Early stimulated thyroglobulin after thyroidectomy for thyroid cancer predicts preradioiodine therapy thyroglobulin values

BACKGROUND

Follow-up of patients who undergo a total thyroidectomy is performed with thyroglobulin (Tg), and antithyroglobulin antibodies (AbTg). The objective of RAI adjuvant therapy is to negativize Tg to undetectable levels to ease the follow-up. The objective of this study was to evaluate the correlation of serum Tg values measured 2 weeks after surgery with the Tg value prior to RAI adjuvant therapy in order to define its utility as a reliable predictor of pretherapy Tg and as a potential predictor to avoid RAI adjuvant therapy.

METHODS

Retrospective analysis of a cohort recruited prospectively. Adult patients with thyroid carcinoma who underwent total thyroidectomy and classified as intermediate or high risk by ATA guidelines. All patients were left without levothyroxine support after surgery and for at least two weeks. We measured biochemical markers two-four weeks after thyroidectomy and before and after RAI.

RESULTS

We included 75 patients. Thirty-three (44.0%) patients were classified as ATA high risk. In the post-RAI scan, only 1 (1.3%) showed distant metastases. The comparison between early postoperative and pretherapy Tg values showed that Tg decreased or remained stable at postoperative levels in 75 patients (100%).

CONCLUSIONS

Postoperative Tg measurements are a reliable marker of pretherapy Tg levels in patients with intermediate- and high-risk thyroid carcinoma who are candidates for RAI adjuvant therapy. These results need correlation with outcomes and response to therapy in high-risk patients.

Lymph node ratio independently associated with postoperative thyroglobulin levels in papillary thyroid cancer

OBJECTIVES

To investigate the impact of the lymph node ratio (LNR) on postoperative thyroglobulin (Tg) levels in patients with papillary thyroid carcinoma (PTC).

PATIENTS AND METHODS

This was a retrospective, cohort study. The association between clinicopathological variables and postoperative unstimulated Tg (uTg) levels, preablative-stimulated Tg (sTg) levels, and postablative unstimulated Tg levels was analysed.

RESULTS

A total of 300 patients with PTC were identified. Multivariate logistic analysis showed that M classification (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.62-3.34), and postoperative thyroid-stimulating hormone levels (OR, 1.01; 95% CI, 1.01-1.02) were independently associated with postoperative uTg levels. One hundred and sixteen patients underwent radioactive iodine (RAI) therapy. Multivariate analysis showed that LNR in the central neck (OR, 1.24; 95% CI, 1.02-1.51), LNR in the lateral neck (OR, 1.73; 95% CI, 1.09-2.77), RAI dose (OR, 1.43; 95% CI, 1.21-1.69), and M classification (OR, 1.79; 95% CI, 1.22-2.61) were independently associated with preablative sTg levels. Tumour size (OR, 1.01; 95% CI, 1.00-1.01), LNR in the central neck (OR, 1.28; 95% CI, 1.08-1.51), LNR in the lateral neck (OR, 1.66; 95% CI, 1.10-2.49), RAI dose (OR, 1.54; 95% CI, 1.34-1.79), and M classification (OR, 1.56; 95% CI, 1.12-2.19) were also independently associated with postablative uTg levels.

CONCLUSION

LNR was independently associated with postoperative Tg levels in patients with PTC. Patients with high LNR were more likely to have incomplete biochemical responses after surgery.

Prognostic value of postoperative stimulated thyroglobulin in differentiated thyroid cancer

BACKGROUND

Thyroglobulin (Tg) level is used for long-term follow-up of differentiated thyroid cancer (DTC). However, the prognostic value of the postoperative level and the level which can be considered risky are not clear in literature.

PURPOSE

To evaluate the prognostic value of postoperative Tg in DTC for subsequent disease-free status. Also, to determine the cutoff with the highest sensitivity and specificity.

METHODS

A retrospective analysis was performed of 62 patients with non-metastatic DTC presenting to our department from January 2018 to December 2019. Three groups were formed according to postoperative stimulated thyroglobulin (sTg) level: <1ng/ml, 1-5ng/ml, and >5ng/ml. Outcomes were compared at 12 months. ROC curve analysis determined the cutoff with the highest sensitivity and specificity.

RESULTS

Seven the 62 patients showed persistent or recurrent disease at 12 months after diagnosis. Comparing outcomes in the 3 sTg groups showed thyroglobulin to be a significant prognostic variable. A cut-off of 3.15ng/ml had the highest sensitivity and specificity on ROC curve analysis.

