Management of Hemodialyzed Patients Treated with Radioactive Iodine for Thyroid Cancer: How Could We Improve It?...

The use of radioactive iodine (RAI) for patients with thyroid cancer (TC) who are also treated with hemodialysis for end-stage renal disease (HD-ESRD) remains challenging, with several issues still unresolved. We report our tertiary referral center experience and provide suggestions for management improvement. Methods: We included all HD-ESRD patients that required RAI for TC in our institution. Oncologic results and toxicity risk were evaluated. Blood marrow (BM) absorbed dose was estimated on the basis of current guidelines and compared with 2 alternative models that adapt to the inability of using biexponential models for hemodialyzed patients. We emulated the impact of high RAI activity on the BM absorbed dose. Dialysis parameters were reviewed to correlate with kinetics of RAI activity. The impact of 2 different schema of recombinant human thyrotropin stimulating hormone was also studied. Results: In total, 16 patients were included. Fifteen patients were prepared with recombinant human thyrotropin stimulating hormone (5 with 1 injection on day 2, 10 with 2 injections on days 10 and 2). Median RAI activity was 2913 MBq, and immediate and late tolerance was good. The median BM absorbed dose was 0.72, 0.81, and 0.67 Gy with models 1, 2, and 3, respectively, statistically different among all calculation methods. There was no significant correlation between total blood activity decrease and total purified blood volume. No patient crossed the 2-Gy threshold with a delivered activity of 3700 MBq. Conclusion: On the basis of the largest series of HD-ESRD patients treated with RAI for TC, we present findings that could enhance their management. With our hemodialysis protocol, we suggest that routine reductions in RAI activity may be overly cautious and unnecessary. Oncologic outcomes were favorable, without significant hematologic toxicity. A 65-70 L of purified blood volume per session target results in over 90% reduction in radioactivity after 2 dialysis sessions.