Panel discussion - thyroidPanel discussion - thyroid

Billroth

1870’s-80’s – Billroth – emerges as leader in thyroid surgery (Vienna)

Mortality 8%Shows need for RLN preservationDefines need for parathyroid preservation (von Eiselberg)Emphasis on speed

HISTORY OF THYROID SURGERY

Kocher

Kocher – emerges as leader in thyroid surgery (Bern)Emphasis on meticulous techniquePerformed 5000 cases by death in 1917Awarded 1909 Nobel Prize for efforts

EPIDEMIOLOGY – RADIATION

1946 – Nobel prize awarded to Muller for linking radiation to genetic mutations

1950 – Duffy & Fitzgerald link thyroid cancer to childhood XRT exposure

Appears to be dose-dependentERR 7.7 at 100 cGyMaximum risk approximately 30 years laterNodule in radiated patient: 35-40% cancerData suggest no more agggresive behavior over spontaneously-occuring cancers, but may be larger at presentation

Epidemiology – Nodule

Nodules common, whereas cancer relatively uncommonGoal is to minimize “unnecessary” surgery but not miss any cancer

Framingham studyAges 35 – 59

Women 6.4 %Men 1.5 %

Acquisition rate of 0.09 % per year

Mayo study (autopsy series – no thyroid hx)21% had 1 or more nodules by direct palpation

Of those, 49.5% had histological nodules35.5% greater than 2 cm

Epidemiology – Pregnancy

Pregnancy increases riskOne study: u/s detection nodules –

9.4% nulliparous women25% women previously pregnant

Attributed to increased renal iodide excretion and basal metabolic rateRosen: Nodules presenting during pregnancy –

30 patients, 43% were cancerHCG may be growth promoter (TSH-like activity)

Some author recommendations:Surgery done for cancer before end of 2nd trimester, else post-partumWomen with h/o thyroid cancer – avoid pregnancy

Epidemiology – Children

Nodule more likely to be cancer than adults1950s: 70% Current: approx 20%

10% thyroid cancer age <21Thyroid ca 1.5-2.0% all pedi malignanciesMore likely to present with neck metsMost common cause thyroid enlargement is chronic lymphocytic thyroiditis

Medullary Thyroid CarcinomaFMTC, MEN 2A, MEN 2BRET proto-oncogene (chromosome 10)Calcium / Pentagastrin stimulationProphylactic thyroidectomy recommended age 2-6

Superior laryngeal N.

Recurrent laryngeal N.

AnattomyLymphatic drainage• Level 6• Level 4,3• Level 5

AnattomyLymphatic drainage• Level 6• Level 4,3• Level 5

BENIGN THYROIID NODULES

Colloid nodule Cyst Simple cyst Mixed cystic-solid

Thyroid adenoma Non functional orhypofunctional Autonomous

Thyroiditis Infection Granulomatous disease Abscess Developmental Unilateral lobe agenesis Cystic hygroma Dermoid

HISTORY

AGE & GENDER

• 4x more prevalent in women than in men

• among pts with nodules,, rate off carcinoma

2x as high in men as in women (8% vs.. 4%)

• higher rate off cancer in extreme age group

( < 20,, > 60 yrs )

History

Hyper- / Hypo- thyroidism

Rapid change in size

With pain may indicate hemorrhage into nodule

Without pain may be bad sign

History

Exposure to Radiation

chiildhood : large thymus,malignancies

30%-50% chance to be malignant

Mostly papillary carcinoma

Family history

Medullary Thyroid Carcinoma

Gardner Syndrome (familial adenomatous polyposis)

Cowden Syndrome

Mucocutaneous hamartomas,, keratoses,,fiibrocystiic breast changes & GI polyps

Other thyroid carcinoma

History

Hiistory suggestiive off malignancy::

Age < 20 or > 60 years

Male sex

Exposure to ionizing radiation

Family history of thyroid cancer

Progressive enlargement

Hoarseness

Dysphagia, Dyspnea

Physical Examination

Sign of hyperthyroidism Multinodular vs.. Solitary nodule multinodullar – 4..7% chance off malignancy solittary nodulle – 4..1% chance off malignancy

Indirect or fiberoptic laryngoscopy

Cervical lymphadenopathy

Pemberton’s sign

Physical Examination

Physical findings suggestive of malignancy:

