How to manage patients with differentiated thyroid cancer and a rising serum thyroglobulin level

Management of Recurrent Well-Differentiated Thyroid Carcinoma in the Neck: A Comprehensive Review

Surgery has been historically the preferred primary treatment for patients with well-differentiated thyroid carcinoma and for selected locoregional recurrences. Adjuvant therapy with radioactive iodine is typically recommended for patients with an intermediate to high risk of recurrence. Despite these treatments, locally advanced disease and locoregional relapses are not infrequent. These patients have a prolonged overall survival that may result in long periods of active disease and the possibility of requiring subsequent treatments. Recently, many new options have emerged as salvage therapies. This review offers a comprehensive discussion and considerations regarding surgery, active surveillance, radioactive iodine therapy, ultrasonography-guided percutaneous ablation, external beam radiotherapy, and systemic therapy for well-differentiated thyroid cancer based on relevant publications and current reference guidelines. We feel that the surgical member of the thyroid cancer management team is empowered by being aware and facile with all management options.

The Role of Thyroglobulin in Preoperative and Postoperative Evaluation of Patients With Differentiated Thyroid Cancer

Thyroglobulin (Tg) is secreted by thyroid follicular cells and stored in the thyroid follicular lumen as a component of thyroid hormone. It is known that both benign and well-differentiated malignant thyroid tissue can secrete Tg. In recent years, growing lines of evidence have shown that Tg plays an important role in the diagnosis and metastasis of preoperative differentiated thyroid carcinoma (DTC). The levels of Tg, whether in the serum or in a fine-needle aspiration washout fluid, are usually viewed as an excellent indicator in the monitoring of postoperative DTC, including the guidance and evaluation of radioactive iodine ablation. Nevertheless, some factors limit the application of Tg, such as the method used to measure Tg and the presence of Tg antibodies. This review aimed to summarize the role of Tg in the preoperative and postoperative evaluation of patients with DTC, and the factors influencing Tg. This review could provide a reference for a more accurate application of Tg in patients with DTC.

Management of the Neck in Well-Differentiated Thyroid Cancer

PURPOSE OF REVIEW

In this narrative review, we discuss the indications for elective and therapeutic neck dissections and the postoperative surveillance and treatment options for recurrent nodal disease in patients with well-differentiated thyroid cancer.

RECENT FINDINGS

Increased availability of advanced imaging modalities has led to an increased detection rate of previously occult nodal disease in thyroid cancer. Nodal metastases are more common in young patients, large primary tumors, specific genotypes, and certain histological types. While clinically evident nodal disease in the lateral neck compartments has a significant oncological impact, particularly in the older age group, microscopic metastases to the central or the lateral neck in well-differentiated thyroid cancer do not significantly affect outcome. As patients with clinically evident nodal disease are associated with worse outcomes, they should be treated surgically in order to reduce rates of regional recurrence and improve survival. The benefit of elective neck dissection remains unverified as the impact of microscopic disease on outcomes is not significant.

Surgical options for thyroid cancer and post-surgical management

INTRODUCTION

Differentiated thyroid cancer (DTC), which includes papillary and follicular, is the most common type of thyroid cancer and the incidence is rising. Survival rates of DTC are excellent, so the focus of management should be to optimize the initial oncological surgical resection, while providing follow up and adjunct therapies to improve long-term outcomes.

AREAS COVERED

It is important for providers to be aware of the most recent guidelines for DTC management, as practices have changed in recent years. In this review, we will highlight some of the updates in the American Thyroid Association (ATA) guidelines and the American Joint Committee on Cancer (AJCC) edition changes in order to better guide practitioners in the management of the evolving treatment strategies. Management of DTC includes diagnosis of thyroid nodules, defining the best operative or non-operative treatment for patients using a multidisciplinary approach, and surveillance of DTC to optimize patients in terms of both clinical and quality of life outcomes.

EXPERT COMMENTARY

As the rate of DTC rises yet the mortality remains stable, management focuses on disease-free follow up and optimal long-term outcomes. Current controversies in management of DTC include proper oncological surgery depending on the nature and size of the DTC, the cytopathology nomenclature, management of lymph node disease, and appropriate surveillance strategies. Preoperative risk stratification is key. We have many modalities to aid in that stratification, such as identifying known concerning features of nodules with expert-performed ultrasound, thyroglobulin (Tg) levels, molecular testing, and evidence based outcomes data for recurrence rates. However, many individual cases still present with multiple management options, thus highlighting the importance of patient discussion and a multidisciplinary approach. It is important for providers to recognize that the short and long-term follow up must be guided by surveillance studies, and patients need to be re-risk stratified in order to optimize detection of recurrence yet sustain quality of life.

