Thyroid cancer symptoms can vary and may not always be noticeable in the early stages. Common signs include a lump in the neck, voice changes, and difficulty swallowing.

What causes thyroid cancer?

Thyroid cancer is not among the most common types of cancer, accounting for approximately 1% of all malignancies across various organs. It primarily affects women and individuals over the age of 40. Moreover, the likelihood of developing thyroid cancer increases by several percent with each passing decade.

Like many other diseases, thyroid cancer arises from multiple factors. Individuals with goiter are at significantly higher risk, as studies indicate that goiter contributes to 80% of all thyroid malignancies. Additionally, both men and women should be particularly vigilant about their health if they have:

• Chronic inflammation in the thyroid gland
• Long-term inflammatory conditions or tumors (even benign) in the reproductive system or mammary glands (in women)
• Thyroid adenoma or cystadenoma, both considered precancerous conditions
• A family history of cancer, endocrine tumors, or glandular dysfunction
• Hereditary genetic conditions affecting the thyroid gland
• Hormonal fluctuations related to pregnancy, breastfeeding, menopause, or hormonal imbalances
• Harmful habits, particularly smoking

While genetics play a role in thyroid cancer, hormonal changes also contribute significantly to its development.

Environmental and occupational risk factors

Exposure to X-rays or radioactive radiation, especially during childhood or adolescence, is another significant risk factor. Additionally, working conditions involving heavy metals or toxic fumes may increase susceptibility to thyroid cancer. However, the highest risk occurs when multiple factors combine—such as genetic predisposition, hormonal imbalances, and environmental exposure.

Types of thyroid cancer

Thyroid cancer can develop from various cell types. Malignant tumors are classified as either epithelial (capable of penetrating the gland’s outer membrane) or non-epithelial (remaining within the thyroid tissue). The most common epithelial thyroid cancers include:

Papillary carcinoma

This tumor resembles a capsule from which multiple papillary structures extend. It is highly differentiated, meaning it grows slowly and remains confined to the thyroid for an extended period. Women between 30 and 50 years old are most affected, while men are diagnosed with this cancer three times less frequently.

Follicular cancer

This form originates in thyroid follicles and consists of vesicle-like structures. While still classified as differentiated, it is more aggressive than papillary carcinoma. In about one-third of cases, the tumor does not metastasize, but in most instances, malignant cells gradually invade blood vessels, lymph nodes, bones, and lungs. Recovery rates are higher in patients under 50, while older individuals are more likely to develop distant metastases, lowering survival chances.

Medullary type

This cancer arises from parafollicular cells and has the ability to penetrate the thyroid membrane, affecting nearby muscles and the trachea. Unlike other types, medullary cancer occurs at similar rates in both men and women and typically develops after age 45. It is fast-progressing compared to differentiated thyroid cancers.

Anaplastic type

Originating from B cells, this tumor is undifferentiated and highly aggressive. It leads to a rapid increase in atypical cells, which lose their original function entirely. Anaplastic thyroid cancer has the worst prognosis, as it spreads quickly throughout the body.

Prevalence of types

• Papillary carcinoma: 70% of cases
• Papillary-follicular carcinoma: 20%
• Medullary carcinoma: 5–8%
• Anaplastic carcinoma: 2%

In about 20% of cases, thyroid cancer develops from pre-existing benign conditions such as thyroiditis and nodular goiter. Additionally, secondary thyroid cancer can occur when malignant cells from other organs metastasize to the thyroid.

Symptoms and risk factors

In the early stages, disease often lacks noticeable symptoms, making diagnosis challenging. Many oncologists believe that the disease initially develops without distinct warning signs.

Common symptoms

Some symptoms of thyroid cancer are non-specific, meaning they may also occur in other conditions. However, the following signs should not be ignored, as they may indicate malignancy:

• A palpable lump or nodule in the neck, either movable or attached to the skin (growth rate varies)
• Swollen lymph nodes in the lower neck, larynx, or trachea
• Discomfort or pain in the neck and behind the ears, occurring when the tumor invades adjacent tissues or compresses nerve fibers
• Persistent low-grade fever, despite the absence of infections or inflammatory diseases
• Hoarseness, chronic cough, and difficulty swallowing
• Stridor (wheezing) and breathing difficulties, especially after light physical exertion
• Dysphonia (loss of voice) due to tumor pressure on the vagus nerve’s laryngeal branch
• Visible vascular changes in the neck, caused by tumor compression of blood vessels

When patients present with these symptoms, doctors often suspect thyroid cancer. However, it’s important to note that only 1 in 20 thyroid nodules is malignant.

Symptoms on latent stage

In the early stages, thyroid cancer progresses in a latent (hidden) form. It is useful to understand the symptoms of thyroid cancer that endocrinologists may detect during patient examinations.

