Thyroid nodules basics Flashcards
What is a nodule?
Growth of abnormal tissue (Typically firm and palpable)
What is the difference between a thyroid nodule and small thyroid lesion
- Thyroid nodules are >1cm
- Small thyroid lesions are <1cm
What are some neck-specific consultation questions for thyroid nodules?
Lump size
Changes
Pain
Duration
Voice changes
Swallow changes
What structures need to be examined in suspected thyroid nodule?
Eyes
Neck and neck triangles
Thyroid gland
Tongue protuberances
Water swallow test
What are some features that predict malignancy?
- New thyroid nodule age <20 or >50
- Male
- Nodule increasing in size
- Lesion >4cm in diameter
- History of head and neck irradiation
- Vocal cord palsy
What are some blood tests required in suspected thyroid nodule?
- TSH (If low, then unlikely to be cancer)
- Calcitonin
- Thyroglobulin
- Thyroglobulin antibody
- PTH
When should thyroglobulin be tested for in cases of surgery?
Pre and post operative
Negative thyroglobulin is only a sign that the tumour has been fully removed if pre-operative levels were high
What are some imaging techniques used in suspected thyroid malignancy?
- Ultrasound (1st line)
- Radioisotope scan - If TSH suppressed
- CT - Used in local cancer invasion or advanced disease
- Laryngoscopy - If vocal cord palsy
What is the ultrasound grading system for thyroid nodules?
- U1 - Normal
- U2 - Benign
- U3 - Indeterminate
- U4 - Suspicious
- U5 - Malignant
What is the fine needle aspiration grading system used in thyroid nodules?
- Thy1 - Non-diagnostic
- Thy2 - Benign
- Thy3 - Indeterminate
- Thy4 - Suspicious
- Thy5 - Malignant
What patients will undergo thyroid lobectomy with isthusectomy in case of thyroid nodule?
- Papillary microcarcinoma
- Minimally invasive follicular carcinoma with capsular invasion only
- Patients in AMES low risk group
What are the indications of sub-total or total thyroidectomy in thyroid nodule formation?
- DTC with extra-thyroidal spread
- Bilateral multifocal DTC
- DTC with distant metastases
- DTC with nodal involvement
- Patients in AMES high risk group
- Thy5 >4cm = Total thyroidectomy
What are some complications of thyroidectomy?
- Superficial haematoma - common and settles
- Hypocalcaemia - Only after total thyroidectomy due to parathyroid function
- Wound infection - Uncommon
- Scar - Abnormal scarring uncommon
- Stridor - Deep haematoma causing laryngeal haematoma
- Nerve injury - Voice change and swallow problems
- Chyle leak - Possible with left level VI lymph node dissection
- Other nerve injury
What is performed in cases of macroscopic lymph node disease in metastatic thyroid malignancy?
Central compartment clearance and lateral lymph node sampling
What risk stratification method is used for post-operative risk stratification?
- A - Age
- M - Metastases
- E - Extent of primary tumour
- S - Size of primary tumour
Who would be AMES low risk?
Young patients (M<40, F<50) with no evidence of metastasis or an older patients with an intrathyroidal papillary lesion or minimally invasive follicular lesion and primary tumour <5cm, with no distant metastasis
What is the 20 year survival rate for low-AMES patients?
99%
Who would be AMES high risk?
Any patient with distant metastases, extrathyroidal disease in papillary cancer, significant capsular invasion with follicular carcionoma, primary tumour >5cm in older patients
What is the 20 year survival rate for AMES high risk?
61%
What will be performed post-operatively in thyroidectomy?
- Calcium checked within 24 hours
- Calcium replacement if corrected calcium below 2mmol/L
- IV calcium for calcium levels <1.8mmol/L or if symptomatic (Shaky, hungry, heart symptoms)
- Patient discharged on T3 or T4
When would whole body iodine scanning be performed?
3-6 months after a sub-total or total thyroidectomy
What is the purpose of whole body iodine scanning?
Low dose radioactive iodine is given and is scanned for, to show where there is thyroid tissue in the body (Metastasis)
What used to be done about a patients T3 and T4 medication before whole body iodine scanning?
- T3 and T4 used to have to be stopped as this would cause a reduction in TSH levels
- TSH stimulates iodine uptake into the thyroid and stimulates T3 and T4 production
- If TSH levels are low, then the radioactive iodine would not be taken up
What is now done about a patients T3 and T4 medication before whole body iodine scanning?
They are given rhTSH injection which allows for transport of the radioisotope despite suppressed TSH levels
What treatment can be performed on remnant thyroid tissue after thyroidectomy?
Thyroid remnant ablation
What occurs in thyroid remnant ablation?
-Patients are admitted to an isolated, lead lined room with non-mains sewerage
-Anything taken in is classified as radioactive waste
-The patient is pre-treated with rhTSH and then a 2-3 GBq capsule of radioactive iodine (I-131)
-This aims to ablate residual thyroid tissue to destroy occult microfoci
What are some forms of systemic anti-cancer therapies used in thyroid nodules?
Sorafenib and lenvatinib for patients with refractory DTC following radioactive iodine
