Thyroid Cancer: Types, Symptoms, Diagnosis and Treatment

Thyroid cancer has several subtypes, including papillary, follicular, medullary, anaplastic and oncocytic thyroid cancer. These cancers differ in their development, spread and response to treatment. This article discusses their frequency, symptoms, diagnosis, treatment and disease course in detail.

Differentiated Thyroid Cancer

Differentiated thyroid cancer includes papillary, follicular and oncocytic (Hürthle cell) subtypes. These cancer cells resemble normal thyroid cells under the microscope. They generally grow slowly, are treatable and can often be completely cured. 

Papillary Thyroid Cancer

• Accounts for 80% of thyroid cancers and is the most common type.
• Usually arises in one lobe of the thyroid gland and grows slowly.
• May spread to neck lymph nodes, but can often be treated successfully.
• Some variants may behave more aggressively and require more intensive treatment.

These variants include:

1. Follicular variant
2. Tall cell (elongated cells)
3. Columnar, insular, clear cell
4. Trabecular, hobnail, diffuse sclerosing

Follicular Thyroid Cancer

• Accounts for approximately 10% of thyroid cancers.
• Generally more common in iodine-deficient regions of the world.
• Lymph node spread is rare, but it may spread to distant organs such as the lungs or bones.
• In general, the prognosis is good.

Oncocytic (Hürthle Cell) Thyroid Cancer

• Rare, accounting for 3–4% of all thyroid cancers.
• More common in women aged 50–60.
• More prevalent in populations with iodine deficiency or high goiter rates.
• May behave more aggressively and tends to spread through the body.
• Although 5-year survival is high, early diagnosis is important.

Medullary Thyroid Cancer (MTC)

• Accounts for 1–2% of all thyroid cancers.
• Arises from the thyroid gland’s C cells, which secrete the hormone calcitonin.

Types of MTC

• Sporadic MTC:
• Approximately 75% of all MTC cases.
• Not inherited.
• Usually affects one thyroid lobe and occurs at older ages.

Familial MTC (FMTC):

• Approximately 25% of all MTC cases.
• Genetically inherited and may begin in childhood/early adulthood.
• Usually affects both lobes and may spread early.

MTC has a worse prognosis than papillary or follicular cancer, but may progress slowly and can be cured with early surgery.

Anaplastic Thyroid Cancer

• Accounts for approximately 2% of all thyroid cancers.
• In some cases, it may develop from preexisting papillary or follicular cancers.
• Grows rapidly, spreads to surrounding tissues and is difficult to treat.
• Has the poorest prognosis of all thyroid cancer types.

Symptoms of Thyroid Cancer

Common symptoms that may indicate thyroid cancer include:

• Swelling or a rapidly growing mass in the neck
• A painful or painless nodule at the front or side of the neck
• Pain radiating from the neck to the ear
• Voice changes, hoarseness
• Difficulty swallowing or breathing
• Persistent cough

Papillary and follicular cancers usually present as painless, slow-growing nodules.

Medullary thyroid cancer may present as a painful neck mass.

Anaplastic thyroid cancer presents as a rapidly growing mass causing pressure.

Thyroid Cancer Diagnosis

Diagnosis uses biopsy methods and laboratory tests :

• Fine-needle aspiration biopsy (FNA)
• Core needle biopsy (core biopsy)
• Lobectomy (surgical removal of a thyroid lobe)

If MTC is suspected, blood tests measure tumor markers such as calcitonin and CEA .

Thyroid Cancer Treatment Methods

Treatment varies by cancer type and stage. General approaches are summarized below:

• Papillary, follicular, oncocytic:

1. Usually surgical removal of the entire thyroid or the cancerous lobe
2. Lymph node dissection

• Medullary (MTC):

1. Total thyroidectomy and removal of lymph nodes
2. If needed, radiotherapy, targeted therapies or chemotherapy

• Anaplastic:

1. Surgery if feasible
2. Radiotherapy, chemotherapy or targeted therapy

When the thyroid gland is completely removed, patients need thyroid hormone for life.

Thyroid Cancer Survival Rates

According to American Cancer Society data (2012–2018), 5-year relative survival rates:

For oncocytic cancer, 10-year survival exceeds 90%, particularly with early diagnosis and appropriate treatment.

Summary

• The most common thyroid cancer types are papillary, follicular and oncocytic.
• These cancers generally progress slowly, are treatable and have a good prognosis.
• Medullary and anaplastic cancers are rarer and may be more aggressive.
• Treatment generally includes surgery ; in some cases, radiotherapy, chemotherapy or targeted therapies may be added.
• Survival rates are very high with early diagnosis.