Understanding Thyroid Dysfunction: A Look at Thyroid Illnesses and Cancers

Illustration of the thyroid
The thyroid is a butterfly-shaped gland in the base of the neck.

Located at the base of your neck, your thyroid is an important, butterfly-shaped gland that regulates many aspects of your health. When it's functioning normally, you probably don't think twice about it...but when it's not, it can lead to a number of illnesses, including cancer.

We spoke with Doctors Lukasz Czerwonka, Clinical Assistant Professor of Surgery, and Christopher Vanison, Clinical Assistant Professor of Surgery, of Stony Brook's Division of Otolaryngology–Head and Neck Surgery (ENT) to find out what you need to know about thyroid disease and available treatment options to address these illnesses. We also asked them what thyroid issues, such as some thyroid cancers, may require surgery.

What types of illnesses, injuries or dysfunctions can affect the thyroid?

VANISON: Thyroid function can be affected by autoimmune conditions, which cause the thyroid gland to function less effectively.

CZERWONKA: Thyroid dysfunction usually occurs in the form of hypofunctioning from inflammation in the thyroid, termed Hashimoto's thyroiditis. This is very common and easily treated with thyroid hormone replacement.

VANISON: There are also conditions which can make the thyroid become overactive. The most common example of this is called Grave’s disease. In this condition, the gland produces too much hormone and patients will have very different symptoms compared to those with low thyroid function.

CZERWONKA: Grave's disease can be treated with medications at first, but if it persists it usually requires a radiation pill or surgery to remove the thyroid.

VANISON: In general, hyperthyroidism is less common than hypothyroidism.

The thyroid gland can also be affected by benign or cancerous tumors. Benign masses in the thyroid gland are much more common than malignant masses, and we typically refer to these as nodules or adenomas.

CZERWONKA: Malignant [tumors] may require [surgically] removing half or the entire thyroid. Fortunately, the vast majority of thyroid cancers are very low risk.

Doctors Vanison and Czerwonka
Doctors Christopher Vanison and Lukasz Czerwonka, respectively.

VANISON: The most common [cancerous] form is called Papillary Thyroid Carcinoma. There are many variants of this type of cancer, but most of them are easily treatable and survival outcomes are excellent. In general, benign and cancerous thyroid nodules are more common in women than men.

Finally, there are also situations when the thyroid gland grows very large, either on one side or both sides. This, in general terms, is referred to as a “goiter.” This can be due to the gland itself growing or can be due to multiple nodules within the gland growing.

What are the signs/symptoms of these types of thyroid issues? How would a person know when to seek medical treatment?

VANISON: Symptoms of hypothyroidism, or underactive thyroid function, include weight gain, frequently feeling cold, thinning hair/hair loss, constipation and feeling very fatigued. Hyperthyroidism, or overactive thyroid function, typically causes patients to experience weight loss, difficulty sleeping, sweating, diarrhea, palpitations or racing heart. In cases of Grave’s disease, [it] may also cause the eyes to bulge or cause blurred vision and red, itchy eyes.

CZERWONKA: Thyroid nodules [or tumors] are usually asymptomatic but when very large can cause discomfort and difficulty with swallowing.

VANISON: Occasionally,...large [nodules] can be felt when palpating the neck and they may even be visible....as the thyroid and the nodule or mass will move up and down each time a swallow is performed.

When thyroid nodules or goiters become large enough, they can cause what we call “compressive symptoms.” Most commonly, this results in changes in swallow function, particularly with solids. A patient may notice that it is more difficult to get solids or pills down and they may occasionally have a sensation that foods are getting stuck lower in their throats. Less commonly, when the thyroid grows large enough, a patient may also notice that they cannot breathe as comfortably, typically when lying flat.

When patients have thyroid cancer, and the cancer becomes quite advanced, they may begin to experience [a] hoarse or weak voice. This is because thyroid cancers can invade and damage the nerves that make the vocal cords open and close. This is an uncommon symptom of thyroid cancer.

The thyroid gland can also be affected by benign or cancerous tumors.  Benign masses in the thyroid gland are much more common than malignant masses, and we typically refer to these as nodules or adenomas.

Can a thyroid that isn't functioning normally impact other health issues?

CZERWONKA: A thyroid that is hyperfunctioning can cause issues with your heart as it can make it race and may cause arrhythmias if severe.

VANISON: In rare cases, uncontrolled hyperthyroidism can result in life-threatening changes in heart rate and rhythm....which may necessitate medications to control heart rate.

