Treatment of Thyroid Cancer: 2007—A Basic Review

The missing link between cancer stem cells and immunotherapy

Cancer stem cells (CSCs) are cancer cells that can self-renew and give rise to tumors. The multipotency of CSCs enables the generation of diverse cancer cell types and their potential for differentiation and resilience against chemotherapy and radiation. Additionally, specific biomarkers have been identified for them, such as CD24, CD34, CD44, CD47, CD90, and CD133. The CSC model suggests that a subset of CSCs within tumors is responsible for tumor growth. The tumor microenvironment (TME), including fibroblasts, immune cells, adipocytes, endothelial cells, neuroendocrine (NE) cells, extracellular matrix (ECM), and extracellular vesicles, has a part in shielding CSCs from the host immune response as well as protecting them against anticancer drugs. The regulation of cancer stem cell plasticity by cancer-associated fibroblasts (CAFs) occurs through specific signaling pathways that differ among various types of cancer, utilizing the IGF-II/IGF1R, FAK, and c-Met/FRA1/HEY1 signaling pathways. Due to the intricate dynamics of CSC proliferation, controlling their growth necessitates innovative approaches and much more research. Our current review speculates an outline of how the TME safeguards stem cells, their interaction with CSCs, and the involvement of the immune and inflammatory systems in CSC differentiation and maintenance. Several technologies have the ability to identify CSCs; however, each approach has limitations. We discuss how these methods can aid in recognizing CSCs in several cancer types, comprising brain, breast, liver, stomach, and colon cancer. Furthermore, we explore different immunotherapeutic strategies targeting CSCs, including stimulating cancer-specific T cells, modifying immunosuppressive TMEs, and antibody-mediated therapy targeting CSC markers.

Quality of Life and Surgical Outcome of Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA) versus Open Thyroid Surgery: Experience from a Single Center in Vietnam

Background

It has been widely assumed that TOETVA has demonstrated a new technique and a promising approach as it is both minimally invasive and optimally cosmetic. The objective of this study was to assess the surgical outcome, aesthetic satisfaction, and postoperative quality of life of TOETVA in comparison with open thyroid surgery. Patients and Methods. The study was designed as a prospective study, in which 121 patients from a single center in Vietnam underwent thyroid surgery, and the study was divided into two groups: 60 patients in the TOETVA group and 61 patients in the open surgery group. The patients have been followed up including surgical outcomes, cosmetic satisfaction, and quality of life. These criteria were assessed at 4 weeks, 8 weeks, and 12 weeks after the surgery using SF-36 and thyroid surgery-specific questionnaire.

Results

Patients in the TOETVA group are significantly younger than patients in the open surgery group (35.8 + 10.3 vs 46.9 + 11.5, p < 0.001). The mean operating time was longer in the TOETVA group (102.9 ± 26.1 mins) than that in the open surgery group (66.8 ± 23.8 mins) with p = 0.0001. Cosmetic outcomes and overall satisfaction were significantly greater in the TOETVA group p = 0.0001. The SF-36 QOL scores of the patients in the TOETVA group were generally higher than the open surgery group.

Conclusions

TOETVA has been widely used with a low complication rate, cosmetic appeal, and surgical efficacy. Postoperative quality of life, cosmetic outcomes, and overall satisfaction were significantly superior to the open surgery group.

UHRF1 Induces Metastasis in Thyroid Cancer

Background

Ubiquitin-like with PHD and ring-finger domain 1 (UHRF1) has been defined as an oncogene in tumor cells. However, the role of UHRF1 in mediating metastasis in thyroid cancer remains unexplored. In this study, we aimed to investigate the metastatic function and the potential mechanisms of UHRF1 in thyroid cancer.

Methods

Transwell assays were used to detect the metastatic capability of thyroid cancer. Dual-luciferase reporter assays were applied to examine the activation of transcription factors. Coimmunoprecipitation assays and immunofluorescence staining assays were used to elucidate the potential mechanisms of UHRF1 in promoting the metastasis of thyroid cancer.

