Thyroid Disorders & Thyroid Cancers
Thyroid disorders are very common in the United States; over 20 million people are under treatment. An estimated 2 million others have an undiagnosed thyroid problem. Women are especially vulnerable, and if they have a personal or family history of insulin-dependent diabetes mellitus, rheumatoid arthritis, pernicious anemia, prematurely graying hair, vitiligo or other autoimmune disease, there is a 25% greater risk of thyroid malfunction.
Anatomy & Function of the Thyroid gland:
- Butterfly-shaped gland consisting of two lobes and connected by an isthmus
- Located in front of the neck, along the trachea
- Produces 2 hormones:
- Thyroid hormones - regulates the body’s metabolism, heart rate, blood pressure, body temperature, and weight
- Calcitonin - involved in calcium regulation
- Behind the thyroid gland are the 4 parathyroid glands, which produce parathyroid hormone are involved in calcium regulation
Thyroid and parathyroid |
Conditions
- Thyroid Disorders
- Hyperthyroidism
- Hypothyroidism
- Graves disease
- Hashimoto's Hypothyroidism
- Thyroid Cancers
- Multi-nodular goiter
- Follicular cancer
- Medullary cancer
- Anaplastic
- Papillary cancer
|
Treatments
- Medication Treatment
- Radioactive iodine
- Hemi and total thyroidectomy
|
Discharge Instructions
 Discharge Thyroidectomy |
Thyroid Disorders:
Hyperthyroidism, or overactive thyroid, is a disease that often presents with nervousness, palpitations, heat intolerance and weight loss. It is estimated that there are approximately 1 million patients in the United States suffering from Graves' disease, the most common form of hyperthyroidism. Fifteen percent of these cases are seen in the general population over the age of sixty.
Hypothyroidism, or underactive thyroid, is due to an insufficient amount of thyroid hormone. Patients with Hashimoto's thyroiditis, the most common cause of an underactive thyroid, experience fatigue, weight gain, difficulty concentrating and depression. At least 10% of women in the United States will have signs of a failing thyroid by the age of fifty. At age 60, 17% of women and 8% of men have signs of a failing thyroid.
Hypoparathyroidism, or low parathyroid activity, may occur through physician or treatment-induced injury, or, rarely, as an autoimmune-related condition.
Women and thyroid disease
Thyroid disease is up to eight times more common in women than in men. At least 8% of women will have thyroid dysfunction following pregnancy. Thyroid dysfunction in the post partum period may play a role in some cases of postpartum depression. Additionally, thyroid disease may contribute to infertility if it is not recognized and treated.
Thyroid nodules
Approximately 5% of the population worldwide have goiter or benign thyroid enlargement. Patients who have had x-ray treatment to the head and neck regions for conditions such as acne, thymus enlargement, recurrent tonsillitis, chronic ear infections and birthmarks are at a greater risk for thyroid nodules and thyroid cancer. Most thyroid nodules are harmless, but some may produce excess thyroid hormone, and others may be cancerous. There are over 30,000 new cases of thyroid cancer each year and the incidence of thyroid cancer is increasing faster than any other cancer in the United States. Surgery is usually curative.
Neonatal thyroid disease
One in every 5,000 babies born in the United States suffers from thyroid disease. Most of these patients are detected in infancy through a routine blood screening. Patients who are not treated with thyroid hormone within three months may develop complications such as mental deficiency, inadequate growth, or abnormal development. Affected children must continue thyroid treatment and examinations throughout their life.
Hypothyroidism treatment:
- thyroid hormone replacement pills
Hyperthyroidism treatment:
- medication to block the effects of excessive production of thyroid hormone
- radioactive iodine to destroy the thyroid gland
- surgical removal of the thyroid gland
Goiters (lumps):
If you experience this condition, your doctor will propose a treatment plan based on the examination and your test results. He may recommend:
- a fine needle aspiration biopsy—a safe, relatively painless procedure. With this procedure, a hypodermic needle is passed into the lump, often after administration of local anesthesia into the skin, and tissue fluid samples containing cells are taken. Often several passes with the needle are required. Sometimes ultrasound may be used to guide the needle into the nodule. There is little pain afterward and very few complications from the procedure occur. This test gives the doctor more information on the nature of the lump in your thyroid gland and specifically may help to differentiate a benign from a malignant thyroid mass.
thyroid surgery—may be required when:
- the fine needle aspiration is reported as suspicious for or suggestive of cancer
- the trachea (windpipe) or esophagus are compressed because both lobes are very large
Historically, some malignant thyroid nodules have shown a reduction in size with the administration of thyroid hormone. However, this treatment, known as medical “suppression” therapy, has proven to be an unreliable treatment method.
What is thyroid surgery?
