THYROID FUNCTION TEST and RADIONUCLIDE THERAPY Ajalaya Teyateeti, M.D. Division of Nuclear Medicine Department of Radiology
I. Thyroid function test OUTLINE Application and interpretation of in vitro TFT Principle, application and interpretation of in vivo TFT II. Radionuclide therapy in thyroid disease Indication, treatment and follow-up Hyperthyroidism and differentiated thyroid cancer III. Case demonstration
THYROID FUNCTION TEST Outline Thyroid anatomy Thyroid physiology Thyroid hormone synthesis Thyroid function tests
Thyroid anatomy Normal thyroid gland Anterior superior aspect of trachea just below the thyroid cartilage Two lobes and isthmus Normal weight 20 gm.
Thyroid anatomy Pyramidal lobe May be identified in some Extend toward hyoid bone Thyroglossal duct remnant
Thyroid physiology Hypothalamic-pituitary-thyroid axis Control function of thyroid gland Stimulating hormone : TRH, TSH Inhibiting hormone : T3 and T4 (convert to T3 by type II deiodinase)
Thyroid hormone synthesis Trapping of iodide (I - ) Oxidation : Change iodide to iodine (I) by peroxidase Organification : Iodination of thyroglobulin and forming MIT and DIT Coupling : Conjugation of MIT + DIT to form T3 and DIT + DIT to form T4 Thyroid hormone release
Thyroid hormone synthesis
Thyroid function test I. In vitro tests (clinical application) 1. Serum T3 and T4 2. Free T3 and free T4 3. Thyroid stimulating hormone (TSH) 4. Thyroglobulin (Tg) 5. Anti-thyroid antibody
1. Total T3 and T4 T3 More metabolically active than T4 Often useful to diagnose hyperthyroidism or to determine the severity of the hyperthyroidism T4 Include both bound and free forms Binds to circulating protein
2. Free T3 and Free T4 Free form = Active form Serum protein affect total T4 level Protein binding of T3 is 10 times less than T4 No significant difference between free T3 and total T3
3. Serum TSH Best initial and most sensitive test to evaluate thyroid function High TSH level indicates primary hypothyroidism Low TSH indicates primary hyperthyroidism
Common clinical application Status T3 T4 TSH Euthyroid Normal Normal Normal Hyperthyroidism 1 High High Low Subclinical Normal Normal Low Hypothyroidism 1 Low Low High Subclinical Normal Normal High
4. Thyroglobulin Protein precursor of thyroid hormone Made by normal thyroid cells or thyroid cancer cells Most reliable tumor marker for DTC following thyroidectomy and 131 I treatment Interfere with TgAb
5. Anti-thyroid antibody Thyroglobulin antibody (TgAb) Anti-microsomal antibody Thyroid peroxidase antibody (TPOAb) Thyroid stimulating hormone receptor antibody (TRAb) To diagnose and monitor autoimmune thyroid disease
Thyroid function test II. In vivo tests 1. Thyroid scan 2. Thyroid uptake 3. Diagnostic RAI whole body scan (Dx-WBS)
1. Thyroid scan Indications : To evaluate I. Cause of thyrotoxicosis II. Function of thyroid nodule III. Location of ectopic thyroid tissue IV. Cause of neonatal hypothyroidism V. Substernal goiter VI. Post-operative residual thyroid tissue/tumor
Radionuclide Tracer Advantages Disadvantages 123 I - Retrosternal goiter - No beta emission Ideal tracer 131 I - Same as 123 I with lower cost and more available - Higher cost - Less convenient (imaging 24 hr.) - Less available - Higher radiation (Beta) 99m TcO 4 - Less expensive - More available - More rapid examination (imaging 20 min.) - Trapped, not organified - Esophageal & vascular activity
1. Thyroid scan Imaging 131 I 50 100 uci, oral Imaging at 24 hr. 99m Tc-pertechnetate 2 mci, IV Imaging at 20 min. Sternal notch
Normal thyroid scan Right lobe may be slightly larger. Amount of activity in isthmus is vary Salivary gland activity seen on 99m Tc-pertechnetate imaging 99m Tc-pertechnetate Background is higher in 99m Tc imaging
