Thyroid Cancer Patient Information

Anh Q. Truong, MD

Bellevue ENT

1231 116th Avenue NE, Suite 915

Bellevue, WA 98004

Phone: (425) 454 - 3938

What is the thyroid gland?

The thyroid gland is a butterfly-shaped endocrine organ located in the front of your neck, under the skin and muscle and over the trachea (windpipe). The thyroid gland has two lobes, one on each side of the trachea, and it is usually not visible or palpable externally.

Typically, there are two parathyroid glands located behind each thyroid lobe. Although there is a close anatomical relationship, the parathyroid glands are separate organs from the thyroid gland and serve a different function – primarily regulating calcium level in the blood. In addition, coursing immediately behind each thyroid lobe is a nerve called the recurrent laryngeal nerve. The nerves originate in the chest and innervate the vocal cords, essential in controlling voice and breathing function. Other nearby structures include the superior laryngeal nerves, which control throat sensation and the pitch of your voice, and the carotid arteries.

Figure 1. Anatomy of the thyroid gland and surrounding structures. Source: JAMA.com and Rochester.edu

What are the functions of the thyroid gland?

The thyroid gland secretes thyroid hormone, which regulates physiological function in your body including metabolism. Thyroid hormone has a major role in regulating body temperature, weight, heart rate, mood, energy level, libido, sleep, growth, GI function and brain maturation (in children).

Disorders of thyroid function can lead to hypothyroidism (e.g. Hashimoto thyroiditis) or hyperthyroidism (e.g. Grave’s thyroiditis), altering normal physiologic function. Secretion of thyroid hormone is generally controlled by the pituitary gland in the brain that secretes thyroid stimulating hormone (TSH). The thyroid gland also secretes calcitonin, which plays a minor role in bone and calcium metabolism.

What are papillary and follicular thyroid cancer?

Papillary thyroid carcinoma and follicular thyroid carcinoma are well-differentiated thyroid cancer that originates from thyroid cell. With malignant transformation, the cancerous cells will grow without appropriate check and balance, potentially leading to local invasion, regional metastasis (spread) to lymph nodes in the neck and distance metastasis to other organs such as the lungs.

Papillary and follicular thyroid cancers are the most common type of cancer deriving from the thyroid gland. Fortunately, they also have the best prognosis among other thyroid cancers, which includes medullary and anaplastic thyroid cancer. The risk factors for thyroid cancer include previous radiation treatment, female gender, family history, low iodine diet, race and a history of breast cancer.

How does papillary or follicular thyroid cancer typically present?

Most thyroid cancers are discovered incidentally through a routine exam or from head and neck imaging for other reasons. Initially, a thyroid nodule may be discovered. About 5-10% of nodules can be cancerous after a thorough workup is completed. Some patients may notice a lump in the center of the neck when looking in the mirror or feeling the neck. Some thyroid cancers may initially present as a lump on the side of the neck due to metastasis to the lymph node. In most cases, patients are completely asymptomatic when the cancer is found. In rare cases, the cancer can be large enough to cause compressive symptoms including trouble swallowing, trouble breathing, voice change, and pain.

What should I expect during my visit with an ENT doctor for a papillary or follicular thyroid cancer?

During your visit, your ENT doctor will perform a complete history and physical exam. Your doctor may evaluate your larynx and vocal cord with a mirror or a fiberoptic endoscopic laryngoscopy. Depending on your history and examination, your physician may refer you to obtain additional studies including a blood test, imaging, and a biopsy.

What are additional tests needed for work-up of a papillary or follicular thyroid cancer?

Once a thyroid mass is determined to be thyroid cancer, additional workup is based on the type of cancer diagnosed. Typically, observation or surgical excision is recommended as the next step of management for papillary or follicular thyroid cancer. However, depending on the presentation, additional molecular and genetic testing along with imaging of the neck to evaluate for metastasis may be performed.

Figure 5. Thyroid ultrasound and fine needle aspiration of a thyroid nodule. Source: MedlinePlus and drug.com

What are the different types of thyroid cancer?

