Thyroid Cancer
Thyroid cancer is the most common type of endocrine cancer. Although a
diagnosis of cancer is always concerning, the vast majority of thyroid
cancers are very treatable and are associated with an excellent prognosis.
There are four main types of cancer of the thyroid:
•
Papillary thyroid cancer is the most common, comprising about 80% of all thyroid cancers. It tends
to grow slowly but may spread to lymph nodes in the neck or elsewhere
in the body. With early intervention, however, papillary thyroid cancer
generally has an excellent prognosis.
•
Follicular thyroid cancers represent about 15% of all thyroid cancers. Follicular thyroid cancers
usually do not spread to the lymph nodes, however, in some cases they
can spread to other parts of the body, such as the lungs or bones.
•
Medullary thyroid cancer (MTC) represents about 3% of all thyroid cancers. There are two types
of medullary thyroid cancer: sporadic and familial. Approximately 35%
of all MTC runs in families and may be associated with other endocrine
tumors. Genetic testing (of the RET proto-oncogene) is recommended for
those newly diagnosed with MTC. For individuals with a family history,
it is helpful to determine whether there are genetic markers present.
In individuals with these genetic changes, prophylactic surgery has a
high probability of being curative.
•
Anaplastic thyroid cancer is difficult to control and treat because it is a very aggressive type
of thyroid cancer. Anaplastic thyroid cancer is quite rare, making up
less than 2% of patients with thyroid cancer.
Risk Factors and Causes of Thyroid Cancer
There are several risk factors that can increase an individual’s
chances of developing thyroid cancer, such as a family history of thyroid
cancer, gender (women have a higher incidence of thyroid cancer), age
(the majority of cases occur in individuals over age 40, although thyroid
cancer can affect all ages), and history of ionizing radiation exposure.
If you have a family history of thyroid cancer, or other risk factors,
speak with your physician about whether thyroid screening and
genetic testing may be appropriate for you.
Symptoms of Thyroid Cancer
Many individuals, especially in the early stages of thyroid cancer, do
not experience symptoms. Your physician may feel it during a routine examination
or a thyroid nodule is found during imaging studies performed for another
reason. As a cancer develops, a patient may feel a nodule (lump) in the
front of the neck or notice that one side of your neck looks different.
If the nodule is large, it may cause neck or facial pain, swollen lymph
nodes, shortness of breath, difficulty swallowing, cough unrelated to
a cold, hoarseness or difficulty speaking.
Most thyroid nodules are benign (non-cancerous), so having these symptoms
does not necessarily mean you have thyroid cancer. However, if you’re
experiencing any unusual symptoms, it’s important to speak to your
physician since early diagnosis of cancer leads to better outcomes.
Diagnosing Thyroid Cancer
Diagnosing thyroid cancer in its earliest stages can increase the probability
of your treatment being more successful. Hoag’s thyroid cancer team
is highly skilled in diagnosing and staging thyroid tumors using the latest
in state-of-the-art imaging, ultrasound-guide needle biopsy and other
specialized tests, including advanced nuclear medicine studies. Upon analysis
of test results, Hoag’s multidisciplinary thyroid cancer team develops
a personalized treatment plan that addresses all facets of care.
Blood Tests
There are several types of blood tests that may be utilized to diagnose
and monitor thyroid cancer patients during and after treatment. Tests
for thyroid management include: thyroid hormone levels, thyroid stimulating
hormone (TSH) and thyroglobulin. Other blood testing involving molecular
markers may also be used, as well as genetic testing for certain types
of thyroid cancer.
Imaging Tests
There are several types of imaging studies that may be utilized during
diagnosis and to monitor thyroid cancer patients during and after treatment.
The most common imaging tests used for diagnosing thyroid cancer include:
•
Ultrasound. Ultrasound is an imaging study that uses high-frequency sound waves to
create pictures of internal organs. This non-invasive test can help physicians
determine the number and size of nodules on the thyroid. It can also help
determine whether a nodule is solid, filled with fluid (cyst) or complex
(mixed solid and fluid). Ultrasound is an excellent modality for evaluation
of the lymph nodes in the neck for possible involvement with thyroid cancer.
•
Computerized Tomography (CT). A CT scan is procedure that uses a computer to produce three-dimensional,
cross-sectional images of inside the body. CT scans are sometimes ordered
for patients with thyroid cancer to examine parts of the neck that cannot
be optimally visualized with ultrasound, as well as to determine if the
cancer has spread to other areas of the body.
