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Prof. S. Deivanayagam MS Professor & HOD of Surgery Madras Medical College Carcinoma of Thyroid

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Ca. Thyroid - Types : - Primary / secondary Follicular cell-derived Papillary thyroid cancer Follicular thyroid cancer Anaplastic thyroid cancer Lymphocyte derived Lymphoma C-Cell derived Medullary thyroid cancer Secondary breast, colon, melanoma

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Differentiated Thyroid Ca. : - 85% of all thyroid cancers Derived from follicular cells Types Papillary carcinoma Follicular carcinoma Mixed Papillary Follicular Hurthle cell carcinoma

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Etiology & Risk factors : - Male sex Previous neck irradiation For Hodgkins lymphoma Papillary ca. Pre-existing lesions MNG Follicular ca. Hashimotos Papillary ca. (controversial) Iodine deficiency Follicular ca Family H/O Familial Syndromes

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Familial Non-Medullary Thyroid ca : -

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Clinical Features : - MC presentation Painless swelling in the neck Pain Dysphagia Stridor Rapid enlargement Hoarseness of voice (most important) Dyspnoea, Hemoptysis (late & rare) Lateral aberrant thyroid lymphnode mets in papillary ca. thyroid Pulsatile bony secondaries in follicular thyroid ca.

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Papillary Thyroid Ca. : - Most common type (~80%) Young females (mean age 30 - 40 yrs) Least malignant one of the curable malignancies Commonly metastasize to neck nodes Distant metastasis uncommon Minimal or occult/microcarcinoma refers to tumours of 1 cm or less in size with no evidence of local invasiveness through the thyroid capsule or angioinvasion, and that are not associated with lymph node metastases

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PTC Neck secondaries : -

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PTC Types : - Types Follicular variant Tall cell Columnar cell Diffuse sclerosingPoor Prognosis Insular Breaking of capsule

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PTC Pathology : - Gross : - Multi-focal Unencapsulated but often has pseudocapsule Microscopic : - Closely packed Papillae Psammoma bodies Oval or elongated pale staining nuclei with ground glass appearance Orphan Annie eye cells

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Papillae : -

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Psammoma bodies : -

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Orphan Annie Cells : -

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Orphan Annie : -

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Investigations : - USG neck To identify the lesion To categorize the nodule To detect associated lymphadenopathy To take guided FNAC FNAC Best first line diagnostic procedure for papillary ca. Thyroid function test

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PTC Prognostic Systems : - AGES Age, Grade, Extent & Size AMES Age, Mets, Extent & Size GAMES Grade, Age, Mets, Extent & Size FactorsLow RiskHigh Risk Age40 yrs SexFemaleMale ExtentIntrathyroidalExtrathyroidal MetastasisNonePresent Size4 cm GradeWell differentiated Poorly differentiated

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PTC Prognostic Systems : - DeGroots classification Class I Intra-thyroidal Cass II Cervical node mets Class III Extra-thyroidal invasion Class IV Distant mets Most important prognostic factor Age at diagnosis Lymph node mets No prognostic significance

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Follicular Thyroid Ca. : - Accounts for ~10% of thyroid ca. Common in females Mean age 40 50 yrs Common in iodine deficient areas May coexist with MNG Metastasize to flat bones pulsatile bony secondaries Lymph node metastasis uncommon

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FTC Bone Mets : -

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FTC Types : - Minimally invasive Capsular invasion without involvement of surrounding parenchyma and vascular invasion (except those within tumour) Widely invasive Surrounding parenchymal and / or vascular invasion

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FTC Pathology : - Gross Solitary & Encapsulated Microscopic Well differentiated cells Presence of Vascular and / or capsular invasion FNAC & frozen section cannot distinguish between follicular adenoma & carcinoma Minimal tissue required - Hemithyroidectomy

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FTC Capsular Invasion : -

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TNM Classification : - Common for all differentiated thyroid carcinomas The only TNM system to incorporate the age of the patient Separate for differentiated, medullary and anaplastic ca.

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TNM for DTC AJCC 7 th : - T1Tumour 2cm or less & confined to thyroid T2Tumour 2 4 cm & confined to thyroid T3 Tumour >4cm or minimal extra-thyroid extension (Invasion of sternothyroid/perithyroid soft tissues) T4aInvasion of larynx, trachea, oesophagus or RLN T4bInvasion of prevertebral fascia or carotid a.

