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Cardiac Effects and Risks Among Thyroid Cancer Patients

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Cardiac Effects and Risks Among Thyroid Cancer Patients

There are various types of thyroid cancer. They may not show initial symptoms and grow gradually. Other types develop aggressively and may cause swelling and pain in the neck.

Doctors treat this disease depending on the stage and type of cancer. However, certain complications arise due to these cancer treatments.

One of the thyroid cancer complications is cardiovascular disease(1). These patients should also consider alternative treatments for these cardiovascular comorbidities.

Thyroid problems may be determined through the following symptoms(2):

  • Difficulty swallowing
  • Swollen lymph nodes
  • A noticeable lump in the neck
  • Pain in the throat and neck
  • Voice changes

Women are more prone to developing cancer of the thyroid than men(3). However, there are other factors to consider in evaluating the risk of thyroid cancer aside from gender.

Genetic syndromes, like endocrine neoplasia, familial medullary thyroid cancer, familial adenomatous polyposis, and Cowden’s syndrome, may increase the risk of cancer in the thyroid(4).

Additionally, excessive radiation exposure due to radiation therapy and treatments may increase the possibility of developing thyroid problems(5).

Risk Factors of Cardiac Complications

Thyroid hormone deficiency (hypothyroidism) may result in high blood pressure and reduce the elasticity of the arteries. It can also slow up the heart rate and escalate a person’s cholesterol levels(6).

Contrastingly, the profusion of these thyroid cells (hyperthyroidism) may trigger quicker, harder, and irregular heartbeats(7).

These abnormal mutations of the thyroid may cause rapid development and multiplication of cells. This occurrence may induce tumor growth and may lead to cancer of the thyroid(8).

Several factors may contribute to the correlation between cardiovascular diseases and thyroid cancers.

Thyroid cancer survivors are susceptible to multiple cardiovascular complications. The most common causes of these conditions are cancer treatments and diagnoses(9).

1. Thyroidectomy

This thyroid cancer treatment is done when cancer has increasingly developed in the neck and the thyroid gland’s lymph nodes.

A study on the risks and complications of thyroid and parathyroid surgery indicated that thyroid cancer patients have additional risk variables, such as central neck dissection and coronary artery disease(10).

During thyroidectomy, the thyroid gland is removed to prevent cancer from spreading to the other parts of the body.

This procedure may slow down thyroid cancer recurrence. However, it may be associated with a higher risk of cardiovascular complications(11).

Other risks of this procedure include(12):

  • Bleeding
  • Infection
  • Parathyroid damage
  • Low calcium levels
  • Damage in the vocal cords
  • Difficulty breathing

2. Radioactive Iodine

Thyroid cancer treatment using radioactive iodine has been associated with cardiovascular complications.

A scientific comparison of the risks of thyroidectomy and the use of radioactive iodine was made to determine cardiovascular disease risks among patients.

The study stated that individuals with hyperthyroidism that have been treated with radioactive iodine have a higher cardiovascular risk than those who underwent thyroidectomy(13).

Additionally, radioactive iodine increases the occurrence of small artery stiffness and large artery impairment. Results showed that this treatment has also increased the possibility of cardiac arrhythmia and hypertension(14).

Radioactive iodine subdues the cancerous thyroid and normal thyroid tissues by binding to and destroying them.

Prolonged exposure to thyroxine may increase the risk of cardiovascular comorbidities(15).

Other adverse effects of radioactive iodine are(16):

  • Altered sense of smell or taste
  • Mouth pain
  • Fatigue
  • Dry mouth
  • Eye inflammation

3. Levothyroxine Suppression

High doses of levothyroxine are utilized to replace the thyroid hormone after surgery or radioactive iodine treatment. Hyperthyroidism suppresses the thyroid-stimulating hormone.

This hormone instigates the thyroid gland to produce thyroxine and triiodothyronine, responsible for the body’s metabolism.

The suppression of thyroid-stimulating hormones may prevent cancer from reoccurring in the thyroid(17).

Still, high doses of levothyroxine are linked to the elevated risk of cardiovascular diseases and rapid, irregular heart rate (atrial fibrillation)(18).

One side effect of levothyroxine is it may also potentially stimulate the residual cancer cells to grow(19).

Management of Cardiac Risks

Thyroid cancer patients must consider the risks of the treatments before undergoing them to avoid further complications.

These complications may cause mental and physical distress among patients. However, healthcare specialists must encourage patients to manage these risks effectively.

Thyroid cancer patients should have regular doctor’s appointments that include the following tests:

  • Heart rhythm assessment
  • Blood pressure monitoring
  • Physical examination

Observe if there are any symptoms of thyroid problems. Patients should also take note of any signs of hypertension or heart diseases.