Cervical lymphadenopathy

Vocal cord paralysis

Very firm nodule

Rapid tumor growth

Fixation to adjacent structures

INVESTIGATIONSINVESTIGATIONS

SerumSerum TestingTesting

TSH – first-line serum test Identifies subclinical thyrotoxicosis T4, T3 Thyroglobulin Post-treatment good to detect

recurrence Calcitonin – only in cases of medullary Antibodies – Hashimoto’s RET proto-oncogene

ULTRASONOGRAPHYULTRASONOGRAPHY

Thyroid vs. non-thyroid Solitary nodule vs. multinodular goiter Cystic vs. solid Localization for FNA or injection Serial exam of nodule size LN enlargement and calcifications Noninvasive and inexpensive

ultrasonographyultrasonography

Findings suggestive of malignancy: Presence of halo Irregular border Presence of cystic components Presence of calcifications Heterogeneous echo pattern Extrathyroidal extension No findings are definitive

ULTRASONOGRAPHYULTRASONOGRAPHY

When to use Ultrasonography..?

Evaluation of a thyroid nodule: when a nodule is difficult to palpate or is deepseated screening : familial thyroid cancer, childhoodcervical irradiation Long term follow-up

Thyroid scanThyroid scan Technetium 99m cost-effective, readily available short half-life trapped but not organified by the thyroid

Radioactive iodine radioactive iodine (I-131, I-125, I-123) trapped and organified can determine functionality of a thyroid nodule

Thyroid scanThyroid scan

When to use thyroid scanning..?

Thyroid nodule with suppressed TSH Large MNG, esp. with substernal extension In search of ectopic thyroid tissue Immediately postop for localization of residualcancer or thyroid tissue Follow-up for tumor recurrence or metastasis

Thyroid scan

cold 15-25% cancer Warm 10%9% cancer Hot 5..5%1-4 % cancer

Other imaging modalitiesOther imaging modalities

CT / MRI

Evaluate local invasion Extension to substernal region Thyroid/non-thyroid nodule Recurrent or persistent thyroid tumor / scar …Iodine contrast …!

Fine Needle Aspiration Fine Needle Aspiration CytologyCytology

Safe, efficacious, cost-effective Results comparable to large-needle biopsy,less complications Allow preop. diagnosis and planning Sensitivity 70-98% Specificity 72-99 %

Fine Needle Aspiration Fine Needle Aspiration CytologyCytology

Results: Benign Malignant : papillary ,medullary ,anaplastic Suspicious/Indeterminate : follicularneoplasms, Hürthle cell neoplasms, papillarycancer, or lymphoma. Insufficient/Inadequate

MANAGEMENTMANAGEMENT

Benign thyroid noduleBenign thyroid nodule

Thyroid suppressive therapy

several reports - shrinkage of thyroid nodules

clinically significant decrease in nodule volume in only 20%

effect in larger nodules is probably smaller

Thyroid suppressive therapyAdverse Effects.

decrease in bone density in postmenopausalWomen

3-fold increase in atrial fibrillation and increasedmortality attributable to cardiovascular diseases

Thyroid suppressive therapy Should be avoided in patients with large thyroid nodules or long-standing goiters,

TSH < 1 μIU/mL

postmenopausal women or men > 60 years

patients with osteoporosis, cardiovascular disease, or systemic illnesses.

Benign Thyroid Nodule Surgical Indications.

Compressive symptoms Suspicious malignancy Associated Hyperthyroidism. Cosmetic STN : Unilateral thyroid lobectomy MNG : Bilateral subtotal thyroidectomy

Radioiodine Therapy

gradual decrease in thyroid volume radiation-induced thyroid dysfunction (hyperthyroidism in 5%, hypothyroidism in 20-30%) risk of induction of carcinoma alternative to surgery in elderly patients and those

with cardiopulmonary disease

Toxic nodular goitreToxic nodular goitre

overt hyperthyroidism : Rx is always indicated

subclinical hyperthyroidism : Rx in elderlypatients and in younger ones who are at riskfor cardiac disease or osteoporosis

