Routine thyroglobulin, neck ultrasound and physical examination in the routine follow up of patients with differentiated thyroid cancer-Where is the evidence?

Limited Utility of Routine Surveillance Ultrasound in Differentiated Thyroid Cancer Patients With Undetectable Postoperative Thyroglobulin Levels

BACKGROUND

Neck ultrasound (US) and serum thyroglobulin (Tg) measurements are mainstays of long-term differentiated thyroid cancer (DTC) surveillance. Given the high sensitivity of serum Tg, we aimed to assess the utility of neck US in DTC patients who underwent total thyroidectomy and have undetectable serum Tg.

METHODS

We performed a retrospective cohort analysis of DTC patients who underwent a total thyroidectomy at our institution (2010-2023) and received US-guided fine needle aspiration (FNA) during their surveillance. Patients were categorised into three lab categories based on serum Tg and Tg antibody (Tg Ab) status before the biopsy: (1) 'Negative Tg' if undetectable Tg ( < 0.2 ng/dL) and Tg Ab, (2) 'Positive Tg' if detectable Tg and undetectable Tg Ab, and (3) 'Positive Tg Ab' if detectable Tg Ab. To calculate the positive predictive value (PPV) of neck US, we defined the 'true positive' of US as findings that prompted an FNA biopsy resulting with DTC, and 'false positive' findings prompting an FNA biopsy that did not result as DTC.

RESULTS

A total of 118 patients were included, encompassing 146 FNA biopsies: 33 (23%) had Negative Tg, 84 (57%) had Positive Tg, and 29 (20%) had Positive Tg Ab lab results before their biopsies. The PPV of neck US in the setting of Negative Tg was 3% (one true positive, 32 false positives), while the PPV was 50% (42 true positives, 42 false positives) for Positive Tg, and 52% (15 true positives, 14 false positives) for Positive Tg Ab cohorts. Sub-analysis of the Positive Tg cohort using different serum Tg level cutoffs revealed a PPV of 29% at just detectable serum Tg of 0.2 ng/dL, and PPV of 38% for Tg < 1.0 ng/dL. The PPV stabilised at 58% for Tg levels ≥ 1 ng/dL.

CONCLUSION

With the low PPV of neck US, high cost of surveillance, and the advent of ultra-sensitive serum Tg measurements, future guidelines should consider reducing routine neck US surveillance in patients with undetectable serum Tg and only performing it when there is a rise in serum Tg levels.

Contribution of neck ultrasonography to patient management in patients with differentiated thyroid carcinoma with excellent response to therapy

PURPOSE

To assess the contribution of intense neck ultrasonography (US) follow-up in the clinical management of differentiated thyroid carcinoma (DTC) patients with the American Thyroid Association (ATA) low-intermediate-risk of recurrence and an excellent response after total thyroidectomy and radioiodine therapy.

MATERIALS AND METHODS

Medical records of patients who underwent serial follow-up neck US examinations between 1996 and 2022 were analyzed retrospectively. The utility of serial US examinations in detecting structural recurrence was assessed in all patients and different subgroups-categorized per the initial risk of recurrence and stimulated thyroglobulin (sTg) level at 1-year response assessment.

RESULTS

Among 2823 US examinations in 296 patients, 2 (0.1%) were categorized as true-positive, 2670 (94.6%) as true-negative, and 151 (5.3%) as false-positive, whereas no false-negative results were observed. Thus, sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy [confidence interval] in all patients were 100% [34.2-100%], 94.7% [93.8-95.4%], 1.3% [0.36-4.6%], 100% [99.9-100%], and 94.7% [93.8-95.4%], respectively. Non-significant higher PPVs were calculated in intermediate-risk patients and patients having sTg ≥0.1 ng/mL, while slightly lower specificity and accuracy were demonstrated in the former group. No recurrence was identified in patients with a low risk of recurrence and those having sTg <0.1 ng/mL.