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TNM for DTC AJCC 7 th : - N1aMetastasis to level VI nodes N1b Involvement of unilateral/bilateral lateral group nodes(level I - V) or mediastinal nodes (level VII) M0No distant metastasis M1Distant metastasis

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TNM Stage Grouping : - AGE < 45 years IAny TAny NM0 IIAny TAny NM1

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TNM Stage Grouping : - AGE > 45 years IT1N0M0 IIT2N0M0 IIIT1 T3N1aM0 IVT4a / T4bN1bM1

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DTC - Treatment : - Surgery remains the main stay of treatment for DTC Types of Surgeries : - Total thyroidectomy Removal of all thyroid tissue with preservation of parathyroids Total thyroidectomy remains Gold standard

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Total thyroidectomy Rationale : - Total thyroidectomy Pros : - Enables usage of RAI effectively Makes serum Tg a sensitive marker for recurrence Enables better removal of central compartment nodes Reduces the risk of recurrence Reduces the risk of re-operation Total thyroidectomy Cons : - Risk of RLN injury & hypocalcemia

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Node management in DTC : - Without lateral group enlargement Total thyroidectomy with central compartment node dissection With unilateral lateral group nodes mets Total thyroidectomy with MRND With b/l lateral group nodes mets Total thyroidectomy with b/l MRND Prophylactic neck dissection NOT indicated

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Post-op 131 I adjuvant therapy : - Specific uptake into follicular cells Emits both particles and rays rays are therapeutic while particles produce radiation toxicity Indications : - Positive radio-iodine uptake scan post total thyroidectomy

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131 I ablation continued Precautions : - Stop thyroxine for 4-6 wks TSH > 30-50 mU/L for maximal effect Avoid iodinated contrast CTs, salts & pain balms Therapeutic dose : - Low risk pt. 30-100mCi High risk pt. 100-200mCi

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Role of Chemo & Radiotherapy : - Radiotherapy - Indications : - Unresectable disease Metastasis in support bones to avoid fractures Painful metastasis No role for routine chemotherapy Doxorubicin is commonly used mainly as a radiation sensitizer

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Post-op follow up : - Suppressive dose of thyroxine till TSH 95% 10yr relapse free survival Subsequent scans only if clinically indicated Thyroglobulin : - Level >2ng/ml suggestive of recurrence / mets Tg & anti-Tg antibodies level should be measured every 6mth in first year, and then annually

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Hurthle Cell Ca. : - Variant of Follicular cell ca. Women > Men Affects older age group ~65 yrs Defn. - An encapsulated group of follicular cells with at least a 75% Hurthle cell or Oncocyte component Large, polygonal, eosinophilic thyroid follicular cells with abundant granular cytoplasm and numerous mitochondria - Askanazy

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Hurthle Cell Ca : -

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Hurthle Cell Ca. continued..: - Often multicentric Diagnosis requires demonstration of capsular and / or vascular invasion Regional lymph nodes involved ~30% & is a poor prognostic indicator Distant metastasis in ~15% More aggressive & poorer prognosis

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Hurthle cell ca. Treatment : - Total thyroidectomy & central compartment node dissection recommended MRND done in case of enlarged lateral nodes Post op management : - Thyroid suppression Serum thyroglobulin measurement every 6 months Postoperative radioactive iodine is usually not effective (10% concentrate iodine)

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Medullary Carcinoma : - Arises from Para-follicular C cells from neural crest Constitutes 3 10 % of all thyroid cancers Types Sporadic Hereditary (Familial or MEN II)

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Clinical features: - Symptoms due to the tumour Both lymphatic & hematogenous spread common Paraneoplastic Syndromes Due to secretion of calcitonin, VIP, serotonin and somatostatin Diarrhoea most common

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Medullary Ca. - Peculiarities : - Characteristic amyloid stroma on HPE Doesnt take up radioactive iodine Both I-131 scan and radio-iodine ablation are of no use Serum calcitonin elevation tumour marker Presence of lymph node metastasis is a poor prognostic indicator

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Investigations : - FNAC USG / CT neck Calcitonin confirms the diagnosis CEA (>50% of tumours) USG abdomen & 24hr urine catecholamines to rule out pheochromocytoma

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Amyloid Stroma : -

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Treatment : - Without neck nodes Total thyroidectomy with central compartment neck dissection With neck nodes Total thyroidectomy with MRND of the involved side External beam RT Extra-thyroidal extension(T4 disease) Unresectable / metastatic disease as palliation Follow up serum calcitonin & CEA monitoring

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Anaplastic Carcinoma : - Most aggressive and fortunately rarest variety Invariably well advanced at presentation Worst prognosis Treatment Palliative External beam RT Surgery isthumusectomy to relieve tracheal obstruction

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Carry Home Message : - DTC carries very good prognosis and when detected early is a curable disease Total thyroidectomy with central node dissection is the gold standard treatment in both DTC & MTC MRND is optional RAI ablation plays a key role in metastatic disease in DTC

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Thank You