Thyroid cancer: symptoms, causes, treatment, prognosis

What is Thyroid Cancer?

Cancer (carcinoma) thyroid gland Is a cancer that affects the thyroid gland, a butterfly-shaped structure located at the base of the neck. The thyroid gland (thyroid gland) is part of the endocrine system, a network of hormones secreting glands. Thyroid hormones regulate chemical processes (metabolism) that affect body activity, and also regulate heart rate, body temperature and blood pressure. Hormones are released directly into the bloodstream, from where they travel to various areas of the body.

Many patients have no symptoms associated with thyroid carcinoma. Some people may have neck pain, hoarseness, and swollen lymph nodes, especially in the neck. Thyroid cancer is the most common cancer affecting the endocrine system. Most forms rarely cause pain or disability and are easily treatable with surgery and subsequent therapy. However, some forms are aggressive and more difficult to treat.

The term "cancer" refers to a group of diseases characterized by abnormal uncontrolled cell growth that invades surrounding tissues and may spread (metastasize) to distant tissues or organs through the bloodstream, lymphatic system, or others ways. Various forms of cancer, including thyroid cancer, can be classified according to the type affected cells, the specific nature of the malignant neoplasm and the clinical course diseases. The four main types of thyroid cancer are papillary, follicular, bone marrow, and anaplastic. Rare forms of thyroid carcinoma include thyroid teratoma, lymphoma, and squamous cell carcinoma. Papillary carcinoma is the most common, accounting for about 80% of all thyroid carcinomas.

Malignant cells transmit their abnormal changes to all their "daughter" cells and, as a rule, grow and sharing at an unusually fast, uncontrollable rate that cannot be contained by natural immune defenses organism. Eventually, this proliferation of abnormal cells can lead to the formation of a mass known as a tumor (neoplasm). Disease progression can be characterized by invasion of surrounding tissues, infiltration of regional lymph nodes, and the spread of the malignant neoplasm through the bloodstream, lymphatic circulation, or by other means to other tissues and organs body.

Signs and symptoms

The vast majority of people with thyroid cancer have no symptoms. In most cases, a small growth or lump (nodule) found by the patient, doctor, or accidentally on imaging examination (such as computed tomography, MRI, or ultrasound of the carotid artery) is the first sign of thyroid cancer glands. "Lumps" or lumps in the thyroid gland can be caused by a variety of diseases and do not necessarily mean a person has cancer. In fact, over 90 percent of thyroid nodules are not cancerous (benign).

Symptoms that may be associated with thyroid carcinoma include:

• hoarseness of the voice;
• difficulty breathing or swallowing;
• swollen lymph nodes, especially in the neck;
• sore throat or neck.

Cancer can arise from any type of thyroid cell. About 90 percent of thyroid cancers arise from follicular cells (the cells that make up most of the thyroid gland and produce thyroid hormone). Most of the remaining cases are due to C cells (parafollicular cells). Cancer caused by white blood cells (lymphocytes), known as lymphoma, can also occur. Extremely rare forms of thyroid cancer include squamous cell carcinoma and teratoma.

Thyroid cancer can also be classified as well differentiated or poorly differentiated. Differentiation refers to how abnormal cells look under a microscope, how fast they grow and retain the properties of normal thyroid cells, such as the ability to trap iodine. Well-differentiated cancers are made up of cells that retain the appearance of the cells from which they originated (for example, thyroid follicular cells). More "poorly differentiated" or "undifferentiated" cancers are made up of cells that have undergone transformation and return to a less specialized, more primitive form. Consequently, they are no longer able to perform their “putative” specialized functions in the tissue in question.

Well-differentiated thyroid carcinoma usually refers to papillary or follicular thyroid cancer. These forms of thyroid carcinoma are sometimes simply called differentiated thyroid cancer (TC). Islet carcinoma of the thyroid gland refers to poorly differentiated thyroid cancer. Anaplastic cancer is called undifferentiated thyroid cancer. Naturally, well-differentiated carcinomas have a better prognosis.

—​ Papillary thyroid carcinoma.

