Approach to Thyroid Nodule[1]

APPROACH TO THYROID NODULE

Dr. (Maj. Gen.) K J Shetty Consultant Endocrinologist MD, FRCP (Edin.), FICP

INTRODUCTION Thyroid Nodule: – Common Outpatient Clinical Problem 4 to 8% OF ADULTS 13 to 67% ON USG EXAM (Female : Male – 8:1)

– Importance: Concern of Carcinoma 5% Malignant Relative Common-ness and possibility of complete cure if detected early

– Solution: Evolve a safe, expedient, reliable and cost effective management strategy

PRESENT SCENARIO Widely Divergent Approach – Primary Consultant : GP, Internist, Surgeon, ENT Specialist, Surgical Oncologist – Bias of the consultant - reluctance to follow guidelines – Inadequate use/ Improper prioritization of investigative tools – Insufficient knowledge of pathophysiology natural history of thyroid nodule indications, merits, and shortcomings of various investigative tools

Approach to Thyroid Nodule Steps: Evaluation – – – – –

Morphology Functional Immunological Cytological Histopathological

Tools Available – – – –

Clinical History & Examination Biochemical / Immunological Tests Imaging – USG/SCAN Aspiration Cytology

Thyroid Nodule Steps in Evaluation: – Clinical Examination – Biochemical Examination – Ultrasound Evaluation – Cytology

Clinical Evaluation Asymptomatic Symptomatic Hyper/ Hypo-thyroidism Mechanical Dyspnoea Dysphagia Hoarseness Pain Rapid Increase In Size Cosmetic Past History (Previous Surgery, Irradiation) Family History

CLINICAL EVALUATION (cont’d) General – Sex: M > F – Age: < 20 ; > 60 Yrs

Systemic : EUTHYROID/ HYPO/ HYPER Neck : NODULE: SOLITARY / MULTINODULAR – – – –

Size/ Intra-thoracic/ Extension Consistency: Firm/Hard/Cystic Mobile/Fixed Tenderness

Lymph nodes : Number and level

CLINICAL POINTERS TO MALIGNANCY Main Pointers – – – – – – –

Recent Rapid Increase In Size Development of Hoarseness of voice Positive Family History Age & Sex Past History of Neck Irradiation Hard Fixed Nodule Regional lymph nodes

Misconcepts of Malignancy – – –

Size: Smaller Ones – NO RISK Multi-Nodular – NO RISK Pain – HIGH RISK

Biochemical Evaluation – Lab Evaluation – First Step: Assess Functional Status by TFT – TSH Assay: Most Useful – T3/T4: Not Necessary if TSH is normal – TSH: Absent/ Low - Toxic Nodule : T3/ T4 Indicated Elevated - Hypothyroid : T4 indicated

– FT3/FT4: Preferred to TT3/ TT4 – Thyroid Antibodies Thyroid Peroxidase (TPO) ANTI-THYROGLOBULIN Ab (TgAb) TSH Receptor Antibodies (TSIAb) Graves (Not Routinely Available)

(Hashimotos and Graves)

Ultrasonography (USG) *High Resolution USG: Exceptional Clarity *Nodules < 1.5 cm *Metastatic Nodules In Neck (Clinically not palpable)

• • •

Assists in Localising Nodules for FNAC Inexpensive, non invasive, readily available USG to Endocrinologist Stethoscope to Cardiologist • Limitation: Little help in differentiating benign from cancer

No Single Characteristic: Predictive for malignancy Denote Higher Risk in combination of some: Composition Incidence percentage – – –

Solid Mixed (complex) Pure cystic

27% 7% > 4 cm: 6% < 4 cm: Negligible

Calcification – Microcalcification : x 3 higher risk without calcification – 95% specificity

- Coarse Calcification x 2 Risk Cervical Lymph Nodes : Highly Suggestive of PTC

Fine Needle Aspiration Cytology (FNAC) / Biopsy (FNAB) Crucial Step in evaluation Simple, safe, accurate and cost effective Assess Reliability Guidelines (Mayo Clinic) – – –

Experienced, Preferably dedicated cyto-pathologist Multiple Sites of Aspiration (2-4) A Low False Negative Rate Literature 1 – 11 % Acceptable < 5% Diagnostic Sample : 2 Slides - > 6 Groups Each > 10 Follicular Cells In each group

Benign………………………. 70% Indeterminate………………..10% Malignant…………………… 5% Non Diagnostic………………15%

