CARCINOMA OF THE THYROID Dr Sami Asfar

CARCINOMA OF THE THYROID “Surgical Aspects” Sami Asfar M.B.,Ch.B, MD (UK), FRCSEd, FACS Professor and Chairman, Department of Surgery Faculty of Medicine, Kuwait University Prof. Sami Asfar Embryology Thyroid Descent Prof. Sami Asfar Embryology Thyroid and Parathyroid Glands Pouch I Eustach tube & Middle ear Pouch II Tonsil Pouch III Inf. Parathyroid &Thymus Pouch IV Superior Parathyroid Thyroid (Floor of pharynx) Prof. Sami Asfar Surgical Anatomy of Thyroid Gland •Pretracheal Fascia: –Extends from the hyoid bone to the fibrous pericardium –Encloses the neck viscera : •Thyroid, trachea, larynx, pharynx & oesophagus •Thyroid moves with swallowing Prof. Sami Asfar Surgical Anatomy of Thyroid Gland Blood Supply • Two main arteries (Thyroidea ima artery) • Three main veins Prof. Sami Asfar Recurrent Laryngeal Nerve Prof. Sami Asfar CARCINOMA OF THE THYROID • The most common reason for thyroid surgery today is to diagnose and treat a suspected thyroid neoplasm • Usually presents as solitary or prominent thyroid nodule in an asymptomatic patient Prof. Sami Asfar Solitary Thyroid Nodule • Most solitary nodules are benign • Malignant until proven otherwise Prof. Sami Asfar Assessment of a Thyroid Nodule 1. 2. 3. 4. 5. 6. 7. Age Sex Family history History of radiation exposure Characteristics of the nodule Cervical lymph nodes Vocal cords mobility Prof. Sami Asfar Assessment of a Thyroid Nodule 1. 2. 3. 4. 5. 6. 7. Age Sex Family history History of radiation exposure Characteristics of the nodule Cervical lymph nodes Vocal cords mobility Prof. Sami Asfar Assessment of a Thyroid Nodule  Age: Children: 10-15% malignant Child bearing age: Most nodules are benign After 40 yrs age:  Cancer increases by 10% for each 10 years Prof. Sami Asfar Assessment of a Thyroid Nodule 1. 2. 3. 4. 5. 6. 7. Age Sex Family history History of radiation exposure Characteristics of the nodule Cervical lymph nodes Vocal cords mobility Prof. Sami Asfar Assessment of a Thyroid Nodule  Sex: Thyroid nodules are more common in Females Female : Male 4:1  High risk of malignancy: Female > 50 years Male > 40 years Prof. Sami Asfar Assessment of a Thyroid Nodule 1. 2. 3. 4. 5. 6. 7. Age Sex Family history History of radiation exposure Characteristics of the nodule Cervical lymph nodes Vocal cords mobility Prof. Sami Asfar Assessment of a Thyroid Nodule  Family history of thyroid cancer: Medullary thyroid cancer May be transmitted as autosomal dominent trait  History of Radiation Exposure: Therapeutic radiation to head and neck: 5-10 fold increase in incidence of thyroid cancer Prof. Sami Asfar Assessment of a Thyroid Nodule 1. 2. 3. 4. 5. 6. 7. Age Sex Family history History of radiation exposure Characteristics of the nodule Cervical lymph nodes Vocal cords mobility Prof. Sami Asfar Assessment of a Thyroid Nodule  Characteristics of the nodule:  Consistency: Firm Soft Suggest malignancy Probably benign   Infiltration Number of nodules: Solitary Cold nodule 20% Malignant 25-30% Malignant Prof. Sami Asfar Assessment of a Thyroid Nodule 1. 2. 3. 4. 5. 6. 