Nodules can be caused by a variety of factors including an overgrowth of normal tissue, cysts or inflammation. Most nodules are benign but for a small majority of patients (5-7%), these nodules may be cancerous. In a patient with a known thyroid nodule, the initial step is to determine the risk for cancer. High-risk features include:
- Being male under the age of 40
- A history of radiation therapy to the head or neck
- Big lymph nodes in the neck
- Problems swallowing
- Problems speaking
- A family history of thyroid cancer
The next step is an ultrasound of the thyroid to determine the size of the nodule(s) and if it has certain characteristics that increase the possibility of it being cancer. An ultrasound-guided fine needle aspiration biopsy is then performed to obtain tissue from the thyroid nodule to determine whether the nodule is benign or malignant.
The specimen obtained from the fine needle aspiration is examined by a pathologist. There are four general categories of possible results for a FNA: 1) Benign, 2) Malignant, 3) Nondiagnostic, 4) Indeterminate. If the lesion is benign, the patient is monitored via ultrasound for the growth of the nodule(s) or development of new nodules. If there is growth, another biopsy may be performed. If the lesion is malignant, the patient is referred to one of the Thyroid Cancer Program surgeons for removal of the thyroid.
About 10% of the time, the pathologist is unable to provide a diagnosis due to lack of specimen from the aspiration. An indeterminate biopsy result confers an increased risk for malignancy and your doctor will discuss the benefits and risks of surgery versus monitoring.
Usually, the entire thyroid is removed (total thyroidectomy), although in selected instances, only a part of the gland may be removed. At surgery, lymph nodes also may be removed to determine any possible spread of the tumor beyond the thyroid gland. Subsequent therapy depends upon the findings at the time of surgery. Some patients may merely be placed on thyroid hormone and followed with blood tests and ultrasound examinations, while other will receive radioactive iodine to destroy the residual thyroid tissue and then be followed with blood tests and ultrasounds.
Using this type of therapy, the majority of cancers will be either cured or controlled and less than 20 percent will recur. Most of the time, residual cancer can be treated with additional surgery or radioactive iodine. Occassionally, external beam radiation (EBRT) may be needed to treat thyroid cancers that cannot be fully resected or that persist despite RAI treatment. Lastly, there are clinical trials with newer therapies such as targeted chemotherapies that a patient may qualify for if they have aggressive disease.