Erbil and colleagues have noted that thyroid cancer occurred more often in smaller thyroid glands and in bigger thyroid nodules. They report that 69 of 365 consecutive patients (18.9%) undergoing thyroidectomy for an MNG and a dominant thyroid nodule without a history of exposure to low-dose therapeutic radiation; clinical manifestations suggesting thyroid cancer, such as ipsilated lymph adenopathy or hoarseness; or a family history of thyroid cancer had thyroid cancer.
Overall, 100 thyroid cancers were identified in these 69 patients, 41 in the dominant nodule and 59 elsewhere in the thyroid gland. Smaller thyroid glands (< 38 mL) had a 48-fold increased rate of malignancy, whereas large nodules (> 7 mm) also had a significantly increased rate of being thyroid cancer. This overall cancer rate of 18.9% seems a little higher than expected. This may be due to the use of fine-needle aspiration cytology. The increased rate of thyroid cancer may also be caused by some selection or referral bias. The authors' findings seem to make sense, since patients with larger goiters have a reason other than cancer for an enlarged thyroid gland, including growth factors, such as epidermal growth factor, thyroid-stimulating hormone, and insulin like growth factor. When I examine a patient with a thyroid nodule, I try to palpate the rest of the thyroid gland as well as the pyramidal lobe. When I palpate the pyramidal lobe, I know that there is a general stimulus to the thyroid gland so that a malignant neoplasm is less likely.
Clark OH. Effect of Thyroid Gland Volume in Preoperative Detection of Suspected Malignant Thyroid Nodules in a Multinodular Goiter—Invited Critique. Arch Surg. 2008;143(6):563. doi:10.1001/archsurg.143.6.563