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There are three main treatments for Hürthle cell adenomas. Once the adenoma is detected most often the nodules removed to prevent the cells from later metastisizing. A total thyroidectomy is often performed, this results in a complete removal of the thyroid. Some patients may only have half of their thyroid removed, this is known as a thyroid lobectomy. Another treatment option includes pharmacological suppression of thyroid hormone. The thyroid gland is responsible for producing the thyroid hormones triiodothyronine (T3) and thyroxine (T4). Patients with suppressed thyroid function often require oral thyroid replacement (e.g. levothyroxine) in order to maintain normal thyroid hormone levels. The final treatment option is RAI abaltion (radioactive iodine ablation). This treatment option is used to destroy infected thyroid cells after total thyroidectomy. This treatment does not change prognosis of disease, but will diminish the recurrence rate. Also, Hürthle cells do not respond well to RAI. However, often doctors suggest this treatment to patients with Hürthle cell adenoma and Hürthle cell carcinoma because some Hürthle cells will respond and it will kill remaining tissue.
Clinical trials of protein kinase inhibitors, which block the abnormal kinase proteins involved in the development and growth of medullary cancer cells, showed clear evidence of response in 10-30% of patients. In the majority of responders there has been less than a 30% decrease in tumor mass, yet the responses have been durable; responses have been stable for periods exceeding 3 years. The major side effects of this class of drug include hypertension, nausea, diarrhea, some cardiac electrical abnormalities, and thrombotic or bleeding episodes.
Vandetanib, trade name Caprelsa, was the first drug (April 2011) to be approved by US Food and Drug Administration (FDA) for treatment of late-stage (metastatic) medullary thyroid cancer in adult patients who are ineligible for surgery.
Cabozantinib, trade name Cometriq, was granted marketing approval (November 2012) by the U.S. FDA for this indication. Cabozantinib which is a potent inhibitor of RET, MET and VEGF was evaluated in a double-blind placebo controlled trial. It was shown to improve overall survival by 5 months for the treated cohort vs. placebo, which was not statistically significant. However, cabozantinib was particularly effective in patients with the RET M918T mutation, extending overall survival by roughly 2 years, doubling survival vs. untreated patient (4 years vs. 2 year). Treatment with cabozantinib did require many dose reduction to mitigate side effects. It has been suggested that the trial dose of 140 mg was excessive, particularly in lower body mass patients. Ongoing trials have been scheduled to identify more optimal dosing regimes. Activity has been observed, in practice at doeses of 1.2 mg/kg.
External beam radiotherapy is recommended when there is a high risk of regional recurrence, even after optimum surgical treatment. In this study, patients treated with external beam radiation were compared to a control group. Disease control with radiation was far superior in the group receiving radiation. The authors of the study [14] wrote: "in 40 high risk patients (microscopic residual disease, extraglandular invasion, or lymph node involvement), the local/regional relapse free rate was 86% at 10 years with postoperative external beam radiation (25 patients), and 52% for those with no postoperative external radiation (p = 0.049). To optimize local/regional tumor control, we therefore continue to advise external beam radiation in patients at high risk of local/regional relapse."
Unlike other differentiated thyroid carcinoma, there is no role for radioiodine treatment in medullary-type disease.
Levothyroxine is a stereoisomer of thyroxine which is degraded much slower and can be administered once daily in patients with hypothyroidism.
Treatment of a thyroid nodule depends on many things including size of the nodule, age of the patient, the type of thyroid cancer, and whether or not it has spread to other tissues in the body.
If the nodule is benign, patients may receive thyroxine therapy to suppress thyroid-stimulating hormone and should be reevaluated in 6 months. However, if the benign nodule is inhibiting the patient's normal functions of life; such as breathing, speaking, or swallowing, the thyroid may need to be removed.
Sometimes only part of the thyroid is removed in an attempt to avoid causing hypothyroidism. There's still a risk of hypothyroidism though, as the remaining thyroid tissue may not be able to produce enough hormones in the long-run.
If the nodule is malignant or has indeterminate cytologic features, it may require surgery. A thyroidectomy is a medium risk surgery that can result complications if not performed correctly. Problems with the voice, nerve or muscular damage, or bleeding from a lacerated blood vessel are rare but serious complications that may occur. After removing the thyroid, the patient must be supplied with a replacement hormone for the rest of their life. This is commonly a daily oral medication prescribed by their endocrinologist.
