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Thyroid Cancer

Thyroid Cancer

Thyroid cancer is rarer than other cancers. In the USA in 2010; An estimated 45,000 patients have been diagnosed with thyroid cancer, compared to approximately 200,000 breast cancer and 140,000 colon cancer patients. However, fewer than 2,000 patients die from thyroid cancer each year. In 2008, when statistics were last collected, there were over 450,000 patients diagnosed and living with thyroid cancer. Thyroid cancer is usually a treatable disease and is often treated with surgery and, if necessary, with radioactive iodine. Effective and well tolerated treatments are available for the most common forms of thyroid cancers, even when they are very advanced. It is interesting that the number of individuals newly diagnosed with thyroid cancer – both men and women – is increasing at a faster rate than other types of cancer. The reason for this is unknown. Although the diagnosis of cancer is quite frightening, the forecast for thyroid cancer patients is generally excellent.

What are the Symptoms of Thyroid Cancer?

Thyroid cancer often occurs as a swelling or nodule and does not cause any symptoms. Laboratory tests are generally not helpful in diagnosing thyroid cancer. Thyroid tests, such as TSH, are usually normal even in the presence of cancer. The best method for diagnosing thyroid cancer is to make sure your thyroid gland contains nodules or is enlarged. Neck examination by your doctor is the best method in this regard. Thyroid nodules are often detected incidentally on imaging modalities such as CT (computerized tomography) scans and neck ultrasounds performed for completely unrelated reasons. Sometimes patients detect thyroid nodules themselves by noticing a swelling in their neck while looking in the mirror, tying a tie or wearing a necklace. Rarely, thyroid cancer and nodules can cause symptoms. In these cases, patients; They may complain of neck, jaw or ear pain. If the nodule is large enough to press on the windpipe or esophagus; It may cause difficulty in breathing, swallowing or a tickling in the throat. More rarely, hoarseness can occur if the cancer damages the nerve that controls the vocal cords.

Important points to remember are: cancers that occur in thyroid nodules are usually asymptomatic, thyroid tests are typically normal even when cancer is present, and the best method for detecting a thyroid nodule is to have your doctor examine your neck.

What are the Causes of Thyroid Cancer?

Thyroid cancer; It is more common in patients with a history of high-dose radiation exposure, a family history of thyroid cancer, and over 40 years of age. However, we do not know why most patients develop thyroid cancer.

High-dose radiation exposure, especially in childhood, increases the risk of developing thyroid cancer in susceptible patients. Before the 1960s, X-ray therapy was frequently used in conditions such as acne, tonsillitis, adenoid and lymph node inflammation, and in the treatment of an enlarged gland in the chest called the thymus. All these treatments have been associated with an increased risk of developing thyroid cancer in the future. Even X-ray therapy used to treat serious cancers such as Hodgkin’s disease (lymph node cancer) and breast cancer has been associated with an increased risk of developing thyroid cancer if head, neck or chest exposure occurred during treatment. Routine X-ray exposures such as dental or chest X-rays or mammograms have not been shown to cause thyroid cancer.

Thyroid Cancer and Nuclear Disasters

Thyroid cancer; It can also occur due to radioactive iodine released during nuclear disasters, such as the 1986 accident at the Chernobyl power plant in Russia or the 2011 nuclear disaster due to the tsunami in Fukushima Japan. It is usually children who are most affected, and cancer often develops several years after exposure. However, even in exposed adults, even 40 years after exposure, there is an increased incidence of thyroid cancer development.

In cases of nuclear disaster, thyroid cancer can be prevented by taking potassium iodide. Potassium iodide inhibits the absorption of radioactive iodine and has been shown to reduce the risk of thyroid cancer. The American Thyroid Association recommends giving potassium iodide to anyone living within 300 km or more of a nuclear accident.

How is Thyroid Cancer Diagnosed?

The diagnosis of thyroid cancer is usually made by fine-needle aspiration biopsy from a thyroid nodule or after surgical removal of the nodule. Although thyroid nodules are quite common, cancer is detected in less than 1 in 10.

