Thyroid Surgery Year 2 2024-2025 RCSI PDF

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Title Thyroid Surgery Class Year 2 Course Surgery Year 2024-2025 LEARNING OBJECTIVES At the end of this session you should know and be able to Recall anatomy of thyroid gland and its surrounding structu...

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Title Thyroid Surgery Class Year 2 Course Surgery Year 2024-2025 LEARNING OBJECTIVES At the end of this session you should know and be able to Recall anatomy of thyroid gland and its surrounding structures & its vascular supply. Discuss the indications for lobectomy vs total thyroidectomy. Discuss the role of radioactive iodine in the management of thyroid cancer Describe the surgical approach, its complications and recent advances TEST YOUR KNOWLEDGE Which of the following is a differentiated thyroid cancer? 1. Anaplastic carcinoma of the thyroid 2. Medullary carcinoma of the thyroid 3. Papillary carcinoma of the thyroid 4. Lymphoma of the thyroid 5. Sarcoma of the thyroid TEST YOUR KNOWLEDGE What is the commonest clinical presentation of thyroid cancer? 1. Exophthalmos (bulging eyes) 2. Uniformly enlarged goiter 3. A solitary thyroid nodule 4. Hoarse voice 5. Difficulty swallowing TEST YOUR KNOWLEDGE Which of the following is an indication for thyroid surgery? Answer True or False for each stem. 1. Cosmesis 2. Thyroid cancer 3. Toxic thyroid nodule 4. Grave’s disease (in certain settings) 5. Difficulty swallowing TEST YOUR KNOWLEDGE Which of these nerves is at risk of being injured during thyroid surgery? 1. Superior laryngeal nerve 2. Recurrent laryngeal nerve 3. Accessory nerve 4. Vagus nerve 5. Phrenic nerve ANATOMY OF THE THYROID  IMPORTANT NEARBY ANATOMICAL STRUCTURES The recurrent laryngeal nerve lies in a groove between the trachea and oesophagus, emerging medial to the inferior portion of the gland. The external laryngeal nerve passes medially to the superior portion of the gland to innervate cricothyroid How does damage to these nerves present? Thyroid Surgery  THYROID NODULE – DIFFERENTIAL DX Vast Majority of thyroid nodules are benign Benign Malignant Multinodular goitre Papillary carcinoma Follicular adenoma Follicular carcinoma Thyroglossal cyst Medullary carcinoma Graves disease Anaplastic carcinoma Colloid Goitre Lymphoma Thyroiditis Metastatic - RARE!  TYPES OF THYROID CANCERS Differential Diagnosis of a Malignant Lesion ▪ Papillary Thyroid Carcinoma Differentiated ▪ Follicular Thyroid Carcinoma Thyroid Cancers ▪ Medullary Thyroid Carcinoma ▪ Anaplastic Thyroid Carcinoma ▪ Lymphoma ▪ Sarcoma ▪ Metastasis (breast, colon, renal, melanoma)  PAPILLARY THYROID CANCER Peak onset between 30-50 years Female:male – 3:1 Risk factors: Radiation exposure Family history Typically spreads through lymphatics Rarely metastasises – lung, bone (rarer sites include brain, kidneys, liver) THYROID MALIGNANCY Frequently presents as a solitary thyroid nodule Clinical features associated with increased risk of malignancy in patients with a thyroid nodule: – Age 60 – Firmness on palpation – Rapid growth – Fixation to adjacent structures – Hoarseness / Vocal cord paralysis – Associated lymphadenopathy – History of neck irradiation – Family hx of thyroid cancer – Hx of Hashimoto’s thyroiditis (for lymphoma) FOLLICULAR THYROID CANCER Second most common thyroid cancer Peak onset 40-60 years F:M = 3:1 Risk factors: Radiation exposure Family history Iodine deficiency – Metastatic activity: typically spreads via haematogenous route – Bone(lytic lesions), lungs ,but may also involve the brain, liver, bladder, and skin – Metastases may be hormonally active - hyperthyroidism  MEDULLARY THYROID CANCER Neuroendocrine tumour of the parafollicular or C cells TFTs usually normal Production of calcitonin is a feature – tumour marker for medullary ca May occur sporadically or as part of an inherited syndrome Sporadic: 80%, slight female predominance Present with single nodule and often cervical lymphadenopathy Familial: as part of MEN-2 Prior to surgery, patients must be evaluated for other neuroendocrine tumours  ANAPLASTIC THYROID CANCER Undifferentiated tumours of thyroid follicular epithelium Aggressive disease, mortality approaching 100% May present with signs of local invasion- hoarse voice, difficulty swallowing Typically older patients Early palliative care input important Usually no indication for surgical intervention Palliative chemoradiotherapy may be of some value in selected cases  MULTIPLE ENDOCRINE NEOPLASIA MEN 1 Autosomal dominant. Mutation of RET gene. Parathyroid, Pituitary and Pancreatic endocrine (gastrinomas/insulinomas). MEN 2 Mutation of RET gene, autosomal dominant. 2a : Medullary Thyroid, Phaeochromocytoma, hyperparathyroidism. 2b : Medullary Thyroid, Phaeochromocytoma, ganglioneuromas, marfanoid habitus. EVALUATION OF THYROID NODULE Pathology - FNA DIAGNOSIS Clinical Radiology: Hx, examination, U/S.isotope scan, blood tests +/- CT, MRI Clinical examination Radiology Pathology Physical examination – Ultrasound assessment Thy 1 – Non-diagnostic *from column guide* U1-Normal/Simple cyst Thy 2 – Non-neoplastic Blood tests – Thyroid function tests U2-Benign features Thy 3a – Cytological atypia of (Thyroid stimulating hormone uncertain significance (~90% T4 & T3) U3-Indeterminate Benign) (Homogenous, hyperechoic, halo, central vascularity) Thy 3f – Follicular lesion / suspected follicular neoplasm U4-Suspicious (Solid/ (~80% Benign) hypoechoic, disrupted peripheral calcification, Thy 4 – Suspicious of lobulated outline malignancy (80% Malignant) U5- Suggestive of cancer, Thy 5 – Malignant associated LN POOR PROGNOSTIC FACTORS Older age Large tumour size Soft tissue invasion Distant metastases Overall, the prognosis of papillary cancer is good Indications for thyroidectomy Benign Malignant  THYROIDECTOMY – INDICATIONS BENIGN DISEASE Goitre Compression of adjacent structures Cosmesis  THYROIDECTOMY – INDICATIONS BENIGN DISEASE Control of thyrotoxicosis Toxic multinodular goitre Toxic adenoma Graves disease – Not responsive to medical treatment – If medical management not be advised, e.g. patient planning to become pregnant – Refractory hyperthyroidism/carbimazole failure. – patient preference- following doctor-patient discussion  THYROIDECTOMY – INDICATIONS MALIGNANT DISEASE Total Thyroidectomy - Indications High-risk differentiated thyroid cancer (tumour ≥4 cm or with gross extrathyroidal extension) Clinically apparent metastatic lymph nodes or distant metastases Medullary thyroid cancer Thyroid cancer in a patient with prior radiation to the head and neck or family history of differentiated thyroid cancer in a first-degree relative (due to high recurrence risk)  THYROIDECTOMY – INDICATIONS MALIGNANT DISEASE Thyroid Lobectomy – Indications Low-risk differentiated thyroid cancer - between 1 and 4 cm without gross evidence of extra thyroidal extension or clinical lymph node metastases. Unifocal differentiated thyroid cancers that are