Thyroid Cancer Guide

Incidence and Types of Thyroid Cancer

Papillary, Follicular, Medullary, and Anaplastic Thyroid Cancer

The National Cancer Institute indicates that thyroid cancer is the most common type of endocrine-related cancer and estimates 60,220 new cases in 2013. Thyroid cancer represents approximately 3.6% of all new cancer cases.1 Although a diagnosis of thyroid or any type of cancer is frightening, the vast majority of thyroid cancers is highly treatable and in most cases curable with surgery and other treatments.

The purpose of this Patients' Guide to Thyroid Cancer is to provide you trustworthy information about thyroid cancer. In this Guide, we explain:

  • 4 types of thyroid cancer
  • symptoms, risks, and related factors
  • oncology specialists who diagnose and treat thyroid malignancy
  • tumor staging and how it affects treatment recommendations
  • treatment of thyroid cancer

About Your Thyroid
Your thyroid is located at the front of your neck near the base of your throat. The butterfly-shaped gland wraps around your windpipe. The thyroid gland is part of your endocrine system, a group of hormone-secreting glands that regulate body functions. Your thyroid gland secretes hormones to regulate your body's heart rate, blood pressure, temperature, and metabolism.

Types of Thyroid Cancer
Cancers arise from cells that have undergone a change (malignant transformation) and begin to abnormally divide and multiply. Tumor growth may be slow or progress rapidly and invade or spread (metastasize) into other tissues. There 4 types of thyroid cancer based on their cell of origin and their appearance and/or characteristics.

Thyroid cancer is generally first suspected by a lump or nodule in the thyroid gland. To make an accurate diagnosis of thyroid cancer, the thyroid cells will need to be closely examined. Since a cancer cell looks different than a normal cell, the type of thyroid cancer is determined by microscopic examination of the thyroid cells found in the nodule (neck lump) or growth. During surgery the nodule or mass can be removed and examined by a pathologist to establish the diagnosis.

Papillary Thyroid Cancer1-4

  • Most common type of thyroid cancer: 70% to 80% of all thyroid cancers are papillary thyroid cancer
  • Commonly diagnosed between the ages of 30 and 50
  • Females are affected 3 times more often than males
  • Usually not aggressive
  • May spread, but usually not beyond the neck
  • Papillary cells resemble finger-like projections
  • Tumor development can be related to radiation exposure, such as radiation treatments for acne or adenoid problems as a child

Follicular Thyroid Cancer1-4

  • Makes up about 10% to15% of all thyroid cancers
  • Often diagnosed between the ages of 40 and 60
  • Females are affected 3 times more often than males
  • Cancer cells may invade blood vessels and travel to other body parts such as bone or lung tissues
  • Follicular cells are sphere-shaped
  • Can be more aggressive in older patients

Medullary Thyroid Cancer1-4

  • Makes up about 5 % to 10% of all thyroid cancers
  • More likely to run in families and associated with other endocrine disorders
  • Develops from the C Cells or parafolicullar cells that produce calcitonin (regulates calcium and phosphate blood levels and promotes bone growth)
  • An elevated calcitonin level can indicate cancer
  • Often diagnosed between the ages of 40 and 50
  • Females and males are equally affected
  • Forms of medullary thyroid cancer include sporadic (not inherited), MEN 2A and MEN 2B (multiple endocrine neoplasia, genetic syndromes that involve other parts of the endocrine system), and familial (genetic, but not linked to other MEN-related endocrine tumors)

Anaplastic Thyroid Cancer1-4

  • Very rare—affects fewer than 5% of thyroid cancer patients
  • Usually occurs in patients older than 65 years
  • Females are affected more often than males
  • Aggressive and invasive
  • Least responsive to treatment
  • Anaplastic (anaplasia) means the cells lose normal structure and organization