How is thyroid cancer treated?

What is thyroid cancer?

Thyroid cancer is a type of cancer that develops in the thyroid gland. This cancer is a relatively rare type of cancer, but its incidence has been increasing in recent years. The cause of thyroid cancer is not known, but some factors such as radiation exposure, family history of thyroid cancer and heredity and some genetic conditions may increase the risk of developing the disease. The most common symptom of thyroid cancer is a lump or swelling in the neck, but other symptoms may include hoarseness, difficulty swallowing, and enlarged lymph nodes. Treatment options for thyroid cancer depend on the type and stage of the cancer and may include surgery, radioactive iodine therapy, and thyroid hormone therapy. With appropriate and timely treatment, most people with thyroid cancer have an excellent recovery process.

What are the ways to treat thyroid cancer?

Thyroid cancer may not need immediate treatment, but its treatment methods depend on various factors, including the type and stage of cancer, and the treating doctor can use one or a combination of these methods. In the following, we have introduced these methods:

Surgical treatment of thyroid cancer

For most patients with thyroid cancer, surgery is chosen as the first treatment method and the most basic method. The goal of surgery is to remove the cancerous thyroid gland and any nearby lymph nodes that may contain cancer cells. In this procedure, part or all of the thyroid is removed to remove cancer cells. Depending on the size and location of the tumor, a lobectomy (removal of a thyroid lobe) or a total thyroidectomy (removal of the entire thyroid gland) may be performed. Lobectomy is sometimes used to treat differentiated thyroid cancers (papillary or follicular) and lobectomy is also used to diagnose thyroid cancer. The advantage of this procedure is that some patients may not need thyroid hormone pills after surgery. The most common thyroid surgery is thyroidectomy. If the thyroid is completely removed during this surgery, after the surgery, the patient must regularly receive thyroid hormone medication to act as a thyroid replacement. This drug is used to control the level of thyroid hormone in the patient’s body.

Treatment of thyroid cancer with drugs

If the thyroid cancer is in the early stages, the doctor may suggest the use of drugs as a medical treatment method. These drugs are usually used to reduce the volume of cancer cells or reduce the level of thyroid hormone in the patient’s body. In this treatment, drugs are used that target specific molecules that play a role in the growth and spread of cancer cells. Targeted drug therapy is a newer treatment option for advanced thyroid cancer and is generally used when other treatments have not worked.

In some cases, drugs such as Lutroxin are prescribed as thyroid replacement for patients who have had their thyroid completely removed.

Chemotherapy and thyroid hormone therapy are two methods of thyroid cancer treatment that are done by drugs. These two methods are explained below.

• Chemotherapy

  : In this treatment, drugs are used to destroy cancer cells. Chemotherapy is generally not very effective for thyroid cancer, but it may be used in cases where the cancer has spread outside the thyroid gland.

• Thyroid hormone therapy

  : This treatment involves the use of thyroid hormone replacement drugs to replace the hormones that the thyroid gland normally produces. In this method, it is used to prevent the growth of any of the remaining thyroid tissues and to suppress the production of thyroid stimulating hormone (TSH), which can stimulate the growth of the remaining thyroid cells.

Treatment of thyroid cancer with radioiodine or iodine therapy

In some cases, the doctor may prescribe radioiodine to the patient after surgery. This treatment is used to destroy the remaining cancer cells in the thyroid. Radioiodine is taken orally and destroys cancer cells by absorbing the radioactive substances it contains. After the treatment with radioiodine, all the radioactive substances remaining in the patient’s body must be removed.

In radioactive iodine treatment, iodine is used to destroy the remaining thyroid tissue after surgery. Radioactive iodine is taken orally and absorbed by the remaining thyroid cells, which are then destroyed using radiation.

External radiation therapy: In this treatment, high-energy X-rays are used to destroy cancer cells. In cases where the cancer has spread outside the thyroid gland or when surgery is not possible, external radiation therapy is used.

Treatment of thyroid cancer with a combination of different methods

In some cases, your doctor may recommend a combination of different methods to treat thyroid cancer. For example, in some cases after surgery, radioiodine is prescribed to the patient to act as a complementary treatment. In some cases, drugs such as Lutroxin are prescribed as thyroid replacement for patients who have had their thyroid completely removed.

What are thyroid cancers and what are their treatment methods?

There are different types of thyroid cancer and each of them is treated in special ways, which include:

Papillary cancer and its types

If the neck and thyroid develop papillary cancer, an ultrasound-guided biopsy is performed to confirm the cancer. If the tumor seems resectable, surgery is often used. If the cancer shows up on a radioactive iodine scan (meaning the cells are taking up iodine), radioactive iodine (RAI) therapy may be used alone or with surgery. If the cancer does not show up on the radioactive iodine scan but is found by other imaging tests (such as an MRI or PET scan), external beam radiation may be used.

If the cancer has spread to multiple sites and RAI and other treatments are not helpful, targeted therapy drugs such as lenvatinib (Lenvima) or sorafenib (Nexavar) may also be tried. If these drugs don’t work, cabozantinib (Cabometyx) may be an option. Other targeted drugs may also be helpful, especially if the cancer cells have changes in certain genes (such as the RET or NTRK genes). Since these cancers can be difficult to treat, participating in a clinical trial of a newer treatment is another option.