I. Evaluate causes of thyrotoxicosis Hyperthyroidism VS Thyroiditis Thyrotoxicosis - Hypermetabolic state resulting from excessive thyroid hormone due to hyperthyroidism or parenchymal destruction Hyperthyroidism - Overactive gland producing excessive hormone Graves disease, toxic MNG, toxic adenoma
I. Evaluate causes of thyrotoxicosis Graves disease Toxic MNG Toxic adenoma Sub-acute thyroiditis
II. Evaluate function of thyroid nodule Hot nodule Cold nodule Indeterminate nodule
II. Evaluate function of thyroid nodule Hot nodule Hyper-functioning nodule producing thyrotoxicosis Likelihood of malignancy < 1% Cold nodule Benign 80% - Cyst, adenoma, hemorrhage, abscess, focal thyroiditis Likelihood of malignancy 20%
II. Evaluate function of thyroid nodule Indeterminate nodule Palpable detected nodule with equal radiotracer uptake to surrounding tissue May be a cold nodule arising from posterior aspect with superimposed normal glandular activity Likelihood of malignancy : Same as cold nodule ( 20%)
III. Localize ectopic thyroid tissue Location Anywhere along the line of descent Most common site : Base of tongue Lingual and sublingual thyroid
IV. Evaluate cause of congenital hypothyroidism Causes of congenital hypothyroidism Iodine deficiency - most common Agenesis or hypoplasia of thyroid gland Ectopic thyroid Dyshormonogenesis (Organification defect) Agenesis of thyroid gland
IV. Evaluate cause of congenital hypothyroidism Dyshormonogenesis Increased uptake at normal position Ectopic thyroid Normal uptake, abnormal position
V. Evaluate substernal goiter Sub-sternal goiter Use radioactive iodine Limitation of 99m Tc-pertechnetate Attenuate by sternum & soft tissue Blood pool activity
VI. Evaluate post-op. residual thyroid Residual thyroid tissue
2. Thyroid uptake study Indications To determine cause of thyrotoxicosis To calculate therapeutic dose of 131 I To evaluate post-op. residual thyroid tissue
Thyroid uptake study Preparation : Discontinues interfering agents Factors Thyroid hormone - LT3 - LT4 Excess iodine - KI, cough med., iodinated skin ointment - Iodinated drug Radiographic contrast PTU MMI Duration of effect 2 wk. 4 wk. 2-4 wk. wk. to months. 4 wk. 3-5 days 5-7 days
Thyroid uptake study Procedure Oral administration of radioactive iodine Quantify percentage (%) of thyroid uptake Measure at 24 hr. (routine)
Factor affecting increased uptake Hyperthyroidism : Graves disease, toxic MNG, toxic adenoma, TSH-producing pituitary tumor, trophoblastic tumor Iodine deficiency Enzyme defect Early Hashimoto thyroiditis Rebound effect after withdraw anti-thyroid drug
Factor affecting decreased uptake Hypothyroidism Primary (thyroid) or secondary (pituitary) Blocked trapping Iodine overload Blocked organification : Anti-thyroid drugs Parenchymal destruction : Thyroiditis
3. Dx-WBS Indications Thyroid cancer To evaluate treatment response To detect metastases Detect struma ovarii
Patient preparation Low iodine intake Thyroid hormone withdrawal Procedures 131 I 2-5 mci 123 I 1-3 mci Oral administration Scan at 2-7 days 3. Dx-WBS
3. Dx-WBS Normal Dx-WBS DTC S/P total thyroidectomy and RAIT Physiologic activity - Nasopharynx, oropharynx, salivary glands, stomach, intestine and bladder
3. Dx-WBS Struma ovarii - Abnormal uptake in pelvis due to ectopic thyroid tissue in ovary, intense uptake in thyroid SPECT/CT pelvis Dx-WBS
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RADIONUCLIDE THERAPY Outline Principle of radionuclide therapy Applications of 131 I treatment Hyperthyroidism Thyroid cancer
Radionuclides therapy Administration of radioactive agents that will be trapped in the target organ or tissue for therapeutic purpose. Internal radiotherapy Local irradiation Relatively less toxicity to adjacent tissue or organ
131 I treatment Beta rays : Treatment Gamma rays : Imaging 131 I; radioactive iodine enter the thyroid hormone synthesis pathway same as 127 I; stable iodine.
