Thyroid Ca

• A nodule is a term used to define a firm lump underneath the skin, usually greater than 1cm.
• A goitre is a term used to describe a swelling in the neck due to the enlargement of the thyroid gland.
• Anatomy:

  • Receives sympathetic innervation from the sympathetic chain
  • Lymphatic drainage is to the paratracheal and deep cervical lymph nodes
  • Follicular cells - produce thyroid hormone
  • Parafollicular cells - produce calcitonin which reduces serum calcium
• Papillary thyroid Ca:

  • Most common
  • Characteristically spreads via lymphatics
  • Commonly presents as a neck node
  • Associated with radiation exposure
• Follicular Ca:

  • Second most common
  • More likely to present with thyroid swelling
  • Haematogenous route of spread
• Medullary thyroid carcinoma:

  • Cancer of the calcitonin cells
  • Associated with MEN type 2A
  • More likely to have a family history
  • May have other features of MEN 2 e.g. hypertension secondary to phaeochromocytoma
• Anaplastic thyroid carcinoma is an undifferentiated thyroid cancer. It is characterised by aggressive disease and metastases at presentation. It has a poor prognosis, and survival following diagnosis is usually limited to several months only.
• Risk factors for thyroid cancer include:

  • Female sex (the reason for this is unclear)
  • Obesity
  • Benign thyroid disease (Hashimoto’s, thyroid adenomas, a goitre)
  • Radiation exposure (thyroid gland is sensitive to radiation)
  • Family history (certain genetic disorders such as multiple endocrine neoplasia)
  • Systemic lupus erythematosus (SLE)
• Typical symptoms of thyroid cancer include:

  • Neck lump
  • Hoarse voice
  • Dysphagia
  • Odynophagia
  • Dyspnoea
  • Stridor
• General symptoms may include:

  • Weight loss, anorexia
  • Lethargy, fatigue
  • Diarrhoea
  • Bone pain (metastatic disease)
  • Pulsatile lesion (metastatic disease)
• Typical clinical findings may include:

  • General cachexia
  • Neck lump
  • Thyroid goitre
  • Stridor or hoarseness
• When assessing a thyroid nodule, features that increase suspicion of malignancy include: 

  • Age <20 years or >60 years
  • Firmness of nodule
  • Rapid growth
  • Fixed to adjacent structures
  • Vocal cord paralysis
  • Regional lymphadenopathy
  • History of neck irradiation
  • Family history of thyroid cancer
• Relevant bedside investigations include:

  • ECG: endocrine disorders of the thyroid gland can cause arrhythmias (e.g. hyperthyroidism and atrial fibrillation)
  • Urinalysis: the presence of urinary catecholamines may indicate a phaeochromocytoma or paraganglioma, which may indicate a diagnosis of MEN
• Relevant laboratory investigations include:

  • Thyroid function tests: thyroid cancer is usually associated with a euthyroid state; however, advanced cancers can cause hypothyroidism (due to the destruction of healthy thyroid tissue) or hyperthyroidism (due to the presence of more active cells)
  • Thyroid autoantibodies
  • Plasma calcitonin and carcinoembryonic antigen (CEA): if suspicious for MEN
• Imaging:

  • US - all patients, determines if fine needle aspiration is needed
  • CT/MRI - if retrosternal disease or suspicion of metastatic disease
• Fine needle aspiration results are graded using the Thy classification
• NICE advises considering a 2-week wait (urgent suspected cancer) referral for all patients with an unexplained thyroid lump, especially if they have red flag features:

  • Unexplained hoarseness or voice changes
  • Associated lymphadenopathy
  • Sudden onset of an expanding painless thyroid mass
  • Any other red flags of malignancy
  • Compressive symptoms of dysphagia, or breathlessness
• Patients who have undergone total thyroidectomy will require life-long thyroxine replacement. If the parathyroids have been removed, patients may also require calcium replacement.
• Serum thyroglobulin is a marker used to monitor for signs of disease recurrence. This protein is only produced by follicular cells. When raised, it is suspicious for disease recurrence and should prompt further investigation.
• The primary treatment modality for thyroid cancer is surgery. There is a role for adjuvant therapy in certain cases.
• Follicular thyroid Ca cannot be diagnosed with fine needle aspiration
• Calcitonin is used to monitor medullary thyroid cancer