Papillary Thyroid Cancer

Papillary thyroid cancer is the most common of all thyroid cancers (>85%). It can also be called “papillary thyroid carcinoma” since carcinoma implies a certain type of cancer. Papillary thyroid cancer typically arises as an irregular, solid or cystic mass that arises from otherwise normal thyroid tissue. Although many cancers are decreasing in their incidence, papillary thyroid cancer is clearly increasing in its incidence both in the United States and globally. Papillary thyroid cancer affects women more commonly than men. Thyroid cancer is now the fifth most common malignancy among women (and seventeen among men) in the United States. If you have recently undergone a needle biopsy suggesting papillary thyroid cancer, don’t worry, this page has been created just for you.

Papillary thyroid cancer (carcinoma) is a common diagnosis among young women but affects patients of all ages from early childhood to advanced ages. Your endocrinologist, primary care doctor, gynecologist, or physician diagnosing a mass by serendipity from neck imaging (due to screening or any other reasons) may have lead to a needle biopsy and diagnosis of papillary thyroid cancer. Because papillary thyroid cancers often presents without any symptoms, the duration that a patient has possessed the cancer is often difficult to determine. The presence of lymph node metastases on initial presentation is common with papillary thyroid cancer and may occur in 20 to up to 40% of patients with smaller thyroid nodules. In patients with larger papillary thyroid cancers, lymph node metastases within the neck may occur in up to 75% of cases.

The presence of lymph node metastasis in these cervical areas may be associated with a higher recurrence rate but not necessarily a higher mortality rate. In fact, among patients less than 45 years of age, even with spread to neck lymph nodes, survival rates exceed 97%. Distant metastasis (spread to other organs of the body) is uncommon, but lung and bone are the most common sites if it does spread out of the neck. Tumors that invade or extend beyond the thyroid capsule have a worsened prognosis because of a high local recurrence rates.

What is critically important to you is that you are evaluated and managed by a highly experienced interdisciplinary team whom are experts in the imaging, staging, cytopathologic analysis (the way individual cells look under a microscope) and surgical management of papillary thyroid cancer. Editorial note: studies have clearly shown that over 10% of patients with papillary thyroid cancer have persistent cancer after initial surgery for the most favorable stage I and II patients and recurrence rates up to 30%. Locally persistent and recurrent papillary thyroid cancers are largely preventable events in skilled surgical hands.

Staging of Papillary Thyroid Cancer

Papillary thyroid cancer has a staging system that is not like other cancers. This staging system for papillary thyroid cancer takes into account the age of the patient. The staging system also includes the size of the papillary thyroid cancer in the thyroid gland itself and whether or not the cancer has spread into lymph nodes around the thyroid or sides of the neck. The staging system for papillary thyroid cancer also includes whether or not the cancer has spread into the fat and muscles around the thyroid (called local extension). Finally, this staging system includes the “differentiation” of the cancer which is what it looks like under a microscope and whether or not the thyroid cancer cells look mature or young and more “angry”.  The last component of papillary thyroid cancer staging is the presence of distant metastases, which means whether the cancer has spread to distant (far way) areas like the lungs.

Important- There is a lot written about the genetic foundation of papillary thyroid cancer and we have been involved in some of the ground breaking research in this area. Nevertheless, the genetic analysis of papillary thyroid cancer is rarely indicated in the evaluation of patients with previously untreated papillary thyroid cancers. Papillary thyroid cancers are rarely hereditary, so you should generally not be concerned about the risk to your children except in the following circumstances. Those individuals which may be at higher risk of developing papillary thyroid cancer include:

• Those with a family history of papillary thyroid cancer
• A personal or family history of goiters
• A history of radiation therapy to the thyroid area such as for: Bone marrow transplantation Mantle field radiation for lymphoma
• Exposure to high levels of radiation due to nuclear accidents or weapons testing
• Having a personal or family history of congenital syndromes such as Cowden’s syndrome (a disorder characterized by benign tumors of the skin and mucous membranes called hamartomas)

• Conventional papillary thyroid cancer - By far the most common
• Follicular variant of papillary thyroid cancer - Very common type of Papillary thyroid cancer that behaves quite similar to conventional type
• Sclerosing papillary thyroid cancer - Almost appears scar like. Can be a technically more challenging surgery
• Poorly differentiated (more aggressive variants and more commonly in the later decades of life)
  • Tall cell variant papillary thyroid cancer
  • Columnar variant of papillary thyroid cancer
  • Hobnail papillary thyroid cancer

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
• Can be a radiation induced cancer
• Spread to lymph nodes of the neck present in up to 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 half of the thyroid (called the lobe) which contains the tumor will provide as good a chance of cure as removing the entire thyroid. These proponents of conservative (non-aggressive) 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 where both thyroid lobes are removed) 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 (thyroid lobectomy) and isthmusthectomy. The detection of lymph nodes in the central (midline ) or lateral (side) neck is an indication for total thyroidectomy. In most circumstances, lateral neck lymph nodes will be identified prior to surgery with high resolution ultrasound of the neck by an expert diagnostician (that’s what we do). Sometimes the central neck lymph nodes are found at the time of surgery and the extent of surgery extended to include the entire thyroid gland and the midline lymph nodes as well. 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 that will have an influence on whether the surgeon should take all the thyroid out--items such as vascular invasion, nerve invasion and capsule (soft tissue) invasion.

The Use of Radioactive Iodine Post-Operatively for Papillary Thyroid Cancer

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. Rarely will other cells in the body 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 “targeted therapy” will little or no potential down-sides (no hair loss, nausea, weight loss, etc.).

Radioactive iodine uptake is enhanced by high TSH levels; thus patients should be off of thyroid hormone replacement and on a low iodine diet for at least two weeks prior to therapy. It is usually given 6 weeks post surgery (this is variable) can be repeated every 12 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?

All papillary thyroid cancer patients are followed lifelong for their disease and hormone monitoring. Patients should receive an annual blood thyroglobulin level as well as high resolution ultrasound surveillance of the neck. Serum thyroglobulin are generally not useful as a screen for the 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 structural (identifiable) recurrence even if an iodine scan is negative. Low unstimulated thyroglobulin levels in the 1-3 pg/ml may not be associated with identifiable structural disease.