131 I treatment in hyperthyroidism Overactive thyroid gland Presented with symptoms of excessive thyroid hormone Thyrotoxicosis
Graves disease Diagnosed by symptoms Exophthalmos Confirmed by laboratory testing T3, T4, TSH TSH receptor antibody - Not necessary Normal gland Pretibial myxedema Diffused goiter
Toxic nodular goiter Presentation Thyrotoxicosis Obstructive symptoms Asymptomatic, esp. with small nodules : size < 2.5-3.0 cm. Diagnosis Toxic adenoma Toxic MNG Slightly high or normal T3 and T4 Slightly suppressed TSH
Treatment of hyperthyroidism Options Medical treatment Surgical treatment Radioactive iodine treatment
Medical treatment Control of hyperthyroidism : Anti-thyroid drug Thionamides Methimazole - MMI and Propylthiouracil - PTU Action : Inhibit peroxidase PTU also inhibit peripheral conversion Always consider as 1 st treatment for hyperthyroidism
Medical treatment Control of hyperthyroidism : Anti-thyroid drug Advantage Rapid improvement in 2-4 wks. Disadvantage Adverse reaction - Rash, fever, GI symptoms, hepatitis, arthritis, agranulocytosis High rate of relapse ( 50% remission)
Medical treatment Control of symptoms : Beta-blockers Action : Inhibit adrenergic effects and peripheral conversion Treatment of choice for thyroiditis Use with caution in older patient, pre-existing COPD, asthma, heart disease
Surgical treatment Treatment of choice Pregnancy (2 nd trimester) Large goiters with compressive symptoms Possible co-existing thyroid cancer
Surgical treatment Advantage Low rate of relapse Disadvantage High rate of hypothyroidism Risk of hypoparathyroidism Laryngeal nerve injury Requires euthyroidism before surgery
Radioactive iodine treatment Treatment of choice Failed medication (unable to titrate down ATD or unable to control hyperthyroidism) Relapse after receiving medical or surgical treatment Major adverse reactions from anti-thyroid drug Life-threatening conditions requiring euthyroid in short period (AF, CHF, cardiomyopathy, periodic paralysis)
Radioactive iodine treatment Advantage Low rate of relapse Disadvantage o o Delayed control of symptoms High rate of hypothyroidism Contraindication Pregnancy, breast feeding, young children
Radioactive iodine treatment Patient preparation To reduce iodine pool - Low-iodine diet for 1 wk. Time of withdrawal Anti-thyroid drug Expectorants, Lugol s solution Contrast media Amiodarone PTU 3-5 day, MMI 5-7 day 1-3 wk. 1 mo. 3-6 mo.
Radioactive iodine treatment Prescribed dose Based on thyroid volume and uptake Dose of 131 I = Gland size (gram) x Standard dose x 100 % 24 hr. 131 I Uptake x 1000 Standard dose : 80-200 uci/gram vary on severity of disease
Radioactive iodine treatment Side effects Transient radiation sickness Transient exacerbation of hyperthyroid in first month Follow-up Re-start ATD in 5-7 days to control thyrotoxicosis Re-evaluate symptoms and titrate down ATD by monitoring TFT in 1-2 month intervals Evaluate treatment outcome at 6 month
Radioactive iodine treatment Outcome of 131 I treatment High cure rate with single treatment Euthyroid - Most desirable outcome, small group Hypothyroid - Acceptable outcome, large group ** Always advice this potential outcome ** Subclinical or persistent hyperthyroidism or unable to withdraw/taper down ATD at 6 month post-treatment Re-evaluate with 24 hr. 131 I uptake ± retreat 2 nd dose
131 I treatment in thyroid cancer 4 major pathological types of thyroid cancer Papillary Follicular Anaplastic Medullary Differentiated thyroid cancer (DTC) 131 I treatment Incidence Papillary : 60-70% Follicular : 15-20%
Treatment of differentiated thyroid cancer 1. Surgery 2. Staging and risk stratification 3. 131 I-treatment 4. Follow-up and therapeutic response evaluation Reference: ATA guideline 2015
1. Surgery Thyroidectomy : 1 st treatment Adequate surgery for cancer = Total thyroidectomy If previously done lobectomy, Completion thyroidectomy must be performed.