CONCLUSION

Postoperative stimulated thyroglobulin is a useful prognostic tool in the postoperative categorization of patients and can subsequently be tested for its value to guide radioactive iodine therapy.

Improving the prediction of persistent and recurrent differentiated thyroid cancer using the American Thyroid Association 2015 risk stratification system

PURPOSE

The 2015 American Thyroid Association risk stratification system (ATA RSS) is used in patients with differentiated thyroid carcinoma (DTC) to assess their risk of persistent/recurrent disease. Our aims were to validate the 2015 ATA RSS in a registry of DTC patients and to examine whether the addition of factors not included in it, such as pre-radioactive iodine therapy stimulated thyroglobulin (pre-RAI sTg), gender, and age could increase its predictive ability.

METHODS

We studied 403 patients with DTC, treated at a tertiary center from 1990 to 2018 and subjected to total thyroidectomy. All patients had received RAI therapy, except those with low-risk papillary microcarcinoma.

RESULTS

Of our patients, 81.9% were women and 91.1% had papillary thyroid carcinoma. After a median follow-up of 5.0 years, 53 cases of persistent and 21 cases of recurrent disease were recorded. The proportion of variance explained (PVE) regarding the outcome (presence or absence of recurrent/persistent disease) using the 2015 ATA RSS alone was 18.3% (persistence) and 16.9% (recurrence), increasing to 74.4% and 52.0%, respectively, when pre-RAI sTg was added to the logistic regression model. Gender and age were not associated with the disease outcome. In ROC analysis, pre-RAI sTg had a high predictive value for persistent (AUC 0.983, 95% CI 0.962-1.000) and recurrent disease (AUC 0.856, 95% CI 0.715-0.997). The optimal cut-offs and sensitivity, specificity, and positive and negative predictive value for pre-RAI sTg were the following: for persistence 12.75 ng/ml, 100%, 90.5%, 64%, and 100%, and for recurrence 8.05 ng/ml, 77.8%, 85.5%, 36.8%, and 97%.

CONCLUSIONS

The 2015 ATA RSS displayed moderate performance in predicting recurrent/persistent disease in patients with DTC, which improved with the inclusion of pre-RAI sTg values; pre-RAI sTg was an independent predictor of the disease outcome, with high negative prognostic value.

Predictors of thyroglobulin in the lymph nodes recurrence of papillary thyroid carcinoma undergoing total thyroidectomy

BACKGROUND

To investigate the association between postoperative lymph nodes (LNs) recurrence and distinct serum thyroglobulin (Tg) levels in patients with papillary thyroid carcinoma (PTC).

METHODS

This study included PTC patients who underwent total thyroidectomy (TT) with at least central neck dissection and then re-operated due to recurrence of LNs between January 2013 and June 2018. These patients were grouped by negative or positive serum Tg levels according to the American Thyroid Association guidelines.

RESULTS

Of the 60 included patients, 49 underwent radioactive iodine (RAI) treatment. Maximum unstimulated Tg (uTg) ≥ 0.2 ng/mL were associated with larger diameter of recurrent LNs (P = 0.027), and higher rate of metastatic LNs (P < 0.001). Serum-stimulated Tg (off-Tg) ≥ 1 ng/mL (P = 0.047) and unstimulated Tg (on-Tg) ≥ 0.2 ng/Ml (P = 0.013) were associated with larger diameter of recurrent LNs. Number of metastatic LNs ≥ 8 was an independent predictor for postoperative maximum uTg ≥ 0.2 ng/mL (OR = 8.767; 95% CI = 1.392-55.216; P = 0.021). Ratio of metastatic LNs ≥ 25% was an independent predictor for off-Tg ≥ 1 ng/mL (OR = 20.997; 95% CI = 1.649-267.384; P = 0.019).

CONCLUSION

Postoperative Tg-positive status was associated with larger size of recurrent LNs. Number of metastatic LNs ≥ 8 and ratio of metastatic LNs ≥ 25% were independent predicators for uTg-positive and off-Tg-positive status, respectively.

Can patients with papillary thyroid carcinoma and low postoperative thyroglobulin in the presence of clinically apparent lymph node metastases (cN1) be spared from radioiodine?