Clinical Impact of Detectable Antithyroglobulin Antibodies Below the Reference Limit (Borderline) in Patients with Papillary Thyroid Carcinoma with Undetectable Serum Thyroglobulin and Normal Neck Ultrasonography After Ablation: A Prospective Study

BACKGROUND

Interference of antithyroglobulin antibodies (TgAb) with serum thyroglobulin (Tg) can occur even at detectable TgAb concentrations below the reference limit (borderline TgAb). Thus, borderline TgAb is considered as TgAb positivity in patients with thyroid cancer. This prospective study evaluated patients with papillary thyroid carcinoma with undetectable Tg and normal neck ultrasonography (US) after total thyroidectomy and ablation with ¹³¹I, and compared tumor persistence/recurrence and long-term Tg and TgAb behavior in those with borderline versus undetectable TgAb.

METHODS

A total of 576 patients were evaluated, divided into two groups: group A with undetectable TgAb (n = 420), and group B with borderline TgAb (n = 156).

RESULTS

Groups A and B were similar in terms of patient and tumor characteristics. The time of follow-up ranged from 24 to 120 months. During follow-up, 11 (2.6%) patients in group A and 5 (3.2%) in group B developed a recurrence (p = 0.77). In group A, recurrences occurred in 9/390 patients who continued to have undetectable TgAb and in 1/9 patients who progressed to borderline TgAb. In group B, recurrences were detected in 1/84 patients who progressed to have undetectable TgAb, in 1/45 who still had borderline TgAb, and in 3/12 who developed elevated TgAb. In the presence of Tg levels <0.2 ng/mL, recurrences were detected in 2/486 patients with undetectable TgAb, in 0/67 with borderline TgAb, and in 3/12 with elevated TgAb. The results of post-therapy whole-body scanning (RxWBS) of 216 patients with Tg ≤0.2 ng/mL and normal US at the time of ablation were also analyzed. In low-risk patients, none of the 40 patients with borderline TgAb and none of the 94 with undetectable TgAb exhibited ectopic uptake on RxWBS. In intermediate-risk patients, lymph node metastases were detected by RxWBS in 1/25 (4%) with borderline TgAb and in 2/57 (3.5%) with undetectable TgAb.

CONCLUSIONS

The results suggest that among low- or intermediate-risk patients with undetectable Tg and normal US after thyroidectomy, those with borderline TgAb are at no greater risk of tumor persistence or recurrence than those with undetectable TgAb. When undetectable Tg levels persist, recurrence should be suspected in the case of a TgAb elevation above the reference limit.

Serum Thyroglobulin Doubling Time in Progressive Thyroid Cancer

BACKGROUND

Tumor marker doubling time (DT) has been proposed as a prognostic marker for various types of cancer. The present study analyzed the DT of the thyroid-specific tumor marker thyroglobulin (Tg), focusing on patients with progressive differentiated thyroid cancer (DTC).

METHODS

A total of 144 Tg courses of 99 patients with progressive or recurrent DTC were included (median observation period 19 months, 3-11 Tg measurements per course) in this retrospective study. The distribution of Tg-DT was determined for both a highly sensitive assay (functional working range 0.03-3 ng/mL) and a routine assay. Tg-DT and other prognostic markers were used to perform uni- and multivariate statistical analyses for survival predictors.

RESULTS

The median Tg-DT was 212 days (95% percentile: 49-961 days). No significant differences were observed between DT derived from Tg values in the very low range using a highly sensitive assay and DT calculated from Tg values measured by a conventional Tg assay. Multivariate analysis yielded no simple correlation between Tg-DT and survival rate, but the mortality risk of patients with a Tg-DT <5 months was more than twice as high as compared with a Tg-DT of >14 months. Highly significant differences on survival rates were only observed in patients with a high tumor load (Tg >100 ng/mL).

CONCLUSIONS

Tg-DT alone is not an independent survival predictor in all patients with progressive DTC; however, analyzing only patients with a high tumor load, we found highly significant differences in survival rates.

Comprehensive management of recurrent thyroid cancer: An American Head and Neck Society consensus statement: AHNS consensus statement

This American Head and Neck Society (AHNS) consensus statement focuses on the detection and management of recurrent thyroid cancer. This document describes the radiologic approach to defining structural recurrent disease and the operative and nonoperative rationale in addressing identified structural disease to create equipoise in the personalized treatment strategy for the patient. The recommendations of this AHNS multidisciplinary consensus panel of the American Head and Neck Society are intended to help guide all multidisciplinary clinicians who diagnose or manage adult patients with thyroid cancer. The consensus panel is comprised of members of the American Head and Neck Society and its Endocrine Surgical Committee, and there is representation from medical endocrinology and both national and international surgical representation drawn from general/endocrine surgery and otolaryngology/head and neck surgery. Authors provided expertise for their respective sections, and consensus recommendations were made regarding the evaluation and treatment of recurrent thyroid cancer. Evidence-based literature support is drawn from thyroid cancer studies, recurrent thyroid cancer studies, and American Thyroid Association (ATA) guidelines. The manuscript was then distributed to members of the American Head and Neck Society Endocrine Committee and governing counsel for further feedback. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1862-1869, 2016.