1. Surgery Cervical LN dissection : Optional Clinically involved CLN in central or lateral compartment Prophylactic dissection in advanced PTC
2. Staging and risk stratification Post-operative staging Based on ptnm parameters and age Predict disease mortality Risk of recurrence stratification Use for follow-up Both staging and risk of recurrence are used to determine 131 I treatment.
Staging T - Tumor size & extension N Lymph node metastasis M Distant metastasis
AGE < 45 Stage I or II depends on presence of metastasis Staging
Risk of recurrence stratification
Risk of recurrence stratification ATA low risk - Intra-thyroidal DTC PTC - LN micro-metastasis, no aggressive histology FTC - Minimal vascular invasion (< 4 foci)
Risk of recurrence stratification ATA intermediate risk - Microscopic ETE, CLN metastases PTC with vascular invasion Aggressive histology
Risk of recurrence stratification ATA high risk - Distant metastasis Macroscopic ETE Incomplete tumor resection Pathologic LN Ø > 3 cm. Widely invasive FTC
Purpose of 131 I treatment Ablation Adjuvant therapy 1. Remnant ablation Treatment To destroy post-op. residual thyroid tissue For intra-thyroidal DTC with complete resection Facilitate follow up
Purpose of 131 I treatment 2. Adjuvant therapy To destroy suspected but unproven residual disease For microscopic ETE, vascular invasion, LN metastasis 3. Treatment To treat known or persistent disease For incomplete tumor resection, distant metastasis
Indication and benefit of 131 I Intra-thyroidal DTC, size < 1cm. No indication of 131 I ablation
Tumor > 1 cm. Considered 131 I treatment based on adverse features e.g. aggressive histology, vascular invasion, advanced age
Microscopic ETE, LN metastasis Generally favored 131 I treatment
Macroscopic ETE, distant metastasis 131 I treatment is indicated Benefits - Improve disease specific survival and disease free survival
3. 131 I-treatment Pre 131 I-treatment evaluation To evaluate residual thyroid tissue 24 hr. 131 I uptake, thyroid scan, ultrasound Significant amount of residual tissue Re-surgery To evaluate functioning metastasis Dx-WBS, CT scan If present, it may lead to increase 131 I-treatment dosage
3. 131 I treatment Patient preparation Rule out pregnancy and breast feeding Advise birth control Review isolation requirement Discontinue iodine supplements or containing agents
3. 131 I treatment Patient preparation Withdraw thyroid hormone to elevate serum TSH Stimulate iodine trapping in thyroid remnant and functioning metastasis Can use exogenous TSH (rh-tsh) instead of thyroid hormone withdrawal
3. 131 I treatment 30-100 mci Remnant ablation 100 mci Adjuvant therapy (up to 150 mci) Structural disease (up to 200 mci)
3. 131 I treatment Hospital stays Low-dose (< 30 mci) : Not require High dose Stay in hospital until radiation level is sufficiently low. (about 2-3 days in general) Isolation room
3. 131 I treatment Early side effects Radiation thyroiditis Dysphagia Radiation sialadinitis GI discomfort Nausea Reduced taste Pain at metastatic sites Late side effects Xerostomia BM suppression Pulmonary fibrosis Transient amenorrhea or oligomenorrhea Infertility Second malignancy
3. 131 I treatment Post-therapeutic total body scan Obtain at 2-7 days after treatment dose Baseline imaging Not an imaging to evaluate treatment response
4. Follow-up and therapeutic response evaluation Follow-up Initial follow-up Initial TSH suppression Therapeutic response evaluation Long-term follow-up Long-term TSH suppression Disease surveillance