Papillary thyroid cancer Is the most common form of thyroid cancer, accounting for about 80 percent of patients. The disease arises from the follicular cells of the thyroid gland. This cancer is usually a single growth in the thyroid gland and often progresses slowly. Papillary carcinoma tends to spread (metastasize) through the lymph nodes and the lymphatic system, especially to local lymph nodes in the neck.

Papillary cancer can affect people of any age, including children, but most often affects people between the ages of 30 and 50. Women are affected more often than men.

Papillary carcinoma options:

There are several subtypes or variants of this form of carcinoma; Common subtypes include follicular, high cell, and diffuse sclerosis. These names refer to how thyroid cancer looks under a microscope.

The follicular variant of papillary carcinoma, which differs from the follicular thyroid carcinoma, is the most common subtype. The follicular variant is a slow-growing form of cancer. The clinical behavior of this subtype is generally similar to that of the papillary.

The high cell variant of papillary carcinoma is a relatively rare form of thyroid cancer. The high cell variant may be more aggressive than papillary carcinoma in general and has a higher recurrence rate. Most cases tend to occur in older people. The high-cell variant of papillary cancer gets its name because the height of the characteristic cells is two to three times the width. More than 70% of cancer cells in this tumor must be "tall" cells to diagnose high cell thyroid cancer. The size of the tumor is usually larger than the size of the tumor usually associated with papillary cancer. Some researchers believe that the high cell variant of carcinoma remains undiagnosed.

Diffuse sclerosis is more common in young people, especially young women. It often develops between the ages of 15-30. The first sign is often an enlarged thyroid gland (goiter). This subtype of papillary carcinoma can spread to the lymph nodes or the lungs. Relapse is more likely with diffuse sclerosing than with papillary carcinoma in general.

- Follicular thyroid carcinoma.

Although follicular carcinoma is the second most common form of thyroid cancer, it only accounts for about 10 percent of patients. Like papillary thyroid carcinoma, follicular carcinoma also arises from thyroid follicular cells, but is much less likely to spread to lymph nodes. It can spread to the lungs, brain, or bones. Follicular cancer is often classified as minimally invasive or widely invasive. Follicular cancer is usually a painless lump (nodule) in the thyroid gland.

Most people with follicular carcinoma are over 50 years old. Women are affected more often than men.

Poorly differentiated (islet) thyroid carcinoma is a rare subtype of follicular carcinoma. It is extremely rare but aggressive and often spreads to the surrounding lymph nodes and other parts of the body, especially the lungs, bones, or brain, where it can cause life-threatening complications. This form of thyroid cancer also usually presents as a mass in the neck.

Poorly differentiated thyroid carcinoma usually affects people age 55 and older and is twice as likely to affect women as men. Although most of the medical literature classifies low-grade thyroid carcinoma as a form of follicular thyroid carcinoma, its cellular composition may also be associated with papillary carcinoma thyroid gland.

- Gürtle cell carcinoma.

The World Health Organization (WHO) classifies this form of thyroid cancer as a subtype of follicular carcinoma, although recent research suggests it is a separate form of cancer. Gürthle cell cancers account for approximately 3 percent of thyroid cancers. This form of thyroid cancer can affect any age group and usually occurs in people between the ages of 40 and 50. Gürthle cell carcinoma affects women more often than men and is believed to have a worse prognosis than normal follicular thyroid carcinoma. This cancer is also known as oncocytic thyroid carcinoma.

The first sign of Gürthle cell carcinoma is usually a painless neck mass. Gürthle cell carcinoma can spread to bones, liver or lungs. Described rare cases that spread to adrenal glands and the brain.

- Medullary thyroid cancer (MTC).

This type of cancer accounts for approximately 2-3 percent of thyroid cancers. MTC arises from "C cells" (also called parafollicular cells); this type of cell produces the hormone calcitonin (hence called "C-cells"). Calcitonin helps regulate calcium and sodium metabolism in animals and may have an effect on the skeletal defense against calcium loss in humans. MTC is a more aggressive form of cancer than differentiated thyroid cancer and can spread through the lymph nodes or the bloodstream to other organs. The first sign of MTC is often a dense formation in the thyroid gland or an abnormal enlargement of nearby lymph nodes (lymphadenopathy). In some cases, MTC may have already spread (metastasized) to other organs before a tumor is detected.