• Magnetic Resonance Imaging (MRI). MRI produces images of the body’s internal structures by passing
radio waves through a powerful magnetic field. Differing frequencies of
radio waves are produced by the different body structures. In return,
these are mapped and converted into digital images by a computer. MRI
helps clinicians to distinguish between normal and diseased tissue to
identify cancerous cells within the body, and is also useful for exposing
metastases. MRI provides greater contrast within soft body tissues as
compared to a CT scan.
• Laryngoscopy. Because the thyroid gland is so close in proximity to the vocal cords,
thyroid tumors may sometimes affect them. During a laryngoscopy procedure,
a thin, flexible scope is guided to the larynx, allowing the physician
to examine the throat and larnyx for abnormalities, as well as determine
how well the vocal cords are functioning.
• Thyroid scan. A thyroid scan is a nuclear medicine imaging study that uses a radioactive
iodine tracer to assess the function of the thyroid gland. Typically,
this test is only used in cases of hyperthyroidism with the presence of
a thyroid nodule. During the test, nodules that produce excess thyroid
hormone (called hot nodules) show up on the scan because they absorb more
of the iodine tracer. If the nodule absorbs less iodine than the rest
of the thyroid gland, then the nodule is called a “cold nodule.”
Hot nodules are almost always benign (noncancerous). Although cold nodules
have a higher incidence of malignancy than hot nodules, most are benign.
Thyroid scans may also be used to detect possible recurrence of previously
treated thyroid cancers.
•
Positron emission tomography (PET) is a nuclear medicine imaging study that creates detailed, computerized
pictures of organs and tissues inside the body. A PET scan is usually
combined with a CT scan, called a PET-CT scan. Tumors take up sugar differently
than normal tissues do, so a weak radioactive tracer is attached to a
sugar molecular and then the PET scan shows area of increased uptake provide
images that pinpoint the location of abnormal metabolic activity within
the body. For thyroid cancer, this test is a useful alternative to radioiodine
scans for patients whose thyroid cancer is not radioactive iodine avid.
Fine Needle Aspiration (FNA) Biopsy
Fine Needle Aspiration (FNA) is the most reliable way to determine whether
a nodule is benign or malignant. FNA biopsy is an outpatient procedure
in which the area around the nodule is numbed and a thin, hollow needle
inserted into the nodule to aspirate (take out) some cells into a syringe.
The physician usually repeats this process a few times, taking samples
from several areas of the nodule. This procedure is generally done under
ultrasound guidance for preciseness and to ensure that enough cells are
extracted for evaluation. The extracted cells are then examined under
a microscope by pathologists to determine if they are benign or cancerous.
In cases where a diagnosis is not clear after an FNA biopsy, cells may
be sent for a molecular analysis of the genes in the thyroid nodule. In
some equivocal cases, a surgical procedure is needed.
Proper diagnosis is vitally important in determining the best treatment
protocol personalized for you. At Hoag, our multidisciplinary thyroid
cancer team is highly skilled in the diagnosis and treatment of all types
and stages of thyroid cancer.
Treatment Options for Thyroid Cancer
Patients receive comprehensive and personalized treatment plans that take
into account all facets of care. Treatment plans vary, but most often
include surgical resection, radioactive iodine treatment, and other targeted
therapies specific to the type and stage of cancer for best outcomes.
Surgery
Surgery is the most common initial form of treatment for thyroid cancer
and provides excellent outcomes, especially when performed by experienced
surgeons who specialize in endocrine surgery.
At Hoag, our highly skilled thyroid surgeons have extensive experience
in performing advanced surgical procedures. Most thyroid surgeries can
be accomplished using a small incision. Whenever possible, the incision
is placed over a natural skin crease to achieve the best cosmetic result.
Your surgeon will discuss the best type of procedure for you, depending
on the size and characteristics of your cancer, and whether it has spread
to other areas in the body. The most common surgical options include:
•
Lobectomy. This surgery removes only the side of the thyroid where the cancerous
nodule is located.
•
Near-total thyroidectomy. Also called subtotal thyroidectomy, this surgery removes all but a small
part of the thyroid gland.
•
Total thyroidectomy. This surgery removes the entire thyroid.
In addition, your surgeon may perform a lymph node dissection at the time
of surgery to remove all of the lymph nodes in the neck that may contain
cancer. The lymph nodes are then biopsied to determine if they contain
cancer. This is an important step in helping your physician provide a
comprehensive treatment plan.