Symptoms of papillary thyroid cancer

• The initial nodular formation appears on one side of the thyroid gland. It has a rounded shape with microscopic, non-palpable protrusions resembling papillae. The formation may be mobile or fixed, and in most cases, there is no discomfort or pain.
• Ultrasound can detect tumor infiltration into the thyroid capsule and surrounding tissues.
• The node enlarges slowly. Its diameter often does not exceed 10 microns but can reach 40 microns or more.
• Enlargement of cervical lymph nodes due to the tumor, with the affected nodes being relatively soft.
• If one thyroid lobe is affected, the opposite lobe is often involved as well.
• Blood tests reveal elevated levels of the tumor marker thyroglobulin.
• Serum levels of carcinoembryonic antigen (CEA) are elevated.
• In most cases, thyroid function remains unaffected.

To confirm a diagnosis, symptoms alone are not sufficient. Immunochemical blood tests, fine-needle aspiration biopsy, and histological analysis of the biopsy sample are necessary.

Symptoms of follicular thyroid cancer

• The thyroid gland is significantly enlarged, with diffuse growth.
• The gland tissues undergo sclerosis, and calcified lipid-protein formations (psammoma bodies) may appear.
• A solid tumor (compact mass) is present, either rounded or arranged in trabecular (cord-like) structures.
• The tumor consists of atypical A-cells (follicular cells) containing thyroid colloid.
• In most cases, the tumor is encapsulated, meaning it has a protective outer layer.
• Extrathyroid invasion is observed, meaning tumor cells spread into surrounding soft tissues and blood vessels.
• Cervical lymph nodes become hypertrophied (enlarged).
• Blood tests show increased levels of thyroglobulin and CEA.
• Thyroid dysfunction manifests as hypothyroidism, characterized by reduced thyroid hormone levels.

As the disease progresses, more noticeable symptoms appear, including pain in the tumor area, persistent coughing, hoarseness, fatigue, excessive sweating (hyperhidrosis), and unexplained weight loss.

Symptoms of medullary thyroid cancer

• A solitary tumor (single node) develops, affecting the gland’s parenchyma and leading to fibrosis.
• The tumor originates from parafollicular C-cells, which produce the hormone calcitonin.
• Blood serum shows a significant increase in CEA levels.
• Calcitonin levels in the blood exceed 100 pg/mL.
• Amyloid deposits (glycoprotein compounds synthesized by malignant cells) are present in glandular tissue.
• High parathyroid hormone levels are observed when metastases affect the parathyroid glands.

The most critical diagnostic marker for medullary thyroid cancer is elevated calcitonin secretion. Excess calcitonin leads to symptoms such as muscle weakness, high blood pressure, diarrhea, a sensation of heat, and flushing of the skin.

According to oncologists specializing in endocrinology, medullary thyroid cancer progresses more rapidly than other types, spreading to cervical lymph nodes, the trachea, nearby muscles, the lungs, skeletal bones, and the liver. Distant metastases often affect the liver first.

Symptoms of recurrent thyroid cancer

Clear signs of thyroid cancer recurrence—whether due to malignant transformation of residual tissue after surgery or involvement of regional lymph nodes—are typically detected through routine ultrasound scans and blood tests.

Indicators of thyroid cancer recurrence include:

• Presence of calcitonin in the blood.
• Elevated thyroglobulin levels in the blood.
• Increased blood levels of epidermal growth factor (EGF), which stimulates cell proliferation.

To detect cancer recurrence after treatment for papillary or follicular carcinoma, patients undergo scintigraphy with radioactive iodine isotopes. Malignant cells absorb iodine, allowing visualization on a tomographic scan.

As you can see, thyroid cancer presents with a wide range of symptoms. This is why it is essential to pay attention to even the slightest health changes that may be linked to thyroid function. Early diagnosis significantly improves treatment outcomes, and thyroid cancer is no exception. The key is to prevent the disease from progressing to a stage where symptoms become severe and unmistakable.

Progressive symptoms

As the cancer advances, the symptoms become more noticeable and may include:

• Swelling or enlargement in the neck – The thyroid gland may become visibly larger, causing asymmetry in the neck.
• Pain in the neck or throat – Some women experience persistent pain that can radiate to the jaw or ears.
• Shortness of breath – A growing tumor may press against the windpipe, making it harder to breathe, especially when lying down.
• Difficulty speaking – If the cancer spreads to the nerves that control the vocal cords, it can lead to voice changes or even loss of voice.
• Enlarged lymph nodes – Swollen lymph nodes in the neck that do not decrease in size over time could indicate cancerous spread.