Thyroid hormone suppression Rationale Differentiated thyroid cancer express TSH receptor on cell membrane. Suppress TSH with supra-physiologic thyroid hormone to decrease risk of recurrence
Initial TSH suppression Initial dosage - Thyroxine 2 µg/kg/day TSH level - Depends on risk of recurrence Risk of recurrence TSH level (mu/l) Low Suppressed Tg < 0.2 ng/ml 0.5-2.0 Suppressed Tg 0.2 ng/ml 0.1-0.5 Intermediate 0.1-0.5 High < 0.1
Therapeutic response evaluation Criteria Perform at 6-12 months post 131 I treatment Clinical - Physical examination Biochemical - Lab Tg, TgAb Suppressed Tg - Low TSH, on thyroxine Stimulated Tg - High TSH, off thyroxine Imaging - Dx-WBS, US and others
Therapeutic response evaluation 4 categories of response Excellence response Biochemical incomplete response Indeterminate response Structural incomplete response Guide for further management and intensity of follow-up
Excellence response Disease free status or NED Def. - Negative clinical, imaging & lab Mx. - Decrease intensity of F/U
Biochemical incomplete response Def. - Negative clinical & imaging, positive lab Mx - Serial F/U
Indeterminate response Def. - Negative clinical, non-specific imaging or lab Mx - Serial F/U
Structural incomplete response Def. - Positive clinical or imaging Mx Additional Tx
Long-term TSH suppression TSH level depends on Risk of recurrence Therapeutic response Risk of TSH suppression e.g. age > 60 yr., osteopenia, osteoporosis, tachycardia, AF
Long-term TSH suppression Suppression TSH level (mu/l) Indication No 0.5-2.0 All NED exc. high risk of recurrence keep TSH 0.1-0.5 in first 5 years Mild 0.1 0.5 Most of indeterminate & biochemical incomplete response* Moderate to complete < 0.1 Most of structural incomplete response* * Less suppression in patients with higher risk of TSH suppression
Long-term TSH suppression
Disease surveillance Physical examination Serial Tg, TgAb Imaging - Dx-WBS, US, others imaging as indicated Intensity depends on Risk of recurrence Disease status NED or non-ned
KEYS
Thyroid function test In vitro Most sensitive - TSH Tumor marker for DTC Tg, interfered by TgAb In vivo Thyroid uptake Conditions affecting uptake - Increased VS decreased Preparation - Withdraw ATD & thyroid hormone
Thyroid function test In vivo (cont.) Thyroid scan Radiotracer : 99m Tc-pertechnetate VS RAI Findings - Graves disease, toxic MNG, toxic adenoma, thyroiditis Function of thyroid nodule - Risk of malignancy
Treatment of hyperthyroidism Advantages VS disadvantages Medication - Rapid improve VS side effects, high rate of relapse Surgery - Low rate of relapse VS risk of surgery 131 I - Low rate of relapse VS hypothyroidism, contraindication
Treatment of hyperthyroidism Candidate Medication - 1 st treatment Surgery - Suspected CA, compressive symptoms 131 I - Failed medication, relapse, require euthyroid in short period, major adverse reactions from ATD
Treatment of DTC Surgery - Total or complete thyroidectomy Staging and risk stratification Staging - Predict disease mortality Risk of recurrence - Follow-up Determine 131 I treatment
Treatment of DTC Benefit of 131 I - Disease spec. survival & free survival No benefits in intra-thyroidal tumor < 1 cm. Indicated in gross ETE and distant metastases Common side effect of 131 I Early - Acute radiation sickness, thyroiditis, sialadenitis Delayed - Xerostomia
