For March 11, 1999
Heart to Heart Talk
With Philip S. Chua, M.D.
What is Thyroid Gland?
Located in front of, and in the lower portion of the neck, one on each side of the
trachea (breathing pipe) by and just a little below the Adam's apple, are the two lobes of
the thyroid gland. The thyroid gland produces thyroid hormone. The two major
physiologic effects of this essential hormone are increase in protein synthesis (metabolism)
and increase in oxygen consumption. This is one of the most important hormone producing
glands in the body.
What is Graves' Disease?
Graves' Disease, also known a Diffuse Toxic Goiter, Basedow's Disease, Plummer's
Disease, or Thyrotoxicosis is a malady where the Thyroid Gland is hyperfunctioning
(Hyperthyroidism), producing an abnormal "long-acting thyroid stimulator" (LATS)
circulating in the blood serum. The cause is not totally understood but probably
immunologic. The thyroid gland enlarges diffusely many times its normal size. In some
case, the size of the gland could be almost as large as half of the person's head. The human
body is like a "perfect" chemical laboratory where all the chemicals it produces must be in
a specific and precise "balance" to maintain health and well-being. When an "imbalance"
in the physiology occurs, a cascade of reaction starts and illness sets in.
What are the symptoms of Graves' Disease?
Gland enlargement may not be obvious in some cases. In others, they develop into a
large "tumor" in the neck, involving the entire gland. The eyes of the patient "pop" out
resulting in a wide staring look (medically called exophthalmos). The skin is fine, moist and
warm, with increased sweating. The heart rate is fast and the patient is nervous, possibly
with hand and finger tremors. Although the appetite is increased, there is weight loss and
fatigue. There is insomnia, weakness and some patients even have diarrhea.
Does Iodine deficiency cause Goiter?
Iodine is an essential ingredient in thyroid hormone synthesis. Deficiency can cause
the thyroid gland to enlarge. In many regions in the Philippines, this is endemic. The
introduction of iodized salt in the market has helped prevent a lot of this condition.
What is the difference between solitary and multiple thyroid
While the gland enlargement in Graves' Disease is uniformly diffused, tumors of the
thyroid could also be solitary or multiple. Solitary nodule or tumor in the thyroid gland is
considered malignant until proven otherwise. Multiple nodules in the thyroid gland, on the
other hand, are benign, unless there are findings of recurrent laryngeal nerve palsy,
firmness, rapid growth, enlarged lymph nodes). This is why it is very important that a
physician be consulted when any tumor in the neck or any part of the body is discovered on
self-examination in order to differentiate a benign tumor from a malignant (cancerous)
What are the main types of solitary thyroid nodules?
When the thyroid nodule is solitary, it could be a nodular goiter with one dominant
nodule (in 50% of the cases), adenoma (benign tumors, in 20%), cancer (in 20%),
thyroiditis (inflammation, in 5%) and cysts (5%).
What test is needed to find out if a solitary nodule is solid or cystic?
An Ultrasound or Fine-Needle Aspiration Biopsy (FNAB) will differentiate between
a solid and cystic thyroid mass. This distinction is important since solid nodule could be
cancerous, while cystic lesions are usually benign.
What is Fine-Needle Aspiration Biopsy?
This is a test done under local anesthesia where a fine needle is inserted to hit the
nodule or tumor in the thyroid gland and aspiration ("suctioning") biopsy of the tissue is
done. The tiny sample of the tissue inside the needle is then examined for cancerous cells
How reliable is FNAB cytology?
In experienced hands, the false negative diagnosis (where cancer was present but
not diagnosed) is between 1% to 10%. The false positive (where the diagnosis was cancer,
but there was actually NO cancer) is between zero to 2%. The medical community
considers this a simple and very good test. FNAB has decreased the number of thyroid
operations by 33% (compared to the era before FNAB was available), and has increased
the yield of cancer (accuracy of diagnosis) per operation.
Does a "cold" nodule on Thyroid Scan indicate it is cancer?
Many benign adenomas and cysts appear as "cold" nodules on scintiscan and some
cancerous tumors show up as "warm" nodules, which should be the opposite. Therefore,
scintiscans are NOT reliable in diagnosing malignancy in thyroid nodules.
What are the types of cancers of the thyroid gland?
Papillary (70%), Follicular (15-20%), Medullary (5%) and Anaplastic and
Lymphoma (5%). Each has different speed of growth, spread, prognosis and mortality,
and therefore, treatment varies. Papillary cancers metatasize to the neck (local), while
Follicular cancer of the thyroid spread to other parts of the body by blood stream.
How would the surgeon approach solitary nodule of the thyroid?
After complete history and physical examination, the surgeon will do a biopsy of
any lymph nodes in the neck. He might order a Fine-Needle Aspiration Biopsy of the
thyroid tumor, or remove the one lobe of the thyroid and obtain a frozen section (instant
microscopic examination by a pathologist in the operating room). If the diagnosis on the
tumor is benign (or if it is a papillary cancer that is less than 1.5 cm in size with no lymph
glands involved), nothing more needs to be done, except for regular follow-ups. After the
surgery, patients are given thyroid replacement pills (thyroxin).
What is the treatment for each type of cancers?
Larger Papillary cancers are surgically removed (total or near-total) with excision
of lymph nodes involved, and post-operative radioiodine, if any remaining tissue takes up
radioiodine. Patient with distant spread is treated similarly. All patients should take
thyroxin for the rest of their life. For Follicular cancers, total thyroidectomy, and if there is
no invasion through its capsule, no vascular spread or distant spread, radioiodine therapy
may be held in reserve. For Medullary cancers, total thyroidectomy and lymph node neck
dissection is done to remove all palpable lymph nodes. The undifferentiated (other than the
types mentioned above) cancers are totally removed and external X-Ray treatment is done.
What are the 10-year survival rates for these treatment modalities?
Papillary cancers, 85% of treated patients are alive after 10 years; Follicular, 85%
when localized, 20% if there was spread at the time of surgery; Medullary, 85% when
lymph nodes removed were negative, and 45%, when the lymph nodes were positive for
cancer; and Anaplastic type, zero, none was alive after ten years.
In our fight against cancer, any type of cancer, anywhere in our body, prevention
(where possible, as in quitting cigarette smoking) and early detection are most essential, if
we are to improve the chances of living a healthy, productive and comfortable life, or, in
cases of a serious illness, a cure and prolonged survival.
Usual Footnotes here, please. Thanks.