Transarterial Oncologic Interventions in Children

Primary malignant liver tumors are rare in children, accounting for 1%-2% of all pediatric cancers. When chemotherapy fails, transarterial radioembolization with yttrium-90 (TARE Y-90) may offer an alternative therapy as a bridge to surgical resection or liver transplant or for palliation.¹ IO Learning invited Allison S. Aguado, MD, to discuss her 2021 Society of Interventional Radiology (SIR) presentation on the efficacy of minimally invasive interventional radiology treatments in pediatric cancer patients. 

Tell me about your background with interventional radiology in pediatric cases.

I am an interventional radiologist at Nemours Children’s Health System. I have fellowship training in pediatric interventional radiology (IR) and adult IR, and I subspecialize in pediatric interventional oncology. I started treating children with unresectable liver tumors about 6 years ago, where I used transarterial radioembolization with yttrium-90 (TARE-Y90) for palliative therapy; at Nemours, we’ve been using it as an upfront therapy with a curative intent. 

Tell us about your presentation at the 2021 SIR meeting. 

I was invited to speak about pediatric transarterial oncologic interventions; specifically, transarterial chemoembolization (TACE) and TARE-Y90. The focus of my work has been with TARE-Y90. I discuss two papers that I’ve published.^1,2 The first is a series of 10 pediatric patients who were treated with TARE-Y90 as salvage therapy, and then a more recent paper from Nemours where we treated patients with the intent to cure. So far, we have treated 3 patients at Nemours who are alive, with no evidence of disease at 3 and 2 years post completion of chemotherapy and 1 patient who had surgical resection 2 weeks ago.

What is your take on the current status of non-invasive IR treatments in pediatric cases in the United States?  

IR procedures have been well-established in adults for many years; we are starting to have more pediatric referrals with the support of our transplant/oncologic surgeons and medical oncologists. We are still in the early stages, but I attend multidisciplinary tumor boards here at Nemours, and our colleagues know about TARE-Y90 and are very supportive and interested in it. 

The recent LEGACY, DOSISPHERE, and TARGET studies have presented data regarding tumor response to a substantial increase in tumor-absorbed dose with Y-90. Do you see this shift toward a higher dose carrying over to pediatric patients?

I do see that shift, and I try to maximize the dose to the tumor while minimizing the dose to the lungs in children. I have been treating pediatric patients with doses analogous to what we would give adults. 

Can you discuss any limitations in treating children with Y-90? For example, are you limited by available equipment sizes?

I have an approximately 10-kilogram weight limit, where I like the patient’s artery to be sizable enough for a 4 Fr catheter. We also do lung segmentation with every patient, so I will measure lung volumes and density to calculate the weight of the lungs, which I use to modify the dosimetry for TARE-Y90. For example, if a pediatric patient has a lung weight that is half that of an adult, it would double the amount of radiation that goes to their lungs, so I have to be cognizant of how much radiation will be shunted to the lungs based on the size of the patient. 

Are you involved in any ongoing studies on non-invasive IR treatments in pediatric patients?

Nemours currently has an institutional review board approved study that is enrolling patients entitled “Clinical Outcomes and Quality of Life After Radioembolization in Children With Liver Tumors.” 

Any final thoughts on the differences between treating pediatric cases versus treating adults?

One main difference is that we always use general anesthesia. We also require a pediatric intensive care unit to be available for sedation post procedure, specifically for very young children to keep their legs straight if they are unable to cooperate. We’ve seen encouraging results in the first 3 patients that we have treated with intent to cure who would not have been able to be resected without this treatment.

References

1. Aguado A, Ristagno R, Towbin AJ, et al. Transarterial radioembolization with yttrium-90 of unresectable primary hepatic malignancy in children. Pediatr Blood Cancer. 2019;66:e27510. Epub 2018 Nov 8. 

2. Aguado A, Dunn SP, Averill LW, Chikwava KR, Gresh R, Rabinowitz D, Katzenstein HM. Successful use of transarterial radioembolization with yttrium-90 (TARE-Y90) in two children with hepatoblastoma. Pediatr Blood Cancer. 2020;6:e28421. Epub 2020 Jun 30.