Treatment of DTC Initial F/U TSH suppression level - Depends on risk of recurrence Therapeutic response at 6-12 mo. post-rai treatment 4 categories Excellence - Disease free status Structural incomplete - Further treatment
Treatment of DTC Long-term F/U TSH suppression level - Depends on risk of recurrence, therapeutic response and risk of TSH suppression Intensity of F/U - Depends on risk of recurrence and disease status
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CASE DEMONSTRATION
CASE I A 45-year-old woman CC : Palpitation and sweating for 2 weeks PE : Normal size thyroid, generalized mild tenderness Fine tremor of both hands PR 100/min, regular Treatment : Beta-blockers
CASE I This patient Normal T3 230 80 200 FT4 1.9 0.93 1.7 TSH 0.07 0.27 4.2 QUESTION 1 - What is the investigation of choice to evaluate cause of thyrotoxicosis? A. Thyroid scan B. Thyroid uptake C. Either
CASE I - Pearls
CASE II A 60-year-old woman with relapse Graves disease PE : Diffuse goiter 40 gm. PR 80/min, regular Treatment : MMI (5) 2 x 1 Propanolol (10) 1 x 2 This patient Normal T3 185 80 200 FT4 1.4 0.93 1.7 TSH 0.01 0.27 4.2
CASE II 24-hour 131 I uptake performed to calculate dose of 131 I treatment = 24% (normal 15-45%) QUESTION 2 - What are the possible causes of normal thyroid uptake in hyperthyroidism patient?
CASE II
CASE II S/P 131 I treatment 10 mci (uptake 60%, thyroid 40 gm.) Re-start MMI (5) 2 x 1 in 7 days after 131 I treatment F/U at 1 month after RAI treatment On MMI (5) 2 x 1 Clinical mild hyperthyroidism
CASE II Pre- RAIT 1 mo. Normal T3 185 210 80 200 FT4 1.4 1.8 0.93 1.7 TSH 0.01 0.007 0.27 4.2 QUESTION 3 - What is the most appropriate management? A. Advice, continue MMI (5) 2 x 1 B. Increases dose of ATD - MMI (5) 3 x 1 C. 2 nd RAI treatment
CASE II F/U at 2 months after RAI treatment Clinical - Euthyroidism
CASE II 1 mo. 2 mo. Normal T3 210 120 80 200 FT4 1.8 1.1 0.93 1.7 TSH 0.007 0.5 0.27 4.2 QUESTION 4 - What is the most appropriate management? A. Continue MMI (5) 2 x 1 B. Reduce dose of ATD - MMI (5) 1 x 1
CASE II F/U at 4 months after RAI treatment.. Clinical - Euthyroid
CASE II 2 mo. 4 mo. Normal T3 120 87 80 200 FT4 1.1 0.96 0.93 1.7 TSH 0.5 9.43 0.27 4.2 QUESTION 5 - What is the most appropriate management? A. Reduce dose of MMI (5) to ½ x 1 B. Off MMI C. Off MMI and start thyroxine
CASE II F/U at 6 months after RAI treatment.. Clinical - Hypothyroidism
CASE II 4 mo. 6 mo. Normal T3 87 60 80 200 FT4 0.96 0.4 0.93 1.7 TSH 10.44 50.33 0.27 4.2 QUESTION 6 - What is the most appropriate management?
CASE II - Pearls
CASE III A 35-year-old woman CC : Right thyroid nodule with palpitation and sweating for 6 months PE : Palpable right thyroid nodule, size 3 cm. PR 90/min, regular
CASE III This patient Normal T3 224 80 200 FT4 1.6 0.93 1.7 TSH 0.1 0.27 4.2 QUESTION 7 - What is the investigation of choice to evaluate function of thyroid nodule? A. Thyroid scan B. Thyroid uptake C. Either
CASE III - Pearls
CASE IV A 22-year-old woman, underlying hyperthyroidism CC : Progressive enlargement of a left thyroid nodule PE : Diffuse goiter with a palpable left thyroid nodule Exophthalmos both eyes PR 88/min, regular Treatment : MMI (5) 1x1
CASE IV This patient Normal T3 190 80 200 FT4 1.6 0.93 1.7 TSH 0.1 0.27 4.2 QUESTION 8 - What is the investigation of choice to evaluate function of thyroid nodule? A. Thyroid scan B. Thyroid uptake C. Either
CASE IV What to do next?
