Radio active Iodine in Thyroid Cancer

Q) Which of the following is not true about Radioactive Iodine (RAI) use in thyroid cancer? (Thyroid onco) 

a) Screening with RAI  is less sensitive than Thyroglobulin estimation in most differentiated thyroid cancers for detecting metastasis

b) Metastatic differentiated thyroid carcinoma can be detected by  131I in about 50% of patients

c) Current guidelines s recommend RAI after total thyroidectomy only for patients with known distant metastases

d) Hurthle cell cancer des not take up RAI

 

Thyroid Questions

Q) Which of the following thyroid cancers do not take up radio active iodine

a) Medullary carcinoma thyroid

b) Papillary  carcinoma

c) Follicular carcinoma

d) Hurthle cell carcinoma

Free Answer

a - Medullary carcinoma

Medullary carcinoma of the thyroid is a tumor that arises from the C cells ie the parafollicular cells and not from cells of thyroid follicles.

These are not TSH dependent and hence do not take up radioactive iodine

Hurthle cell carcinoma is a variation of follicular carcinoma only.

In these tumors lymph node involvement is about 60%

Bailey page 769