Most people with MTC develop it by chance without a known cause (sporadic cases). However, about 30% of patients may have a type that is transmitted in the family (familial MTC), affecting only the thyroid gland or as part of a rare condition known as multiple endocrine neoplasia 2 types (MEN 2 types).

- Anaplastic (undifferentiated) thyroid carcinoma.

Anaplastic cancer accounts for approximately 5 percent of all thyroid carcinoma cases and mainly affects people aged 70 and over. Anaplastic cancer is very aggressive and often spreads rapidly to surrounding lymph nodes and organs, especially the windpipe (trachea), lungs, or bones. Anaplastic cancer can quickly lead to life-threatening complications such as tracheal blockage or massive bleeding. Anaplastic carcinoma often develops from preexisting follicular or papillary cancers.

- Thyroid lymphoma.

Primary thyroid lymphoma does not arise from follicular or C cells, but arises from cells of the immune system known as lymphocytes. Most lymphomas develop in the lymph nodes, but can also occur in other organs, such as the thyroid gland. Thyroid lymphoma is extremely rare, accounting for less than 2 percent of thyroid cancers.

Lymphoma spreads rapidly and quickly replaces thyroid tissue. Thyroid lymphoma usually affects people over the age of 70 and affects women three times more often than men. Lymphoma is most common in women who have a history of hypothyroidism due to autoimmune thyroiditis (Hashimoto's disease).

Causes and risk factors

The cause (s) of thyroid cancer is unknown. Researchers suggest that genetic and immunological abnormalities, environmental factors (for example, certain chemicals, ionizing radiation), diet and / or other factors may play a role in the occurrence of certain types of cancer. In rare cases, thyroid cancer can be hereditary, especially medullary cancer, as noted above. Researchers are conducting ongoing basic research to learn more about the many factors that can lead to cancer.

Current research shows that abnormalities in DNA (deoxyribonucleic acid), which is the carrier of the body's genetic code, underlie malignant cell transformation. In people with cancer, including thyroid cancer, malignant neoplasms are most common develop due to abnormalities in the structure of specific genes known as "oncogenes" or "suppressor genes tumors ". Oncogenes control cell growth; tumor suppressor genes control cell division and ensure that cells die at the right time. These abnormal genetic changes can occur spontaneously for unknown reasons, or, less commonly, can be inherited. Childhood exposure to ionizing radiation from medical procedures or nuclear fallout is the most well established environmental factor.

DNA mutations causing papillary or follicular carcinoma have been found in several different genes located on different chromosomes. For example, some patients with papillary thyroid carcinoma have gene mutations RET on chromosome 10. Gene mutations BRAF and gene family RAS are also often associated with papillary carcinoma. These genes usually regulate cell growth and differentiation, and mutations can lead to unlimited growth and de-differentiation. Most of these genetic mutations are acquired during life, are found only in cancer cells, and are not passed on to the children of a sick person.

In thyroid cancer, DNA damage can occur due to external radiation. People who have received radiation therapy to the head and neck area, especially children, are more likely to develop carcinoma than the general population. People who were exposed to radioactive particles during childhood or adolescence, for example, as a result of testing nuclear weapons or accidents at nuclear power plants (such as Chernobyl) also have a higher risk of cancer. Diagnostic x-rays, such as chest x-rays, dental x-rays, and the like, do not cause cancer.

Medullary thyroid cancer can occur spontaneously without a known cause (sporadically), as part of an isolated hereditary syndrome (for example, familial medullary thyroid cancer [familial MTC]) or as part of a more complex disease called type II multiple endocrine neoplasia (MEN 2 type). (For more information on these disorders, see in the Related Disorders section)

DNA is the code that allows the cells in the body to make proteins. DNA forms genes that are translated by the cells of the body into proteins necessary for its functioning. Cells have two genes for each protein, one from the father and the other from the mother. Dominant genetic disorders occur when only one copy of an abnormal gene is needed for a disease to appear. Familial medullary thyroid carcinoma and type II multiple endocrine neoplasia are inherited as autosomal dominant traits. The abnormal gene can be inherited from either parent, or it can be the result of a new mutation (gene change) in an affected person. The risk of passing the abnormal gene from the affected parent to the offspring is 50% with every pregnancy, regardless of the gender of the child born. Familial MTC and MEN type 2 have been associated with gene mutations RET on chromosome 10.