Antithyroid-Drug TherapyAntithyroid-Drug Therapy

hyperthyroidism is reversible, but always recursafter discontinued indicated • before thyroid surgery before and sometimes after radioiodine treatment

in elderly patients and those with other health problems

SurgerySurgery

Uninodular : Lobectomy simple and effective

recurrences after surgery are rare

hypothyroidism develops in 10-20%

recommended in children and adolescents; may be preferred in patients with large nodules

Multinodular : Bilateral subtotal thyroidectomy

incidence of persistent and recurrent hyperthyroidism should be less than 10-20%

widely varying rates of post-treatment hypothyroidism

recommended in patients with large goiters

Radioiodine TherapyRadioiodine Therapy as effective as surgery

more gradual than that after surgery

hypothyroidism : less than 20% in most studies

in a large follow-up study, the risk of thyroid carcinoma was not increased

attractive option for the majority of patients

Suspicious Thyroid Nodule by FNASuspicious Thyroid Nodule by FNA

20% are found to be malignant lesions

Recommend surgical excision: Lobectomy and isthmectomy

Total thyroidectomy in :• history of irradiation• multiple thyroid nodules

Nondiagnostic Cytologic SpecimenNondiagnostic Cytologic Specimen

Usually results from a cystic nodule

US-FNA directed is indicated

5% of thyroid nodules remain nondiagnostic.

such nodules should be surgically excised

Indications for reaspirationIndications for reaspiration Follow-up of benign nodule

Enlarging nodule

Recurrent cyst

Thyroid nodule > 4 cm

Initial nondiagnostic FNA biopsy

No shrinkage of nodule after T4 therapy

Thyroid Nodules in ChildrenThyroid Nodules in Children

Infections and developmental abnormalities are more common than in adults

Incidence of cancer : 30% (14–61% )

FNA has not been used in very young children , surgery may be used to identify the

cause

Management of thyroid cancerManagement of thyroid cancer

Surgery is the definitive management of thyroidcancer, excluding most cases of ATC andLymphoma

Types of operations: lobectomy with isthmectomy total thyroidectomy subtotal thyroidectomy

LobectomyLobectomyvs..vs..

Totall thyroidectomyTotall thyroidectomyManagement (WDTC) ::Management (WDTC) ::Papillary and FollicularPapillary and Follicular

Rationale for total thyroidectomyRationale for total thyroidectomy

30%-87.5% of PTC involve opposite lobe 7%-10% recurrence in the contralateral lobe Lower recurrence rates, some studies show increased survival Facilitates earlier detection & Rx for recurrent or metastatic carcinoma with iodine Potential to differentiate to ATC

Rationale for lobectomy

Lower incidence of complications• Hypoparathyroidism (1%-29%)• Recurrent laryngeal nerve injury (1%-2%)• Superior laryngeal nerve injury

Long term prognosis is not improved by total thyroidectomy

Prognostic factorsPrognostic factors AMES (Lahey Clinic, Burlington, MA)

AGES (Mayo Clinic, Rochester, MN)

GAMES (Memorial Sloan Kettering Cancer Center, NY)

• Grade

• Age ( > 45 yrs )

• Metastases of the tumor (other than Neck LN)

• Extent of primary tumor ( Extraglandular )

• Size of tumor (> 4 cm)

Indications for total thyroidectomyIndications for total thyroidectomy Age < 15 y or > 45 yrs Radiation history Known distant metastases Bilateral nodularity Extrathyroidal extension Tumor > 4 cm in diameter Cervical lymph node metastases Aggressive variant

Managing lymphatic involvementManaging lymphatic involvement

If any cervical nodes are clinically palpable oridentified by MR or CT imaging as beingsuspicious, a neck dissection should be done

Elective neck dissections are not done

Hurthle Cell CarcinomaHurthle Cell Carcinoma

Total thyroidectomy is recommendedbecause: Lesions are often Multifocal They are more aggressive than WDTCs Most do not concentrate iodine

Medullary CarcinomaMedullary Carcinoma

Recommended surgical management total thyroidectomy central lymph node dissection lateral jugular sampling Prophylactic thyroidectomy recommended age 2-6 If patient has MEN syndrome: remove pheochromocytoma before thyroid surgery

Anaplastic CarcinomaAnaplastic Carcinoma

Most have extensive extrathyroidal involvement at the time of diagnosis

surgery is limited to biopsy and tracheostomy

Radiotherapy and Chemotherapy

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