Endocrinologists Suemi Marui and Rosa Paula Biscolla told Dr. Roberto Kalil on CNN's Sinais Vitais program on Saturday, September 12, that thyroid nodules are extremely common, affecting about 50% of the population, and that the proportion rises to 70% among people over 70. Despite how common they are, the risk that a nodule is cancerous remains relatively low, with only 5% to 10% of cases turning out to be malignant tumors, the doctors said.
Sinais Vitais is a weekly health program on CNN Brasil hosted by Kalil, a cardiologist known for his work in cardiac surgery, in which he interviews medical specialists on a range of health topics.
Thyroid cancer usually does not cause obvious symptoms, the endocrinologists said. But certain signs should raise concern, they added: a nodule that has grown quickly in recent weeks, a hardened consistency when touched, swollen lymph nodes on the same side as the nodule, hoarseness and difficulty swallowing.
Biscolla said that when a patient notices a nodule that is hard, and a doctor's examination confirms it is hard and accompanied by a lymph node on the same side, the finding is significant.
Types of thyroid cancer
The endocrinologists identified two main types of thyroid cancer. The most common, papillary and follicular carcinoma, accounts for about 85% of cases.
In this type, doctors consider a familial origin only when three or more members of the same family are diagnosed with the disease. Biscolla explained that up to two cases in a family is generally considered a coincidence, but three or more cases suggests a more familial pattern.
The second type, medullary thyroid carcinoma, is rarer but carries greater hereditary potential, with about 25% of cases having a familial character, according to the endocrinologists.
Genetic testing and outlook
In cases of medullary carcinoma, the endocrinologists said, a diagnosed patient should undergo genetic testing to identify the gene associated with the tumor. If a genetic alteration is confirmed, all first-degree relatives should also be tested.
Asked which type is more aggressive, Biscolla said the answer depends directly on the stage at which the cancer is diagnosed. If caught early, she said, the chances of a cure are similar for both types. However, medullary carcinoma is more likely to spread to lymph nodes and glands, even when the tumor is still small, compared with the follicular type.