Individuals who have a benign disease or a family history of benign thyroid disease are at greater risk of developing cancer than the general population. Benign thyroid disease include goiter, nodules, or inflammation of the thyroid gland (thyroiditis).

People with certain genetic disorders are also at greater risk of developing thyroid cancer. These disorders include familial adenomatous polyposis (FAP), Gardner's syndrome, tumor syndrome PTEN-hamartom and Carney-complex.

Affected populations

The incidence is 6 cases per 100,000 population. More than 300,000 new cases of thyroid cancer are registered in the world every year, and about 12,000 in Russia. The disease can be detected at any age - both in children and adults. Most cases of thyroid cancer are diagnosed in patients over the age of 30. The disease is approximately 3 times more likely to be diagnosed in women than in men.

Overall, for unclear reasons, the incidence of thyroid cancer has risen rapidly over the past few decades. Some researchers believe this increase in frequency is due to the increased use of imaging techniques (e.g. chest CT, MRI cervical spine), resulting in an increased incidence of small forms of thyroid cancer that may have never been detected in life person. However, there may also be an increase in the incidence of larger cases of thyroid cancer, possibly due to environmental factors.

Related disorders

Type 2 multiple endocrine neoplasia (MEN) is a rare genetic cancer syndrome in which tumors develop in endocrine glands (e.g. thyroid, parathyroid, adrenal glands). There are two main subtypes called MEN 2A and MEN 2B. Familial medullary thyroid carcinoma (familial MTC) is considered the third subtype. Nearly all people with MEN 2 develop MTC at some point.

Diagnostics

The diagnosis of thyroid cancer is based on a thorough clinical assessment, including a detailed history patient and physical examination, as well as a range of specialized blood and imaging tests research. Such examination often includes microscopic evaluation of tumor cells obtained by fine-needle aspiration biopsy.

In rare cases, people may notice a hard, fixed mass or lump (nodule), usually to the left or right of the Adam's apple. Occasionally, a doctor can detect such a node during a routine physical examination. Often, a nodule is found incidentally on x-rays for a different purpose. Thyroid nodules - a common occurrence, and as people get older, the frequency increases; in some reports, up to 50-75% of older adults have nodules that can be found on a thyroid sonogram (ultrasound). Fortunately, over 90 percent of these are not cancerous (i.e., benign).

- Analyzes and examination.

Various tests, including blood tests, ultrasound scans, and fine needle aspiration biopsy, may be done to confirm the diagnosis of thyroid cancer.

Blood tests can reveal general thyroid function by measuring thyroid-stimulating hormone (TSH) levels. TSH is a hormone produced by the pituitary gland that promotes the growth of the thyroid gland and most likely stimulates the growth of thyroid cancer cells. However, in most patients with thyroid cancer, thyroid function is normal.

During ultrasound examination the reflected sound waves create an image of the thyroid gland. A device known as a transducer creates these sound waves and then records a pattern as they reflect off the thyroid gland (echo pattern). Normal tissue and thyroid nodules have different echo patterns, so a doctor can see if whether the nodule is suspicious that may require further evaluation, usually with biopsy. In addition, an ultrasound scan of the lymph nodes in the neck and a biopsy of suspicious lymph nodes may be done before surgery.

Additional specialized imaging techniques can be used to help estimate size, location and spread of the tumor and serve as an aid for future surgical procedures. Such imaging techniques may include computed tomography (CT) and magnetic resonance imaging (MRI). During computed tomography computer and X-rays are used to create film showing cross-sectional images of specific tissue structures. MRI uses a magnetic field and radio waves to produce cross-sectional images of selected organs and tissues of the body. Laboratory tests and specialized imaging tests can also be done to determine possible infiltration of regional lymph nodes and the presence of distant metastases.