Benign: Colloid Nodules – 70% Simple Cysts – AutoImmune/ Lymphocytic Thyroiditis

Malignant: – Papillary (Commonest) 83% – Follicular : 11% – Medullary (MTC) 5% – Anaplastic 1%

Indeterminate Category: (10%) 2 GROUPS: – Suspicious for malignancy: definitive evidence for malignancy not evident – Follicular neoplasm: not possible to differentiate from adenoma and carcinoma (capsular/ lymphovascular invasion)

Both sub-groups qualify for surgery

Non-Diagnostic (20%) Solid Lesion - Insufficient No. of follicular Cells - Re-Aspiration Indicated after 4 weeks – diagnostic aspirate in 50% – if non diagnostic : surgery

Cystic Lesion - Aspirate Unsatisfactory - Solid Component- Biopsy Mandatory

- If not feasible - Surgery

THYROID SCINTIGRAPHY Using Radioactive Iodine (I131) / Technitium (99 mTc) Depending on uptake classified as: – – – – –

HOT: 5% Toxic Nodule : < 5% Malignant COLD: 80 – 85% : 10 – 15% Malignant WARM 10-15% : 9% Malignant Expensive/ Availability Only In Special Centres Overlap: Small Nodules Masked

Use Limited To : – Indeterminate (Suspicious/Follicular) on FNAC – Follow Up of “hot” nodule – Diagnosis of ectopic goitre / Substernal Extension

NORMAL Tc99m THYROID UPTAKE

HOT NODULE

COLD NODULE

MULTI-NODULAR GOITRE

MANAGEMENT Based on Combination of Input From:

– – – –

History Clinical Examination Ultrasound Evaluation Cytology

( Benign Nodules, Malignant Nodules, Indeterminate, Nondiagnostic)

Therapeutic Options: 1. 2. 3. 4.

Follow-Up With Periodic Clinical and lab input Surgery Radiotherapy Medical therapy

MANAGEMENT (contd….) BENIGN NODULES (70%): – Euthyroid: No Pressure symptoms Cosmetically Acceptable – – – –

Yearly Follow up Clinical/Biochem./ USG > 20% ↑ - Repeat FNAC Role of Suppressive Rx with T4 – Not Proven Beware of subclinical Hyperthyroidism Euthyroid: Pressure + Cosmetic Problem – Limited Surgery Toxic Nodule: Medical (CMZ/PTU + Propranolol) I 131 / Surgery

MANAGEMENT (cont…)

Malignant Nodules: 5% PTC : Total Thyroidectomy with Ipsilateral Central Compartment Lymph Node Clearance FTC: Non/Min. Invasive – Lobectomy Invasive: Complete Thyroidectomy (Total) Follow Up for Both : I131 ablation after 6/52 High Dose Thyroxine TSH Suppression ( 4 cm – REPEATED FNAC – NONDIAGNOSTIC/ SURGERY

NODULE – – SURGERY – EXCISIONAL BIOPSY

APPROACH TO THYROID NODULE – AN ALGORITHM PATIENT WITH THYROID NODULE CLINICAL EVALUATION + TFT + IMMUNOLOGY

HYPERTHYROID

EUTHYROID

HYPOTHYROID

ANTITHYROID DRUGS/

USG

T4 REPALCEMENT

I 131 ABLATION / SURGERY

SOLID

COMPLEX CYSTS WITH SOILD COMPUND

PURE CYSTS

< 4cm FNAC

FOLLOW UP

> 4 cm SURGERY

ALGORITHM (CONTD….) FNAC OF NODULE CYTOLOGY REPORT

BENIGN (70%)

MALIGNANT (5%)

PRESSURE SYMPTOMS/ COSMETIC PROBLEMS – NIL YEARLY FOLLOWUP SUPPRESSION WITH T4 – 6– 12 MONTHS

INDETERMINATE (10%) SCINTIGRAPHY (I131/ 99 mTc)

WARM

> 20% INCREASE Rpt

FOLLOWUP

FNAC

SUSPICIOUS

SURGERY

COLD

NON DIAGNOSTIC (15%)

Rpt FNAC WITH USG

DIAGNOSTIC

NONDIAGNOSTIC

CONCLUSION Thyroid Nodule- A common Problem Evaluation: – Arbitrary, Inconsistent, Divergent – Based on Personal Preference

Long-term experience & advances in diagnostic aids: – Fresh Guidelines laying down systematic step-wise approach – Misconcepts corrected

THANK YOU