It is best to ask physicians for medications that may manage blood pressure, regulate heart rhythm, and lessen the risk of blood clots.

Risk calculators are available to evaluate a person’s susceptibility to developing cardiovascular diseases.

These tools assess the following patient details:

  • Gender
  • Age
  • Weight
  • Height
  • Race

Other useful details include questions about former surgeries or procedures done, a family history of diseases, cholesterol levels, blood pressure, and medications.

Diagnosis of Thyroid Cancer

One of the gold standards for the assessment of thyroid cancer is magnetic resonance imaging (MRI)(20). However, there are a series of initial treatments to check a person for cancer.

Physical Tests

Patients are examined for physical changes and indications of thyroid abnormalities. Doctors check the patient’s neck and thyroid nodules for any lumps, swelling, or growth.

Genetic Testing

The doctor will ask for a family history of thyroid or endocrine cancers. In some instances, there are inherited medical conditions that may increase the risk of thyroid cancer.

Once the doctor finds that the patient has a high risk of developing cancer, they may suggest possible management and treatment plans

Blood Tests

Testing the blood helps indicate the proper function of the thyroid gland. This test measures the level of thyroid-stimulating hormones released by the pituitary gland.

Thyroid Tissue Sample

There are cases when doctors conduct fine-needle aspiration biopsy to remove samples of thyroid tissues from unusual nodules.

A biopsy is often accompanied by ultrasound imaging to accurately guide the fine needle to the thyroid nodules. These samples are analyzed for cancer cells.

Common Types of Thyroid Cancer

Papillary Thyroid Cancer

This thyroid cancer originates from the follicular cells, which release thyroid hormones. Papillary thyroid cancer is the predominant type of thyroid cancer(21). It primarily affects people from 30 to 50 years old.

Medullary Thyroid Cancer

Medullary thyroid cancer starts from the C cells that produce the calcitonin hormone. This type of thyroid cancer is diagnosed by looking at the calcitonin levels.


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1. Clinical Thyroidology for the Public, (n.d.), THYROID CANCER Cardiovascular risk and risk of death in patients with a history of thyroid cancer, retrievd from
2. The Mayo Clinic, (n.d.), Thyroid Cancer, Causes, retrieved from
3. Ibid.
4. Ibid.
5. Ibid.
6. Harvard Health Publishing, (Semptember 2019), Thyroid hormone: How it affects your heart, retrieved from
7. Ibid,
8. The Mayo Clinic, Op. Cit.
9. Park, J., Balckburn, B. E., Ganz, P. A., et., al., (May 2018), Risk Factors for Cardiovascular Disease Among Thyroid Cancer Survivors: Findings From the Utah Cancer Survivors Study, retrieved from
10. Meltzer, C., Klau, M., et. al., (May 2016), Risk of Complications after Thyroidectomy and Parathyroidectomy: A Case Series with Planned Chart Review, retrieved from
11. Park, J., et. al., Op. Cit.
12. The Mayo Clinic, Op. Cit.
13. Ryödi E, Metso S, Huhtala H, Välimäki M, Auvinen A, Jaatinen P. Cardiovascular Morbidity and Mortality After Treatment of Hyperthyroidism with Either Radioactive Iodine or Thyroidectomy. Thyroid. 2018 Sep;28(9):1111-1120. doi: 10.1089/thy.2017.0461. Epub 2018 Jul 23. Erratum in: Thyroid. 2018 Dec;28(12):1731. Essi, Ryödi [corrected to Ryödi, Essi]; Saara, Metso [corrected to Metso, Saara]; Heini, Huhtala [corrected to Huhtala, Heini]; Matti, Välimäki [corrected to Välimäki, Matti]; Anssi, Auvinen [corrected to Auvinen, Anssi]; Pia, Jaatinen [corrected to Jaatin. PMID: 29882483.
14. Park, J., et. al., Op. Cit.
15. Ibid.
16. The Mayo Clinic, Op. Cit.
17. Thyroid Cancer Survivors’ Association, (n.d.), Thyroid Stimulating Hormone (TSH) Suppression, retrieved from
18. Cappola, A. R., Desal, A. S., et. al., (May 2019), Thyroid and Cardiovascular Disease, retrieved from
19. The Mayo Clinic, Op. Cit.
20. Bruixola G, Segura A, Caballero J, Andrés A, Reche E, Escoín C, Díaz-Beveridge R. Heart failure as first sign of development of cardiac metastases in a patient with diagnosis of papillary thyroid carcinoma on treatment with tyrosine-kinase inhibitors: differential diagnoses and clinical management. Case Rep Oncol. 2014 Aug 20;7(2):591-9. doi: 10.1159/000366192. PMID: 25298765; PMCID: PMC4178319.
21. The Mayo Clinic, Op. Cit.

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