Fine needle aspiration biopsy (TAPB) is the most accurate diagnostic test. TAPB involves inserting a thin hollow needle through the skin and inserting it into the nodule under ultrasound guidance to remove small tissue samples from the nodule. This procedure can be repeated several times to collect tissue samples from different parts of the nodule. If there are several nodules, the procedure can be performed on each of them. The collected tissue is then smeared onto glass slides, stained with colored paint and examined under a microscope. This is similar to what is done with the Pap test for cervical cancer. Newly developed genetic tests can also be performed on biopsy specimens. These tests can help clarify whether the nodule is benign or malignant with more the likelihood that the biopsy sample is "undefined", i.e. neither clearly benign nor malignant. Vague biopsy results occur in about 25% of nodules.

In cases where MTC is suspected, blood tests may be done to determine calcitonin levels. Patients can also undergo genetic testing to detect the presence of a gene mutation RETto confirm the diagnosis of familial MTC. Family members of people who have this mutation should also be examined for the presence of the mutation. RET. Nearly 100% of people who have this gene mutation will eventually develop MTC. Consequently, many scientists recommend that people who have this particular genetic change undergo prophylactic thyroid surgery during childhood. Removing the thyroid gland before cancer develops has a very high chance of being cured.

Standard treatments

Therapeutic management of patients with thyroid cancer may require coordinated efforts by a team of medical professionals such as specialists in the diagnosis and treatment of hormonal diseases (endocrinologists), thyroid surgeons, specialists in the use of radioactive iodine (nuclear medicine), doctors who use radiation to treat cancer (radiation oncologists), and other specialists in the field health care. Doctors who specialize in the diagnosis and treatment of cancer (oncologists) usually do not treat thyroid cancer, except in rare, advanced cases.

Specific therapeutic procedures and interventions can vary depending on many factors, such as the size and location of the primary tumor, the grade of the primary tumor (stage) and the degree malignancy; Whether the tumor has spread to lymph nodes or distant sites age and general health of a person; and / or other elements. Decisions regarding the use of specific interventions should be made by doctors and other members of the medical team after careful consultation with the patient, based on the specifics of his case; a detailed discussion of the potential benefits and risks; patient preferences; and other relevant factors.

The various methods used to treat thyroid cancer include surgery first intervention, sometimes followed by radioactive iodine therapy, external beam irradiation and, in rare cases, chemotherapy. Hormone replacement therapy is used in combination with these treatments in patients who have had all or part of their thyroid removed.

- Operation.

In almost everyone with thyroid cancer, standard initial therapy includes surgical removal of the cancer and the affected tissue, including the entire thyroid gland (thyroidectomy). In many cases of follicular and papillary carcinoma, especially in larger and more invasive tumors, surgical removal of as much of the thyroid gland as possible (almost complete thyroidectomy). In such cases, an almost complete thyroidectomy reduces the likelihood of recurrence, in contrast to surgery to remove only part of the thyroid gland (for example, one lobe). On the other hand, removal of one thyroid lobe is sufficient in patients with uncomplicated tumors, such as tumors <4 cm. If suspicious or malignant lymph nodes are found before or during surgery, they will also be removed.

- Hormone replacement therapy.

After thyroidectomy, patients must take levothyroxine to replace the hormones normally produced by the thyroid gland so that people do not develop hypothyroidism. Levothyroxine also inhibits the activity of thyroid-stimulating hormone (TSH) produced by the pituitary gland, which stimulates the growth of normal thyroid tissue as well as any remaining cancer cells. Many lobectomy patients do not require hormone therapy because the remaining the lobe can produce enough thyroid hormone to maintain normal levels hormones.

- Radioactive iodine.

Studies have shown that radioactive iodine therapy can improve survival rates in patients with more advanced follicular and papillary carcinoma. However, radioactive iodine therapy is generally not recommended for low-risk individuals who make up the majority of patients who have an excellent prognosis after surgery, even without radioactive iodine. Iodine is a chemical used by the thyroid gland to synthesize hormones. Since iodine is also absorbed by differentiated thyroid cancer cells, radioactive iodine can be used to target cancer tissue while preserving the rest of the body.