CONCLUSION

Frequent US examination yields remarkably low PPVs in identifying recurrences in ATA low-intermediate-risk patients with DTC and attaining excellent response after total thyroidectomy and radioiodine ablation. Therefore, US surveillance protocol should be individualized per the initial risk of recurrence and Tg levels at response assessment.

Impact of periodic neck ultrasonography on locoregional disease control in surveillance after total thyroidectomy for patients with low- and intermediate-risk papillary thyroid carcinoma: a propensity score-matched study

This study aimed to evaluate the impact of periodic neck ultrasonography (US) on postoperative surveillance for locoregional disease control of patients with low- and intermediate-risk papillary thyroid carcinoma (PTC) who underwent total thyroidectomy. This retrospective cohort study included patients with PTC who underwent total thyroidectomy and central neck dissection at our institution between January, 2000 and December, 2016. The patients were divided into two groups: the physical examination (PE) group (follow-up by PE without periodic US) and the US group (follow-up by PE with periodic US). Serum thyroglobulin levels were measured periodically in both groups. Propensity score matching was used to rigorously balance the significant variables and assess the 10-year postoperative outcomes between the groups. Of the 189 patients, 150 were included after matching (75 in each group). There were no significant differences between the two groups in terms of background characteristics. The median follow-up period was 127.9 months. There was no significant difference in locoregional relapse-free survival between the PE and US groups (97.0 vs. 98.7%, p = 0.541). The overall survival was 96.7% and 98.7% in the PE and US groups, respectively, with no significant difference (p = 0.364). This study demonstrated that the addition of periodic US to PE for postoperative surveillance of patients with low- and intermediate-risk PTC who underwent total thyroidectomy did not significantly affect locoregional control.

The diagnostic performance of neck ultrasound in follow-up of advanced stage differentiated thyroid cancer

BACKGROUND

Differentiated thyroid cancer (DTC) requires long-term follow-up due to the risk of delayed recurrence. Follow-up surveillance involves serial neck ultrasound (US) and thyroglobulin (Tg); however, the optimal frequency and diagnostic performance of neck US outside of specialized thyroid cancer centres in higher risk patients is not well defined. We sought to evaluate the diagnostic performance of US and serial Tg in advanced stage DTC.

METHODS

We retrospectively reviewed our thyroid cancer database for patients with stage III and IV DTC from 2006 to 2018, total thyroidectomy, and at least 2 years follow-up to assess recurrence rates. Those with hemi-thyroidectomy or anti-Tg antibodies were excluded. Diagnostic performance of US and Tg were assessed using a composite reference standard of follow-up imaging and pathology. All relevant US were reviewed by a blinded expert radiologist for uniformity.

RESULTS

Of 136 included patients (91 females, mean age 58.9), 26 (19%) had recurrence of DTC over median follow-up of 6.6 years (IQR 5.3-9.3). The sensitivity and specificity of US in diagnosing cervical recurrence were 73.3% (95% CI 0.51-0.96) and 68.3% (95% CI 0.60-0.77) based on historical reports, respectively, and 80% (95% CI 0.60-1.00) and 87.8% (95% CI 0.82-0.93) based on blinded expert review, respectively. Tg had a sensitivity of 95.5% (95% CI 0.89-1.0) and specificity of 96.2% (95% CI 0.92-0.99) in detecting cervical recurrence or distant metastases. False positive US findings on historical US and subsequent review occurred in 38 (28%) and 15 (11%) patients, respectively, while 5 (3.6%) had false positive Tg results.

CONCLUSION

Serial Tg has better sensitivity and specificity than US for detecting recurrence of advanced stage DTC. Furthermore, re-interpretation of abnormal findings using structured US reporting with a subspecialized reader may improve diagnostic performance of US and improve its utility in clinical care.