CASE IV QUESTION 9 - What is the treatment of choice for this patient? A. Anti-thyroid drug B. Surgery Total thyroidectomy C. Radioactive iodine
CASE IV - Pearls
CASE V A 37-year-old woman CC : Palpitation, sweating, weight loss 5kg. in 3 mo. PE : Slightly enlarged thyroid gland Fine tremor of both hands No exophthalmos PR 98/min, irregular
CASE V This patient Normal T3 478 80 200 FT4 4.1 0.93 1.7 TSH < 0.005 0.27 4.2 QUESTION 10 - What is the treatment of choice for this patient? A. Anti-thyroid drug B. Surgery C. Radioactive iodine
CASE V Treatment :.. 2 months after receiving treatment, presented with MP rash Work-up : CBC, LFT, UA - normal This patient Normal T3 215 80 200 FT4 1.67 0.93 1.7 TSH 0.01 0.27 4.2
CASE V QUESTION 11 - What is the most appropriate treatment for this patient? A. Change anti-thyroid drug B. Surgery C. Radioactive iodine
CASE V Treatment :.. Persistent hyperthyroidism after 2 years of treatment This patient Normal T3 215 80 200 FT4 1.81 0.93 1.7 TSH 0.01 0.27 4.2
CASE V QUESTION 12 - What is the most appropriate treatment for this patient? A. Anti-thyroid drug B. Surgery C. Radioactive iodine
CASE V - Pearls
CASE VI A 24-year-old woman CC : Progressive enlargement of a palpable right thyroid nodule, size 3 cm. for 6 months PE : Clinical euthyroid Right thyroid nodule
CASE VI QUESTION 13 - What is the investigation of choice to evaluate thyroid nodule? A. Thyroid scan B. Thyroid uptake C. US-guided FNA
CASE VI QUESTION 14 - What is the most appropriate treatment for this patient? A. Radioactive iodine B. Surgery C. Repeat US-guided FNA
CASE VI S/P Right lobectomy Pathology : Papillary thyroid cancer, classical variant Size 3.2 x 2.5 x 1.8 cm. Microscopic extra-thyroidal invasion No vascular invasion
CASE VI QUESTION 15 - What is the most appropriate treatment for this patient? A. Radioactive iodine B. Completion thyroidectomy C. Long-term follow-up
CASE VI.. QUESTION 16 - Stage Due to QUESTION 17 - Risk of recurrence Due to
CASE VI QUESTION 18 - What is an objective of 131 I treatment for this patient? A. Remnant ablation - To facilitate follow-up B. Adjuvant therapy - To destroy suspected but unproven residual disease
CASE VI Post-Tx WBS 131 I treatment 150 mci Hospital stay 3 days This patient Normal T4 1.2 5.1 14.1 TSH > 100 0.27 4.2 Anterior neck Stim. Tg < 0.04 - TgAb 17.3 < 40
CASE VI Start thyroxine 2 µg/kg/day Initial F/U at 2 month after 131 I treatment QUESTION 19 - Initial TSH suppression level depends on This patient Normal T4 10.2 5.1 14.1 TSH 0.2 0.27 4.2
CASE VI At 6 month after 131 I treatment This patient Normal T4 10.2 5.1 14.1 TSH 0.1 0.27 4.2 Supp. Tg < 0.04 - TgAb < 10 < 40
CASE VI Dx-WBS At 8 month after treatment US thyroid - Negative This patient Normal T4 1.5 5.1 14.1 TSH > 100 0.27 4.2 Stim. Tg < 0.04 - TgAb < 10 < 40 Anterior neck
CASE VI Therapeutic response.. Risk of recurrence.. Risk of TSH suppression..