What are the Types of Thyroid Cancer?

Papillary thyroid cancer;

Papillary thyroid cancers constitute 70-80% of thyroid cancers and are the most common type. Papillary thyroid cancers can occur at any age. Papillary cancer tends to grow slowly and often spreads to the neck lymph nodes. However, unlike most other cancers, even if papillary cancer has spread to the lymph nodes, there is an excellent course.

Follicular thyroid cancer;

Follicular thyroid cancers, which constitute 10-15% of thyroid cancers, tend to be seen in older patients compared to papillary thyroid cancer. Like papillary cancer, follicular cancer may spread primarily to the neck lymph nodes. Follicular cancer can also spread to blood vessels more frequently than papillary cancer, and from there it can spread to distant areas such as the lung and bone.

Medullary thyroid cancer;

Medullary thyroid cancer, which constitutes 5-10% of all thyroid cancers, tends to show familial inheritance more frequently and to be associated with other endocrine problems. In family members of an affected person, genetic mutation testing in the RET proto-oncogene can provide early diagnosis and thus early and definitive treatment of medullary thyroid cancer.

Anaplatic thyroid cancer;

Anaplastic thyroid cancer is the most advanced and aggressive thyroid cancer and has the least chance of responding to treatment. Fortunately, anaplastic thyroid cancer is rare and accounts for less than 2% of thyroid cancer patients.

What is Thyroid Cancer Treatment?

Surgical! The primary treatment for all types of thyroid cancer is surgery. The generally accepted approach today is the complete removal of the thyroid gland by surgery called total thyroidectomy. Some patients may have thyroid cancer in the lymph nodes of the neck or upper chest. These lymph nodes are removed during or sometimes after thyroid surgery. After surgery, patients receive lifelong thyroid hormone therapy. Thyroid cancer can often be cured by surgery alone, especially if the cancer is small. If the cancer is larger, has spread to the lymph nodes, or if your doctor considers you at high risk for recurrence; Radioactive iodine can be used to remove any cancer cells that may remain after the thyroid gland is removed. Please read the Thyroid Surgery brochure further to learn more about the risks and benefits of surgery and what kind of recovery to expect.

RADIOACTIVE IODINE THERAPY:

Thyroid cells and most thyroid cancers absorb and concentrate iodine. For this reason, radioactive iodine is used quite effectively to remove all remaining normal or cancerous tissue after thyroidectomy. The process of removing thyroid tissue is called radioactive iodine ablation. In this case, a high dose of radioactive iodine is collected in the thyroid tissue, thus damaging the DNA of the thyroid cells and ultimately the cells die. Radioactive iodine used in the ablation process has little or no effect on non-thyroid tissues, as other tissues in the body do not absorb and concentrate iodine effectively. . Two risks are known to occur. In some patients, radioactive iodine can affect the salivary glands, causing dry mouth to develop. In some patients, however, there is a small risk of developing other cancers in the future if they require high doses of radioactive iodine. These are minor risks, but the higher the dose of radioactive iodine, the greater the risk. The potential risks of treatment can be minimized by using the lowest possible dose of radioactive iodine. If radioiodine therapy is recommended, balancing the potential risks and benefits of radioiodine therapy is an important issue to discuss with your doctor.

If your doctor recommends radioactive iodine treatment, your TSH levels should be increased before treatment. This can be accomplished in two ways. The first is not to take the thyroid hormone pill (levothyroxine) for 4-6 weeks. In this case, hypothyroidism occurs and your body naturally produces high amounts of TSH. However, hypothyroidism can cause significant fatigue in some cases. To minimize the symptoms of hypothyroidism, your doctor may prescribe you T3 (Cytomel), a short-acting thyroid hormone, for up to 2 weeks before treatment, often when levothyroxine treatment is stopped. Alternatively, TSH can be raised simply by injecting TSH without putting you in a hypothyroid state. Two injections of recombinant human TSH (rhTSH, Thyrogen) can be given within a few days before thyroid hormone therapy. The benefit of this approach is that she can continue on thyroid hormone therapy and not develop hypothyroidism. You may also be asked to start a low-iodine diet 1-2 weeks before treatment. In this case, the iodine in your body is depleted and thus the absorption of radioactive iodine increases, increasing the effectiveness of the treatment.