Thyroid surgery is an operation to remove part or all of the thyroid gland. It is performed in the hospital, and general anesthesia is usually required. Typically the operation removes the lobe of the thyroid gland containing the lump and possibly the isthmus. A frozen section (an immediate microscopic reading) may or may not be used to determine if the rest of the thyroid gland should be removed.
Sometimes, based on the result of the frozen section, the surgeon may decide not to remove any additional thyroid tissue, or proceed to remove the entire thyroid gland, and/or other tissue in the neck. This is a decision usually made in the operating room by the surgeon, based on findings at the time of surgery. Your surgeon will discuss these options with you preoperatively.
There may be times when the definite microscopic answer cannot be determined until several days after surgery. If a malignancy is identified in this way, your surgeon may recommend that the remaining lobe of the thyroid be removed at a second procedure. If you have specific questions about thyroid surgery, ask your otolaryngologist and he or she will answer them in detail.
What happens after thyroid surgery?
During the first 24 hours:
After surgery, you may have a drain (a tiny piece of plastic tubing), which prevents fluid and blood from building up in the wound. This is removed after the fluid accumulation has stabilized, usually within 24 hours after surgery. Most patients are discharged later the same day or the day following the procedure.
Complications are rare but may include:
- bleeding
- a hoarse voice
- difficulty swallowing
- numbness of the skin on the neck
- vocal cord paralysis
- low blood calcium
At home:
Following the procedure, if it is determined that you need to take any medication, your surgeon will discuss this with you, prior to your discharge.
Medications may include:
- thyroid hormone replacement
- calcium and/or vitamin D replacement
Some symptoms may not become evident for two or three days after surgery. If you experience any of the following, call your surgeon:
- numbness and tingling around the lips and hands
- increasing pain
- fever
- swelling
- wound discharge
If a malignancy is identified, thyroid replacement medication may be withheld for several weeks. This allows a radioactive scan to better detect any remaining microscopic thyroid tissue, or spread of malignant cells to lymph nodes or other sites in the body.
How is a diagnosis made?
The diagnosis of a thyroid function abnormality or a thyroid mass is made by taking a medical history and a physical examination. Specifically, your doctor will examine your neck and ask you to lift up your chin to make your thyroid gland more prominent. You may be asked to swallow during the examination, which helps to feel the thyroid and any mass in it. Other tests your doctor may order include:
- evaluation of the larynx/vocal cords with a mirror or a fiberoptic telescope
- an ultrasound examination of your neck and thyroid
- blood tests of thyroid function
- a radioactive thyroid scan
- a fine needle aspiration biopsy
- a chest X-ray
- a CT or MRI scan
Thyroid Cancer:
- The most common endocrine cancer and can occur in all age groups
- The American Cancer Society estimates that in the US in 2009 there will about 37,200 new cases (27,200 in women and 10,000 in men) and 1,630 deaths
- There are four main types of thyroid cancer and are based on how the cancer cells look under a microscope:
- Papillary
- Follicular
- Medullary
- Anaplastic
- (each described in detail below)
Risk factors:
- Diet low in iodine
- Radiation exposure (ie) history of head or neck radiation treatment in childhood, radioactive fallout (ie nuclear plant accidents, atomic weapons testing)
- Hereditary factors
- Personal history of goiter or benign thyroid nodules
- Gender (females greater than males)
- Age, most commonly in the 20-60 year old age group
Signs & Symptoms:
- In the early stages, symptoms are often absent
- As the cancer grows, signs and symptoms may include:
- Nodule, lump, or swelling in the neck
- Hoarseness/voice changes
- Swollen lymph nodes in the neck
- Difficulty in swallowing or breathing
- Pain in neck or throat that does not go away
- Important to note that many of these signs or symptoms can be caused by other non-cancerous conditions
- Thyroid nodules are common and usually benign
Diagnosis:
- Physical exam: feeling the thyroid for size and nodules, checking the neck for enlarged lymph nodes
Blood tests:
- TSH (thyroid stimulating hormone) levels in the blood: too much or too little TSH means the thyroid is not working properly
- Calcitonin: if MTC is suspected. Also useful to look for recurrence of MTC after treatment
- Thyroglobulin: thyroid hormone precursor protein made by the thyroid gland. Not useful in diagnosing thyroid cancer but can be useful to look for recurrence after treatment. Levels should be low after treatment. If the level is high, it may mean the thyroid cancer is still present or if it is rising, the cancer may be recurring.
Ultrasound: uses sound waves instead of radiation to create images. Useful in determining if a thyroid nodule is solid or fluid-filled. It can also show thyroid nodules too small to be felt.
Radioiodine scan: radioactive iodine is swallowed or injected and absorbed by the thyroid gland. In high doses, it is used as treatment to destroy the thyroid. In smaller does, it can be used as a scan to see where the radioactivity has gone. A camera is used to measure the amount of radiation. Abnormal areas in the gland where there is less radioactivity absorbed than in surrounding areas are called “cold” nodules; where there is more radiation uptake, they are called “hot” nodules. Hot nodules are usually not cancerous. Cold nodules may be benign or cancerous.