CASE VI This patient Normal T4 8.2 5.1 14.1 TSH 0.8 0.27 4.2 QUESTION 20 - What is the appropriate long-term TSH suppression level for this patient? A. Moderate to complete suppression, TSH < 0.1 B. Mild suppression, TSH 0.1 0.5 C. No suppression, TSH 0.5 2.0
CASE VI - Pearls
CASE VII A 58-year-old woman CC : Progressive enlargement of right thyroid nodule for 6 months PE : Nodular enlargement of right thyroid gland Palpable right cervical LNs
CASE VII Neck CT scan Mass at right thyroid lobe Right cervical LN
CASE VII S/P Total thyroidectomy with right CLN dissection Pathology : Papillary thyroid cancer, Ø 4.0 x 3.2 x 2.8 cm. Presence of angiolymphatic invasion Presence of perithyroidal soft tissue invasion Right cervical LNs level II-IV - Metastatic LN 15/21, maximum Ø 2.5 cm.
CASE VII Base on pathological report Stage. Risk of recurrence. Due to
CASE VII Post-Tx WBS Admitted for 131 I treatment 150 mci Hospital stay 3 days This patient Normal T4 1.5 5.1 14.1 TSH > 100 0.27 4.2 Stim. Tg 66.8 - TgAb < 10 < 40 Anterior neck
CASE VII Lung metastasis on post-tx WBS Change stage to stage Change risk of recurrence to SPECT SPECT/CT
CASE VII Initial F/U at 2 month after treatment QUESTION 21 - What is the appropriate initial TSH suppression level for this patient? A. < 0.1 (high) B. 0.1 0.5 (intermediate) This patient Normal C. 0.5 2.0 (low) T4 12.2 5.1 14.1 TSH 0.07 0.27 4.2
CASE VII At 6 month after treatment This patient Normal T4 11.5 5.1 14.1 TSH 0.08 0.27 4.2 Supp. Tg 1.2 - TgAb < 10 < 40
CASE VII Dx-WBS At 8 month after treatment This patient Normal Anterior neck T4 1.4 5.1 14.1 TSH 70.23 0.27 4.2 Stim.Tg 15.3 - TgAb < 10 < 40
CASE VII Therapeutic response.. Risk of recurrence.. Risk of TSH suppression..
CASE VII QUESTION 22 - What is the most appropriate management for this patient? A. Moderate to complete TSH suppression, TSH < 0.1 B. Admit for 2 nd 150 mci 131 I treatment C. Both
CASE VII - Pearls
CASE VIII A 35-year-old woman CC : Incidentally found right thyroid nodule from annual check-up PE : A palpable 1 cm. right thyroid nodule No palpable cervical LNs
CASE VIII US-guided FNA : Suspicious of papillary thyroid CA S/P Total thyroidectomy Pathology : Papillary thyroid cancer, classical variant Right lobe Ø 1.2 cm. Absence of angiolymphatic invasion Absence of perithyroidal soft tissue invasion
CASE VIII Base on pathological report Stage. Risk of recurrence.
CASE VIII QUESTION 23 - What is an objective of 131 I treatment for this patient? A. Remnant ablation - To facilitate follow-up B. Adjuvant therapy - To destroy suspected but unproven residual disease
CASE VIII Post-Tx WBS 131 I ablation 30 mci OPD case This patient Normal T4 2.3 5.1 14.1 TSH 60 0.27 4.2 Stim. Tg 10.4 - TgAb 53.4 < 40 Anterior neck
CASE VIII After RAI treatment 2 month - TSH 0.5 6 month This patient Normal T4 9.7 5.1 14.1 TSH 0.6 0.27 4.2 Supp. Tg < 0.04 - TgAb < 10 < 40
CASE VIII Dx-WBS At 8 month after treatment US thyroid - negative This patient Normal T4 1.4 5.1 14.1 TSH 76.23 0.27 4.2 Stim.Tg < 0.04 - TgAb < 10 < 40 Anterior neck
CASE VIII QUESTION 24 - What is the therapeutic response (among 4 categories) of this patient? A. Excellence response B. Biochemical incomplete response C. Indeterminate response D. Structural incomplete response
CASE VIII - Pearls
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