Management of differentiated thyroid cancer

Dr. Leung Tak Lun Canice

North District Hospital

Differentiated thyroid cancer

• Derived from follicular cells– Papillary carcinoma– Follicular carcinoma– Mixed papillary follicular– Follicular variant of papillary carcinoma

• 85% of all thyroid cancers» Udelsman et al. Lancet Oncol. 2005 Jul;6(7):529-31.

Prognostic scoring system

• AGES (Age, Grade, Extent, Size)

• AMES (Age, Metastasis, Extent, Size)

• MACIS (Metastasis, Age, Completeness of resection, Invasion and Size)

Case

• F/45

• Filipino

• Right neck lump for 4 months

• USG neck– 3cm nodule in right lobe of thyroid– Small nodules in left lobe– Bilateral LN metastasis

• FNAC confirmed papillary CA

Treatment modality

• Surgery

• Radioactive iodine ablation

• Others– TSH suppression– RT, Chemotherapy

Surgery

• First line treatment

• The extent?– Thyroid lobectomy and isthmusectomy?– Total thyroidectomy?

• Lymph node dissections?

Total thyroidectomy

• Bilateral thyroid cancers are common– 30-80% of papillary thyroid cancer– 23% of follicular tumours

Udelsman et al. Lancet Oncol. 2005 Jul;6(7):529-31.

Total thyroidectomy

• Bilateral thyroid cancers are common– Lobectomy alone

• 5-10% recurrence rate in contralateral lobe• Higher tumour recurrence rate• Higher pulmonary metastasis

Dackiw et al. Surg Clin North Am 2004; 84 817-32

• Higher 20 yrs local recurrence (14% vs 2%) • Higher 20 yrs nodal metastasis (19% vs 6%)

Hay et al. Surgery 1998;124:958-64

• One third of patient with recurrence subsequently died of thyroid cancer

Total thyroidectomy

• Radioactive iodine– Lower dose ablation– Detect recurrence

» Marraferri EL et al. J Clin Endocinol Metab 2001;86:1447-63» Maxon HR et al. J Nucl Med 1992;33:1132-6

Total thyroidectomy

• Thyroglobulin measurement– Monitor for recurrent disease

• Thyroid hormone withdrawal • rhTSH-stmulated

Total thyroidectomy

• Avoid reoperation– Higher morbidity

• Permanent vocal cord paralysis 1-12%• Permanent hypoparathyroidism 0-3.5%

Kim et al. Arch Otolaryngol Head Neck Surg. 2004 Oct;130(10):1214-6.

Lymph node surgery

• Papillary thyroid cancer – 30% -80% have positives node– Only 10% develop clinically significant

disease – Prophylactic modified neck dissections are

not recommended

Lymph node surgery

• Central compartment dissection has similar complication rates

Montesani et al. Ann Ital Chir. 2004 May-Jun;75(3):299-303

• Reoperative central compartment dissection with increased morbidity

Lymph node dissection

• Functional neck dissection– Indicated when there is clinical or radiological

evidence of lateral lymph node metastasis

Radioactive iodine

• Ablation– Aims to destroy residual normal thyroid tissue– Decreases local recurrence and distant metas

tasis Sawka et al. J Clin Endocrinol Metab 89: 3668-3676,2004

– Recommended in • All follicular CA• High risk papillary CA (MACIS 6 or more)

Tx

• TSH suppression

• External beam RT – Controversial– Not indicated in patients with good prognostic

features

Follow-up

• Physical examination

• Serum thyroglobulin measurement

• Radioactive scanning and USG neck when suspicious of recurrence

Case

• Total thyroidectomy with central compartment dissection and bilateral functional neck dissection

Case

• Post-op uneventful

• No vocal cord palsy

• No hypocalcaemia

• D/C on day 4

Summary

• Total thyroidectomy is recommended in all patients