time Trend Analysis of 5,000 Robotic Thyroidectomies via Bilateral Axillo-Breast Approach

BACKGROUND

This study aimed to investigate the time trends of surgical outcomes in patients who underwent bilateral axillo-breast approach robotic thyroidectomy (BABA RT) over the last 14 years.

METHODS

From February 2008 to September 2021, we conducted a retrospective medical chart review of 5,011 consecutive patients who underwent BABA RT at three Seoul National University-affiliated hospitals. The patients were divided into three groups based on the main model of the da Vinci robotic surgical system to evaluate trends in surgical treatment strategies and outcomes after BABA RT.

RESULTS

Of the 5,011 patients (4,706 malignant and 305 benign), the most common histological subtype was papillary thyroid carcinoma (n = 4,584; 97.4%). The mean tumor size significantly increased from 0.8 cm to 1.2 cm (p < 0.05). The mean numbers of metastatic and harvested lymph nodes from the central neck dissection and the lateral neck dissection showed a significant difference and tendency to increase (from 0.9 to 1.6, 4.7 to 6.2, p < 0.05, and from 0.6 to 3.9, 5.3 to 17.9, p < 0.05), respectively, throughout the study period. Permanent hypoparathyroidism decreased from 3.4 to 2.9%. The rate of transient and permanent vocal cord palsy decreased from 15.2 to 2.7% and from 0.7 to 0.2%, respectively.

CONCLUSION

With advancements in robotic surgical systems and improvements in the BABA RT technique, surgical indications have expanded to include more advanced thyroid diseases, and surgical outcomes have improved over the last 14 years.

Pulmonary metastasectomy for thyroid cancer as salvage therapy for radioactive iodine-refractory metastases

OBJECTIVES

Distant metastasis arising from thyroid cancer is rare but has been associated with significantly reduced long-term survival, especially when refractory to radioactive iodine ablation. We provide one of the largest studies worldwide reporting the outcome after salvage pulmonary metastasectomy for this entity, aiming to identify prognostic factors and to analyse surgical indication.

METHODS

We retrospectively analysed the medical records of 43 patients who had undergone pulmonary metastasectomy for radioactive iodine-refractory thyroid cancer from 1985 to 2016.

RESULTS

The median follow-up period was 77 (95% confidence interval 41-113) months. Twenty-three (53%) patients were alive at the time of analysis. The majority of tumours were follicular thyroid cancer by histology, with 23% identified as Hurthle cell subtype. Five- and 10-year disease-specific (DS) survival was 84% and 59%, respectively. Thirty-one (72%) patients underwent R0-resection with a 5- and 10-year DS survival of 100% and 77%, respectively. This was significantly reduced to 62% and 22% (P = 0.013) in case of incomplete resection, respectively. Ten years after R0-metastasectomy, 17 (55%) patients were recurrence-free. Systematic mediastinal lymphadenectomy was performed in 16 (37%) patients and was associated with improved long-term DS survival (10 years 88% vs 46%, P = 0.034). Moreover, a reduction of > 80% in serum thyroglobulin levels post-metastasectomy correlates with better long-term DS survival (10 years 81% vs 36%, P = 0.007).

CONCLUSIONS

Pulmonary metastasectomy is associated with good survival for selected patients with radioactive iodine-refractory metastases of differentiated thyroid cancer, especially if R0-resection can be achieved. Moreover, it is worth considering whether a significant reduction of tumour load, as indicated by thyroglobulin serum levels, seems possible.

Multiple-factor analysis of the first radioactive iodine therapy in post-operative patients with differentiated thyroid cancer for achieving a disease-free status

¹³¹I treatment is an important management method for patients with differentiated thyroid cancer (DTC). Unsuccessful ¹³¹I ablation drastically affects the prognosis of the patients. This study aimed to analyze potential predictive factors influencing the achievement of a disease-free status following the first ¹³¹I therapy. This retrospective review included 315 DTC patients, and multiple factors were analyzed. Tumor size, pathological tumor stage, lymph node (LN) metastasis, distant metastasis, American Thyroid Association recommended risks, pre-ablation thyroglobulin (Tg), and thyroid stimulating hormone (TSH) displayed significant differences between unsuccessful and successful group. Cutoff values of Tg and TSH to predict a successful outcome were 3.525 ng/mL and 99.700 uIU/ml by receiver operating characteristic curves analysis. Binary logistic regression analysis showed that tumor stage T3 or T4, LN metastasis to N1b station, intermediate and high risks, pre-ablation Tg ≥ 3.525 ng/ml and TSH <99.700 μIU/mL were significantly associated with unsuccessful outcomes. Logistic regression equation for achieving a disease-free status could be rendered as: y (successful treatment) = −0.270–0.503 X₁ (LN metastasis) −0.236 X₂ (Tg) + 0.015 X₃ (TSH). This study demonstrated LN metastasis, pre-ablation Tg and TSH were the most powerful predictors for achieving a disease-free status by the first ¹³¹I therapy.