The function of the thyroid is intimately tied in to many other functions of the body. Because the thyroid gland is very closely involved in metabolism, under- or over-activity can cause...weight gain or weight loss, respectively. In women, abnormalities in thyroid hormone function can affect one’s ability to become pregnant and also may cause changes in the menstrual cycle. Underactive thyroid can result in poorer healing after surgery or when patients have chronic wounds.

What types of surgeries are performed for thyroid issues? What is the long-term outlook for patients who have thyroid surgery and what do patients who have a total thyroidectomy need to know?

CZERWONKA: Surgery of the thyroid involves taking out half or the entire thyroid. The surgery is done while the patient is completely asleep through a small incision in a natural skin crease in the neck that heals very well and disappears in most people.

VANISON: If a patient has a large goiter causing compressive symptoms on only one side, then only that half of the thyroid needs to be removed [a hemi-thyroidectomy]. This is also sometimes performed for very small thyroid cancers called microcarcinomas. In cases of goiters affecting both sides of the thyroid, or in larger or multi-focal cancers, the entire thyroid gland is removed....[and] in patients with uncontrolled hyperthyroidism who are recommended to have surgery, a total thyroidectomy is performed.

Sometimes, when there are high-risk cancer features, or if there is evidence that thyroid cancer has spread to nearby lymph nodes, an additional procedure called a “central neck dissection” is performed.  This means that the lymph nodes surrounding the thyroid and the upper trachea are removed in addition to the thyroid gland.

For the most common types of thyroid cancer, the prognosis is excellent, with the vast majority of patients going on to live a normal life span.

CZERWONKA: The biggest risk of the surgery is damage to the nerves to the voice box which can cause hoarseness, so it is important to have a surgeon who does these operations frequently perform the surgery.

VANISON: Most patients who undergo hemi-thyroidectomy will be able to continue on without requiring thyroid hormone medication. However, up to 20% of patients who have half of their thyroid glands removed will need to take thyroid hormone medication after surgery.

All patients who undergo total thyroidectomy will need to be started on thyroid hormone replacement medication–-this is a once-daily pill that he or she will need to take for the rest of [their] lives. Sometimes, the dose of this medication will need to be changed over time in case the thyroid hormone levels are found to be too high or too low.

For people who have had thyroid surgery for cancer, there are cancer surveillance recommendations that will need to be followed. This will include periodic laboratory work and imaging of the neck and lymph nodes- –this is typically [done by] an ultrasound, but sometimes may include CT scans, PET scans or nuclear thyroid scans.

For the most common types of thyroid cancer, the prognosis is excellent, with the vast majority of patients going on to live a normal life span. A percentage of these patients may still deal with recurrence of the cancer in the lymph nodes and may require additional surgery or other treatments such as radioactive iodine treatment or formal radiation therapy. Some rarer types of thyroid cancer behave more aggressively and can be life-threatening. 

Is there anything a person can do to ensure thyroid health?

CZERWONKA: There are no commonly recommended interventions to improve thyroid health. Iodine deficiency is highly uncommon in the United States due to widespread iodine supplementation in salt. Most primary care doctors monitor thyroid function with a simple yearly lab test termed TSH (thyroid stimulating hormone). Screening for thyroid nodules is not recommended unless they can be palpated or patients are symptomatic with swallowing difficulty or voice changes.

VANISON: A certain type of thyroid cancer called medullary thyroid carcinoma can be passed on genetically to other family members in about 25% of cases. So, it is important with patients diagnosed with this type of cancer, as well as their family members, to undergo genetic testing.

Thank you Doctors Czerwonka and Vanison. We appreciate you sharing your expertise and educating our community regarding thyroid illnesses.

If you are experiencing any of the symptoms mentioned in this article, please contact your physician. Thyroid illnesses are extremely treatable, but as with most illnesses, it's best to get treatment sooner rather than later.

As a recap, here are some potential signs of hypothyroidism, hyperthyroidism or thyroid cancer:


  • Weight gain
  • Frequently feeling cold
  • Thinning hair or hair loss
  • Constipation
  • Feeling very fatigued


  • Weight loss
  • Difficulty sleeping
  • Sweating
  • Diarrhea
  • Palpitations or racing heart
  • Grave’s disease may also cause the eyes to bulge or cause blurred vision or red, itchy eyes

Nodules/Thyroid Cancer

  • Large nodules can be felt when palpating the neck
  • They may even be visible when a swallow is performed
  • Less common, a patient may also notice that they cannot breathe as comfortably, typically when lying flat
  • Hoarse or weak voice with advanced thyroid cancer

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