Optimization of the management of hemodialyzed patients treated with 131I radioiodine for thyroid cancer: The Lille experience

Background & objectives

The use of 131I radioiodine (RAI) for patients with thyroid cancer (TC) also treated with hemodialysis for end stage renal disease (HD-ESRD) remains challenging, with several issues still poorly known: adaptation of RAI activity and previous preparation, estimation of bone marrow (BM) absorbed dose, impact of dialysis parameters, oncological outcome and toxicity risk. We wanted to report our tertiary referral center experience and suggestions for improvement regarding these points.

Material & methods

We included all HD-ESRD patients that required RAI for TC in our institution. Oncological results and toxicity risk were evaluated. BM absorbed dose was estimated based on current guidelines and compared with two optimized models that took account the variability observed in HD patients. We simulated the impact of high RAI activity on BM-absorbed dose. Dialysis parameters were reviewed to correlate with kinetics of RAI activity. The impact of two different schema of rhTSH was also studied.

Results

Sixteen patients were included. Fifteen patients were prepared with rhTSH (5 with one injection on D-2, 10 with two injections on D-10/D-2). Median RAI activity was 2913 MBq, immediate and late tolerance was good. Median BM absorbed dose was 0.72 Gy; 0.81 Gy and 0.67 Gy with models 1; 2 and 3 respectively, statistically different between all groups. There was no significant correlation between the decrease in blood activity and purified blood volume per dialysis session neither total purified blood volume. No patient would have crossed the 2 Gy threshold with a delivered activity of 3700MBq.

Conclusion

Based on the largest series of HD-ESRD patients treated with RAI for TC, we present findings that could enhance their management. Our dosimetry models provide a more accurate reflection of biological reality, making them valuable for planning dosimetry. Our simulations suggest that routine reductions in RAI activity may be overly cautious and unnecessary. Oncological outcomes were favorable, without cancer-related deaths or significant hematological toxicity. A target of 65–70 liters of purified blood volume per session results in over 90% reduction in radioactivity after two dialysis sessions. Two rhTSH injections at D-10/D-2 before RAI may be a viable alternative to hormone withdrawal.