BACKGROUND

The study evaluated the recurrence rate in patients with papillary thyroid carcinoma (PTC) and clinically apparent lymph node metastases (LNM) (cN1) who had low thyroglobulin (Tg) after total thyroidectomy and who were not submitted to adjuvant therapy with ¹³¹I.

METHODS

This was a prospective study. It included 82 cN1 patients (≤3 LNM ≤1.5 cm without macroscopic extracapsular extension) with tumors ≤4 cm without macroscopic extrathyroid invasion (T1-2) and who after thyroidectomy had unstimulated Tg (u-Tg) < 0.3 ng/ml, negative antithyroglobulin antibodies (TgAb), and neck ultrasonography (US) showing no anomalies. The patients were not submitted to therapy with ¹³¹I.

RESULTS

The time of follow-up ranged from 24 to 156 months (median 84 months). Seventy-nine patients (96.3%) continued to have u-Tg < 0.3 ng/ml and negative US. Three patients (3.6%) exhibited an increase in Tg and structural recurrence was detected in two. After treatment, these patients achieved u-Tg < 1 ng/ml and the imaging methods revealed no apparent tumor.

CONCLUSIONS

The results suggest that even cN1 patients, given the absence of extensive LNM or other adverse findings, who have low Tg and neck US showing no anomalies after thyroidectomy do not require radioiodine.

Outcomes after completion thyroidectomy versus total thyroidectomy for differentiated thyroid cancer: A single-center experience

BACKGROUND

Thyroid cancer diagnoses are often discovered after diagnostic thyroid lobectomy. Completion thyroidectomy (CT) may be indicated for intermediate or high-risk tumors to facilitate surveillance and/or adjuvant treatment. The completeness of thyroid resection and the safety of CT compared to total thyroidectomy (TT) is unclear. We assessed outcomes after TT or CT to determine completeness of resection and risk of complications.

METHODS

Patients undergoing TT or CT between 2000 and 2018 were retrospectively reviewed. Pathology, unstimulated thyroglobulin (uTg), parathyroid hormone (PTH), rates of hematoma, and recurrent laryngeal nerve (RLN) injury were compared.

RESULTS

Differentiated thyroid cancer (DTC) was identified in 954 patients undergoing TT and 142 patients undergoing CT. Postoperative uTg at 6 months was not different between TT and CT, 0.2 vs 0.2 ng/mL, P = .37. Transient hypoparathyroidism with immediate postoperative PTH less than 10 was more common after TT, 14.3 vs 6.0% (P = .009). No differences were noted regarding postoperative hematoma, transient RLN injury, permanent hypoparathyroidism, and permanent RLN injury.

CONCLUSIONS

If CT is required for DTC, a complete resection, as assessed by postoperative uTg, can be achieved. Furthermore, CT is significantly less likely to result in transient hypoparathyroidism and poses no additional risk of RLN injury, hematoma, or permanent hypoparathyroidism.

Management and follow-up of differentiated thyroid cancer not submitted to radioiodine treatment: a systematic review

INTRODUCTION

The treatment of differentiated thyroid cancer (DTC) has been changing. In low (LR) and intermediate (IR) risk DTC, surgery is becoming more conservative and the usefulness of radioiodine (¹³¹I) has been questioned. An increasing number of patients are treated with lobectomy or total thyroidectomy (TTx), but without ¹³¹I. Consequently, the management and the follow-up of these patients need to be revised.

EVIDENCE ACQUISITION

We reviewed the available data about the management of these growing categories of patients. We focused on the emerging roles of the conventional tools in the follow-up [thyroglobulin (Tg), thyroglobulin antibodies (TgAb) and neck ultrasound (US)]. Moreover, we evaluated the changes in the use of levothyroxine (L-T4) therapy, and the role of the ongoing risk re-stratification.

EVIDENCE SYNTHESIS

Tg, TgAb and neck US continue to represent the cornerstone of the follow-up, however, a change in their interpretation is needed. In particular, the absolute value of Tg and TgAb lost their clinical meaning, while their trend over time acquired a greater value. At variance, the diagnostic role of neck US is becoming very relevant for the early identification of the local recurrences. In addition, L-T4 therapy should be personalized according with the type of surgery, the age of patients and their comorbidities.

CONCLUSIONS

Management of DTC treated with lobectomy or TTx but without ¹³¹I is worldwide changing. The evidences suggest that in this setting of patients with LR or IR of recurrences, a relaxed surveillance could represent the most reasonable choice.