Thyroid Cancer: Types, Symptoms, Causes and Treatment

Thyroid cancer is the fastest-growing cancer of the thyroid gland, with women being three times more likely to develop the condition than men. While this statistic might sound alarming, thyroid cancer is highly treatable, mainly when detected early. The five-year survival rate for localised cases approaches 100%.

This blog explores the essential aspects of thyroid cancer, from its various types and symptoms to diagnosis methods and treatment options, helping readers understand this condition better.

What is Thyroid Cancer?

The thyroid gland, a butterfly-shaped organ situated at the base of the neck just below the Adam's apple, serves as the starting point for thyroid cancer. This small gland produces hormones that regulate essential bodily functions, including heart rate, BP, body temperature, and weight.

Thyroid cancer develops through abnormal cell growth within the thyroid gland. Most thyroid cancers progress slowly, although certain types can be aggressive. The condition typically starts without noticeable symptoms.

Thyroid Cancer Types

Doctors classify thyroid cancer based on how the cells appear under a microscope and the specific cells from which they develop. 

• Papillary thyroid cancer stands as the most prevalent form, accounting for 80% to 85% of all cases. This slow-growing cancer develops from follicular cells and can affect one or both thyroid lobes. Even if it spreads to nearby lymph nodes, papillary thyroid cancer often responds well to treatment.
• Follicular thyroid cancer ranks as the second most common type. This variant occurs more frequently in regions with insufficient dietary iodine intake. Unlike papillary cancer, follicular carcinomas rarely spread to lymph nodes but may travel to other organs, notably the lungs or bones.
• Medullary thyroid cancer develops from C-cells, representing 4% to 10% of all cases. This aggressive form tends to spread more readily to lymph nodes & other organs compared to differentiated thyroid cancers. 
• Anaplastic thyroid cancer, occurring in 2% to 3% of cases, presents the most aggressive form. These undifferentiated cells look markedly different from normal thyroid tissue and spread rapidly throughout the body.
• Hürthle cell thyroid cancer, a rare subtype of follicular carcinoma, accounts for less than 5% of all cases. This variant typically affects people over 40 years of age.

Based on cell appearance, thyroid cancers fall into three categories:

• Well-differentiated: Cells closely resemble normal thyroid tissue and offer the most favourable prognosis
• Poorly differentiated: Cells show more abnormalities, representing 3% to 5% of cases
• Undifferentiated: Cells bear little resemblance to normal thyroid tissue, making treatment more challenging

Symptoms of Thyroid Cancer

The following are some common thyroid cancer symptoms:

• A noticeable lump in the neck stands as the primary sign of thyroid cancer. This growth typically appears in the front lower part of the neck and feels hard to touch. The lump might grow steadily without causing pain, warranting immediate medical attention.
• Voice changes, specifically increasing hoarseness that persists
• Difficulty swallowing or breathing
• Pain in the neck, sometimes extending to the ears
• Persistent cough unrelated to cold
• Swollen lymph nodes in the neck region
• Sensation of tightness around shirt collars

As the condition advances, additional symptoms might surface, indicating the spread of cancer to other body parts. These advanced symptoms include:

• Unexplained tiredness
• Reduced appetite
• Frequent nausea accompanied by vomiting
• Unintentional weight loss

Thyroid Cancer Causes and Risk Factors

Thyroid cancer risk factors fall into several key categories that everyone should be aware of:

• Non-modifiable Risk Factors:
  • Gender: Women face 8-9 times higher risk than men
  • Age: Most common between ages 30-60
  • Family History: Having a first-degree relative with thyroid cancer increases the possibility
  • Genetic Conditions:
    • Multiple Endocrine Neoplasia type 2 (MEN2)
    • Familial Adenomatous Polyposis (FAP)
    • Cowden Syndrome
• Medical and Environmental Factors:
  • Previous radiation exposure to the head or neck
  • Graves’ disease complications
  • Autoimmune thyroid conditions
  • Exposure to:
    • Air pollutants (PM2.5 and PM10)
    • Endocrine-disrupting chemicals
    • Perfluoroalkyl substances
• Modifiable Risk Factors:
  • Higher body mass index (BMI)
  • Low physical activity levels
  • Exposure to secondhand smoke
  • Tobacco use
  • Dietary factors:
    • Irregular iodine intake
    • High animal fat consumption

Complications of Thyroid Cancer

Cancer recurrence in up <10% of cases. The slow-growing nature of thyroid cancer means recurrence might surface anywhere from 5 to 20 years after initial treatment. The cancer might return in:

• Lymph nodes in the neck
• Residual thyroid tissue
• Other body parts, including lungs and bones

Post-surgical complications can arise following thyroid removal procedures. These include temporary or permanent changes in hormone production, which might lead to several health conditions. This can be safely treated by hormone supplements. Rarely  Cancer spread (metastasis) represents another potential. When thyroid cancer metastasises, it commonly travels to the lungs, bones, brain tissues & neurons, liver, and skin.