WHEN TSH LEVELS ARE HIGH ENOUGH;

An iodine scan is often done by administering a small dose of radioactive iodine prior to treatment. This scan determines how much thyroid tissue needs to be damaged and allows the doctor to calculate how high a therapeutic dose of radioactive iodine should be administered. When used correctly, radioactive iodine therapy has been proven to be safe and well tolerated. Moreover, it has even been able to treat thyroid cancers that have spread to other parts of the body, such as the lungs.

Treatment of Advanced Thyroid Cancer;

Thyroid cancer that spreads (metastasizes) to distant places in the body is rare but can be a serious problem. Surgery and radioactive iodine remain the best modalities for treating this type of cancer, as long as they continue to work. However, for more advanced cancers, or where radioactive iodine therapy is ineffective, other means of treatment are needed. External beam radiation directs precisely focused X-rays to areas that need to be treated—often metastases to bone or other organs. This can kill certain tumors or stop their growth. Additional treatments are needed in cancers with wider spread. The use of new chemotherapy agents, which have promising results in the treatment of other advanced cancers, is also increasing in the treatment of thyroid cancer. These drugs rarely provide cure (full cure) in advanced cancers. However, it can slow or partially reverse the growth of cancer. These treatments are often given by an oncologist and require care at regional or university-owned medical centers.

What is seen in the follow-up of patients with thyroid cancer?

Intermittent follow-up exams are essential for all patients with thyroid cancer because even years after successful primary treatment, your thyroid cancer can return. These follow-up appointments include a careful history and physical examination, with a particular focus on the neck area. Neck ultrasound is also a very important tool in imaging the neck and monitoring nodules, swellings, and cancerous lymph nodes that may be a sign of cancer recurrence. Blood tests are also very important for thyroid cancer patients. Every patient who has undergone thyroidectomy surgery needs thyroid hormone replacement therapy with levothyroxine when the thyroid gland is removed. The dose of levothyroxine prescribed by your doctor is determined in part by the extent of your thyroid cancer. More common cancers require higher doses of levothyroxine to suppress TSH. It is safe to keep TSH in the normal range for low-risk cancers. TSH levels are the most sensitive indicator of correct adjustment of the levothyroxine dose and should be followed regularly by your doctor.

Another important blood test is the measurement of thyroglobulin. Thyroglobulin is produced by thyroid tissue and most types of thyroid cancer and is usually checked at least annually. Following thyroidectomy and radioactive iodine ablation, thyroglobulin levels should remain undetectable for life. Therefore, a detected high thyroglobulin level should raise suspicion for a possible cancer recurrence. Detectable increases in thyroglobulin levels may require additional testing and, possibly, further treatment with surgery and radioactive iodine. Thyroglobulin, either; during thyroid hormone therapy with low or normal TSH levels, or; It is measured after discontinuing thyroid hormone therapy for 3-6 weeks or after TSH rises with Thyrogen injection. In 25% of patients with intervening thyroglobulin antibodies in their blood, thyroglobulin measurement may not be possible. Different tools are often used for follow-up in these patients.

IN ADDITION TO ROUTINE BLOOD TESTS;

Your doctor may repeat the whole body iodine scan intermittently to determine if thyroid cells remain. Whole-body scanning is also done after your TSH levels have been raised by discontinuing thyroid hormone use or by injecting Thyrogen. These scans are being performed with increasing frequency for high-risk patients and have been largely superseded by routine neck ultrasound and thyroglobulin measurement methods, which have higher diagnostic sensitivity, especially when used together.