Thyroid disease

The treatment for thyroid cancer has two main components:

• Surgery
• Radioiodine

Thyroid surgery

During thyroid surgery, the entire thyroid gland or part of the gland is removed:

• Total thyroidectomy – removal of the entire thyroid gland
• Lobectomy (hemithyroidectomy) – removal of half the gland (one of the lobes of the gland)
• Isthmusectomy – removal of the small “bridge” of thyroid tissue that connects the two lobes of the gland

Radioiodine

Some patients are treated with radioiodine (radioactive iodine) in addition to surgery. The radioiodine is given by mouth as a capsule or liquid. The need for radioiodine treatment is determined from several factors, including the patient’s age, the size of the cancer, the presence of lymph node metastases, and the spread of cancer outside the thyroid gland. In general radioiodine may be recommended for two reasons

• Prophylactic treatment (to reduce the risk of the cancer coming back after surgery – local recurrence)
• Treatment for recurrent cancer and/or spread to other areas of the body (distant metastases)

For more information on these topics, see Chapter 6: Thyroid Surgery and Chapter 7: Radioactive iodine treatment in Thyroid Cancer and Thyroid Nodules In 30 Minutes.

Most thyroid nodules are benign but they may also contain cancer. The incidence of thyroid cancer in the population has trended upwards during the last several decades. The good news is that most thyroid cancers are treatable and associated with an excellent prognosis. The most common forms of thyroid cancer are

• Papillary thyroid cancer (70-80%)
• Follicular thyroid cancer (10-20%)
• Medullary thyroid cancer (3-5%)
• Anaplastic thyroid cancer (1-2%)

Classification of cytology and staging of thyroid cancer

The classification of cytology is based on the microscopic appearance of the cells obtained during a FNA. The so-called Bethesda system includes six classes (Bethesda I to Bethesda VI). The Bethesda classification is used to assess the risk of malignancy in a thyroid nodule with higher Bethesda classifications being more suspicious for cancer.

The staging of a thyroid cancer is used to help decide best treatment and estimate the prognosis. The most commonly used staging is the TNM system based on the size of the tumor (T), the absence or presence of lymph node metastases (N) and distant metastases (M). Thyroid cancers are staged from I to IV, with the higher stages representing more advanced cancers requiring more aggressive treatment.

Importantly, the cancer staging requires that tissue is examined (as opposed to the Bethesda classification that is based on examination of cells). Staging of the cancer therefore is typically not performed until after surgery has been performed.

For more information on these topics, see Chapter 3: Doctors, tests, and classifications and Chapter 5: Thyroid Cancer in Thyroid Cancer and Thyroid Nodules In 30 Minutes.

The book Thyroid Cancer & Thyroid Nodules In 30 Minutes contains easy-to-understand information about common disorders of the thyroid gland, the ways to make the diagnosis, and how to treat benign and malignant nodules (lumps) in the thyroid gland.

The book is written by an experienced thyroid surgeon who is also a Professor of Surgery at the Harvard Medical School. The basic concepts related to thyroid cancer and thyroid nodules are explained using a language adapted to patients and their families.

How thyroid nodules are discovered

• The patient may see or feel a “lump on the neck”
• The nodule may be discovered by the patient’s physician during a physical examination
• The nodule may be discovered as an incidental finding when an imaging test (X-ray, ultrasound, CAT scan, or MRI) of the neck is performed for unrelated reasons

The workup of thyroid nodules

When there is suspicion of a thyroid nodule, the workup mainly consists of:

• Thyroid ultrasound
• Fine needle aspiration (FNA): with a thin needle inserted into a thyroid nodule, cells are aspirated (sucked out) for microscopic evaluation
• Cytology (microscopic evaluation of cells obtained during a FNA)

For more information on this topic, see Chapter 2: Case studies and Chapter 4: Benign thyroid nodules in Thyroid Cancer and Thyroid Nodules In 30 Minutes.