Thyroid Cancer
Papillary Cancer...The Most Common Thyroid Cancer
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 This page includes more advanced information on a specific type of thyroid cancer. . . Papillary Thyroid Cancer. Please read our Introduction to Thyroid Cancer page first which gives a general overview of all types of thyroid cancer since it will make this page easier to understand.
Papillary tumors are the most common of all thyroid cancers (>70%). Papillary
carcinoma typically arises as an irregular, solid or cystic mass that arises
from otherwise normal thyroid tissue. This cancer has a high cure rate with ten
year survival rates for all patients with papillary thyroid cancer estimated at 80-90%. Cervical metastasis (spread to lymph nodes in the neck) are
present in 50% of small tumors and in over 75% of
the larger thyroid cancers. The presence of lymph node metastasis in these cervical areas
causes a higher recurrence rate but not a higher mortality rate.
Distant metastasis (spread) is uncommon, but lung and bone are the most
common sites. Tumors that invade or
extend beyond the thyroid capsule have a worsened prognosis because of a high local recurrence rate.
Characteristics of Papillary Thyroid Cancer
 Peak onset ages 30 through 50
Females more common than males by 3 to 1 ratio
Prognosis directly related to tumor size [less than 1.5 cm (1/2 inch) good prognosis]
Accounts for 85% of thyroid cancers due to radiation exposure
Spread to lymph nodes of the neck present in more than 50% of cases
Distant spread (to lungs or bones) is very uncommon
Overall cure rate very high (near 100% for small lesions in young patients)
Management of Papillary Thyroid Cancer
 Considerable controversy exits when
discussing the management of well differentiated thyroid carcinomas (papillary and even follicular). Some experts contend than if these tumors are small and not invading other tissues (the usual case) then simply removing the lobe of the thyroid which harbors the tumor (and the small central portion called the isthmus)
will provide as good a chance of cure as removing the entire thyroid. These proponents of conservative surgical therapy relate the low rate of
clinical tumor recurrence (5-20%) despite the fact that small amounts of tumor cells can be found in up
to 88% of the opposite lobe thyroid tissues. They also cite some studies showing an increased risk of hypoparathyroidism and
recurrent laryngeal nerve injury in patients
undergoing total thyroidectomy (since there is an operation on both sides of the neck). Proponents of total thyroidectomy (more aggressive surgery)
cite several large studies that show that in experienced hands the
incidence of recurrent nerve injury and permanent hypoparathyroidism
are quite low (about 2%). More importantly, these studies show that
patients with total thyroidectomy followed by radioiodine therapy and
thyroid suppression, have a significantly lower recurrence rate and
lower mortality when tumors are greater than 1.5cm. One must
remember that it is also desirable to reduce the amount of normal
gland tissue that will take up radioiodine.
Based on the these
studies and the above natural history and epidemiology of papillary
carcinoma, the following is a typical plan: Papillary
carcinomas that are well circumscribed, isolated, and less than 1cm
in a young patient (20-40) without a history of radiation exposure may
be treated with hemithyroidectomy and isthmusthectomy. All others
should probably be treated with total thyroidectomy and removal of any enlarged lymph nodes in the central or lateral neck areas. The surgical options are covered in greater detail (with drawings) on another "surgical options" page.
Often other characteristics of the tumor that can be seen under the
microscope will have an influence on whether the surgeon should take
all the thyroid out--items such as vascular invasion, nerve invasion
and capsule invasion.
The Use of Radioactive Iodine Post-Operatively
Thyroid cells are unique in that they have the cellular mechanism to absorb iodine. The iodine is used by thyroid cells to make thyroid hormone. No other cell in the body can absorb or concentrate iodine. Physicians can take advantage of this fact and give radioactive iodine to patients with thyroid cancer. There are several types of radioactive iodine, with one type being toxic to cells. Papillary cancer cells absorb iodine and therefore they can be targeted for death by giving the toxic isotope (I-131). Once again, not everybody with papillary thyroid cancer needs this therapy, but those with larger tumors, spread to lymph nodes or other areas, tumors which appear aggressive microscopically, and older patients may benefit from this therapy. This is extremely individualized and no recommendations are being made here or elsewhere on this web site...too many variables are involved. But, this is an extremely effective type of "chemotherapy" will little or no potential down-sides (no hair loss, nausea, weight loss, etc.).
Uptake is enhanced by
high TSH levels; thus patients should be off of thyroid replacement
and on a low iodine diet for at least one to two weeks prior to therapy. It is usually given 6 weeks post surgery (this is variable) can be repeated every 6 months if necessary (within certain dose limits).
What About Thyroid Hormone Pills After Thyroid Cancer Surgery?
Regardless of whether a patient has just one thyroid lobe and the isthmus removed, or the entire thyroid gland removed, most experts agree they should be placed on thyroid hormone for the rest of their lives. This is to replace the hormone in those who have no thyroid left, and to suppress further growth of the gland in those with some tissue left in the neck. There is good evidence that papillary
carcinoma responds to thyroid stimulating hormone (TSH) secreted by the pituitary, therefore, exogenous thyroid hormone is given which results in decreased TSH levels and a lower impetus for any remaining cancer cells to grow.
Recurrence and mortality rates have been
shown to be lower in patients receiving suppression.
What Kind of Long-Term Follow Up is Necessary?
In addition to
the usual cancer follow up, patients should receive a yearly chest x-ray as well as thyroglobulin levels Thyroglobulin is not useful as a screen
for initial diagnosis of thyroid cancer but is quite useful in follow
up of well differentiated carcinoma (if a total thyroidectomy has been performed). A high serum thyroglobulin level
that had previously been low following total thyroidectomy especially
if gradually increased with TSH stimulation is virtually indicative
of recurrence. A value of greater than 10 ng/ml is often associated
with recurrence even if an iodine scan is negative.
Overview of Thyroid Cancer
More information about Follicular Thyroid Cancer and Medullary Thyroid Cancer
Surgical Operations for thyroid tumors (includes descriptions and drawings of different thyroid operations)
Thyroid Nodules and thyroid masses, an overview
Characteristics of Worrisome Thyroid Masses and the need to biopsy them
The use of Ultrasound to Examine Thyroid Nodules
EndocrineWeb Home Page
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