The Impact of Zoledronic Acid and Radioactive Iodine Therapy on Morbi-Mortality of Patients with Bone Metastases of Thyroid Cancer Derived from Follicular Cells

An Executive Summary of The Philippine Interim Clinical Practice Guidelines for the Diagnosis and Management of Well Differentiated Thyroid Cancer 2021

Objectives

Thyroid cancer is the most common endocrine cancer in the Philippines affecting primarily women in the reproductive age group. Considering the burden of thyroid cancer in the country, the Department of Health (DOH) called for the development of a national clinical practice guideline that would address patient needs, and aid physicians in clinical decision-making while considering therapeutic cost and availability in the local setting. The 2021 guidelines are aimed at providing optimal care to Filipino patients by assisting clinicians in the evaluation of thyroid nodules and management of well differentiated thyroid cancer.

Methods

A steering committee convened to formulate clinical questions pertaining to the screening and evaluation of thyroid nodules, surgical and post operative management of thyroid cancer, and palliative care for unresectable disease. A technical working group reviewed existing clinical guidelines, retrieved through a systematic literature search, synthesized clinical evidence, and drafted recommendations based on the ADAPTE process of clinical practice guideline development. The consensus panel reviewed evidence summaries and voted on recommendations for the final statements of the clinical practice guidelines.

Results

The guidelines consist of clinical questions and recommendations grouped into six key areas of management of well differentiated thyroid cancer: screening, diagnosis, surgical treatment, post operative management, surveillance, and palliative care.

Conclusion

The 2021 guidelines for well differentiated cancer could direct physicians in clinical decision making, and create better outcomes for Filipino patients afflicted with the disease. However, patient management should still be governed by sound clinical judgement and open physician-patient communication.

Management of radioiodine refractory differentiated thyroid cancer: the Latin American perspective

Radioiodine (RAI) refractory differentiated thyroid cancer is an uncommon and challenging situation that requires a multidisciplinary approach to therapeutic strategies. The definition of RAI-refractoriness is usually a clear situation in specialized centers. However, the right moment for initiation of multikinase inhibitors (MKI), the time and availability for genomic testing, and the possibility of prescribing MKI and selective kinase inhibitors differ worldwide.Latin America (LA) refers to the territories of the world that stretch across two regions: North America (including Central America and the Caribbean) and South America, containing 8.5% of the world's population. In this manuscript, we critically review the current standard approach recommended for patients with RAI refractory differentiated thyroid cancer, emphasizing the challenges faced in LA. To achieve this objective, the Latin American Thyroid Society (LATS) convened a panel of experts from Brazil, Argentina, Chile, and Colombia. Access to MKI compounds continues to be a challenge in all LA countries. This is true not only for MKI but also for the new selective tyrosine kinase inhibitor, which will also require genomic testing, that is not widely available. Thus, as precision medicine advances, significant disparities will be made more evident, and despite efforts to improve coverage and reimbursement, molecular-based precision medicine remains inaccessible to most of the LA population. Efforts should be undertaken to alleviate the discrepancies between the current state-of-the-art care for RAI-refractory differentiated thyroid cancer and the present situation in Latin America.

Tumor-associated macrophages as a potential therapeutic target in thyroid cancers

Macrophages are important precursor cell types of the innate immune system and bridge adaptive immune responses through the antigen presentation system. Meanwhile, macrophages constitute substantial portion of the stromal cells in the tumor microenvironment (TME) (referred to as tumor-associated macrophages, or TAMs) and exhibit conflicting roles in the development, invasion, and metastasis of thyroid cancer (TC). Moreover, TAMs play a crucial role to the behavior of TC due to their high degree of infiltration and prognostic relevance. Generally, TAMs can be divided into two subgroups; M1-like TAMs are capable of directly kill tumor cells, and recruiting and activating other immune cells in the early stages of cancer. However, due to changes in the TME, M2-like TAMs gradually increase and promote tumor progression. This review aims to discuss the impact of TAMs on TC, including their role in tumor promotion, gene mutation, and other factors related to the polarization of TAMs. Finally, we will explore the M2-like TAM-centered therapeutic strategies, including chemotherapy, clinical trials, and combinatorial immunotherapy.

