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RAI Ablation in Stage 1 Papillary Thyroid Cancer?

Last Updated: · Doctors
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Question

After reading Endocrine Practice last month:

Hayes: no I 131 stage 1-2

Mazz: 30 mCi remnant ablation stage 1 disease

My institution uses 150 mCi in this situation (I’m trying to change this)

How would you treat this patient below?

51 yo woman with chronic hashimoto’s, FNA + PTC, undergoes total thyroidectomy post op on cytomel Tg<0.2, TgAb 39, ft4 0.5, TSH 0.5

October 24, 2007 A. THYROID, TOTAL THYROIDECTOMY:

  • PAPILLARY THYROID CARCINOMA, MULTIFOCAL
  • SIZE: 0.7 CM, LARGEST LESION
  • EXTENT: INVOLVES BOTH RIGHT AND LEFT LOBES, MULTIFOCAL
  • NEGATIVE MARGINS OF RESECTION
  • NO LYMPHOVASCULAR INVASION IDENTIFIED
  • ONE LYMPH NODE WITH NO EVIDENCE OF MALIGNANCY (0/1) B. LYMPH NODE CENTRAL COMPARTMENT, EXCISION:
  • SEVEN LYMPH NODES WITH NO EVIDENCE OF MALIGNANCY
  • ONE PARATHYROID IDENTIFIED, NORMAL SIZE
  • AJCC TNM STAGE pT1 NO MX (STAGE 1)
  • CHRONIC LYMPHOCYTIC THYROIDITIS WITH HURTLE CHANGE (HASHIMOTO’S THYROIDITIS) .

Thanks for your help,

Kathleen Hands

Response

In my view RAI thyroid ablation has significant benefits for follow-up of most cancer patients except those with <1cm single focus papillary cancers, although the actual improvement in cancer free survival may be slight. In your case multifocality ups the odds, and the patient has antibodies making use of TG assay problematic. Thirty mCi probably is sufficient and probably as ablative as larger doses, if the remnant tissue is small. Thus 30, or 50 mCi, makes sense. Larger doses surely give the patient considerably more radiation exposure with no proven added benefit, and markedly increased cost.

L De Groot, MD