1. What is a thyroid nodule?

An abnormal growth of cells that form a lump within the thyroid gland, a butterfly-shaped gland at the base of the neck. Most lumps are benign (non-cancerous), however a small number can be cancers (5%).

2. Does a thyroid nodule need surgery?

Thyroid nodules need surgery if they are causing local symptoms due to their size or position. They may cause speech, swallowing or breathing difficulties. Alternatively they may need to be removed if there is a risk of cancer. This is assessed based on the ultrasound appearance of the nodule and a biopsy.

3. What is a TIRADS classification?

This is a risk assessment of a nodule based on its ultrasound appearance and guides the need for biopsy. It is subclassified into:

  • TIRADS 1 - Benign
  • TIRADS 2 - Not suspicious
  • TIRADS 3 - Mildly suspicious. Biopsy if 2.5 cm or larger. Observe with ultrasound if between 1.5 cm to 2.5 cm in size.
  • TIRADS 4 – Moderately suspicious. Biopsy if 1.5 cm or larger. Observe with ultrasound if between 1.0 cm and 1.5 cm in size.
  • TIRADS 5 – Highly suspicious. Biopsy if 1.0 cm or larger. Observe with ultrasound if between 0.5 cm and 1.0 cm in size.

4. How is a biopsy of a thyroid nodule performed?

This is performed by a doctor using ultrasound to guide the biopsy and accurately sample the nodule. For the biopsy, a very thin needle is used to withdraw cells from the thyroid nodule. The needle used is smaller in diameter than those used in most blood draws.

5. What does my thyroid biopsy result mean?

Thyroid biopsies are classified based on the appearance of the cells using the Bethesda classification to give a risk of cancer.

  • Non diagnostic (Bethesda 1)
    • o Needs repeat biopsy
  • Benign (Bethesda 2)
    • Nodule may be observed based on low risk of malignancy in appropriate patients.
  • Atypia of undetermined significance (Bethesda 3)
    • 14 % risk of malignancy
  • Follicular Neoplasm (Bethesda 4)
    • 25 % risk of malignancy
  • Suspicious for malignancy (Bethesda 5)
    • 70% risk of malignancy
  • Malignant (Bethesda 6)
    • 99% risk of malignancy

For Bethesda 3 nodules, after consideration of clinical and ultrasound features, investigations such as repeat FNA or molecular testing may be used to supplement malignancy risk before recommending either surveillance or diagnostic surgery.

Bethesda 4-6 lesions generally require surgery.

6. Can you live a normal life without your thyroid?

People can live full, long lives without a if they take thyroid medication to replace the absence of thyroid hormones in their body.

Dr Chris Lehane
Thyroid, Head and Neck Cancer, Sarcoma Surgeon