Clinicopathologic features of thyroid nodules with PTEN mutations on preoperative testing

The incidence of cancer in thyroid nodules carrying germline or somatic phosphatase and tensin homolog (PTEN) mutations is not well-defined. This study characterizes the clinical and histopathologic features of thyroid nodules with preoperatively detected PTEN mutations and their impact on management. Thyroid nodules with PTEN mutations on molecular testing of fine-needle aspiration (FNA) specimens from November 2017 to July 2020 at our institution were included. Demographic and clinicopathologic data were obtained through retrospective chart review. We identified 49 PTEN mutation-positive nodules from 48 patients. Surveillance was pursued for 28 patients and surgery for 20 patients. There were 14 follicular adenomas (FA), 4 oncocytic adenomas, 1 oncocytic hyperplastic nodule, and 1 encapsulated follicular variant papillary thyroid carcinoma (EFVPTC). The EFVPTC had two somatic PTEN mutations, an NRAS mutation, and was a low-risk tumor with capsular but no angiolymphatic invasion. Four patients, all with multiple nodules, had PTEN hamartoma syndrome (PHTS) with germline mutations or a clinical diagnosis of Cowden syndrome (CS); two had surgery finding FAs, and one previously had follicular carcinoma removed. Among surveillance patients, 1/20 had a significant increase in the size of the thyroid nodule and underwent repeat FNA, and no thyroid malignancy was found with a mean of 1.77 years of follow-up (range 1.00-2.78). Thyroid nodules with isolated somatic PTEN mutations are primarily benign and unlikely to grow at a high rate, at least on short-term follow-up. About 8% of patients with PTEN mutations may have PHTS or CS, which should be suspected in younger patients with multiple thyroid nodules.

The role of neck ultrasound in the follow-up of low- and intermediate- risk papillary thyroid cancer

Introduction

The optimal time for a neck ultrasound (US) in the follow-up of papillary thyroid cancer (PTC) after the first year is undetermined. We aimed to verify the utility of routine neck US in the surveillance of patients diagnosed with low- and intermediate-risk PTC with no evidence of disease at the one-year assessment.

Subjects and methods

We conducted a retrospective longitudinal study of patients with low- and intermediate-risk PTC with normal neck US, unstimulated serum thyroglobulin (Tg) < 1 ng/mL and negative anti-Tg antibodies at the one-year follow-up. Patients were divided into group 1 [undetectable Tg (<0.20 ng/mL)] and group 2 [detectable Tg but < 1 ng/mL]. The negative predictive value (NPV) of the one-year unstimulated Tg at the five-year and last follow-up visits was calculated.

Results

We included n = 88 patients in group 1 and n = 8 patients in group 2. No patient from group 1 presented suspicious US findings at the five-year evaluation [NPV: 100.0% (95% confidence interval (CI): 95.5%-100.0%)], and at the last visit, only one patient had developed a lymph node classified as suspicious [NPV: 98.8% (95% CI: 93.2%-100.0%); mean follow-up: 6.7 years]. In group 2, two patients' USs presented suspicious findings at the five-year evaluation [NPV: 75.0% (95% CI: 34.9%-96.8%)]. At the last visit, only one patient persisted with suspicious findings in the US [NPV: 87.5% (95% CI: 47.4%-99.7%); mean follow-up: 6.5 years].

Conclusion

Low- and intermediaterisk PTC with an excellent response to treatment at the one-year assessment can be safely monitored with regular unstimulated Tg assessments. Conclusions should not be drawn for Tg levels between 0.20-0.99 ng/mL.

Revision Thyroid Surgery

The incidence of recurrence in well-differentiated thyroid malignancies range from 10 to 30%. It is estimated that about 31-46% of patients with differentiated thyroid cancer will have the persistent disease and 1.2-6.8% will have structural recurrences during post-operative monitoring, depending on the initial therapy and prognostic variables. It is challenging to decide on treatment versus active monitoring following repeated or persistent tumour detection. The biological factors of the tumour and the patient guide us in the overall decision-making. Revision thyroid surgery is technically challenging. The morbidity encountered during the revision surgery is related to the anatomy of the region undergoing dissection, the degree of fibrosis and scarring from prior surgery and the operating surgeon's experience. Successful comprehensive management of revision thyroid surgery needs a multi-disciplinary approach. This review article highlights the definition, indications for revision surgery, identification of recurrent disease, management of parathyroid and recurrent laryngeal nerves with neuromonitoring.

