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

2. 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

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

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

5. Familial Non-Medullary Thyroid ca : -

6. Clinical Features : - MC presentation – Painless swelling in the neck
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.

7. Papillary Thyroid Ca. : -
Most common type (~80%)
Young females (mean age 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

8. PTC – Neck secondaries : -

9. PTC – Types : - Types Follicular variant Tall cell Columnar cell
Diffuse sclerosing Poor Prognosis
Insular
Breaking of capsule

10. PTC – Pathology : - Gross : - Microscopic : - 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

11. Papillae : -

12. Psammoma bodies : -

13. Orphan Annie Cells : -

14. Orphan Annie : -

15. Investigations : - USG neck FNAC Thyroid function test
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

16. PTC – Prognostic Systems : -
AGES – Age, Grade, Extent & Size
AMES – Age, Mets, Extent & Size
GAMES – Grade, Age, Mets, Extent & Size
Factors
Low Risk
High Risk
Age
<40 yrs
>40 yrs
Sex
Female
Male
Extent
Intrathyroidal
Extrathyroidal
Metastasis
None
Present
Size
<2 cm
>4 cm
Grade
Well differentiated
Poorly differentiated

17. PTC – Prognostic Systems : -
DeGroot’s 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

18. 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

19. FTC – Bone Mets : -

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

21. FTC – Pathology : - Gross Microscopic
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

22. FTC – Capsular Invasion : -

23. 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.

24. TNM for DTC – AJCC 7th : - T1 Tumour 2cm or less & confined to thyroid
Tumour 2 – 4 cm & confined to thyroid T3
Tumour >4cm or minimal extra-thyroid extension (Invasion of sternothyroid/perithyroid soft tissues)
T4a
Invasion of larynx, trachea, oesophagus or RLN
T4b
Invasion of prevertebral fascia or carotid a.

25. Metastasis to level VI nodes
TNM for DTC – AJCC 7th : -
N1a
Metastasis to level VI nodes
N1b
Involvement of unilateral/bilateral lateral group nodes(level I - V) or mediastinal nodes (level VII) M0
No distant metastasis M1
Distant metastasis

26. TNM – Stage Grouping : -
AGE < 45 years I
Any T
Any N M0 II M1

27. TNM – Stage Grouping : - AGE > 45 years I T1 N0 M0 II T2 III
T1 – T3
N1a IV
T4a / T4b
N1b M1

28. 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

29. 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

30. 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

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

32. 131I ablation continued… Precautions : - Therapeutic dose : -
Stop thyroxine for 4-6 wks
TSH > mU/L for maximal effect
Avoid iodinated contrast CTs, salts & pain balms
Therapeutic dose : -
Low risk pt. – mCi
High risk pt. – mCi

33. 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

34. Post-op follow up : -
Suppressive dose of thyroxine – till TSH <0.1mU/l
RAI Scanning : -
6-12mth after initial ablation
If consecutively negative - >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

35. 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

36. Hurthle Cell Ca : -

37. 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

38. 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)

39. 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)

40. 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

41. Medullary Ca. - Peculiarities : -
Characteristic amyloid stroma on HPE
Doesn’t 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

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

43. Amyloid Stroma : -

44. 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

45. 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

46. 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

47. Thank You