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Advanced Thyroid Cancer

Understanding the Anatomy

When discussing thyroid cancer, you should start by understanding the anatomy. This illustration shows different parts of the neck, where the thyroid gland is located.

The thyroid gland sits in the midline of your neck, just beneath the skin and a few layers of thin muscles. This gland secretes a hormone that is important in regulating many functions of your body. The thyroid gland has a right and left lobe, as well as an isthmus (and occasionally a prominent pyramidal lobe that goes upwards towards the hyoid bone and base of tongue). The thyroid gland is made up of follicular cells that take up iodine and produce a hormone called thyroid hormone. The thyroid hormone is stored within follicles inside the gland. Another type of cell in the thyroid gland is called parafollicular cells (or C-cells); these cells form a hormone called calcitonin, which helps with calcium regulation. Cancer of the C-cells results is medullary carcinoma.

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The blood supply to the thyroid gland is from branches of the thyrocervical trunk and the external carotid artery. Rarely, there is an artery called the ima artery, which runs from below the clavicles on the top surface of the trachea towards the thyroid gland.

Next to the thyroid gland are four parathyroid glands (two on each side). These are critical to your body to regulate levels of calcium in your blood and your bones through secretion of parathyroid hormone.

The recurrent laryngeal nerves (one on each side) run upward from the vagus nerve toward the voice box (larynx) in the groove between the trachea (windpipe) and esophagus. This nerve moves the vocal cords, and it is responsible for speaking and control of the vocal cords during breathing. In extremely rare cases, the right recurrent laryngeal nerve can come straight down from the vagus nerve. This is called a non-recurrent laryngeal nerve because it does not come from below. Surgeons need to always be careful in protecting this nerve to prevent injury.

The superior laryngeal nerves (one on each side) run downward from the vagus nerve. The external branch supplies the cricothyroid muscle and helps with changing the pitch of your voice.

The lymph nodes associated with the thyroid are mainly the central compartment lymph nodes. This includes Levels VI and VII [see illustration above]. Occasionally, thyroid cancers can spread to the lateral neck or retropharyngeal lymph nodes as well.

 

References

1 SEER Fast Facts. http://seer.cancer.gov/statfacts/html/thyro.html Accessed February 2013.

2 Hundahl SA, Fleming ID, Fremgen AM, et al.: A National Cancer Data Base report on 53,856 cases of thyroid carcinoma treated in the U.S., 1985-1995. Cancer. 1998;83:2638-2648.

3 Salerno P, De Falco V, Tamburrino A, Nappi TC, Vecchio G, Schweppe RE, Bollag G, Santoro M, Salvatore G. Cytostatic activity of adenosine triphosphate-competitive kinase inhibitors in BRAF mutant thyroid carcinoma cells. J Clin Endocrinol Metab. 2010;95(1):450-455.

4 Referenced with permission from The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Thyroid Carcinoma V.2.2013. © National Comprehensive Cancer Network, Inc 2013. All rights reserved. Accessed July 24, 2013. To view the most recent and complete version of the guideline, go online to www.nccn.org. NATIONAL COMPREHENSIVE CANCER NETWORK®, NCCN®, NCCN GUIDELINES®, and all other NCCN Content are trademarks owned by the National Comprehensive Cancer Network, Inc.

5 Cooper, D.S., G. M. Doherty, et al. (2009). “Revised American Thyroid Association Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer: the American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer.” Thyroid 19(11): 1167-1214.

6 Ries LAG, Young JL, Keel GE, Eisner MP, Lin YD, Horner M-J (editors). SEER Survival Monograph: Cancer Survival Among Adults: U.S. SEER Program, 1988-2001, Patient and Tumor Characteristics. National Cancer Institute, SEER Program, NIH Pub. No. 07-6215, Bethesda, MD, 2007.