Thyroid Cancer

Thyroid cancer is relatively common (about 1–2% of all cancers), yet because of its excellent prognosis, it remains a rare cause of cancer-related death. Its incidence varies depending on geography, age, sex, and other factors.

Over the past decade, thyroid cancer has shown the highest annual increase in incidence compared with other cancers. This is likely related both to environmental factors and to significant improvements in diagnostic imaging.

Thyroid cancer is 3–4 times more common in women than in men, likely due to hormonal influences.
It is rare in children and adolescents and generally has a very favorable prognosis.
It can occur at any age, but it is most often diagnosed in individuals in their 40s and 50s.

In the vast majority of cases, thyroid cancer causes NO symptoms at all.
It is often detected incidentally as a thyroid nodule on ultrasound.

The tumor may develop silently, without any warning symptoms for the patient.

In the small percentage of patients who develop symptoms, these may include:

• A painless lump or swelling in the front of the neck
• Discomfort or atypical pain in the neck, sometimes radiating to nearby areas
• Hoarseness or voice changes if the tumor affects the recurrent laryngeal nerve
• A sensation of tightness or pressure in the neck
• Difficulty swallowing (dysphagia) or a feeling of a foreign body in the throat
• Persistent cough without respiratory infection or other obvious cause
• Breathing difficulty (dyspnea), if the tumor compresses the trachea
• Firm, painless, enlarged lymph nodes in the neck

The exact cause of thyroid cancer remains unknown—there is no clearly defined cause-and-effect relationship.
However, several risk factors are recognized:

• Radiation exposure. Therapeutic or environmental exposure to radiation, particularly in the head and neck region during childhood, significantly increases the risk. Examples include radiation from medical treatments, nuclear accidents (e.g., Chernobyl), etc.
• Family history and genetic factors. Having first-degree relatives with thyroid cancer increases the likelihood of developing the disease. Additionally, certain genetic mutations, such as in the RET gene, are associated with medullary thyroid carcinoma.
• Sex and age. Thyroid cancer occurs more frequently in women and typically appears in middle-aged individuals.
• Thyroid disorders. The presence of autoimmune thyroid diseases, such as Hashimoto’s thyroiditis, and the existence of goiter are linked to an increased risk of thyroid cancer.
• Obesity. Excess body weight has also been associated with a higher probability of developing thyroid cancer.
• Stress. Numerous scientific discussions and studies suggest a connection between stress, psychological factors, and carcinogenesis.
• Association with other cancers. Women with a history of breast cancer have a 55% higher risk of developing thyroid cancer compared with the general population.

Diagnosis involves a combination of clinical assessment and specialized tests:

• Medical history and clinical examination. This includes a detailed personal and family medical history. Clinical palpation of the neck by the physician unfortunately detects only about 4% of all thyroid nodules that are palpable, while also assessing for enlarged lymph nodes.
• Thyroid and neck ultrasound. This is the most sensitive and specific imaging method for detecting suspicious thyroid nodules. Concerning ultrasound features include microcalcifications, increased vascularity, hypoechogenicity, irregular margins, and others. It is important to emphasize that small size alone does not indicate benignity — nowadays, very small thyroid carcinomas are often discovered that may still exhibit aggressive biological behavior.
• Fine-needle aspiration (FNA). This is the primary test for cytological confirmation of malignancy. It is noteworthy that FNA provides limited information based on a small cell sample, and therefore may not always represent the condition of the entire gland.
• Blood tests. Unfortunately, there are no specific biochemical markers for thyroid cancer, except for calcitonin, which is used in cases of medullary thyroid carcinoma. It should be clearly stated that in the vast majority of thyroid cancer cases, thyroid hormone levels (T3, T4, TSH) remain within normal range.
• Elastography. This ultrasound technique evaluates the stiffness of the nodule, helping to some extent in assessing the probability of malignancy.
• Additional imaging studies. In selected cases, CT/MRI scans or thyroid scintigraphy (for functional assessment and detection of metastases) may be required. In most cases, however, the information obtained from ultrasound alone is sufficient.

In general, diagnosis typically begins with the incidental or targeted discovery of a suspicious nodule, followed by diagnostic tests for accurate characterization and staging of the cancer. Diagnostic assessment is further enhanced by:

• Neck ultrasound mapping, performed by a specialized radiologist, to detect possible lymph node involvement and assist the surgeon in planning the procedure.

Since the exact cause is unknown, there are no specific primary prevention measures beyond a healthy lifestyle.