Can ultrasensitive thyroglobulin immunoassays avoid the need for ultrasound in thyroid cancer follow-up?

PURPOSE

Differentiated thyroid cancer (DTC) is the most common endocrine neoplasm, with a rising incidence and a long life expectancy. It has recently been suggested that patients with low- and intermediate-risk DTC with a good response to treatment at one year could be followed up using only highly sensitive immunoassays for thyroglobulin (Tg). The aim of this study was to examine the serum Tg levels in a series of DTC patients with histologically proven persistent or recurrent diseases.

METHODS

The study involved 50 consecutive patients being routinely followed up at our center, whose clinical, histological, and biochemical data were retrospectively collected.

RESULTS

The false-negative rate of ultrasensitive serum Tg assay was 14.3% (5/35) overall, and limited to anti-thyroglobulin autoantibodies (TgAb)-negative patients. Among them, only one patient had an excellent response to treatment at one-year follow-up and was diagnosed with a 4 mm recurrence, after more than seven years of periodic ultrasounds. The size of the neck lesion documented in the histological report was slightly larger in patients with detectable as opposed to negative Tg values (P < 0.05).

CONCLUSIONS

Serum highly sensitive Tg is undetectable in a proportion of patients with a proven persistent or recurrent DTC. The reasons behind this phenomenon are still unknown. However, in low/intermediate-risk patients cured at one-year follow-up, highly sensitive Tg without neck US seems an appropriate strategy for patients' management.

Serum Linkage-Specific Sialylation Changes Are Potential Biomarkers for Monitoring and Predicting the Recurrence of Papillary Thyroid Cancer Following Thyroidectomy

BACKGROUND

Although papillary thyroid cancer (PTC) could remain indolent, the recurrence rates after thyroidectomy are approximately 20%. There are currently no accurate serum biomarkers that can monitor and predict recurrence of PTC after thyroidectomy. This study aimed to explore novel serum biomarkers that are relevant to the monitoring and prediction of recurrence in PTC using N-glycomics.

METHODS

A high-throughput quantitative strategy based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to obtain serum protein N-glycomes of well-differentiated PTC, postoperative surveillance (PS), postoperative recurrence (PR), and matched healthy controls (HC) including linkage-specific sialylation information.

RESULTS

Serum N-glycan traits were found to differ among PTC, PS, PR, and HC. The differentially expressed N-glycan traits consisting of sixteen directly detected glycan traits and seven derived glycan traits indicated the response to surgical resection therapy and the potential for monitoring the PTC. Two glycan traits representing the levels of linkage-specific sialylation (H4N3F1L1 and H4N6F1E1) which were down-regulated in PS and up-regulated in PR showed high potential as biomarkers for predicting the recurrence after thyroidectomy.

CONCLUSIONS

To the best of our knowledge, this study provides comprehensive evaluations of the serum N-glycomic changes in patients with PS or PR for the first time. Several candidate serum N-glycan biomarkers including the linkage-specific sialylation have been determined, some of which have potential in the prediction of recurrence in PTC, and others of which can help to explore and monitor the response to initial surgical resection therapy. The findings enhanced the comprehension of PTC.

[Clinical practice guidelines "Management of iodine deficiency disorders"]

Iodine deficiency disorders is a sweeping term that includes structural and functional impairment of the thyroid gland.These clinical guidelines include algorithms for the diagnosis and treatment of euthyroid goiter and nodular/ multinodular goiter in adults and children. In addition, these clinical guidelines contain information on methods for an adequate epidemiological assessment of iodine deficiency disorders using such markers as the percentage of goiter in schoolchildren, the median urinary iodine concentration, the level of neonatal TSH, the median thyroglobulin in children and adults. As well from these clinical guidelines, you can get to know the main methods and groups of epidemiological studies of iodine deficiency disorders.

