Short-Course Total Lymphoid Irradiation in Management of Pediatric Heart Transplant Rejection

Abstract

<h3>Purpose/Objective(s)</h3> To evaluate short-course total lymphoid irradiation (TLI) as treatment for refractory heart transplant rejection in pediatric patients. <h3>Materials/Methods</h3> Pediatric patients who received short-course TLI for treatment of recurrent heart transplant rejection at a single institution were retrospectively reviewed. Radiotherapy consisted of 448 cGy in 4 fractions delivered once daily consecutively. This regimen was previously reported in a small series of adults but has not been reported in children. Potential advantages of short-course TLI compared to a more standard 800 cGy in 10 fractions delivered twice weekly (over 5 weeks) include fewer anesthesia sessions, lower cumulative dose, and patient convenience. <h3>Results</h3> Between 2019-2021, 3 pediatric patients (ages 4, 15, 17; 1 girl, 2 boys) received short-course TLI for chronic or recurrent rejection after cardiac allograft transplant. TLI was delivered between 5-51 months after heart transplantation, and time from initial rejection to TLI was 4-30 months. All patients were critically ill with limited medical options to manage rejection at time of TLI. They all received TLI as planned without need for modification due to acute toxicity. Two patients achieved resolution of rejection after TLI. One of these patients was rejection free on endomyocardial biopsy 3 months later and was alive 6 months after TLI with no complications related to TLI. The other patient's endomyocardial biopsy at 3 months also demonstrated no evidence of rejection and was able to undergo a second heart transplant 8 months after TLI for heart failure that was present prior to TLI. This patient was alive 3 years after TLI with no complications related to TLI. One patient died within 1 month of TLI due to multi-organ failure and thus the effects of TLI were not able to be fully assessed. <h3>Conclusion</h3> Short-course TLI was well-tolerated and significantly reduced the duration of the radiation treatment course in comparison to standard course; this is particularly advantageous in young patients who require anesthesia as well as acutely ill patients with poor performance status. Fortunately, alternative anti-rejection therapies are often effective and TLI is rarely requested, but if required a short-course TLI regimen remains an option.