Results

In this study, we found that overexpression of UHRF1 promoted the metastasis of papillary thyroid cancer cells, and suppression of UHRF1 decreased the metastasis of anaplastic thyroid cancer cells. Regarding the signaling pathway in regulating metastasis, UHRF1 directly combined and activated the transcription factor c-Jun/AP-1 in the nucleus, subsequently increasing the transcription of IL-6 and MIF.

Conclusion

Our results suggest that UHRF1 could induce the metastasis of thyroid cancer, and the potential signaling pathway might be that UHRF1 activates c-Jun/AP-1 to increase the expression of IL-6 and MIF. These findings provide a novel mechanism of UHRF1 and illustrate that UHRF1/AP-1 complex could be a potential therapeutic target for patients with thyroid cancer.

Differences in the clinical characteristics of papillary thyroid microcarcinoma located in the isthmus ≤5 mm and >5mm in diameter

Background

The optimal treatment of papillary thyroid microcarcinomas (PTMCs) located in the isthmus (iPTMCs) is still controversial. The purpose of this study was to compare the clinicopathologic features of patients with iPTMCs ≤5 mm and >5 mm in diameter after total thyroidectomy, and to identify the risk factors for recurrence in patients with iPTMCs.

Methods

A total of 102 iPTMC patients who underwent total thyroidectomy were reviewed retrospectively. The clinicopathologic characteristics of iPTMCs ≤5 mm group (n = 29) have been compared with a group >5 mm (n = 73). Univariate and multivariate Cox proportional hazard models served to identify risk factors associated with recurrence-free survival (RFS).

Results

Gender (p = 0.033), multifocality (p = 0.041), and central lymph node metastasis (CLNM) (p = 0.009) of patients in the ≤5 mm and >5 mm groups differed significantly. iPTMC patients with age <55 years, male, multiple tumor, and extrathyroidal extension showed comparatively more frequent of CLNM in >5 mm groups. Of the 102 patients, nine (8.8%) developed recurrence during follow-up (median: 49.5 months). The patients with recurrences had comparatively high rates of CLNM (p = 0.038), extranodal invasion (p = 0.018), and more MNCND (Metastasis Nodes for Central Neck dissection) (p = 0.020). A cutoff of MNCND >2.46 was established as the most sensitive and specific level for the prediction of recurrence based on receiver operating characteristic (ROC) curve analyses. Multivariate analysis showed that the number of MNCND ≥3 was an independent predictor of poor RFS (p = 0.028).

Conclusion

We have found that the recurrence rates are similar in patients with iPTMCs ≤5 mm and >5 mm. The iPTMCs >5 mm were more likely to be associated with pathological features such as multifocality and CLNM. The male gender, extrathyroidal extension, and CLNM were associated with recurrence of iPTMCs except for tumor size and multifocality. Higher risk of CLNM should be considered in iPTMC >5 mm when it reaches some risk factors. The numbers of MNCND ≥3 may be an independent predictor for recurrence, which could help clinicians for the decision of radioiodine administration and the modulation of follow-up modalities.

Quality of life after thyroid surgery

PURPOSE

The purpose of this study was to inquire how patients' quality of life is affected after thyroid surgery and the factors involved.

METHODS

A semi-structured questionnaire and the World Health Organization Quality of Life Scale (WHOQOL-BREF) were applied to 101 patients prior to surgery. Thereafter data was collected in the early and again in the late post-operative period.

RESULTS

Mean general health score for pre-operative quality of life was 6.72 ± 1.53 (3-10), mean physical field score was 22.81 ± 2.77 (17-31), mean psychological field score was 21.69 ± 2.78 (15-28), mean social field score was 11.10 ± 1.94 (5-15) and mean environmental field score was 27.86 ± 4.30 (18-39). In the early post-operative period, mean general health score was 7.05 ± 1.45 (4-10), mean physical field score was 22.84 ± 2.83 (14-29), mean psychological field score was 21.67 ± 2.32 (16-27), mean social field score was 10.89 ± 1.96 (5-15) and mean environmental field score was 28.56 ± 4.18 (18-40). In the late post-operative period, the general health score for quality of life was 7.43 ± 1.34 (4-10), mean physical field score was 23.59 ± 2.70 (17-35), mean psychological field score was 21.75 ± 2.34 (14-29), mean social field score was 11.23 ± 1.94 (6-15) and mean on-field environment score was 29.30 ± 3.96 (16-40). The pre-operative levels of symptoms were found to be higher than early and late post-operative periods.

