the appearance of the nodule tissue under a microscope. This is known as the pathological appearance of the tissue. For our purposes, we just want to know whether the nodule is benign (not cancerous) or malignant (cancerous). Most thyroid nodules — more than 95 percent — are benign.
Evaluating Cancer Risks A number of facts about a patient’s history, signs, and symptoms can help sway the balance toward or away from a diagnosis of cancer: Gender: Doctors find nodules less often in men than women, but nodules are cancerous more often in men. Age: Nodules found in children are cancerous more frequently than they are in adults. However, a nodule in a child is still benign more often than it’s malignant. A nodule in a person over age 70 is also highly suspicious for cancer. Whether a person over 70 should have surgery for such a generally nonaggressive cancer is another issue. Number of nodules: If a patient has many nodules, this suggests that a cancer isn’t present. Most multinodular thyroids are benign. Growth rate: A nodule that grows rapidly is probably a cancer, but if it pops up suddenly and is tender, it may be a hemorrhage. A hemorrhage that suddenly occurs isn’t usually a serious problem, but it does cause discomfort. Additional growths: Finding growths in the neck away from the thyroid suggests cancer that has spread, and those growths must be evaluated by a biopsy. Hoarseness and trouble swallowing: These symptoms suggest cancer, especially if they’re of recent onset. Movement: If the thyroid doesn’t move freely, it’s a sign of fixation, which suggests cancer. Previous exposure to irradiation: (This doesn’t include the use of radioactive iodine in the treatment of hyperthyroidism — see Chapter 6.) A significant increase in reports of thyroid cancer occurred among children exposed to the radiation from the Chernobyl nuclear plant in Russia. In this case, multiple nodules don’t rule out cancer. Almost half the nodules in an irradiated gland turn out to be cancer. Doctors may find the cancer 10 to 30 years after the irradiation. Even today, doctors use radiation to treat tumors in the head and neck, which will result in a certain amount of cases of thyroid cancer.