Metastatic symptoms: when cancer spreads

In advanced stages, thyroid cancer can spread (metastasize) beyond the thyroid gland to other parts of the body, leading to additional symptoms such as:

• Unexplained weight loss – A sudden decrease in weight without changes in diet or exercise.
• Chronic fatigue and weakness – A persistent feeling of exhaustion that does not improve with rest.
• Bone pain – If cancer spreads to the bones, it can cause persistent pain and increase the risk of fractures.
• Breathing difficulties and chest pain – If the lungs are affected, it may result in shortness of breath and chest discomfort.

Diagnostic

A key challenge with thyroid cancer is the high rate of diagnostic errors. This occurs because, in the early stages, the disease lacks pronounced symptoms, particularly in women.

Diagnosis becomes even more difficult when thyroid conditions such as goiter or thyroiditis are present. In these cases, doctors may focus only on the existing thyroid disorder and overlook potential signs of cancer.

However, even tumors smaller than one centimeter can be easily detected using ultrasound.

Warning signs that should prompt an ultrasound examination

• A sensation that the collar of clothing has become tighter.
• The feeling of a lump in the throat.
• Discomfort or difficulty when swallowing food.
• A feeling of pressure in the neck.
• Changes in voice tone.
• Shortness of breath, especially when moving the neck.

If a tumor is detected, a fine-needle aspiration biopsy is performed. A small tissue sample is extracted from the thyroid gland using a needle and syringe. Laboratory analysis then determines whether the tumor is benign or malignant.

Symptoms in men

The symptoms of thyroid cancer in men are similar to those in women. The disease presents with only a few signs, making it difficult to diagnose.

In the early stages, symptoms may include:

• Discomfort when swallowing.
• A choking sensation.
• Persistent cough.
• Hoarseness of voice.

Not all patients recognize these as signs of carcinoma. As the disease progresses, the neck may appear enlarged and immobile due to gland enlargement. In some cases, it is possible to palpate firm nodules.

Once metastases begin to spread, lymph nodes enlarge, and pain or dysfunction may develop in the affected organs.

Symptoms of thyroid cancer in women

Thyroid cancer is often referred to as a “silent” disease due to its subtle onset and lack of pronounced symptoms in its early stages. In women, the condition can be particularly challenging to detect, as many of its initial signs may be mistaken for hormonal fluctuations, stress-related issues, or benign thyroid disorders such as goiter or thyroiditis. However, recognizing the symptoms early can be crucial for timely diagnosis and successful treatment.

Early symptoms

In the beginning, thyroid cancer may not cause any noticeable discomfort. Many women may not realize that anything is wrong, as symptoms often develop gradually. The earliest signs may include:

• A small, painless lump or nodule in the neck – This is often the first noticeable symptom. While many thyroid nodules are benign, any persistent lump should be evaluated.
• Mild discomfort or tightness in the throat – Some women report a strange sensation in the throat, as if something is pressing on it.
• Difficulty swallowing (dysphagia) – As the tumor grows, it can interfere with normal swallowing, leading to discomfort when eating or drinking.
• Changes in voice – A deeper or hoarse voice that does not improve over time may indicate that the tumor is affecting the vocal cords.
• Persistent cough – A chronic, unexplained cough that is not linked to a cold or infection can be an early warning sign.

Why women need to be extra vigilant

Thyroid cancer is significantly more common in women than in men, with women being diagnosed three to four times more often. This higher prevalence may be linked to hormonal influences, particularly fluctuations in estrogen levels. Additionally, because women often experience benign thyroid conditions, cancer symptoms may be overlooked or misattributed to other thyroid disorders.

It is essential for women to monitor any unusual changes in their neck, throat, or overall well-being. Routine thyroid check-ups and ultrasounds can help detect abnormalities early, even before symptoms become obvious.

When to see a doctor?

Any woman experiencing persistent symptoms such as a lump in the neck, voice changes, difficulty swallowing, or unexplained weight loss should seek medical attention promptly. Early detection is key to successful treatment, and a simple ultrasound or biopsy can provide clarity on whether a thyroid nodule is benign or malignant.

Materials and publications:

• https://www.cancerresearchuk.org/about-cancer/thyroid-cancer/symptoms
• https://www.aurorahealthcare.org/services/cancer/thyroid-cancer/papillary-thyroid-cancer-symptoms-treatment
• https://www.cancer.org/cancer/types/thyroid-cancer/detection-diagnosis-staging/signs-symptoms.html
• https://columbiasurgery.org/conditions-and-treatments/papillary-thyroid-cancer
• https://www.macmillan.org.uk/cancer-information-and-support/thyroid-cancer
• https://www.cityofhope.org/clinical-program/thyroid-cancer/types/papillary
• https://www.cancercenter.com/cancer-types/thyroid-cancer/symptoms
• https://www.macmillan.org.uk/cancer-information-and-support/thyroid-cancer/papillary-follicular