Mehdi Djekidel MD, Presenter: Nothing to Disclose

Roderick Richardson, Abstract Co-Author: Nothing to Disclose

Michael J. Bohan BS, Abstract Co-Author: Nothing to Disclose

Thyroid Cancer is usually a slow growing tumor and is of increasing incidence. It has been customary and a great success to use radioactive iodine (RAI) as the magic bullet in order to deliver the highest targeted radiation dose for remnant ablation or for treatment of residual thyroid tumor. RAI effectiveness is due to its targeted nature and rapid non-target tissue clearance, offering a very attractive biological half-life where most of the radiation exposure is minimized through rapid and predominant renal clearance. In patient's with kidney dysfunction or end-stage renal disease, this benefit is lost and therapeutic strategies affecting patient outcomes need to be considered.

We propose to present a brief overview of the clearance kinetics of RAI in ESRD patients on hemodialysis or peritoneal dialysis, as well as discuss therapeutic strategies, outcomes, exposure rates. Potential pitfalls and solutions to RAI treatment.

The general adage has been that higher safe RAI radiation doses would yield the best killing power and that the rapid biological clearance kinetics of RAI required administration of higher non toxic doses in order to maximize targeted tumor radiation. However, this theory does not hold true in ESRD patients. We found not unexpectedly that PD or HD patients retained nearly their whole radiation dose until dialyzed. Dialysis at 48 hours yielded a clearance of on average 62.25% of initial delivered dose, at 96 hours an average of 67.7%. PD yielded better exposure rates because of constant dialysis with an up to 6 fold increased radiation exposure. HD gave up to 10 fold increases in exposure rates. Treatment decreases of 5 to 6 folds of naturally expected prescribed dose is likely necessary. Recirculation of RAI prior to dialysis will increase the effectiveness of the therapy. 24hr Dialysis for the first 3 days will yield the best benefit/risk ratio. Additionally special attention should be paid to iodinated antiseptic compounds used for dialysis patients which may yield a significant unwanted thyroid blockade.

Special precautions should be taken with the administration of RAI in kidney dysfunction and ESRD patients by adjusting prescribed dose, dialysis sessions and antiseptics used.

Very minimal data exists regarding RAI and ESRD. Adjusting the prescribed RAI dose, the schedule of dialysis and paying special attention to wastes is crucial.

Djekidel, M, Richardson, R, Bohan, M, Radioactive Iodine Treatment in End Stage Renal Disease Patients on Dialysis.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12025839.html