Quality indicators for thyroid cancer surgery: current perspective

INTRODUCTION

While the disease specific mortality of differentiated thyroid cancer has remained low with current treatments, its incidence has been steadily rising over the past several decades, and cancer related recurrence and morbidity have remained a significant problem. Quality indicators currently employed are relevant to the surgical intervention, but do not necessarily reflect oncological outcomes. Therefore, thyroid cancer specific surgical quality indicators, that offer insight into risk of cancer related morbidity and mortality are needed.

AREAS COVERED

This review aims to discuss the role of measuring quality in thyroid surgical oncology and carry out a comprehensive review of potential quality indicators for thyroid cancer operations. The three quality indicators reviewed here are the postoperative radioactive iodine update by remnant thyroid tissue, the proportion of resected lymph nodes with evidence of metastases, and the post-operative serum thyroglobulin level. Expert commentary: Together, these quality indicators may be utilized to guide improvement of the quality of surgical care for this unique patient population. A critical future step in establishing the role of quality indicators for thyroid cancer surgery is the determination of cutoff values of each indicator in an evidence-based manner.

Prediction of radioactive iodine remnant ablation failure in patients with differentiated thyroid cancer: A cohort study of 740 patients

BACKGROUND

The purpose of this study was to detect parameters that could serve as predictors of radioactive iodine (I-131) ablation failure in patients with low-risk and intermediate-risk differentiated thyroid carcinoma (DTC).

METHODS

Our cohort study included 740 patients with DTC who received postoperative I-131 remnant ablation. Anthropometric, biochemical, and pathohistological parameters were analyzed and correlated with ablation outcome using multivariable logistic regression models.

RESULTS

Treatment failure rates were higher in patients <53 years, with N1a classification, and lymph node capsular invasion. In patients with N1a disease, thyroglobulin (Tg) > 2.4 ng/mL predicted treatment failure with 93.8% sensitivity and 52.5% specificity, and in patients with N1b disease, Tg > 14.9 ng/mL with 77.8% sensitivity and 92.9% specificity. I-131 activity was not associated with treatment outcome.

CONCLUSION

Patients < 53 years old, with higher Tg levels, N1a classification, and lymph node capsular invasion have a higher risk of ablation failure. Stimulated Tg is an excellent predictor of treatment failure in patients with N1 disease. © 2016 Wiley Periodicals, Inc. Head Neck 39: 109-115, 2017.

Correlation of Consecutive Serum Thyroglobulin Levels During Hormone Withdrawal and Failure of Initial Radioiodine Ablation in Thyroid Cancer Patients

OBJECTIVE

The aim of this study was to evaluate the value of thyroglobulin (Tg) kinetics during preparation of radioiodine ablation for prediction of initial radioiodine ablation failure in thyroid cancer patients.

METHODS

Thyroid cancer patients after total thyroidectomy who underwent radioiodine ablation with 3-4 weeks of hormone withdrawal between May 2011 and January 2012 were included. Consecutive serum Tg levels 5-10 days before ablation (Tg1) and on the day of ablation (Tg2) were obtained. The difference between Tg1 and Tg2 (ΔTg), daily change rate of Tg (ΔTg/day) and Tg doubling time (Tg-DT) were calculated. Success of initial ablation was determined by the results of the follow-up ultrasonography, diagnostic radioiodine scan and stimulated Tg level after 6 to 20 months.

RESULTS

A total of 143 patients were included. Failed ablation was reported in 52 patients. Tg2 higher than 5.6 ng/ml and Tg-DT shorter than 4.2 days were significantly related to a high risk of ablation failure. ΔTg and ΔTg/day did not show significant correlation with ablation failure.

CONCLUSIONS

Thyroglobulin kinetics on consecutive blood sampling during hormone withdrawal may be helpful in predicting patients with higher risk of treatment failure of initial radioiodine ablation therapy in thyroid cancer patients.