Radioactive iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy. External irradiation may be used when the cancer is unresectable, when it recurs after resection, or to relieve pain from bone metastasis.
Most patients with thyroid adenoma can be managed by watchful waiting (without surgical excision) with regular monitoring. However, some patients still choose surgery after being fully informed of the risks. Regular monitoring mainly consists of watching for changes in nodule size and symptoms, and repeat ultrasonography or needle aspiration biopsy if the nodule grows.
Thyroidectomy and neck dissection show good results in early stages of SCTC. However, due to highly aggressive phenotype, surgical treatment is not always possible. The SCTC is a radioiodine-refractory tumor. Radiotherapy might be effective in certain cases, resulting in relatively better survival rate and quality of life. Vincristine, Adriamycin, and bleomycin are used for adjuvant chemotherapy, but their effects are not good enough according to published series.
An alternative using high intensity focused ultrasound or HIFU has recently proved its effectiveness in treating benign thyroid nodules. This method is noninvasive, without general anesthesia and is performed in an ambulatory setting. Ultrasound waves are focused and produce heat enabling to destroy thyroid nodules.
Focused ultrasounds have been used to treat other benign tumors, such as breast fibroadenomas and fibroid disease in the uterus.
A non-minimally invasive Hürthle cell carcinoma is typically treated by a total thyroidectomy followed by radioactive iodine therapy. A Hürthle cell adenoma or a minimally invasive tumor can be treated by a thyroid lobectomy, although some surgeons will perform a total thyroidectomy to prevent the tumor from reappearing and metastasizing.
A modified radical neck dissection may be performed for clinically positive lymph nodes.
Some studies have shown that thyroglobulin (Tg) testing combined with neck ultrasound is more productive in finding disease recurrence than full- or whole-body scans (WBS) using radioactive iodine. However, current protocol (in the USA) suggests a small number of clean annual WBS are required before relying on Tg testing plus neck ultrasound. When needed, whole body scans consist of withdrawal from thyroxine medication and/or injection of recombinant human Thyroid stimulating hormone (TSH). In both cases, a low iodine diet regimen must also be followed to optimize the takeup of the radioactive iodine dose. Low dose radioiodine of a few millicuries is administered. Full body nuclear medicine scan follows using a gamma camera. Scan doses of radioactive iodine may be I or I.
Recombinant human TSH, commercial name Thyrogen, is produced in cell culture from genetically engineered hamster cells.
Surgery remains the mainstay of treatment for papillary thyroid cancer. The Revised 2009 American Thyroid Association guidelines for papillary thyroid cancer state that the initial procedure should be near-total or total thyroidectomy. Thyroid lobectomy alone may be sufficient treatment for small (<1 cm), low-risk, unifocal, intrathyroidal papillary carcinomas in the absence of prior head and neck irradiation or radiologically or clinically involved cervical nodal metastasis.
- Minimal disease (diameter up to 1.0 centimeters) - hemithyroidectomy (or unilateral lobectomy) and isthmectomy may be sufficient. There is some discussion whether this is still preferable over total thyroidectomy for this group of patients.
- Gross disease (diameter over 1.0 centimeters) - total thyroidectomy, and central compartment lymph node removal is the therapy of choice. Additional lateral neck nodes can be removed at the same time if an ultrasound guided FNA and thyroglobulin TG cancer washing was positive on the pre-operative neck node ultrasound evaluation.
Arguments for total thyroidectomy are:
- Reduced risk of recurrence, if central compartment nodes are removed at the original surgery.
- 30-85% of papillary carcinoma is multifocal disease. Hemithyroidectomy may leave disease in the other lobe. However, multifocal disease in the remnant lobe may not necessarily become clinically significant or serve as a detriment to patient survival.
- Ease of monitoring with thyroglobulin (sensitivity for picking up recurrence is increased in presence of total thyroidectomy, and ablation of the remnant normal thyroid by low dose radioiodine 131 after following a low iodine diet (LID).
- Ease of detection of metastatic disease by thyroid and neck node ultrasound.
- Post-operative complications at high-volume thyroid surgery centers with experienced surgeons are comparable to that of hemithyroidectomy.
Arguments for hemithyroidectomy:
- Most patients have low-risk cancer with an excellent prognosis, with similar survival outcomes in low-risk patients who undergo total thyroidectomy versus hemithyroidectomy.
