Diagnosis of Thyroid Cancer
How to diagnose Thyroid Cancer?
Diagnosis is often done after a thorough elicitation of the patient’s history followed by a physical examination.
Investigations of value are:
- Blood tests:
Thyroid function test (TFT) is performed to analyse the level of the hormone Thyroid Stimulating Hormone. As the name suggests, any abnormal value means that the gland is not working properly.If there is suspicion of a medullary cancer, the blood calcium level is assessed and more importantly the level of the hormone calcitonin is checked.
- Ultrasound scan:
The doctor uses an ultrasound device to picture the nodules, learn its size, shape and content. Contents may be solid (more chance of a tumour) or fluid (may be benign). The advantage is that clinically invisible nodules get easily detected.
- Thyroid scan – ‘Blow Hot Blow Cold’:
Here the patient swallows a radioactive substance. The thyroid tissue that takes up this substance is pictured. Based on the uptake a nodule may either be classified as a ‘hot nodule’ (which takes up the substance more than that is absorbed by rest of the normal tissue) or a ‘cold nodule’ (which takes up lesser amount of the substance). Cold nodules are viewed with a bigger index of suspicion, since they may be malignant.
- Biopsy:
This is the test of highest diagnostic value. Here a sample of the tissue is taken and studied by a pathologist.
FNAC: Fine Needle Aspiration Cytology is the most commonly performed one. A thin needle is used to take a little bit of tissue. Sometimes this is done under ultrasound guidance.
Surgical Biopsy: Here the whole nodule is removed by the surgeon during the operation. This is done if the FNAC is non-conclusive. The FNAC is an out-patient procedure whereas a surgical biopsy would require admission and formally get prepared for surgery.
To detect the spread of the cancer that is metastasis, the above investigations are supplemented with further tests like: CT scan, MRI scan, Chest X-ray. Sometimes whole body scans become indicated.
