Seattle Children’s adds smart radiation to its arsenal of tools to fight a deadly childhood cancer.
In 2012, Seattle Children’s became the first hospital in the Pacific Northwest – and one of only 12 in the country – to offer I-131-MIBG therapy, a novel approach to treating high-risk neuroblastoma. Currently, less than half of children with advanced-stage disease will survive, even after receiving aggressive chemotherapy, surgery, transplant and immunotherapy.
MIBG (metaiodobenzylguanidine), a precursor to adrenaline, is taken up by 90% of neuroblastoma cells. MIBG radiolabeled with iodine 123 is used in the imaging process to accurately stage newly diagnosed patients.
Labeling MIBG with iodine-131 and infusing it via an IV delivers a much higher dose of radiation directly to tumors, killing the cancer cells. Concentrating the radiation at the site of the cancer means exposing children to less radiation and fewer long-term risks to their growing bodies. I-131-MIBG therapy is currently only available through clinical trials or compassionate use protocols.
COG studying how best to use MIBG
Dr. Julie Park spearheaded the effort to bring MIBG therapy to Children’s. She leads the Children’s Oncology Group (COG) Neuroblastoma Scientific Committee, which is actively evaluating how best to implement this new therapy. Children’s will participate in the current national clinical trial designed to understand how best to deliver this treatment to patients newly diagnosed with neuroblastoma. A follow-up study will then test whether the addition of MIBG therapy improves the outcome for children with high-risk neuroblastoma.
“MIBG therapy will be incorporated into several clinical trials in the future, with the ultimate goal of making neuroblastoma therapy more effective,” says Park. “Seattle Children’s patients will no longer have to travel outside the region to have access to MIBG therapy.”
Innovating to improve safety
Because I-131 is highly radioactive and the radiation remains at high levels in the child’s body for five to seven days, hospitals offering MIBG therapy must be specially equipped to contain the radiation. Dr. Marguerite Parisi, a radiologist and nuclear medicine specialist with extensive experience with MIBG, led the team that spent nearly two years developing the processes and training to offer this novel therapy as safely as possible.
“While we’re the first pediatric facility on the West Coast to offer this therapy,” notes Parisi, “we’re not the first in the country. So we consulted with hospitals that offer MIBG therapy and then looked for ways we could innovate to improve safety.”
Lisa Aldape, a nuclear medicine technologist who worked closely with Parisi, consulted with design engineers at Medrad, a manufacturer of vascular injection systems, to improve the infusion mechanism. “Until now, a lead lining was typically used to shield the person administering the medicine,” says Aldape. “Medrad worked with us to create a tungsten shielded injector, which is more effective than lead and much lighter. Plus, this new injector can be operated remotely by computer a few feet away from the bedside, further reducing staff exposure.” Children’s is one of the first sites to use the new version of the device for delivery of I-131-MIBG therapy.
Children’s also avoided the significant expense of building a new “hot” lab for preparing the radioactive medication by partnering with a local nuclear pharmacy that already had the necessary facilities to handle high doses of I-131. “Instead of building a lab, we commissioned a special tungsten carrying case for the safe transport of the therapy isotope to Children’s,” says Aldape.
“In addition to being safe, we wanted to be sure that our design met families’ needs,” says Aldape. “So we talked with families whose child had been treated with MIBG at other facilities, and asked how we could improve the experience.”
Because the child must be isolated for up to a week while the radiation is excreted through body fluids, Children’s built a large, dedicated patient room with lead-lined doors and walls, and a room for parents close by. Both rooms have video conferencing equipment, so parents can monitor and communicate with their child at all times. Every parent receives one-on-one training to ensure that they can provide daily care for their child with minimal radiation exposure.
Conviction, expertise and infrastructure
In addition to specialized facilities, I-131-MIBG therapy requires a high level of expertise in nuclear medicine and oncology. “We are one of the few centers with the expertise to deliver this type of cutting edge therapy, and now we’ve got the infrastructure and protocols in place to move forward,” says Park. “This is just one example of Seattle Children’s having the conviction to bring the best and newest therapies to kids with cancer.”
“We consulted with hospitals that offer MIBG therapy and then looked for ways we could innovate to improve safety.”
– Dr. Marguerite Parisi