CONCLUSIONS

Quality of life increased after total thyroidectomy and statistically significant improvement was observed in late post-operative stage.

Identification of Novel Oncogenic Mutations in Thyroid Cancer

BACKGROUND

Thyroid cancer patients frequently have favorable outcomes. However, a small subset develops aggressive disease refractory to traditional treatments. Therefore, we sought to characterize oncogenic mutations in thyroid cancers to identify novel therapeutic targets that may benefit patients with advanced, refractory disease.

STUDY DESIGN

Data on 239 thyroid cancer specimens collected between January 2009 and September 2014 were obtained from the Dana Farber/Brigham and Women's Cancer Center. The tumors were analyzed with the OncoMap-4 or OncoPanel high-throughput genotyping platforms that survey up to 275 cancer genes and 91 introns for DNA rearrangement.

RESULTS

Of the 239 thyroid cancer specimens, 128 (54%) had oncogenic mutations detected. These 128 tumors had 351 different mutations detected in 129 oncogenes or tumor suppressors. Examination of the 128 specimens demonstrated that 55% (n = 70) had 1 oncogenic mutation, and 45% (n = 48) had more than 1 mutation. The 351 oncogenic mutations were in papillary (85%), follicular (4%), medullary (7%), and anaplastic (4%) thyroid cancers. Analysis revealed that 2.3% (n = 3 genes) of the somatic gene mutations were novel. These included AR (n = 1), MPL (n = 2), and EXT2 (n = 1), which were present in 4 different papillary thyroid cancer specimens. New mutations were found in an additional 13 genes known to have altered protein expression in thyroid cancer: BLM, CBL, CIITA, EP300, GSTM5, LMO2, PRAME, SBDS, SF1, TET2, TNFAIP3, XPO1, and ZRSR2.

CONCLUSIONS

This analysis revealed that several previously unreported oncogenic gene mutations exist in thyroid cancers and may be targets for the development of future therapies. Further investigation into the role of these genes is warranted.

Clinical Utility of SPECT/CT Imaging Post-Radioiodine Therapy: Does It Enhance Patient Management in Thyroid Cancer?

BACKGROUND

The aim of this study was to evaluate post-therapy iodine-131 single-photon emission computed tomography/computed tomography ((131)I-SPECT/CT) imaging in comparison to conventional planar (131)I whole-body imaging, and to assess its clinical impact on the management of patients.

METHODS

We retrospectively reviewed planar (131)I whole-body and (131)I-SPECT/CT imaging findings in 67 patients who underwent (131)I therapy for thyroid cancer. Two nuclear medicine physicians reviewed the scans independently. The foci of increased tracer uptake were identified in the neck, thorax and elsewhere. Within the neck, the foci of (131)I-increased uptake were graded qualitatively as probable or definite uptake in thyroid remnants and probable or definite uptake in the lymph nodes. Serum thyroglobulin level, histopathology and other imaging findings served as the reference standard.

RESULTS

Of the 67 patients, 57 (85%) had radioiodine avid disease and 10 (15%) demonstrated non-radioiodine avid disease. Overall, post-therapy (131)I-SPECT/CT downstaged lymph node staging in 10 patients and upstaged it in 4 patients. This translated into a change of management for 9/57 (16%) patients with radioiodine avid disease. A change of management was observed in 5/10 patients with non-radioiodine avid disease confirmed in the post-(131)I-SPECT/CT study. Additionally, clinically significant findings such as incidental lung cancer, symptomatic pleural effusion and consolidation were also diagnosed in both groups of patients.