Preventing Adverse Outcomes
The greatest prevention of injury to your vocal cord or parathyroid glands
is an experienced surgeon. Hoag’s surgical team offers a level of
expertise that is second to none.
Intraoperative Laryngeal Nerve Monitoring
Surgery on the thyroid gland requires special attention and expertise because
of the close proximity of the thyroid gland to the recurrent laryngeal
nerve (RLN). Damage to a RLN can cause paralysis of a vocal cord that
leads to hoarseness of the voice. At Hoag, intraoperative laryngeal nerve
monitoring may be used by surgeons to help them protect the nerves that
run close to your thyroid and also to test their functioning during surgery.
Radioactive Iodine Therapy
Radioactive iodine therapy (RAI) has been shown to improve the survival
rate of patients with papillary or follicular thyroid cancers that have
spread to the neck or other areas, which is why it’s the standard
treatment for such cases. Because thyroid cells collect iodine, RAI is
an effective tool in specifically targeting radiation to thyroid cells,
while leaving other healthy tissue unaffected. During the procedure, the
radioactive iodine collects in any thyroid tissue remaining in the body,
killing the abnormal cancer cells within the thyroid tissue. Radiation
therapy is typically utilized after surgery, and is determined based on
a case-by-case basis.
External Beam Radiation
External beam radiation is another type of radiation therapy that uses
high-energy X-rays to kill microscopic disease in order to reduce the
risk of local recurrence (the cancer returning in the same location).
For thyroid cancer, external beam radiation is used only in certain circumstances,
such as late-stage thyroid cancer that is unresponsive to radioactive
iodine therapy.
Hoag Radiation Oncology offers the latest in advanced technologies in this area.
Chemotherapy
Chemotherapy uses specialized medications to kill cancer cells and is sometimes
used to treat certain cases of thyroid cancer. Chemotherapy is called
a systemic treatment because the medication enters the bloodstream, and
travels throughout the body to kill cancer cells.
Targeted Therapy
Targeted therapy is a treatment that targets the cancer's specific
genes, proteins and other factors that contribute to cancer growth and
survival. This type of treatment blocks the growth and spread of cancer
cells, while limiting damage to the healthy normal cells. Targeted therapies
tend to have less severe side effects and are usually better tolerated
than – and often tried before – standard chemotherapy. The
use of targeted therapy is determined on an individual basis and is most
often given as part of a clinical trial.
Hormone Therapy
Patients who are treated with surgery usually require thyroid hormone therapy
to replace this important hormone that is essential to the body’s
function. For those with papillary and follicular thyroid cancer, the
dose of thyroid hormone replacement is usually high enough to suppress
one’s own thyroid stimulating hormone (TSH) in order to help prevent
the growth of cancer cells, and reduce the risk of one’s thyroid
cancer returning.
Genetic Testing and Counseling
Approximately 10% of thyroid cancer cases are considered to be hereditary.
There are a number of hereditary cancer conditions, which can include
a diagnosis of thyroid cancer, such as Cowden syndrome, Familial Adenomatous
Polyposis (FAP) and Multiple Endocrine Neoplasia. The type of thyroid
cancer is very important in classifying which, if any, hereditary condition
may be involved.
Hereditary cancer risk assessment and
genetic consultation is recommended for all individuals with a diagnosis of medullary thyroid
cancer and for other types of cancer, depending upon the family history.
Confidential genetic counseling and testing is available through Hoag’s
Hereditary Cancer Program to provide patients and physicians with the
information necessary to create a plan for early detection and/or reducing
the risk of developing cancer.
Tumor Board
Hoag’s Thyroid Cancer Program Team meets regularly to discuss every
new patient in the program. At these meetings, our surgical oncologists,
medical oncologists, radiation oncologists, pathologists, radiologists,
endocrinologists and dedicated clinical nurse navigator review patient
history, imaging and tissue slides, making collaborative decisions to
provide the best outcome for each patient on an individualized basis.
Clinical Trials
One of the many advantages Hoag provides is the opportunity for patients
to participate in clinical trials. As a member of the International Thyroid
Oncology Group, Hoag works collaboratively with a multidisciplinary team
of leading physicians, scientists, and advocates to test the safety and
effectiveness of new strategies for diagnosing and treating cancer. If
you’re eligible to take part, you may have access to new treatment
options that aren’t widely available elsewhere.