Identification of Intermediate- to High-Risk Papillary Thyroid Carcinoma Patients Who May Be Safely Managed without the Performance of Delayed Stimulated Thyroglobulin Measurements following Total Thyroidectomy and Radioactive Iodine Therapy

Background. The measurement of stimulated thyroglobulin (sTg) after total thyroidectomy and remnant radioactive iodine (RAI) ablation is the gold standard for monitoring disease status in patients with papillary thyroid carcinomas (PTCs). The aim of this study was to determine whether sTg measurement during follow-up can be avoided in intermediate- and high-risk PTC patients. Methods. A total of 346 patients with PTCs with an intermediate or high risk of recurrence were analysed. All of the patients underwent total thyroidectomy as well as remnant RAI ablation and sTg measurements. Preoperative and postoperative parameters were included in the analysis. Results. Among the preoperative parameters, age below 45 years and preoperative Tg above 19.4 ng/mL were significant risk factors for predicting detectable sTg during follow-up. Among the postoperative parameters, thyroid capsular invasion, lymph node metastasis, and ablative Tg above 2.9 ng/mL were independently correlated with a detectable sTg range. The combination of ablative Tg less than 2.9 ng/mL with pre- and postoperative independent risk factors for detectable sTg increased the negative predictive value for detectable sTg up to 98.5%. Conclusions. Based on pre- and postoperative parameters, a substantial proportion of patients with PTCs in the intermediate- and high-risk classes could avoid aggressive follow-up measures.

Stimulated Serum Thyroglobulin Level at the Time of First Dose of Radioactive Iodine Therapy Is the Most Predictive Factor for Therapeutic Failure in Patients With Papillary Thyroid Carcinoma

PURPOSE

To investigate the clinical importance of serum thyroglobulin (Tg) levels just before high-dose I-131 ablation therapy (preablation Tg) for predicting therapeutic failure in patients with papillary thyroid carcinoma (PTC).

METHODS

Patients with PTC (n = 132) undergoing total thyroidectomy followed by the first high-dose I-131 ablation therapy (HI-Rx) were included in this retrospective review. Just before HI-Rx, preablation Tg, anti-Tg antibody, and TSH were measured. The patients were followed up for a mean period of 7 months (range 6-23 months) by I-123 whole-body scans (f/u IWBS) and stimulated Tg (f/u Tg). Therapeutic failure was defined by positive f/u IWBS or f/u Tg >2 ng/ml. We classified patients into three groups according to the value of preablation Tg (group 1, <1 ng/ml; group 2, ≥1 and <10 ng/ml; group 3, ≥10 ng/ml) and compared clinical variables to therapeutic response.

RESULTS

Therapeutic failure was noted in 39 patients (29.5 %). On univariate analysis, T stage, tumor size, and preablation Tg were the statistically significant factors that could predict therapeutic failure. After multivariate analysis, preablation Tg was the only independent predictor of therapeutic failure (P < 0.001). The therapeutic failure rate was significantly increased as the preablation Tg level increased (11.3 %, 33.3 %, and 87.5 % in groups 1, 2, and 3, respectively; P < 0.001). Individuals with preablation Tg levels ≥10 ng/ml had 25.5 times greater chance of therapeutic failure than those with levels <10 ng/ml (95 % CI = 5.43-119.60; P < 0.001).

CONCLUSIONS

A high preablation Tg level is the most significant predictor of therapeutic failure at the time of first HI-Rx in patients with PTC.

Risk factors for recurrence after therapeutic lateral neck dissection for primary papillary thyroid cancer

BACKGROUND

Lateral lymph node metastasis is an important prognostic factor and is predictive of tumor recurrence and cause-specific survival in patients with papillary thyroid cancer (PTC). However, the factors predicting recurrence and clinical outcomes after therapeutic lateral neck dissection are not well established. The aims of this study were to evaluate the incidence, pattern, and factors predictive of PTC recurrence after therapeutic lateral neck dissection.

MATERIALS AND METHODS

The records of 126 consecutive patients who underwent total thyroidectomy with therapeutic lateral neck dissection for primary PTC at the National Cancer Center were retrospectively reviewed. The factors predictive of recurrence were determined using both univariate and multivariate analyses considering several clinicopathologic variables.

RESULTS

The median follow-up period was 61.2 months, during which 22 patients (17.5 %) experienced recurrence with 1 death (0.8 %) due to disease. Locoregional recurrence and distant metastasis were found in 20 cases (15.9 %) and 2 cases (1.6 %), respectively. Male gender, aggressive histology, number of lymph node metastases, initial level of T4-off Tg per ng/mL, and ATA risk categories (high risk) were independent risk factors for recurrence. Of note, initial T4-off Tg levels greater than 4.2 ng/mL showed highest sensitivity and specificity in predicting recurrence.

CONCLUSIONS

These results provide useful information regarding the clinical outcomes after therapeutic lateral neck dissection for primary PTC and can be used to identify at-risk patients who need aggressive treatment and intensive surveillance for postoperative recurrence.