The most common type of thyroid cancer is papillary and follicular thyroid carcinoma. They are considered well-differentiated thyroid cancers and fortunately, have the best prognosis. Other types of thyroid cancers include medullary thyroid carcinoma and anaplastic thyroid carcinoma. In rare cases, lymphoma and cancer metastasis from other organs may present in the thyroid gland.

How are papillary and follicular thyroid carcinomas staged?

Well-differentiated thyroid cancer is staged based on the size of the tumor, regional lymph node metastasis and distant metastasis to other organs. Patients younger than the age of 45 typically will have a lower stage and better prognosis. Overall, the prognosis for papillary and follicular thyroid cancer is excellent with stage II disease approaching nearly 100% survival at 5 years. Additional prognostic information is available at the American Cancer Society.

When is surgery indicated for papillary or follicular thyroid carcinoma?

The treatment of well-differentiated thyroid carcinoma is complex due to numerous different factors that determine the treatment plan. Typically, surgery such as a thyroid lobectomy or total thyroidectomy is recommended in patients diagnosed with thyroid cancer. However, other factors such as your age, the size of the tumor and other co-morbidities may guide the decision between observation and surgery. Patients who are at high risk for regional metastasis to lymph nodes in the neck or have evidence of nodal metastasis will usually need a concurrent neck dissection (removal of lymph nodes).

Thyroid surgery is performed for both diagnostic and therapeutic purposes. The surgery is performed by making an incision at the front of the neck. Depending on the extent and complexity of your surgery, your surgeon may choose to monitor the recurrent laryngeal nerve throughout the procedure. Learn more about thyroid surgery or post-operative care after thyroid surgery.

How is papillary or follicular thyroid cancer managed after surgery?

The majority of patients with a small thyroid cancer without metastasis or patients with low risk for metastasis do not need any additional treatment after a thyroidectomy. The decision to proceed with post-operative radioactive iodine ablation will be based on the patient’s risk factors and the endocrinologist’s recommendation. Routine surveillance with close follow-up, blood test, and imaging is performed to detect evidence of recurrence. Once the entire thyroid is removed, patients will need to take thyroid hormone as replacement therapy to maintain normal metabolism.

Learn more about thyroid surgery and post-operative instructions after a thyroidectomy.

References:

1. Haugen, Bryan R., et al. "2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer." Thyroid ja (2015).
2. Shindo, Maisie L., et al. "Management of invasive well‐differentiated thyroid cancer: An American head and neck society consensus statement: AHNS consensus statement." Head & neck 36.10 (2014): 1379-1390.
3. Liao, Selena, and Maisie Shindo. "Management of well-differentiated thyroid cancer." Otolaryngologic Clinics of North America 45.5 (2012): 1163-1179.
4. Byrd, J. Kenneth, et al. "Well differentiated thyroid carcinoma: current treatment." Current treatment options in oncology 13.1 (2012): 47-57.
5. Eskander, Antoine, et al. "Pattern of spread to the lateral neck in metastatic well-differentiated thyroid cancer: a systematic review and meta-analysis."Thyroid 23.5 (2013): 583-592.
6. Webb, Richard C., et al. "The utility of serum thyroglobulin measurement at the time of remnant ablation for predicting disease-free status in patients with differentiated thyroid cancer: a meta-analysis involving 3947 patients." The Journal of Clinical Endocrinology & Metabolism 97.8 (2012): 2754-2763.
7. Miller, Mia E., et al. "Positron emission tomography and positron emission tomography‐CT evaluation for recurrent papillary thyroid carcinoma: Meta‐analysis and literature review." Head & neck 33.4 (2011): 562-565.
8. Giovanella, Luca, Massimo Bongiovanni, and Pierpaolo Trimboli. "Diagnostic value of thyroglobulin assay in cervical lymph node fine-needle aspirations for metastatic differentiated thyroid cancer." Current opinion in oncology 25.1 (2013): 6-13.