Ultrasonography surveillance in papillary thyroid carcinoma patients after total thyroidectomy according to dynamic risk stratification

PURPOSE

To investigate the role of neck US surveillance in patients with papillary thyroid carcinoma (PTC) after total thyroidectomy according to dynamic risk stratification (DRS) based on response to initial therapy.

METHODS

This retrospective study included 812 patients with PTC who underwent total thyroidectomy with prophylactic central neck dissection from January 2003 through February 2007. The relative risk of recurrence/persistence according to DRS was evaluated with the multivariable Cox regression proportional hazard model.

RESULTS

There were 132 men and 680 women. The mean age at surgery was 45.2 years. Postoperative US was used for DRS. According to DRS, 676 patients had excellent response, 78 indeterminate response, 40 biochemical incomplete response, and 18 structural incomplete response to initial therapy. Neck US was performed during follow-up and detected locoregional recurrences in 21 patients (2.6%): 12 with excellent response, 2 with biochemical incomplete response, and 7 with structural incomplete response according to DRS. Only 1 patient (0.1%) with excellent response had a locoregional recurrence that exceeded 8 mm in its shortest diameter, which is the size cut-off for diagnostic US fine-needle aspiration in suspicious lymph nodes. This patient did not develop biochemical abnormalities during follow-up.

CONCLUSIONS

Postoperative neck US surveillance after total thyroidectomy with prophylactic central neck dissection is not essential in PTC patients who show excellent response to initial therapy. Future studies are needed to verify the role of US surveillance in patients who receive variable degrees of treatments.

Thyroid Cancer Patients With No Evidence of Disease: The Need for Repeat Neck Ultrasound

CONTEXT

Ultrasonography (US) is considered the most sensitive tool for imaging persistent or recurrent papillary thyroid cancer (PTC) in the neck.

OBJECTIVE

To clarify the usefulness of routine neck US in low- and intermediate-risk patients with PTC with no evidence of disease 1 year after thyroidectomy.

DESIGN

Retrospective analysis of prospectively recorded data.

SETTING

Academic center.

PATIENTS

Two hundred twenty-six patients with PTC with sonographically normal neck lymph nodes and unstimulated serum thyroglobulin (Tg) levels that were either undetectable (<0.20 ng/mL) or low (0.21 to 0.99 ng/mL) at the 1-year evaluation.

INTERVENTIONS

Yearly assessment: unstimulated serum Tg level, anti-Tg-antibody (TgAb) titer, TSH levels, and ultrasound examination of neck lymph nodes.

MAIN OUTCOME MEASURES

Rates of ultrasonographic lymph node abnormalities at the 3-year and last follow-up visits.

RESULTS

In patients with an undetectable Tg level at the 1-year evaluation, sonographically suspicious neck lymph nodes were found in 1.2% of patients at 3 years and in 1.8% at the last visit [negative predictive values (NPVs) of 1-year Tg < 0.2 ng/mL: 98.8% (95% CI 95.8% to 99.9%) and 98.2% (95% to 99.6%), respectively]. Similar NPVs emerged for low detectable 1-year Tg levels [98.2% (90.3% to 99.9%) and 94.5% (84.9% to 98.9%) at the 3-year and last visits, respectively]. Seventy-five percent of the nodal lesions were likely false positive; none required treatment.

CONCLUSIONS

Low- and intermediate-risk patients with PTC with negative ultrasound findings and unstimulated Tg levels <1 ng/mL at the 1-year evaluation can be safely followed with clinical assessments and unstimulated serum Tg determinations. Neck US might be repeated if TgAb titers rise, or unstimulated Tg levels exceed 1 ng/mL.