Thyroid Cancer Smart Snippet: Video Datasource: Thyroid Cancer Solutions The thyroid is a butterfly-shaped gland located in front of the windpipe, low in the neck. Thyroid nodules are very common growths or lumps in the glands, affecting as many as 1 in 3 women. The only way to be sure that a thyroid nodule is not cancerous is to see an endocrinologist or an endocrine surgeon, who may perform a biopsy. The physicians at our Center for Integrative Endocrine Surgery have performed more than 8,000 ultrasound-guided thyroid biopsies since 1991. The best test to determine the true nature of a thyroid nodule is a fine needle aspiration biopsy (FNAB) with ultrasound guidance, which is performed if the nodule is larger than a half-inch in diameter.