Radioactive iodine therapy destroys any normal thyroid tissue left over after an almost complete thyroidectomy. Radioactive iodine therapy can also kill any residual microscopic thyroid cancer, a process called "adjuvant therapy." For radioactive iodine therapy to be most effective, the level of TSH in the blood must be high. TSH stimulates both tissue and thyroid cancer cells to absorb iodine. An increase in the level of TSH in the blood can be achieved by stopping hormone replacement therapy (which leads to a decrease in thyroid hormone [hypothyroidism] and a significant increase in TTG). However, in many people, hypothyroidism in this way causes lethargy and other symptoms such as cold intolerance, weight gain, and constipation. To minimize the effects of hypothyroidism, doctors may prescribe a synthetic form of T3 called cytomel (liothyronine), but this may not prevent the onset of symptoms, as this drug must also be discontinued before starting radioactive therapy iodine.

Also available is a synthetic form of TSH, thyrogen (thyrotropin alpha), made in a laboratory. It is injected into the patient's arm or thigh muscle, thereby achieving high TSH levels without the patient having to stop hormone replacement therapy. Before radioiodine therapy, patients are usually placed on a low iodine diet for 1–2 weeks prior to radioiodine administration. After TSH levels rise, before actual treatment, patients can have a whole body scan for radioactive iodine with using a small amount of radioactive iodine to see how much of the normal thyroid is still present in the neck. If the scan shows that there is a large residual thyroid gland, a large therapeutic dose of radioactive iodine may be given.

Radioactive iodine therapy is often effective when cancer has spread to nearby lymph nodes or other organs in the body (metastases).

Gürthle cell carcinomas and poorly differentiated isolated carcinomas are treated with complete or near total thyroidectomy. These cancers often do not absorb radioactive iodine, so it usually cannot be used to treat these forms of thyroid cancer.

- External exposure.

External radiation is another form of radiation therapy that is sometimes used to treat patients with thyroid cancer. During this procedure, a machine is used to deliver a beam of radiation that destroys cancer cells. External beam radiation therapy is usually used in patients with thyroid cancer who have residual disease, and who do not respond to radiation therapy or in whom the disease has spread beyond the thyroid glands. External beam radiation therapy can also be used for medullary carcinoma and anaplastic thyroid carcinoma.

- Targeted drug therapy (targeted therapy).

Targeted therapies are being studied for patients with advanced thyroid cancer. Targeted therapy is drugs and other substances that prevent the growth and spread of cancer by blocking or inhibiting certain specific molecules (often proteins) that are involved in the growth and distribution of certain species cancer. Typically, targeted therapy is less toxic than other cancer treatments. Targeted therapies for thyroid cancer include protein kinase inhibitors and angiogenesis inhibitors. Lenvima (Lenvatinib) and Nexavar (Sorafenib) are two FDA-approved protein kinase inhibitors the United States Food and Drug Administration (FDA) for use in advanced differentiated Thyroid cancer.

- Medullary thyroid carcinoma.

Patients with medullary carcinoma also undergo surgical removal of the entire thyroid gland. If the cancer has not spread beyond the thyroid gland, the prognosis is excellent. However, at the time of diagnosis, medullary cancer has usually spread to local lymph nodes. The prognosis depends on several factors, including the size of the tumor, the rate at which it grows, and how far and to which organs the cancer has spread. Radioactive iodine therapy is not used in patients with MTC because tumors (which are made up of C cells, not follicular cells) do not take up iodine. In some cases, external radiation therapy or chemotherapy is used to treat patients with MTC.

A drug called vandetanib is approved by the FDA for the treatment of advanced medullary thyroid cancer. Vandetanib is a kinase inhibitor indicated for the treatment of symptomatic or progressive medullary cancer in individuals with inoperable locally advanced or metastatic disease. A kinase inhibitor is a drug that specifically blocks or stops the activity of certain proteins known as kinases.

Another kinase inhibitor called selpercatinib was approved by the FDA in May 2020 for the treatment of MTC and other types of thyroid cancer in patients whose tumors have a gene change RET. Selpercatinib is the first therapy specifically approved for patients with gene changes RET.

