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 Jul;6(7):

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 Jul;6(7):

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; Higher 20 yrs local recurrence (14% vs 2%) Higher 20 yrs nodal metastasis (19% vs 6%) Hay et al. Surgery 1998;124: 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: »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 Oct;130(10):

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 May-Jun;75(3): 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 metastasis Sawka et al. J Clin Endocrinol Metab 89: ,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