Biopsy: the only definitive way of diagnosing thyroid cancer. Tissue samples from the thyroid nodule are sent to a pathologist to look for cancer cells under a microscope
- Fine needle aspiration (FNA): may be done in the doctor’s office. A thin needle is used to take out tissue from the nodule. Ultrasound may be used to help guide needle placement.
- Surgical biopsy: performed in the operating room with the patient under general anesthesia. Done if the FNA result is inconclusive (cannot tell if the nodule is benign or malignant). The whole nodule or lobe may be surgically removed.
Types of Cancer
Papillary Thyroid Carcinoma (PTC):
- The most common thyroid cancer in the US, representing 75-80%
- Peak onset occurs in those between 30-50 years old
- More common in women than men (3:1)
- Originates from follicular cells, is slow growing, with cells arranged in projections or papillae
- Can be purely papillary or mixed with follicular carcinoma
- Spread to cervical lymph nodes in greater than 50% of cases, causing a higher recurrence rate but not a higher mortality rate
- Distant spread to the lungs or bones is uncommon but can occur in the late stages
- Other variants of PTC include tall-cell and columnar cell, which are more aggressive
Follicular Thyroid Carcinoma (FTC):
- Makes up about 15% of all thyroid cancers (the second most common type)
- Peak onset occurs in those between 40-60 years old
- More common in women than men (3:1)
Originates from follicular cells, is slow growing, with cells arranged in small follicles
- More aggressive than PTC
- Rarely associated with radiation exposure
- Spread to lymph nodes is uncommon, occurring in about 10% of cases
- Commonly invades into the vascular structures within the gland
- Distant spread to the lungs or bones is uncommon
- Variant of FTC is Hürthle cell carcinoma, which has higher risk of metastasis and recurrence
Medullary Thyroid Carcinoma (MTC):
- Represents about 5% of thyroid cancers
- More common in females than males (except in inherited cases)
- Arises from C cells, which produce the hormone calcitonin
- MTC can also secrete histaminase, prostaglandins, serotonin, and other peptides
- Spread to lymph nodes in the neck can occur early
- Distant spread via blood to the liver, lungs, bone, brain, and adrenal medulla can occur late
- More aggressive than PTC and FTC
- Occurs in different clinical settings:
- Sporadic: Accounts for 75-80% of MTCs. Peak onset is 40-60 years old, with females affected more than males (3:2). Typically presents unilaterally as a solitary neck nodule and without other endocrinopathies (has no association with other diseases in other endocrine glands).
- MEN (Multiple Endocrine Neoplasia) 2a Syndrome (Sipple Syndrome): Is a group of endocrine disorders, consisting of MTC, hyperparathyroidism, and bilateral pheochromocytoma. It is inherited in an autosomal dominant fashion and associated with a mutation in the RET proto-oncogene on chromosome 10. Males and females are affected equally with peak incidence in the 30s.
- MEN 2b Syndrome: Is a group of endocrine disorders consisting of MTC, bilateral pheochromocytoma, and multiple mucosal neuromas. Patients also present with a marfanoid habitus. It is the more aggressive form of MTC. It is also inherited in an autosomal dominant fashion involving the RET gene with males and females affected equally. MTC tends to occur at an earlier age, grows and spreads faster than those with MEN 2a.
- Familial: Is inherited without associated endocrinopathies and is the least aggressive of MTCs. Peak onset is 40-50 years old.