- Less likelihood of patient requiring lifelong thyroid hormone replacement after surgery.
Thyroid total body scans are less reliable at finding recurrence than TG and ultrasound.
Papillary tumors tend to be more aggressive in patients over age 45. In such cases, it might be required to perform a more extensive resection including portions of the trachea. Also, the sternocleidomastoid muscle, jugular vein, and accessory nerve are to be removed if such procedure allows apparently complete tumor resection. If a significant amount of residual tumor is left in the neck, external radiotherapy has been indicated and has proven useful especially in those cases when the residual tumor does not take up radioiodine.
After surgical thyroid removal, the patient waits around 4–6 weeks to then have radioiodine therapy. This therapy is intended to both detect and destroy any metastasis and residual tissue in the thyroid. The treatment may be repeated 6–12 months after initial treatment of metastatic disease where disease recurs or has not fully responded.
Patients are administered hormone replacement levothyroxine for life after surgery, especially after total thyroidectomy. Chemotherapy with cisplatin or doxorubicin has proven limited efficacy, however, it could be helpful for patients with bone metastases to improve their quality of life. Patients are also prescribed levothyroxine and radioiodine after surgery. Levothyroxine influences growth and maturation of tissues and it is involved in normal growth, metabolism, and development. In case of metastases, patients are prescribed antineoplastic agents which inhibit cell growth and proliferation and help in palliating symptoms in progressive disease.
After successful treatment, 35 percent of the patients may experience a recurrence within a 40-year span. Also, patients may experience a high incidence of nodule metastasis, with 35 percent cases of cervical node metastases. Approximately 20 percent of patients will develop multiple tumors within the thyroid gland.
There is ongoing discussion regarding the best management regarding the optimal surgical procedure for papillary thyroid cancer. Prognosis of patients with papillary thyroid cancer is found to be dependent on the patient's age, the size of the tumor, presence of metastatic disease, and the presence of tumor invasion into adjacent tissues near the thyroid gland. Recent studies have examined a more conservative approach to surgery and have demonstrated that hemithyroidectomy may be acceptable for patients with low-risk papillary thyroid cancer with tumor size 1 cm to 4 cm with no presence of invasion to tissues surrounding the thyroid or metastasis. Studies examining large databases of patients with papillary thyroid cancer have concluded that there is no survival advantage for patients with stage I papillary thyroid cancer size 1–4 cm receiving total thyroidectomy versus hemithyroidectomy. In light of this data, choosing the optimal course of surgical and medical management of papillary thyroid cancer should involve shared decision making from patient, endocrinologists, and surgeons.
Management of MEN2 patients includes thyroidectomy including cervical central and bilateral lymph nodes dissection for MTC, unilateral adrenalectomy for unilateral pheochromocytoma or bilateral adrenalectomy when both glands are involved and selective resection of pathologic parathyroid glands for primary hyperparathyroidism.
Familial genetic screening is recommended to identify at risk subjects who will develop the disease, permitting early management by performing prophylactic thyroidectomy, giving them the best chance of cure.
Prognosis of MEN2 is mainly related to the stage-dependant prognosis of MTC indicating the necessity of a complete thyroid surgery for index cases with MTC and the early thyroidectomy for screened at risk subjects.
Based on overall cancer staging into stages I to IV, papillary thyroid cancer has a 5-year survival rate of 100 percent for stages I and II, 93 percent for stage III and 51 percent for stage IV.
Toxic multinodular goiter can be treated with antithyroid medications such as propylthiouracil or methimazole, radioactive iodine, or with surgery.
Another treatment option is injection of ethanol into the nodules.
The role of external beam radiotherapy (EBRT) in thyroid cancer remains controversial and there is no level I evidence to recommend its use in the setting of differentiated thyroid cancers such as papillary and follicular carcinomas. Anaplastic thyroid carcinomas, however, are histologically distinct from differentiated thyroid cancers and due to the highly aggressive nature of ATC aggressive postoperative radiation and chemotherapy are typically recommended.
The National Comprehensive Cancer Network Clinical Practice Guidelines currently recommend that postoperative radiation and chemotherapy be strongly considered. No published randomised controlled trials have examined the addition of EBRT to standard treatment, namely surgery. Radioactive iodine is typically ineffective in the management of ATC as it is not an iodine-avid cancer.