- Anaplastic carcinoma of the thyroid gland.

In patients with anaplastic carcinoma, complete or near-total thyroidectomy is often performed. However, in some cases, the primary tumor may be inoperable because it involves structures in the neck, such as the trachea or large blood vessels. Radioactive iodine therapy is ineffective because undifferentiated cells do not absorb iodine. External beam radiation therapy is used to treat patients with anaplastic carcinoma and may shrink tumors. For some patients, therapy with certain anti-cancer drugs (chemotherapy) may also be used, possibly in combination with surgical procedures and / or radiation; doctors may recommend combination therapy with multiple chemotherapy drugs, which have different mechanisms of action in destroying tumor cells and / or preventing them reproduction. However, in most cases, chemotherapy and external radiation therapy have had only limited success in slowing down or stopping the progression of anaplastic cancer and could not correct the progression diseases.

In 2018, a combination of taflinar (dabrafenib) and mekinist (trametinib), administered together, was approved by the FDA for the treatment of anaplastic thyroid cancer that cannot be surgically removed or has spread to other parts of the body and has the V600E mutation in gene BRAF.

— Monitoring.

Individuals with thyroid cancer undergo periodic examinations to determine if the cancer has returned. These examinations include a thorough clinical assessment, including a detailed history of the patient, a physical examination of the neck, and the rest of the body, as well as various tests, including blood tests to detect elevated levels of thyroglobulin, a protein thyroid gland. Thyroglobulin is produced only by the tissue of the thyroid gland and differentiated thyroid gland, therefore, after removal of the thyroid gland or therapy with radioactive iodine, thyroglobulin should be absent in the bloodstream. Detection of thyroglobulin in the blood may indicate a return of thyroid cancer. Thyroglobulin is often abbreviated as Tg. Neck ultrasound to examine the central and lateral (sides) of the neck is another cornerstone of thyroid cancer surveillance.

In some cases, doctors may decide to repeat the full-body iodine scan to determine if any thyroid cancer cells have returned. In the past, to achieve the elevated TSH levels required to perform a full body scan on iodine, patients had to stop hormone replacement therapy, which led to hypothyroidism. Thyrogen (thyrotropin alpha), a synthetic form of TSH, provides the necessary TSH levels without requiring patients to stop hormone replacement therapy.

For patients with MTC, doctors may order blood tests to measure calcitonin and carcinoembryonic antigen (CEA) levels. Elevated levels of these substances may indicate a return of thyroid carcinoma, and doctors often order imaging tests to check for residual cancer.

Forecast

Long-term disease-free survival with aggressive treatment and management is nearly 90%. The following factors are associated with the forecast:

• Age: the age of the patient at the time of diagnosis is one of the most important predictors of well-differentiated thyroid carcinoma; Cancer-related death is most likely if the patient is over 40 years of age at the time of diagnosis; relapses are most common in patients diagnosed with disease <20 or> 60 years of age.
• Floor: men are twice as likely to die from thyroid cancer as women.
• The size: the size of the primary tumor is associated with survival; patients with primary tumors> 4 cm have an increased rate of recurrence and cancer mortality (although the study by Nguyen et al. showed that there is no association between increase in tumor size and survival in patients with thyroid cancer until the tumor reaches> 2.5 cm)
• Histology: overall, papillary carcinoma is associated with a cancer mortality rate of 6% over 30 years; follicular carcinoma is associated with cancer mortality in 15% of cases within 30 years.
• Local invasion: invasion of surrounding tissues outside the thyroid gland indicates biological aggressiveness and significantly worsens the patient's prognosis.
• Lymph node metastases: lymph node metastases appear not to be as important in the outcome of highly differentiated thyroid carcinoma as in the outcome of most other solid tumors.
• Distant metastases: distant metastases on initial examination are associated with a 68.1-fold increase in the incidence of death from a particular type of disease.
• Socio-economic factors: a study by Swegal et al. showed that socioeconomic factors influence survival in well-differentiated cancers thyroid gland, with lower income associated with higher mortality associated with disease; 1317 patients were included in the study.