Diagnosis and staging of thyroid cancer
How is thyroid cancer diagnosed?
Thyroid cancer is one of the most curable cancers if diagnosed early and treated before it gets metastasized. Thyroid cancer is diagnosed when any of the signs or symptoms show up usually. Read more about thyroid cancer here. Following tests are often performed to confirm the cancer:
Medical history and physical exam:
These are exams used to check the general health along with the signs of thyroid cancer like nodules and lymph nodes. The patient’s medical history is also evaluated in order to give them appropriate treatment. The size and firmness of the thyroid gland and lymph nodes are of special interest of these tests.
Biopsy for thyroid cancer involves the removal of cells from the suspicious areas and examining them under a microscope. This procedure is often followed by blood tests and other scans. It is one of the most reliable diagnostic procedure for thyroid cancer.
A fine needle aspiration involves removing of cells of the suspected region through a thin needle whereas surgical biopsy means examination of cells removed through or post surgery. During the procedure, the patient is given anesthesia to remove the nodule or get blood cell samples from the nodules. Doctors use an ultrasound during the procedure to see if they are extracting cells from the right place or not. Bleeding is not very common in biopsies unless the patient has bleeding disorders. Read more about surgery for thyroid cancer here.
This test involves the checking of the larynx with a mirror or with a laryngoscope, a thin, tube-like instrument attached with a light and lens. This procedure is mainly performed to check the normal functioning of the vocal cords because the thyroid tumours may press the vocal cords.
Blood hormone tests:
These tests are done to check the levels of certain hormones in the blood and abnormalities in these levels indicate a disease in the organ or tissue related to that particular hormone most important of those is thyroid-stimulating hormone (TSH). This hormone secreted by the pituitary gland in the brain, which is responsible for the simulation of production and growth of thyroid hormone. Other hormones such as calcitonin are also examined along with the antithyroid antibodies in the blood sample.
Blood chemistry studies:
Certain blood tests are performed to check the levels of certain substances, mainly calcium that are released into the blood and abnormalities in these levels indicate certain diseases.
This procedure uses ultrasounds which bounce back on internal tissues or organs in the neck, and make echos. These echoes give a picture of the organs,also known as sonograms.
Ultrasound aims in producing the side of the thyroid nodules and helps in knowing if the nodules are solids or fluid-filled. Ultrasounds are used during biopsies too, to guide the fine-needle aspiration.
CAT or CT scan:
Also known as tomography, computerized tomography, or computerized axial tomography, this scan gives the detailed pictures of the organs from different angles, generated by a computer which is linked to an x-ray machine. For the scan, a dye is give to the patients intravenously or orally for the tissues to be imaged clearly.
How is thyroid cancer staged?
Staging of thyroid cancer helps the doctors figure out how much the cancer has spread in the thyroid gland and determine its best treatment. Staging also helps calculate survival statistics. The lower the number of the stage, the less is the cancer has spread, with early stages being 1 and the most advanced stage being 4. Know more about staging of thyroid cancer here.
Cancer types that form tumours are staged using TNM system and the same method is used for thyroid cancer too. The size of the primary tumour (T), the presence of cancerous lymph nodes (N) and how far the thyroid cancer has spread to a different part of the body (M) can be described using the TNM system.
Tis (carcinoma in situ) is an early stage thyroid cancer, which hasn’t spread. Thyroid cancers at such an early stage cannot be diagnosed.
T1 stage: This stage means that the tumour is less than 2 cm or less in the thyroid in any direction. It is further divided depending on the tumour size: T1A, T1B and T1C in the order of increasing size of tumour.
T2 stage: In this stage, the size of the tumour varies between 2 cm and 4 cm.
T3 stage:Here, the tumour is bigger than 4 cm in size.
T4 stage: In this stage,the cancer has grown out of thyroid to the nearby blood vessels.
The node describes whether the cancer has spread to the lymph nodes or not.
N0 stage: Shows that there are no lymph nodes containing cancer.
N1 stage: There is a presence of 1 to 3 cancerous lymph nodes.
N2 stage4: or more lymph nodes contain cancerous lymph nodes, which means that the cancer can further spread in the body.
This gives information about the cancer spreading to other parts of the body.
M0 stage: The cancer has not spread to other distant parts of the body.
M1 stage: The cancer has spread to other body parts also.
Stages of thyroid cancer:
The exact stages of thyroid cancer depend on the type of thyroid cancer too and are explained in detail in the further articles.