CONCLUSION

In patients with thyroid cancer, (131)I-SPECT/CT is a valuable addition to standard post-therapy planar imaging. SPECT/CT also improved diagnostic confidence and provided crucial clinical information leading to change of management for a significant number of these patients.

New insights in the treatment of radioiodine refractory differentiated thyroid carcinomas: to lenvatinib and beyond

During the past two decades, several key somatic mutations associated with development and progression of differentiated thyroid cancer (DTC) have been revealed. Historically, the treatment for advanced DTC is challenging after patients become refractory to radioactive iodine. The response to doxorubicin, the only chemotherapy agent approved by the US Food and Drug Administration, is disappointing either as monotherapy or combination therapy. Because of the lack of effective systemic treatment coupled with increased understanding of molecular and cellular pathogenesis, multiple kinase inhibitors (MKIs) as an alternative therapy for the treatment of advanced DTC has generated much interest, enthusiasm, and, most excitingly, promising results. After the encouraging results of these agents in earlier trials, the Food and Drug Administration approved sorafenib for the treatment of locally recurrent, progressive, or metastatic DTC refractory to radioactive iodine treatment based on the results of a multicenter DECISION trial. Sorafenib therefore became the first MKI approved for this indication in more than 20 years. However, even more impressive responses and progression-free survival benefits were seen in the phase III SELECT trial with lenvatinib, giving even higher hopes for the future management of what was considered just a decade ago an orphan disease. Given the role of MKIs, a new era in the treatment of advanced DTC has begun. We review the key therapeutic targets, oncogenic pathways, and promising clinical results of these agents in refractory disease, as well as their roles after failure of first line kinase inhibitors.

Preoperative diagnosis of thyroid nodules using the Bethesda System for Reporting Thyroid Cytopathology: a comprehensive review and meta-analysis

Fine-needle aspiration biopsy (FNAB) is the test of choice for the evaluation of nodules, arriving at a cancer diagnosis, and guiding surgical management. This review and meta-analysis aims to objectively evaluate the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) based upon literature reports of histopathological outcomes following cytopathological diagnoses. Thirteen studies were reviewed and the risk of malignancy (ROM) for each of the BSRTC diagnostic categories were calculated as: Non-diagnostic 11-26%, Benign 4-9%, AUS/FLUS 19-38%, FN/SFN 27-40%, SFM 50-79%, and Malignant 98-100%. In typical clinical utilization, the sensitivity and specificity of thyroid FNAB diagnosis using the BSRTC were 96% and 46%, respectively. The BSRTC represents an important advance in standardizing thyroid FNAB cytopathological reporting. Close attention should be paid to the observation that the AUS-FLUS and FN-SFN DCs have overlapping ROMs, and the potential clinical implications of this finding on patient management.

Thyroid cancer stem cells

Thyroid cancer is the most frequently diagnosed endocrine cancer and causes more deaths than all other endocrine cancers combined. Research findings support the concept that a subpopulation of thyroid cancer cells displays properties characteristic of stem cells. These putative cancer-forming entities drive tumorigenesis as a result of their dual ability to undergo self-renewal and to differentiate into various types of cancer cells; they also mediate metastasis and are resistant to the effects of chemotherapy and radiation therapy. This Review discusses the cellular origin of thyroid cancer and the properties of the thyroid cancer stem cell niche. The article critically evaluates the methods used to identify molecular markers expressed by thyroid-cancer-initiating cells and outlines prospective therapeutic strategies to directly target these cells. Stem-cell technology offers an unprecedented opportunity to investigate these crucial cancer stem cell populations and to advance understanding of the molecular mechanisms that control disease processes. Such knowledge could potentially lead to the development of more effective and safer treatment regimens for late-stage thyroid cancer than are currently available.

The role of fine-needle aspiration cytology in the surgical management of thyroid cancer

BACKGROUND

Diagnosis of thyroid malignancy relies on clinical assessment, imaging and fine-needle aspiration cytology 'FNAC' of thyroid nodules. The purpose of this study was to evaluate how effective synoptically reported FNAC is in clinical practice in diagnosing thyroid cancer. We also examined the effectiveness of using preoperative FNAC results to plan the type of operation for treating thyroid cancer.

