How is Thyroid Cancer Diagnosed?
- At some point in their lives, many people will develop a thyroid nodule — and most of these are benign or non-cancerous.
- If a healthcare provider suspects a thyroid nodule may be cancerous, they will order a series of tests — which may include testing TSH (thyroid stimulating hormone) levels, an ultrasound, and a biopsy.
- Once you have completed the steps of checking thyroid function (TSH levels), having an ultrasound evaluation, and undergoing a biopsy (if recommended by your provider), your doctors will determine whether you truly have thyroid cancer and, if so, how far it has spread. This process is called staging.
- Thyroid cancers are typically staged using a system called TNM — which evaluates the size and location of the tumor (T), lymph node involvement (N), and whether the cancer has spread or metastasized (M).
If a nodule is found and your healthcare provider thinks it looks suspicious, a series of tests will be ordered — even if the patient has not experienced any other symptoms like a sore throat or difficulty swallowing.
Read MoreHow is Thyroid Cancer Diagnosed?
The presence of symptoms and, more precisely, when patients note the presence of a nodule, it should start a prompt medical investigation. Thankfully, in most cases, the nodule will be ruled benign (or non-cancerous), and its approach differs from when it turns out to be malignant (cancerous).
“About seven to 10% of thyroid nodules are cancerous. Part of the challenge is identifying which nodules are cancerous compared to the majority,” Dr. Orloff explains.
Following clinical examination, the exams your medical team might use to diagnose thyroid cancer include:
- Thyroid stimulating hormone (TSH) test
- Ultrasound
- Biopsy
TSH testing
The most important consideration for the blood exam is to evaluate the serum levels of a hormone called TSH or thyroid stimulating hormone. This hormone is produced by a small glandule located in the brain (pituitary gland) to stimulate the thyroid to produce and release hormones.
Although it cannot discern between a malign or benign disease, the levels of TSH and thyroid hormones can help doctors determine if the nodule produces hormones. Oftentimes, nodules that make thyroid hormone are not cancerous.
“A high TSH means the patient has not enough thyroid hormone and the brain or the pituitary is releasing more thyroid stimulating hormone to drive the thyroid to work a little harder and make more hormone. On the other hand, if the thyroid is overactive, which can occur with a variety of conditions, then the pituitary decreases its production of TSH. So, the TSH would be very low. A high TSH means a low thyroid function, a low TSH means an over or a high thyroid function,” Dr. Orloff explains.
Ultrasound
When it comes to imaging, ultrasound (USG) is not only comparable to but generally preferred over methods like computerized tomography (CT) or magnetic resonance imaging (MRI) when evaluating thyroid nodules.
Because of its optimal resolution and ability to provide real-time images, ultrasound offers detailed information about the thyroid gland, including its overall size, the presence of nodules, and each nodule’s location, blood supply, depth, and relationship to surrounding structures.
“Ultrasound can detect very subtle changes in the thyroid ranging from small nodules to extensive changes. So, ultrasound is both a blessing and a curse in some ways because ultrasound can lead to the detection of nodules that may or may not be harmful or suspicious,” Dr. Orloff explains.
Biopsy
One of the biggest advantages of ultrasound is that it allows the physician to perform a guided biopsy. In this procedure, a radiologist visualizes the nodule on a screen and directs the needle precisely into the targeted area to collect a tissue sample.
This approach ensures greater accuracy, enhanced safety, and fewer complications compared to biopsies done without imaging guidance. In most cases, it provides doctors (pathologists) with the information needed to determine whether a nodule is benign or malignant, guiding the next steps in your care and treatment.
“The diagnosis of thyroid cancer is usually made through a fine needle biopsy, and that’s a procedure that’s done to confirm or rule out cancer by inserting a needle into a lump, withdrawing some cells, and having the cells examined by a pathologist and sometimes submitted to additional genetic testing that confirms or rules out cancerous changes and mutations in the genes or the DNA or RNA or recognizing changes in the cells that are representative of cancer,” Dr. Orloff explains.
Once you have completed the steps of checking your thyroid function (TSH levels), having a thorough ultrasound evaluation, and undergoing a biopsy (if recommended by your healthcare provider), your doctors will determine whether you truly have thyroid cancer and, if so, how far it has spread. This process is called staging. Staging helps your medical team decide on the best treatment plan for you and predict how the disease might behave.
How Is Thyroid Cancer Staged?
Whenever a new diagnosis of cancer is made, the next question should always be: How much has the disease progressed? To answer this question, doctors need to thoroughly evaluate other organs and systems to learn about your disease and often order a new work-up. This process is called staging.
Most thyroid cancers — especially the common types like papillary and follicular thyroid cancer — are staged using a system called TNM. This system comes from the American Joint Committee on Cancer (AJCC) and is also recognized in official documents, including the NCCN guidelines. Although it sounds a bit technical, the TNM system breaks down as follows:
- T (Tumor): How large is the tumor, and where is it located? For instance, T1 usually means the tumor is smaller and confined to the thyroid. Higher T numbers (like T3 or T4) may mean the tumor is larger or growing into nearby tissues.
- N (Nodes): Has the tumor spread to nearby lymph nodes in the neck? N0 means no spread to lymph nodes, while N1 indicates there is cancer in some lymph nodes.
- M (Metastasis): Has the cancer spread, or metastasized, to other organs like the lungs or bones? M0 means no distant spread; M1 means the cancer has spread to distant organs. Together, doctors use T, N, and M to assign an overall stage (usually from I to IV).
Stage I thyroid cancer is often small and located only within the thyroid gland. Stage II or III typically means the tumor is larger or has started to move into lymph nodes or nearby tissues. Stage IV indicates more extensive spread to lymph nodes in the neck or other areas of the body.
Once your doctors have determined your cancer stage, they will be able to evaluate and discuss the best treatment paths with you.
Questions To Ask Your Doctor
- What sort of testing do you recommend in my case?
- Should I consider a second opinion or additional testing?
- How will you determine stage in my case?
- What is the standard of care for people diagnosed at this stage?
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