Hurthle Cell Cancer - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

The thyroid gland is a butterfly-shaped tiny gland present in the neck. It produces two important hormones, namely T3 (triiodothyronine) and T4 (thyroxin), which regulate different body functions like metabolism, bone growth, brain development, body temperature, menstrual cycles, and digestion. Production of thyroid hormone is controlled by the hypothalamus and pituitary glands which are situated at the base of the skull. The hypothalamus-pituitary complex releases a hormone called thyroid-stimulating hormone (TSH) into the bloodstream, making the thyroid gland release T3 and T4 when there is an imbalance.

What Are the Types of Thyroid Cancer?

Thyroid cancer is of different types based on the type of cells from which it develops and the degree of similarity between normal thyroid cells and cancer cells.

The four main types of thyroid cancer include the following:

1. Papillary Thyroid Cancer- Papillary thyroid cancer, or papillary carcinoma, is the most common form that accounts for around 80 percent of all thyroid cancers. It is a slow-growing type that develops from a type of cell in the thyroid tissue called follicular cells. It can spread to nearby tissues; however, the cancer is treatable, with a positive outlook for the survival of the affected patient.

2. Follicular Thyroid Cancer- It is the second most common type, accounting for around ten percent of all thyroid cancers. It occurs most commonly in countries with a deficiency of dietary iodine. It is more aggressive than the papillary type and can spread to nearby bones or lungs. Hurthle cell cancer is a subtype of follicular cancer that accounts for three percent of all thyroid cancers.

3. Medullary Thyroid Cancer- Medullary thyroid cancer is more aggressive than the above two types, accounting for 4 percent of all thyroid cancers. Medullary cancers can spread to other body parts. Blood levels (calcitonin is a thyroid hormone that helps decrease excess calcium in the blood) and carcinoembryonic antigen (CEA - a protein found in developing babies, which normally decreases after birth) are high in medullary thyroid cancers.

4. Anaplastic Thyroid Cancer- Anaplastic thyroid cancers are the most aggressive type that grows fast and spreads to nearby structures. They account for two percent of all thyroid cancers.

What Is Hurthle Cell Cancer?

Hurthle cell cancer is a rare cancer that affects the thyroid gland. It is more common in women and older individuals. It accounts for three to five percent of all thyroid cancers and is the more aggressive type that spreads to other parts of the body (metastasis).

What Are the Other Names of Hurthle Cell Cancer?

The other names for Hurthle cell cancer include:

• Hurthle cell carcinoma.

• Oxyphilic cell carcinoma.

What Are the Causes of Hurthle Cell Cancer?

The exact etiology of Hurthle cell cancer is unknown. However, researchers believe that changes (mutations) in the DNA (deoxyribonucleic acid) can lead to Hurthle cell cancer. DNA contains instructions that tell the cells what to do. Changes in DNA can direct the thyroid cells to grow and divide quickly, which leads to the formation of a lump referred to as a tumor. Normal cells die due to insufficient oxygen and blood supply. The tumor cells can also spread to nearby tissues or far-off organs through blood vessels.

What Are the Risk Factors of Hurthle Cell Cancer?

The factors that increase the risk of developing Hurthle cell cancer include:

• Elderly age group.

• Being female.

• History of radiotherapy for head and neck cancers.

• Family history of thyroid cancer.

• Long-term iodine deficiency.

What Are the Symptoms?

In most patients, Hurthle cell cancer does not show any symptoms. However, large thyroid nodules can cause signs and symptoms which include:

• Throat pain.

• A lump below Adam's apple in the neck.

• Choking sensation.

• Difficulty breathing or swallowing.

• Swollen lymph nodes (lymph nodes are small structures spread throughout the body that filter toxic substances and produce immune cells that aid in fighting infections).

The presence of the above symptoms does not confirm Hurthle cell cancer. Inflammation or enlargement of the thyroid gland can also cause similar symptoms.

Other symptoms that occur in the whole body may include:

• Tiredness.

• Unexplained weight loss.

• Muscle wasting (muscle loss that causes shrinking and weakening of muscles).

What Are the Complications of Hurthle Cell Cancer?

