Thyroid Neoplasms

Incidence in USA is 23,500 new thyroid cancer cases/y, but incidence is increasing.

Account for approximately 1% of new cancer diagnoses each y.

Hispanics, African Americans, lower rate; Caucasians, moderate rate; Japanese, Chinese, Hawaiian, Filipinos, higher rate.

Overall incidence 3× higher in women than in men; peaks in third and fourth decades of life.

Large thyroid mass may produce airway compression, deviation, or vocal cord paralysis.

Decreased BP, decreased HR, asystole with manipulation of carotid sinus.

Postop complications: Phrenic nerve injury, pneumomediastinum, pneumothorax, tracheomalacia and tracheal collapse postextubation, hematoma or laryngeal edema leads to airway compromise; bilateral laryngeal nerve injury calls for tracheotomy; superior laryngeal nerve injury leads to aspiration.

Accidental removal and/or injury of parathyroid glands causes decrease in Ca ²⁺ .

Occult pheochromocytoma: Bilateral lobe medullary thyroid cancer is associated with MEN IIA and IIB.

Four main types: Papillary (80–90%), follicular (5–15%), medullary (<5%), primary thyroid lymphoma (rare), and primary thyroid sarcomas (rare).

Prognosis of well-differentiated papillary cancer is excellent, especially for age <40 y with small tumors.

Prognosis worsens for large tumors with poorly differentiated, anaplastic histology.

Age at Dx, tumor burden, gender, extra-thyroidal invasion, and distant metastases are important prognostic factors.

Latest research defines subcellular and molecular prognostic factors through genetic studies.

BRAF mutation is the most common mutation in papillary thyroid cancer and is associated with disease aggressiveness and resistance to radioiodine treatment.

Factors include previous radiation, dietary iodine deficiency, goitrogens (chemical or dietary), preexisting benign thyroid disease, and genetic factors (Gardner syndrome, Cowden disease).

Association between primary thyroid cancer and increased incidence of subsequent breast cancer.