Early detection is crucial.
Because thyroid cancer usually causes no symptoms and does not alter thyroid hormone levels, incorporating a thyroid ultrasound into your annual preventive check-up is highly recommended.

Based on cellular origin and histological features, the main types are:

• Papillary thyroid carcinoma (PTC)
  The most common type. Originates from follicular cells, may affect any age group, grows slowly, has an excellent prognosis, and may require radioactive iodine therapy in select cases.
• Follicular thyroid carcinoma (FTC)
  Less common than PTC, occurs more frequently in women over 40, and is slightly more aggressive.
• Hürthle cell carcinoma
  A rare variant, 4% of cases, originating from Hürthle cells, with behavior similar to follicular carcinoma.
• Medullary thyroid carcinoma (MTC)
  Represents 3–5% of cases, arises from parafollicular (C) cells that produce calcitonin, may be sporadic or hereditary, and does not respond to radioactive iodine.
• Anaplastic thyroid carcinoma
  Very rare, highly aggressive, more common in the elderly, with poor prognosis.
• Thyroid lymphoma
  Also rare, originating from lymphocytes; often treated with radiotherapy and chemotherapy.

PTC and FTC are the most common types and generally have an excellent prognosis.
Timely and proper surgical treatment offers complete cure in the vast majority of cases.

Medullary thyroid carcinoma (MTC) is a rare form of thyroid cancer. It can occur spontaneously or as part of genetic syndromes such as Multiple Endocrine Neoplasia type 2 (MEN2).

Diagnosis is closely linked to elevated calcitonin levels. Although more aggressive than follicular-derived cancers, it can be successfully treated surgically with appropriately planned radical operations. If there is a family history, genetic counseling and testing for both the patient and relatives are essential.

It is noteworthy that in cases of mild elevation of calcitonin levels, timely surgical removal of the thyroid gland provides a definitive solution and cure. This intervention prevents disease progression at a benign precancerous stage known as C-cell hyperplasia.

The stages of thyroid cancer are determined using the international TNM classification system, which assesses the local extent of the tumor (T), lymph node involvement (N), and the presence of distant metastases (M), categorizing the disease from stage 0 to stage IV.

Tumor staging plays a critical role in predicting prognosis and ensuring good survival outcomes. Early removal of suspicious lesions—those that raise even the slightest concern for malignancy (“gray zones”)—offers the optimal opportunity to intervene while the disease is still benign and precancerous, or at most in its very early malignant phase. This approach enables complete and effective treatment, allowing patients to continue their lives with confidence and normalcy.

Most common thyroid cancers do not metastasize to distant organs. They usually grow slowly and remain localized. If the tumor extends beyond the thyroid capsule, it may involve nearby lymph nodes—a surgically treatable condition.

In most cases, thyroid cancer is not hereditary.
Genetic predisposition may be present mainly in medullary thyroid cancer.

However, whenever thyroid cancer occurs in a family, preventive ultrasound screening of first-degree relatives is recommended.

Surgery, performed by an experienced endocrine surgeon, is the primary treatment.
It may involve partial or total thyroidectomy, often combined with neck lymph-node dissection if needed.

Radioactive iodine therapy (I-131) may be used postoperatively in selected cases according to international guidelines, to destroy remaining thyroid cancer cells.

At this point, it should be emphasized how greatly the patient benefits from the timely removal of the neoplastic thyroid. By intervening early, according to international guidelines, the patient may avoid the need for radioactive iodine therapy and the associated burden of isolation.

Other treatments, such as radiotherapy or chemotherapy, are rarely required.

No. The prognosis for the most common thyroid cancers is excellent. Therefore, a patient diagnosed with thyroid cancer has every reason to be optimistic, as timely and specialized surgical treatment can completely overcome the disease, allowing for a normal and healthy life.

Dr. Evangelos Karvounis, MD, PhD, FACS, is an award-winning endocrine surgeon, Doctor of the Medical School of the University of Athens and Fellow of the American College of Surgeons.
With expertise in robotic surgery and many years of experience, he currently serves as the Director of Endocrine Surgery at the Euroclinic Athens, where he applies advanced microsurgical techniques. 

Dr. Karvounis is well-equipped to answer any questions regarding thyroid cancer and is a top choice for safe and effective thyroid and parathyroid procedures. Contact him today, either by phone or by completing the contact form, to schedule a consultation for accurate diagnosis and personalized treatment.”