Oral Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

Outcomes of radioactive iodine (RAI) ablation for differentiated thyroid cancer (DTC): no versus low versus high dose– The Alfred Hospital Experience (#258)

Anneke Graf 1 , Melissa Vereker 2 , Jonathan Serpell 2 , Duncan J Topliss 1
  1. Department of Endocrinology, The Alfred, Melbourne, VIC, Australia
  2. Department of General Surgery, The Alfred, Melbourne, VIC, Australia

Aim To assess outcomes in management of DTC with allocation to no, low (30 mCi), or high (100mCi) dose RAI ablation using rhTSH based on risk assessment according to TNM classification.

Method Retrospective chart review, diagnosis 1/1/2007 to 30/6/2013, all data available in Alfred records, review to 31/12/15 (minimum 2.5 years after diagnosis). Outcomes analyzed for no evidence of disease (NED), persistent structural disease (PD), indeterminate disease (IntD), or death.

Results 116 patients, median follow-up 3.9 years (range 0.6 – 8.5), 35 (30%) male, 81 (70%) female, median age 47.5 years (range 15-85), 93 (80%) papillary thyroid cancer (PTC), 23 (20%) follicular thyroid cancer (FTC).

In 12 who intentionally received no ablation, 10 have NED, 2 died from unrelated causes.

In 20 who received low dose ablation 17 have NED, 3 required further high dose RAI, of whom 2 now have IntD and 1 has PD.

In 83 who received high dose ablation 65 have NED, 5 patients have IntD, 6 patients have PD, and 7 patients died (2 from thyroid cancer, 5 unrelated cause). 26 required further RAI therapy.

Conclusions Potentially unnecessary ablation: 4 with low risk PTC (TMN stage T1bN0M0) received low dose ablation and have NED. 2 received low dose RAI for noninvasive, follicular encapsulated variant of PTC (Nikiforov
et al, JAMA Oncol 2016 Apr 14). Potentially excessive ablation: 11 with low risk PTC received high dose ablation. No further RAI was required. 10 have NED. 1 died of an unrelated cause. Potentially inadequate ablation: 3 with intermediate risk PTC (TMN stages T1bN1aM0, T2N1bM0, T2N1bM0) received low dose ablation and required subsequent RAI therapy. Retrospective review of RAI ablation choice suggests a better decision could have been made in 18 of 116 DTC patients. Improved evidence and guideline revision (Thyroid 2016; 26: 1-133) may improve subsequent decision-making.