Imbalances in age, sex, completeness of surgical excision, histological type and stage, between patients receiving and not receiving EBRT, confound retrospective studies. Variability also exists between treatment and non-treatment groups in the use of radio-iodine and post-treatment thyroid stimulating hormone (TSH) suppression and treatment techniques between and within retrospective studies.
Some recent studies have indicated that EBRT may be promising, though the number of patients studies has been small.
Clinical trials for investigational treatments are often considered by healthcare professionals and patients as first-line treatment.
Thyroidectomy and dissection of central neck compartment is initial step in treatment of thyroid cancer in majority of cases. Thyroid-preserving operation may be applied in cases, when thyroid cancer exhibits low biological aggressiveness ("e.g." well-differentiated cancer, no evidence of lymph node metastases, low MIB-1 index, no major genetic alterations like "BRAF" mutations, "RET/PTC" rearrangements, p53 mutations etc.) in patients younger than 45 years.
If the diagnosis of well-differentiated thyroid cancer (e.g. papillary thyroid cancer) is established or suspected by FNA the surgery is indicated, whereas watchful waiting strategy is not recommended in any evidence-based guidelines. Watchful waiting reduces overdiagnosis and overtreatment of thyroid cancer among old patients.
Radioactive Iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy.
External irradiation may be used when the cancer is unresectable, when it recurs after resection, or to relieve pain from bone metastasis.
Sorafenib and sunitinib, approved for other indications show promise for thyroid cancer and are being used for some patients who do not qualify for clinical trials. Numerous agents are in phase II clinical trials and XL184 has started a phase III trial.
In the absence of extracervical or unresectable disease, surgical excision should be followed by adjuvant radiotherapy. In the 18–24% of patients whose tumour seems both confined to the neck and grossly resectable, complete surgical resection followed by adjuvant radiotherapy and chemotherapy could yield a 75–80% survival at 2 years.
There are a number of clinical trials for anaplastic thyroid carcinoma underway or being planned.
The most successful treatment for angiosarcoma is amputation of the affected limb if possible. Chemotherapy may be administered if there is metastatic disease. If there is no evidence of metastasis beyond the lymphedematous limb, adjuvant chemotherapy may be given anyway due to the possibility of micrometastatic disease. Evidence supporting the effectiveness of chemotherapy is, in many cases, unclear due to a wide variety of prognostic factors and small sample size. However, there is some evidence to suggest that drugs such as paclitaxel, doxorubicin, ifosfamide, and gemcitabine exhibit antitumor activity.
Levothyroxine is a stereoisomer of thyroxine (T4) which is degraded much more slowly and can be administered once daily in patients with hypothyroidism. Natural thyroid hormone from pigs is sometimes also used, especially for people who cannot tolerate the synthetic version. Hyperthyroidism caused by Graves' disease may be treated with the thioamide drugs propylthiouracil, carbimazole or methimazole, or rarely with Lugol's solution. Additionally, hyperthyroidism and thyroid tumors may be treated with radioactive iodine. Ethanol injections for the treatment of recurrent thyroid cysts and metastatic thyroid cancer in lymph nodes can also be an alternative to surgery.
Thyroid surgery is performed for a variety of reasons. A nodule or lobe of the thyroid is sometimes removed for biopsy or because of the presence of an autonomously functioning adenoma causing hyperthyroidism. A large majority of the thyroid may be removed ("subtotal thyroidectomy)" to treat the hyperthyroidism of Graves' disease, or to remove a goiter that is unsightly or impinges on vital structures.
A complete thyroidectomy of the entire thyroid, including associated lymph nodes, is the preferred treatment for thyroid cancer. Removal of the bulk of the thyroid gland usually produces hypothyroidism unless the person takes thyroid hormone replacement. Consequently, individuals who have undergone a total thyroidectomy are typically placed on thyroid hormone replacement (e.g. Levothyroxine) for the remainder of their lives. Higher than normal doses are often administered to prevent recurrence.
If the thyroid gland must be removed surgically, care must be taken to avoid damage to adjacent structures, the parathyroid glands and the recurrent laryngeal nerve. Both are susceptible to accidental removal and/or injury during thyroid surgery.
The parathyroid glands produce parathyroid hormone (PTH), a hormone needed to maintain adequate amounts of calcium in the blood. Removal results in hypoparathyroidism and a need for supplemental calcium and vitamin D each day. In the event that the blood supply to any one of the parathyroid glands is endangered through surgery, the parathyroid gland(s) involved may be re-implanted in surrounding muscle tissue.
