How is thyroid cancer diagnosed?
The doctor may use several tests to confirm a diagnosis of thyroid cancer. The size and location of the lump has to be identified and it has to be determined whether the lump is non-cancerous (benign) or cancerous (malignant). Blood tests, such as the thyroid stimulating hormone (TSH) test, may be ordered to check how well the patient's thyroid is functioning.
A test known as the calcitonin test may be ordered if medullary thyroid cancer is suspected. Calcitonin is a hormone produced by the C cells (also called the parafollicular cells) of the thyroid gland, in response to rising levels of calcium in the blood. This hormone lowers calcium levels in blood serum by slowing the rate at which the bones absorb it and increasing the rate at which the kidneys discharge it. When the parafollicular cells of the thyroid become cancerous, they produce too much calcitonin. Because increased serum levels of the calcitonin hormone are characteristic of medullary thyroid cancer, the calcitonin test, which measures serum levels of calcitonin, can be used to confirm a diagnosis of medullary thyroid cancer.
Imaging tests such, as a radioactive scan can be used to identify any abnormal areas in the thyroid. The patient is given a very small amount of radioactive iodine, which can either be taken by mouth or injected into the thyroid. Since the thyroid is the only gland in the body that absorbs iodine, the radioactive iodine accumulates there. A x-ray image can then be taken or an instrument called a "scanner" can be used to identify areas in the thyroid that do not absorb iodine normally. These abnormal spots are called "cold spots" and further tests are performed to check whether the cold spots are benign or malignant tumors. If a significant amount of radioactive iodine is concentrated in the nodule, then it is termed "hot" and is usually benign.
The most accurate diagnostic tool for thyroid cancer is a biopsy. In this process, a sample of thyroid tissue is withdrawn and examined under a microscope. The tissue samples can be obtained either by drawing out a sample of tissue through a needle (needle biopsy) or by surgical removal of the nodule (surgical biopsy). If thyroid cancer is diagnosed, further tests may be done to learn about the stage of the disease and help the doctors plan appropriate treatment.
More information on thyroid cancer
What is thyroid cancer? - Thyroid cancer is a disease in which the thyroid cells become abnormal, grow uncontrollably, and form tumors.
What types of thyroid cancer are there? - There are four major types of thyroid cancer: papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer.
What causes thyroid cancer? - Doctors do not know what causes most cases of thyroid cancer. Exposure to radiation during childhood is a known risk factor for thyroid cancer.
What're the symptoms of thyroid cancer? - The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the neck. Other symptoms are rare.
What're the risk factors for thyroid cancer? - Risk factors for thyroid cancer include radiation, family history, genetic conditions, sex, reproductive history.
How is thyroid cancer diagnosed? - A test known as the calcitonin test may be ordered if medullary thyroid cancer is suspected. Imaging tests identify any abnormal areas in the thyroid.
What's the treatment for thyroid cancer? - Treatment for thyroid cancer depends on the type of cancer and its stage. Surgery is the most common form of treatment for thyroid cancer.
How to prevent thyroid cancer? - Because many people develop thyroid cancer without having any known risk factors for the illness, this form of cancer is hard to prevent.