Novel Therapeutics and Treatment Strategies for Medullary Thyroid Cancer

Medullary thyroid cancer is a rare thyroid malignancy with unique management considerations. In general, small intrathyroidal tumors are cured by total thyroidectomy with central compartment dissection, while large tumors and those with disease spread to regional lymph nodes and distant organs (most commonly lung, liver, and bone) are more difficult to cure. The last decade has seen significant progress in the treatment of advanced MTC, largely due to the discovery and availability of novel targeted therapies, including new drugs specifically targeting the RET protooncogone.

Advancing Treatment of Bone Metastases through Novel Translational Approaches Targeting the Bone Microenvironment

Bone metastases represent a lethal condition that frequently occurs in solid tumors such as prostate, breast, lung, and renal cell carcinomas, and increase the risk of skeletal-related events (SREs) including pain, pathologic fractures, and spinal cord compression. This unique metastatic niche consists of a multicellular complex that cancer cells co-opt to engender bone remodeling, immune suppression, and stromal-mediated therapeutic resistance. This review comprehensively discusses clinical challenges of bone metastases, novel preclinical models of the bone and bone marrow microenviroment, and crucial signaling pathways active in bone homeostasis and metastatic niche. These studies establish the context to summarize the current state of investigational agents targeting BM, and approaches to improve BM-targeting therapies. Finally, we discuss opportunities to advance research in bone and bone marrow microenvironments by increasing complexity of humanized preclinical models and fostering interdisciplinary collaborations to translational research in this challenging metastatic niche.

Bone metastases from differentiated thyroid carcinoma: current knowledge and open issues

Bone represents the second most common site of distant metastases in differentiated thyroid cancer (DTC). The clinical course of DTC patients with bone metastases (BM) is quite heterogeneous, but generally associated with low survival rates. Skeletal-related events might be a serious complication of BM, resulting in high morbidity and impaired quality of life. To achieve disease control and symptoms relief, multimodal treatment is generally required: radioiodine therapy, local procedures-including surgery, radiotherapy and percutaneous techniques-and systemic therapies, such as kinase inhibitors and antiresorptive drugs. The management of DTC with BM is challenging: a careful evaluation and a personalized approach are essential to improve patients' outcomes. To date, prospective studies focusing on the main clinical aspects of DTC with BM are scarce; available analyses mainly include cohorts assembled over multiple decades, small samples sizes and data about BM not always separated from those regarding other distant metastases. The aim of this review is to summarize the most recent evidences and the unsolved questions regarding BM in DTC, analyzing several key issues: pathophysiology, prognostic factors, role of anatomic and functional imaging, and clinical management.

Bone Metastases in Medullary Thyroid Carcinoma: High Morbidity and Poor Prognosis Associated With Osteolytic Morphology

CONTEXT

The clinical relevance of bone metastases (BM) in advanced medullary thyroid carcinoma (MTC) is poorly described.

OBJECTIVE

The objectives of this work are to describe the prevalence of BM, frequency of skeletal related events (SREs), and impact of BM morphology and SREs on prognosis, and to assess the role of antiresorptive treatment (ART).

DESIGN

A retrospective cohort study was conducted.

SETTING

This study was conducted at 4 German referral centers.

PATIENTS

A total of 1060 MTC patients were included.

MAIN OUTCOME MEASURE

Main outcome measures include descriptive statistics, overall survival (OS) by the Kaplan-Meier method, and risk factors by Cox proportional hazards modeling.

RESULTS

A total of 120 of 416 patients (29%) with metastatic MTC had BM, of which 97% had concurrent nonosseous metastases. BM occurred 2.1 years (median, range -0.1 to 20.6 years) after initial diagnosis, were multifocal in 79%, and were located preferentially in the spine (86%) and pelvis (60%). BM morphology was osteolytic in 32%, osteoblastic in 25%, and mixed in 22% of cases (unknown: 21%). Within a median observation period of 26.6 months (range, 0-188 months) after BM diagnosis, 47% of patients experienced one or more SREs (bone radiation 50%, pathological fractures 32%), of which 42% occurred in osteolytic and 17% in osteoblastic BM (P = .047). Presence of osteolytic metastases (hazard ratio 3.85, 95% CI 1.52-9.77, P = .005) but not occurrence of SREs was associated with impaired OS. Among the 36 patients who received ART (no ART: n = 71), SREs were significantly less frequent than in untreated patients (P = .04).

CONCLUSION

BM are common in metastatic MTC and most often with an osteolytic morphology and an unfavorable prognosis. The majority of SREs occur in osteolytic metastases and may be prevented by ART.