Possible complications that can occur in patients with Hurthle cell cancer include:

• Difficulty in Breathing and Swallowing- Cancer that grows in size and causes pressure on the windpipe (trachea) and food pipe (esophagus) can cause complications of difficulty breathing and swallowing.

• Spread of Cancer- Cancer cells can spread to nearby or distant organs, making treatment and recovery difficult.

How to Diagnose Hurthle Cell Cancer?

Doctors advise the following tests to diagnose Hurthle cell carcinoma, which include:

1. Physical Examination- A physical examination of the neck is done to assess the size of the thyroid gland and to check for swollen lymph nodes.

2. Blood Tests- Blood tests help to know if there is an imbalance of thyroid hormones.

3. Imaging Tests- Tests like ultrasound scans and CT (computerized tomography), which help to view the body's internal organs, are done to detect any growth in the thyroid gland.

4. Laryngoscopy- Laryngoscopy is done when cancer cells can spread into the vocal cords, especially when voice changes are noted. The doctor examines the vocal cords using a tiny mirror and light in this technique. Another technique called fiber-optic laryngoscopy is sometimes used in which a thin, flexible tube with a light and a tiny camera is inserted through the mouth or nose to examine the vocal cords.

5. Biopsy- For thyroid biopsy, a thin needle is inserted through the skin into the gland, guided by ultrasound images of the neck. A syringe at the end of the needle withdraws a thyroid tissue sample sent to the laboratory for further analysis.

6. Radioactive Thyroid Scan- A small amount of radioactive iodine is injected into the bloodstream, which is taken up by the cancer cells of the thyroid. The doctor then scans the thyroid gland to check for cancer cells.

How Fast Does Hurthle Cell Cancer Grow?

Hurthle cell thyroid cancers are more aggressive than papillary-type cancers. But metastasis, or the spread of these to other tissues or organs, is comparatively rare. The cancer can spread through the blood or lymph nodes.

How Is Hurthle Cell Cancer Treated?

The treatment modalities followed include:

• Surgery

• Radiation therapy.

• Radioactive iodine therapy.

• Targeted drug therapy.

Surgery:

The most common treatment option for Hurthle cell cancer is total or near-total thyroid gland removal (thyroidectomy). The surgeon removes all of the thyroid tissue, leaving behind small parts close to the parathyroid glands (located beneath the thyroid glands, which regulate calcium levels in the blood).

In cases where there is a suspicion that the cancer cells have spread to the surrounding lymph nodes, they may also be removed.

Risks associated with surgery include:

1. Excessive bleeding.

2. Damage to the nerve supplying vocal cords, causing hoarseness of voice or voice loss.

3. Removal or injury to parathyroids causes an imbalance in blood calcium levels.

Post-surgery, doctors may prescribe a hormone called Levothyroxine, which replaces the hormones produced by the thyroid gland. The hormone has to be taken throughout life.

Radiation Therapy:

Radiation therapy is advised in cases where the cancer cells remain post-surgery or if the cancer has spread to nearby structures. The patient is positioned on a table, and high-energy X-ray beams are passed on to the targeted areas, which kill the cancer cells.

Side effects of radiation therapy include:

1. Skin rash.

2. Sore throat.

3. Tiredness.

Radioactive Iodine Therapy:

In radioactive iodine therapy, a pill containing radioactive liquid is swallowed, which helps destroy any remaining cancer cells that may be present post-surgery.

Side effects of radioactive iodine therapy include:

1. Loss of taste.

2. Dry mouth.

3. Tenderness in the neck.

4. Nausea.

5. Fatigue or tiredness.

Targeted Drug Therapy:

The therapy uses drugs or other substances to identify and eliminate certain types of cancer cells specifically. Targeted drug therapy is under research for more new drugs that can be used in cancer patients.

The side effects that occur are specific to the drugs used; however, the common side effects include:

1. Diarrhea.

2. High blood pressure.

3. Fatigue.

4. Problems of the liver.

Conclusion:

Hurthle cell cancer is an uncommon type of thyroid cancer that occurs commonly in women and the elderly population. A strong support system of family and friends can help cope with anxiety associated with cancer treatment and recovery. Setting reasonable goals, conserving energy for important activities, eating well, and following a healthy daily routine can help overcome the stress and exhaustion of cancer.