Cancer of the thyroid, which is highly curable if detected early, is believed to be caused from exposure to radiation, particularly during childhood. It is a common cancer among people who experienced radioactive fallout from the Chernobyl, Ukraine nuclear power plant disaster in the mid-1980s.

There are about 20,000 new cases of thyroid cancer each year in the United States. Females are more likely to have thyroid cancer at a ratio of three to one. Thyroid cancer can occur in any age group, although it is most common after age 30 and its aggressiveness increases significantly in older patients. The majority of patients present with a nodule on their thyroid which typically does not cause symptoms. Remember, over 99% of thyroid nodules are not cancer!  But, when a thyroid cancer does begin to grow within a thyroid gland, it almost always does so within a discrete nodule within the thyroid.

Occasionally, symptoms such as hoarseness, neck pain, and enlarged lymph nodes do occur. Although as much as 75 % of the population will have thyroid nodules, the vast majority are benign. Young people usually don't have thyroid nodules, but as we get older, more and more of us will develop a nodule. By the time we are 80, 90% of us will have at least one nodule. Far less than 1% of all thyroid nodules are malignant.

A nodule which is cold on scan (shown in photo outlined in red and yellow) is more likely to be malignant, nevertheless, the majority of these are benign as well.

Papillary and/or mixed papillary/follicular ~  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.

• 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)
  
  

Follicular and/or Hurthle cell ~ Follicular carcinoma is considered more malignant (aggressive) than papillary carcinoma. It occurs in a slightly older age group than papillary and is also less common in children. In contrast to papillary cancer, it occurs only rarely after radiation therapy. Mortality is related to the degree of vascular invasion. Age is a very important factor in terms of prognosis. Patients over 40 have a more aggressive disease and typically the tumor does not concentrate iodine as well as in younger patients. Vascular invasion is characteristic for follicular carcinoma and therefore distant metastasis is more common. Distant metastasis may occur in a small primary. Lung, bone, brain, liver, bladder, and skin are potential sites of distant spread. Lymph node involvement is far less common than in papillary carcinoma (8-13%). 

• Peak onset ages 40 through 60
• Females more common than males by 3 to 1 ratio
• Prognosis directly related to tumor size [less than 1.0 cm (3/8 inch) good prognosis]
• Rarely associated with radiation exposure
• Spread to lymph nodes is uncommon (~10%)
• Invasion into vascular structures (veins and arteries) within the thyroid gland is common
• Distant spread (to lungs or bones) is uncommon, but more common than with papillary cancer
• Overall cure rate high (near 95% for small lesions in young patients), decreases with advanced age
  

Medullary ~ Unlike papillary and follicular thyroid cancers which arise from thyroid hormone producing cells, medullary cancer of the thyroid originates from the parafollicular cells (also called C cells) of the thyroid. These C cells make a different hormone called calcitonin (thus their name) which has nothing to do with the control of metabolism the way thyroid hormone does. As you will see below, the production of this hormone can be measured after an operation to determine if the cancer is still present, and if it is growing. This cancer has a much lower cure rate than does the "well differentiated" thyroid cancers (papillary and follicular), but cure rates are higher than they are for anaplastic thyroid cancer. Overall 10 year survival rates are 90% whe all the disease is confined to the thyroid gland, 70% with spread to cervical lymph nodes, and 20 when spread to distant sites is present.

• Occurs in 4 clinical settings, can be associated with other endocrine tumors
• Females more common than males (except for inherited cancers)
• Regional metastases (spread to neck lymph nodes) occurs early in the disease
• Spread to distant organs (metastasis) occurs late and can be to the liver, bone, brain, and adrenal medulla 
• Not associated with radiation exposure
• Usually originates in the upper central lobe of the thyroid
• Poor prognostic factors include age >50, male, distant spread (metastases), and when seen in patients with other endocrine tumors due to MEN II-B syndrome
• Residual disease (following surgery) or recurrence can be detected by measuring calcitonin (a hormone that should be measured every 4 months for the first few years and then every 6 months forever).
   

Anaplastic ~  This cancer has a very low cure rate with the very best treatments allowing only 10 % of patients to be alive 3 years after it is diagnosed. Most patients with anaplastic thyroid cancer do not live one year from the day they are diagnosed. Anaplastic thyroid cancer often arises within a more differentiated thyroid cancer or even within a goiter. Like papillary cancer, anaplastic thyroid cancer may arise many years (>20) following radiation exposure.  Cervical metastasis (spread of the cancer to lymph nodes in the neck) are present in the vast majority (over 90%) of cases at the time of diagnosis. The presence of lymph node metastasis in these cervical areas causes a higher recurrence rate and is predictive of a high mortality rate. The most common way this cancer becomes evident is by the patient or his/her family member noticing a growing neck mass. When the doctor feels the neck mass it is usually large, diffuse, and very hard. These tumors grow very rapidly and the patient will state that this neck mass seemed like they never noticed it until a few days or weeks ago, and now it seems to get bigger every few days.

Anaplastic cancers invade adjacent structures and metastasize extensively to cervical lymph nodes and distant organs such as lung and bone. Tracheal invasion is present in 25% at the time of presentation (said differently, in about 25% of cases, the anaplastic cancer has grown out of the thyroid and grown into the trachea). This is why many patients with anaplastic thyroid cancer will need a tracheostomy while almost nobody with the other types of thyroid cancer will need one. Spread (metastasis) to the lung is present in 50% of patients at the time of diagnosis of anaplastic thyroid cancer is made. Most of these cancers are so aggressively attached to vital neck structures that they are inoperable at the time of diagnosis (the surgeon can't remove it--it's growing into other neck structures). Even with aggressive therapy protocols such as hyperfractionated radiation therapy, chemotherapy, and surgery, survival at 3 years is less than 10%.

• Peak onset age 65 and older
• Very rare in young patients
• Males more common than females by 2 to 1 ratio
• Typically presents as rapidly growing neck mass
• Can occur many years after radiation exposure
• Spread to lymph nodes of the neck present in more than 90% of cases
• Distant spread (to lungs or bones) is very common even when first diagnosed
• Overall cure rate very low

Typically requires a very aggressive treatment plan with surgery, radiation and sometimes even chemotherapy.  Often requires the patient to get a tracheostomy to maintain their airway.