Diagnosis

Doctors begin with a comprehensive physical examination, paying close attention to any changes in the thyroid gland, particularly lumps or nodules.

• Lab Test:
  • Blood tests measuring thyroid-stimulating hormone (TSH) and other thyroid hormones.
  • High-resolution ultrasound imaging 
  • Fine needle aspiration (FNA) biopsy 
• Advanced Imaging Techniques:
  • Radioiodine scans detect thyroid cancer cells throughout the body
  • CT scans determine cancer spread to nearby areas
  • MRI provides detailed images of soft tissues
  • PET scans prove useful when cancer does not absorb radioactive iodine

Thyroid Cancer Treatment

Surgery stands as the primary treatment choice for most thyroid cancers. Doctors typically recommend either a total thyroidectomy or a thyroid lobectomy. A total thyroidectomy involves surgically removing the entire thyroid gland, whereas a lobectomy removes only the affected lobe and isthmus. After complete thyroid removal, patients need daily thyroid hormone pills to replace the natural hormones.

Radioactive iodine therapy is an effective secondary treatment, particularly for differentiated thyroid cancers. This treatment uses radioactive iodine (RAI) that targets thyroid cells throughout the body. 

Targeted drug treatments focus on specific receptors within cancer cells. 

External beam radiation therapy employs high-energy beams to target precise points on the body. 

For aggressive thyroid cancers, doctors may recommend chemotherapy.

When to See a Doctor

Medical consultation becomes imperative under several circumstances:

• Development of a new neck lump or noticeable growth in an existing one
• Persistent hoarseness lasting beyond three weeks
• Unexplained changes in voice quality
• Difficulties with breathing or swallowing
• Swollen lymph nodes in the neck area
• Rapid heart rate without apparent cause
• Sudden weight fluctuations without dietary changes
• Extreme fatigue

Additionally, patients experiencing symptoms associated with metastatic thyroid cancer warrant immediate medical attention, including:

• Localised pain in various body parts
• Persistent nausea accompanied by vomiting
• Decreased appetite
• Unexplained weight loss

Prevention

While complete prevention of thyroid cancer remains challenging, several measures help reduce the risk. Research indicates that most individuals diagnosed with thyroid cancer have no modifiable risk factors, yet certain preventive steps prove beneficial.

• Using thyroid shields during X-rays and imaging tests
• Avoiding unnecessary radiation exposure to head and neck areas
• Opting for the lowest radiation doses that provide clear imaging results
• Discussing alternative imaging options with doctors
• Maintaining a healthy body weight 
• Tobacco Control 
• Regular self-checks and medical examinations facilitate early detection
• Dietary considerations:
  • Iodine-rich foods like fish and shellfish might protect populations with insufficient daily intake.
  • High consumption of fruits and vegetables containing active micronutrients provides antioxidant protection.
  • Bioactive components from fruits and vegetables might help prevent early thyroid cancer.

FAQs

1. Is thyroid cancer curable?

Most thyroid cancers respond excellently to treatment. The prognosis remains positive. Moreover, life expectancy often matches that of the general population.

2. What are the leading causes of thyroid cancer?

DNA changes in thyroid cells trigger abnormal growth and multiplication. Certain inherited genetic syndromes increase risk, namely familial medullary thyroid cancer, multiple endocrine neoplasia, Cowden syndrome, and familial adenomatous polyposis.

3. At what age does thyroid cancer start?

Thyroid cancer affects various age groups differently. The average diagnosis age stands at 51 years. Papillary thyroid cancer typically affects people aged 30-50, whilst follicular thyroid cancer commonly occurs in individuals over 50.

4. What is the blood test for thyroid cancer?

Blood tests measure thyroid-stimulating hormone (TSH) and thyroid hormones (T3 and T4) to assess thyroid function. However, blood tests alone cannot diagnose thyroid cancer; they serve instead as indicators of overall thyroid health.

5. Can thyroid cancer be treated without surgery?

Active surveillance offers a non-surgical option for low-risk thyroid cancers. Studies show that over 85% of patients choosing this approach never needed surgery within 10-20 years. However, strict criteria apply, including small tumour size (typically <1.5 cm) and no lymph node involvement.

6. How to check for thyroid cancer at home?

Regular self-examination helps detect potential thyroid issues. Check the neck area from below the ear to the collarbone. Look for:

• Lumps or swelling in the neck region
• Changes in voice quality
• Difficulty swallowing
• Persistent cough without illness