Anaplastic (undifferentiated) Thyroid Carcinoma:
- Least common of thyroid cancers (~1%) but is the most aggressive form with a high mortality rate
- Often presents in older patients 65 years and older
- More common in males than females (2:1)
- Can occur in those with a long-standing goiter with sudden growth or those with a history of radiation exposure
- Growth is rapid, which can cause airway obstruction
- Diffuse infiltration into the neck
- Spread to lymph nodes in the neck is common (>90% of cases)
- Distant spread to the lungs and/or bones is also common
- Prognosis is very poor due to its aggressiveness and poor response to treatment
Prognosis of PTC and FTC:
- These are referred to as the well-differentiated thyroid cancers and in general have a very good prognosis with a >90% cure rate if diagnosed at an early stage and is appropriately treated
- Multiple factors determine the prognosis, such as age, sex, and the characteristics of the cancer:
- Favorable factors:
- Age less than 45
- Tumor size ≤ 4 cm
- PTC with well-defined capsule
- FTC with minimal invasion of the capsule
- Absence of local invasion
- Absence of blood vessel invasion
- Absence of lymph node metastasis
- Absence of distant metastasis
- Single thyroid cancer
- Female gender
- Presence of Hashimoto’s thyroiditis
- Less Favorable factors:
- Age 45 or older
- PTC with anaplastic transformation
- Poorly differentiated follicular cancer
- Tall-cell, columnar, or diffuse sclerosing variants of papillary cancer
- Hurthle cell type
- Distant metastasis
- Local invasion
- Blood vessel invasion
- Multiple papillary cancers
- Insufficient surgery
- Delay in therapy
- No levothyroxine therapy
- No radioactive iodine treatment (in some patients)
- Male gender
- Presence of Graves’ disease
5 Year Relative Survival Rate:
| Stage |
Papillary |
Follicular |
Medullary |
Anaplastic |
| I |
100% |
100% |
100% |
- |
| II |
100% |
100% |
97% |
- |
| III |
96% |
79% |
78% |
- |
| IV |
45% |
47% |
24% |
9% |
Anaplastic (undifferentiated) carcinomas are all considered stage IV
Staging:
- Size, metastasis (spread), and if metastasis, to where (most often to LNs, bone, lung)
- US, CT, MRI, CXR, whole body scan to see if the cancer has spread to LNs or other areas of the body
Uses the TNM system:
- T: Tumor size
- N: extent of spread to regional lymph nodes
- M: Metastasis (spread) to other areas of the body
| |
Papillary and Follicular Thyroid Carcinoma |
Medullary Thyroid Carcinoma |
| Patients <45 yrs |
|
|
| Stage I (any T, any N, M0) |
Tumor can be any size
Spread to nearby lymph nodes may or may not be present
No spread to distant sites |
Staging for patient of any age with MTC is the same as for PTC or FTC in people older than age 45 |
| Stage II (any T, any N, M1) |
Tumor can be any size
Spread to nearby lymph nodes may or may not be present
Spread to distant sites present |
|
| Patients ≥ 45 yrs |
|
|
| Stage I (T1, N0, M0) |
Tumor <2 cm across
No spread to nearby lymph nodes or distant sites |
|
| Stage II (T2, N0, M0) |
Tumor 2-4 cm across
No spread to nearby lymph nodes or distant sites |
|
Stage III (T3, N0, M0)
or- (T1-3, N1a, M0) |
Tumor >4 cm or has grown slightly outside the thyroid
No spread to nearby lymph nodes or distant sites
- or -
Tumor is any size
Spread to cervical lymph nodes
No distant spread |
|
Stage IVA (T4a, N0-1a, M0)
- or -
(T1-4, N1b, M0) |
Tumor is any size and has grown beyond the thyroid gland to invade nearby tissues of the neck
Spread to lymph nodes around the thyroid (cervical) may or may not be present
No distant spread
- or -
Tumor is any size and may have grown beyond the thyroid gland to invade nearby tissues of the neck
Has spread to lymph nodes in the side of the neck (lateral)
or upper chest (upper mediastinal)
No distant spread |
|
| Stage IVB (T4b, any N, M0) |
Tumor is any size and has grown either back to the spine or into nearby large blood vessels
May or may not have spread to nearby lymph nodes
No distant spread |
|
| Stage IVC (any T, any N, M1) |
Tumor is any size and may or may not have grown outside the thyroid
May or may not have spread to nearby lymph nodes
Has spread to distant sites |
|
Anaplastic thyroid cancers are considered stage IV: |
| |
Anaplastic Thyroid Carcinoma |
|
| Stage IVA (T4a, any N, M0) |
Tumor is still within the thyroid and may be respectable
May or may not have spread to nearby lymph nodes
No distant spread |
|
| Stage IVB (T4b, any N, M0) |
Tumor has grown outside the thyroid and is not respectable
May or may not have spread to nearby lymph nodes
No distant spread |
|
| Stage IVC (any T, any N, M1) |
Tumor is any size and may or may not have grown outside the thyroid
May or may not have spread to nearby lymph nodes
Has spread to distant sites |
|
Treatment depends on patient age, the type and stage of the thyroid cancer:
Surgery:
- Lobectomy: lobe containing the cancer is removed, usually along with the isthmus
- Thyroidectomy: total, near-total, or subtotal
- Lymph node removal
Radioactive Iodine Therapy (131I): Thyroid gland normally takes up iodine. When 131I is taken in, it can destroy any thyroid gland not removed by surgery and any thyroid cancer cells remaining. Used for papillary or follicular thyroid cancer.
Thyroid Hormone therapy: used post-surgically to help maintain normal metabolism in the body as well as helps to stop cancer cells from growing by lowering the TSH level
External Radiation Therapy: Using an external beam for a focused delivery of radiation, it helps to destroy cancer cells or slow their rate of growth. More often used as part of the treatment for medullary and anaplastic thyroid carcinomas but also for any type that cannot be treated with surgery or 131I therapy
Chemotherapy: is a systemic therapy to destroy cancer cells
References:
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