Follicular cell cancer

If the tumor is a follicular cancer, a second operation is usually needed to remove the rest of the thyroid (this is called a supplementary thyroidectomy or total thyroidectomy). If the patient wants only one operation, the doctor may remove the entire thyroid gland in the first operation. However, for most patients, this is not really needed.

If there are signs that the cancer has spread before surgery, the tumor must be cancerous and therefore a thyroidectomy is performed.

Hürthle cell carcinoma (Hurthle) can also be diagnosed based on FNA biopsy. Tumors suspected of Hürthle cell carcinoma are often treated like follicular neoplasms. A lobectomy is usually performed first, and if cancer is confirmed, a total thyroidectomy is performed. If there are signs that the cancer has spread or if the patient wants to avoid further surgery in the future, a thyroidectomy may be performed as the first operation.

As with papillary cancer, some lymph nodes are usually removed and tested for cancer. If the cancer has spread to the lymph nodes, a central compartment or modified neck dissection (surgical removal of lymph nodes from the neck) may be performed. Since the thyroid is removed, patients must also take thyroid hormone, although it is often not started immediately.

A radioactive iodine scan is usually done after surgery to look for areas that are still using iodine. Spread to nearby lymph nodes and to distant sites shown on scans can be treated with radioactive iodine (RAI). For cancers that do not use iodine, external beam radiation therapy may help treat the tumor or prevent it from growing in the neck.

Cancer that has spread to distant sites, such as the lungs or liver, may require treatment with external beam radiation therapy or with targeted therapy drugs such as lenvatinib (Lenvima) or sorafenib (Nexavar). Other targeted drugs may also be helpful, especially if the cancer cells have changes in certain genes (such as the RET or NTRK genes). Another option is to participate in a clinical trial of newer treatments or chemotherapy.

Medullary thyroid cancer

Most doctors recommend that patients with medullary thyroid carcinoma (MTC) be screened for other tumors commonly seen in patients with MEN 2 syndrome. Screening for pheochromocytoma is very important, as anesthesia and surgery can be very dangerous when these tumors are present. If surgeons and anesthesiologists know about such tumors in advance, they can treat the patient with drugs before and during surgery to make the surgery safe.

Stages one and two: Total thyroidectomy is the main treatment for MTC and often cures patients with stage one or stage two MTC. Adjacent lymph nodes are also usually removed. Since the thyroid gland is removed, thyroid hormone therapy is required after surgery. For MTC, thyroid hormone therapy means providing enough hormone to keep the patient healthy, but does not reduce the risk of the cancer returning. Since MTC cells do not take up radioactive iodine, there is no role for radioactive iodine therapy in the treatment of MTC.

Stages three and four: Surgery is the same as stages one and two. Thyroid hormone therapy is usually given after screening for MEN 2 syndrome and pheochromocytoma. When the tumor is extensive and invades many nearby tissues or cannot be completely removed, external beam radiation therapy may be given after surgery to reduce the chance of recurrence in the neck.

For cancers that have spread to distant parts of the body, surgery, radiation, or similar treatments may be used if possible. If these treatments fail, targeted drugs such as vandetanib (Caprelsa) or cabozantinib (Cometriq) may be tried. Other targeted drugs may also be helpful, especially if the cancer cells have changes in certain genes (such as the RET gene). Chemotherapy may be another option. Since these cancers can be difficult to treat, another option is to participate in a clinical trial of a newer treatment.

Anaplastic cancer

Because this cancer is already extensive when diagnosed, surgery is often not helpful as a treatment. If the cancer is limited to the area around the thyroid, which is rare, the entire thyroid and nearby lymph nodes may be removed. The goal of surgery is to remove as much cancer as possible in the neck area and ideally to leave no cancer behind. Because of the way anaplastic cancer spreads, this is often difficult or impossible.

In this cancer, radioactive iodine treatment is not used because it does not work.

External radiation therapy may be used alone or together with chemotherapy, which can be caused by the following.

 Trying to shrink the cancer before surgery to increase the chance of removing it completely

 After surgery to control any remaining cancer in the neck

 When the tumor is too large or widespread to be treated with surgery

If the cancer is causing (or may later cause) breathing problems, a surgical hole may be made in the front of the neck and in the trachea to bypass the tumor and allow the patient to breathe more easily. This hole is called a tracheostomy.

For cancers that have spread, chemotherapy alone can be used. If cancer cells have changes in certain genes, treatment with targeted drugs may be helpful, such as:

 Dabrafenib (Tafinlar) and trametinib (Mekinist) can be used to treat cancers with certain BRAF gene mutations.

 Selpercatinib (Retevmo) can be used to treat cancers with specific RET gene mutations.

 Larotrectinib (Vitrakvi) or entrectinib (Rozlytrek) can be used to treat cancers with NTRK gene mutations.

Since these cancers can be difficult to treat, clinical trials of newer treatments are also an option.

Finally, it should be noted that the treatment of thyroid cancer is different depending on the type and stage of cancer, and it may even be different on an individual basis, so the type of thyroid cancer treatment should be determined by the attending physician. Also, after the treatment, the patient should be regularly examined by the doctor to prevent the occurrence of cancer and its return.