The recurrent laryngeal nerves provide motor control for all external muscles of the larynx except for the cricothyroid muscle, which also runs along the posterior thyroid. Accidental laceration of either of the two or both recurrent laryngeal nerves may cause paralysis of the vocal cords and their associated muscles, changing the voice quality.
The main strategies for the management of thyroid storm are reducing production and release of thyroid hormone, reducing the effects of thyroid hormone on tissues, replacing fluid losses, and controlling temperature. Thyroid storm requires prompt treatment and hospitalization. Often, admission to the intensive care unit is needed.
Iodine
Guidelines recommend the administration of inorganic iodide (potassium iodide or Lugol's iodine) to reduce the synthesis and release of thyroid hormone. Iodine reduces the synthesis of thyroid hormone via the Wolf-Chaikoff effect. Some guidelines recommend that iodine be administered after antithyroid medications are started, because iodine is also a substrate for the synthesis of thyroid hormone, and may worsen hyperthyroidism if administered without antithyroid medications.
Antithyroid Medications
Antithyroid drugs (propylthiouracil or methimazole) are used to reduce the synthesis and release of thyroid hormone. Propylthiouracil is preferred over methimazole due to its additional effects on reducing peripheral conversion of T4 to T3, however both are commonly used.
Beta Blockers
The administration of beta-1-selective beta blockers (e.g. propranolol) is recommended to reduce the effect of circulating thyroid hormone on end organs. In addition, propanolol at high doses also reduces peripheral conversion of T4 to T3, which is the more active form of thyroid hormone. Although previously unselective beta blockers (e.g., propranolol) have been suggested to be beneficial due to their inhibitory effects on peripheral deiodinases recent research suggests them to be associated with increased mortality. Therefore, cardioselective beta blockers may be favourable.
Corticosteroids
High levels of thyroid hormone result in a hypermetabolic state, which can result in increased breakdown of cortisol, a hormone produced by the adrenal gland. This results in a state of relative adrenal insufficiency, in which the amount of cortisol is not sufficient. Guidelines recommend that corticosteroids (hydrocortisone and dexamethasone are preferred over prednisolone or methylprednisolone) be administered to all patients with thyroid storm. However, doses should be altered for each individual patient to ensure that the relative adrenal insufficiency is adequately treated while minimizing the risk of side effects.
Supportive Measures
In high fever, temperature control is achieved with fever reducers such as paracetamol/acetaminophen and external cooling measures (cool blankets, ice packs). Dehydration, which occurs due to fluid loss from sweating, diarrhea, and vomiting, is treated with frequent fluid replacement. In severe cases, mechanical ventilation may be necessary. Any suspected underlying cause is also addressed.
Treatment is varied and depends on the site and extent of tumor involvement, site(s) of metastasis, and specific individual factors. Surgical resection, radiotherapy, and chemotherapy have all been used to treat these masses, although studies on survival have yet to be conducted to delineate various treatment regimens.
Beta blockers, like Atenolol, are sometimes used to help suppress symptoms.
The management of PASH is controversial. Excision may be indicated in enlarging masses or lesions with atypical features.
Many of the common symptoms of hyperthyroidism such as palpitations, trembling, and anxiety are mediated by increases in beta-adrenergic receptors on cell surfaces. Beta blockers, typically used to treat high blood pressure, are a class of drugs that offset this effect, reducing rapid pulse associated with the sensation of palpitations, and decreasing tremor and anxiety. Thus, a patient suffering from hyperthyroidism can often obtain immediate temporary relief until the hyperthyroidism can be characterized with the Radioiodine test noted above and more permanent treatment take place. Note that these drugs do not treat hyperthyroidism or any of its long-term effects if left untreated, but, rather, they treat or reduce only symptoms of the condition.
Some minimal effect on thyroid hormone production however also comes with Propranolol - which has two roles in the treatment of hyperthyroidism, determined by the different isomers of propranolol. L-propranolol causes beta-blockade, thus treating the symptoms associated with hyperthyroidism such as tremor, palpitations, anxiety, and heat intolerance. D-propranolol inhibits thyroxine deiodinase, thereby blocking the conversion of T to T, providing some though minimal therapeutic effect. Other beta-blockers are used to treat only the symptoms associated with hyperthyroidism. Propranolol in the UK, and metoprolol in the US, are most frequently used to augment treatment for hyperthyroid patients.