METHOD

A retrospective case series of all patients undergoing thyroid surgery from 1993 to 2008 was analysed. All data were collected prospectively and recorded in a dedicated endocrine surgery database. Data analysed included age, sex, preoperative FNAC result, type of surgery, final histology and complications. Cytology was reported based on a five-tiered classification system.

RESULTS

There were 1373 patients in total and 125 patients with a final diagnosis of thyroid cancer. Female to male ratio was 3:1. Cytology reported as 'malignant' was confirmed as thyroid cancer in 100% of the cases. Of the patients, 47% with 'suspicious' cytology report and 14% with 'follicular/indeterminate' cytology report had a final diagnosis of cancer. Thyroid cancer subtypes were 90 patients with papillary thyroid cancer 'PTC', 24 with follicular 'FTC', eight with medullary 'MTC' and two with anaplastic cancer. Cytology was suggestive of cancer in 89% of the patients with PTC >10 mm, 75% with FTC and 88% with MTC. Transient hypocalcaemia was the commonest complication occurring in 7.2%. There were no cases of permanent hypoparathyroidism. Recurrent laryngeal nerve neuropraxia occurred in 2.4% with a permanent palsy occurring in 0.8%. There were three cancer-related deaths.

CONCLUSIONS

Preoperative synoptically reported FNAC is effective when used in diagnosing and planning surgery for thyroid cancer.

[Risk groups in differentiated thyroid carcinomas]

INTRODUCTION

Well-differentiated thyroid carcinoma represents 80% of all thyroid malignant tumours, with a survival rate of over 95% at 20 years in 80% of the cases. Although its incidence is increasing, survival remains unchanged. Prognostic factor evaluation allows identifying patients at high or low risk of recurrence, selecting those who will benefit from more aggressive therapy.

MATERIAL

We have reviewed the incidence of malignant thyroid neoplasm, selecting them according to three different system definitions (TNM, GAMES, MACIS), as well as by post-surgical complication rate.

RESULTS

Malignant neoplasm represents 28.8% of the thyroid-operated patients, 88% corresponding to well-differentiated carcinomas. 80% are in the low risk group, with similar numbers in all three staging system definitions. Multicentricity was found in 16%, with 50% of the lesions smaller than 2 cm. Permanent recurrent nerve palsy was 1.2% and 2.7% presented permanent postoperative hypocalcaemia.

CONCLUSIONS

Risk group percentage is similar to that reported in the literature, with 80% having expected survival over 95% at 20 years. Risk factor evaluation should help to individualise treatment options, avoiding overtreatment and complications in patients that will not benefit from more aggressive therapy.

Management of thyroid nodules and surgery for differentiated thyroid cancer

The incidence of well-differentiated thyroid cancer has seen a worldwide increase in the last three decades. Whether this is due to a 'true increase' in incidence or simply increased detection of otherwise subclinical disease remains unclear. The treatment of thyroid cancer revolves around appropriate surgical intervention, minimising complications and the use of adjuvant therapy in select circumstances. Prognostic features and risk stratification are crucial in determining the appropriate treatment. There continues to be considerable debate in several aspects of management in these patients. Level 1 evidence is lacking, and there are limited prospective data to direct therapy, hence limiting decision-making to retrospective analyses, treatment guidelines based on expert opinion and personal philosophies. This overview focuses on the major issues associated with the investigation of thyroid nodules and the extent of surgery. As overall survival in well-differentiated thyroid cancer exceeds 95%, it is important to reduce over-treating the large majority of patients, and focus limited resources on high-risk patients who require aggressive treatment and closer attention. The onus is on the physician to avoid treatment-related complications from thyroid surgery and to offer the most efficient and cost-effective therapeutic option.