7. Age Sex Family history History of radiation exposure Characteristics of the nodule Cervical lymph nodes Vocal cords mobility Prof. Sami Asfar Assessment of a Thyroid Nodule  Cervical Lymph nodes: Enlarged ipsilateral L.N. Malignancy  Vocal cords mobility: Paralysis of ipsilateral cord Malignancy Prof. Sami Asfar Investigations for a Thyroid Nodule 1. Blood tests: a. b. c. d. a. b. c. d. Thyroid Function Test (TFT) Antithyroid Antibodies Serum Thyroglobulin Thyrocalcitonin Assay Plain X-ray neck and chest Ultrasound Thyroid and neck Radioisotope Thyroid Scan CT Scan neck 2. Imaging: 3. Fine Needle Aspiration Cytology Prof. Sami Asfar Investigations for a Thyroid Nodule Blood Tests a. Throid Function Test (TFT) • • Little diagnostic value Hyperfunction: < 1% all thyroid cancers b. Antithyroid Antibodies • • • • • Prof. Sami Asfar Positive in Hashimoto’s Thyroiditis Thyroid cancer may coexist with thyroiditis Does not rule out malignancy if positive Follow up Increased in Medullary Carcinoma c. Serum Throglobulin: d. Thyrocalcitonin Assay Investigations for a Thyroid Nodule Imaging a. Plain X-ray neck and chest • • • Calcifications Deviation of the trachea Retrosternal extension b. Ultrasound Thyroid and neck • • • • Prof. Sami Asfar Size, location, number Cystic, solid, complex Detects nonpalpable nodules Guide FNAC needle Investigations for a Thyroid Nodule Imaging c. Radioisotope Thyroid Scan • • • • Technetium-99m (99mTC) pertechnetate or 123I Detects nodules > 5 mm Retrosternal extension Does NOT differentiate benign from malignant Cold nodule 20-35% malignant Hot nodules usually benign Postoperative: Assess thyroid remnant Recurrence or Metastasis • Prof. Sami Asfar Investigations for a Thyroid Nodule Imaging c. CT neck and upper mediastinum: • • Rarely used Retrosternal extension Prof. Sami Asfar Investigations for a Thyroid Nodule Fine Needle Aspiration Cytology (FNAC) The most powerful test for the diagnosis of a thyroid nodule  Accuracy > 90%  Disadvantage: Cannot Differentiate between Follicular adenoma and Follicular Carcinoma “Follicular Neoplasm” Inadequate Specimen Repeat FNAC Prof. Sami Asfar Investigations for a Thyroid Nodule FNAC Solid Cystic Malignant Follicular Cells Colloid “Benign” Recurs or Residual mass Disappears Surgery Observe Repeat FNAC Observe Surgery Prof. Sami Asfar Surgery for Thyroid Carcinoma Benign solitary nodule Lobectomy + Isthmectomy Final histopathology Malignant Total Thyroidectomy (Near Total Thyroidectomy) Prof. Sami Asfar Follicular cells Lobectomy + Isthmectomy Frozen Section Malignant Benign / Unsure Close (wait final report) Total Thyroidectomy (Near Total Thyroidectomy) Benign Malignant Follow up Prof. Sami Asfar Papillary, Follicular, Hürthle cell, Medullary Carcinoma Total Thyroidectomy (Near Total Thyroidectomy) Lymph Nodes  Berry picking  Central nodes dissection for Medullary Carcinoma Prof. Sami Asfar Anaplastic Carcinoma Total Thyroidectomy Lymph Nodes Radical or Modified Neck Dessection Prof. Sami Asfar Why Total Thyroidectomy? 1. Patients are given replacement thyroid hormone to suppress TSH: No reason to preserve the thyroid 2. 3. 4. 10-30% Thyroid Cancer is multifocal Facilitates postoperative Radioiodine therapy Thyroglobulin levels Undetectable or very low levels following total thyroidectomy & Radioiodine: Improves the chances of this test as a screen for recurrence of disease Fewer recurrence 5. Prof. Sami Asfar Postoperative Complications 1. Recurrent laryngeal nerve injury 0-3% 2. Hypoparathyroidism (permanent) 3. Bleeding Asphexia 0-8% Prof. Sami Asfar Tumour Markers for Follow Up 1. Serum Thyroglubulin: Differentiated carcinoma 2. Serum Calcitonin: Medullary Carcinoma Prof. Sami Asfar Postoperative Therapy for Carcinoma Thyroid 1. TSH Suppression with Thyroxin 2. Radioactive Iodine ablation (RAI): (hold thyroid therapy for 4-6 weeks to induce hypothyroid state and cause TSH elevation to stimulate radioiodine uptake by the thyroid remnant and residual carcinoma )  Ability to ablate depends on the extent of thyroid surgery 3. Deep X-Ray Therapy and Chemotherapy (Doxorubicin based) for Anaplastic Carcinoma Prof. Sami Asfar Prof. Sami Asfar