A novel HSP90 modulator with selective activity against thyroid cancers in vitro

BACKGROUND

Heat shock protein 90 (HSP90) is a chaperone protein regulating several client proteins involved in thyroid cancer development. The purpose of this study was to mechanistically evaluate a novel, natural product drug with anticancer activity in thyroid cancer cell lines in vitro for future translational applications.

METHODS

A total of 285 natural plant extracts and compounds were evaluated for anticancer activity by MTS assay. Apoptosis and cell cycle arrest were characterized by annexin V-propidium iodide (PI) flow cytometry. HSP90 and client protein modulation, as well as apoptosis confirmation, as demonstrated by Western blot analysis.

RESULTS

Of the 285 compounds and products tested, 45 demonstrated antiproliferative activity in thyroid cancers by MTS assay. BTIMNP_D004 demonstrated the greatest inhibition (IC(50) = 155-2,890 nM in thyroid cancers). Activity was cancer-cell selective compared to fibroblasts, with increased potency over 17-AAG in BCPAP, FTC133, and DRO81-1 cells. D004 modulated cell cycle arrest after 18 hours (G(1)/G(0) --> S and G(2)/M) with 30% FTC133 cells shifted, 22% BCPAP cells shifted, and 15% SW1736 cells shifted versus controls (P < .01, P < .01, and P < .05, respectively). A total of 1 muM D004 induced significant apoptosis, with 76% BCPAP cells gated after 18 hours (annexin V-PI staining vs <3% in controls, P < .01; and 80% FTC133 cells vs 4% controls; P < .01). Western blot analysis demonstrated modulation of HSP90 expression levels, with inhibition of HSF-1, AKT, and caspase-3 expression, and cleavage of PARP in both BCPAP and FTC133 cells.

CONCLUSION

BTIMNP_D004 is a novel natural product drug with anticancer activity against thyroid cancers in vitro, and may act through induction of apoptosis, modulation of cell cycle arrest, and modulation of heat shock chaperone proteins including HSP90. These preliminary in vitro data support future preclinical studies for translational applications.

Controversies and challenges in the management of well-differentiated thyroid cancer

The incidence of well-differentiated thyroid cancer has seen a worldwide increase in the last three decades, although whether this is due to a 'true increase' in incidence or simply increased detection of otherwise subclinical disease remains undetermined. Nonetheless, this rising incidence has fuelled an interest in early diagnosis, treatment and follow-up of thyroid cancer along with greater public awareness. The treatment of thyroid cancer revolves around appropriate surgical intervention, minimising complications and the use of adjuvant therapy in select circumstances. Prognostic features and risk stratification are crucial in determining the appropriate treatment. There continues to be considerable debate in several aspects of management in these patients, and there is limited prospective data to direct therapy, hence limiting decision-making to retrospective analyses, treatment guidelines based on expert opinion and personal philosophies. The major controversies are related to diagnostic work-up, extent of surgery and postoperative management including the role of radioactive iodine. There are also differences in opinion regarding management of nodal metastases and follow-up protocols. As overall survival in well-differentiated thyroid cancer exceeds 95%, it is important to reduce over-treating the large majority of patients, and focus limited resources on high-risk patients who require aggressive treatment and closer attention. There needs to be a concerted effort on the part of a multidisciplinary team to recognise the nuances in treating well-differentiated thyroid cancer.

Ultrasound-Guided Needle Localization of Recurrent Paratracheal Thyroid Cancer

Objectives:

Ultrasound-guided needle localization techniques have been used to direct the resection of targeted axillary lymph nodes in the management of breast cancer. To date, there has been only one other description of this technique as a localization method to direct cancer resection in the neck. We offer further support for the broader application of this technique by reporting its use in the successful identification and resection of recurrent papillary thyroid cancer after a paratracheal node dissection failed to localize the cancer.

Methods:

We report a case and discuss the relevant literature regarding ultrasound-guided localization and resection of recurrent well-differentiated thyroid cancer.

Results:

We were able to achieve successful identification and resection of recurrent papillary thyroid cancer using this technique.

Conclusions:

This technique may be useful in the treatment of selected cases of recurrent thyroid cancer to increase the efficacy and safety of surgical resection.