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Riley Lentz: No Stone Unturned

Riley Lentz Cancer

Fifteen-year-old Riley is no stranger to hospitals. Diagnosed with malignant medulloblastoma in 2008, she underwent two open brain surgeries to remove the tumor and later, two noninvasive radiosurgical CyberKnife® procedures.

When the tumor recurred in 2013, she was given high-dose chemotherapy and received a stem cell transplant to help her body bounce back after the infusions.

When Riley’s parents enrolled her in a clinical trial for recurrent medulloblastoma, a fast-growing, high-grade tumor located in the cerebellum, her response to treatment was dramatic. The trial is available only at Children’s Memorial Hermann Hospital in Houston.

“After the chemo, we went until April or May of 2015 before they found another small spot and opted to try the Cyber- Knife for the second time,” says Riley’s mother, Melissa. “At her three-month follow-up MRI, we learned that the procedure didn’t help.”

Somewhere along the way, Melissa joined a Facebook group called Parents of Kids with Medulloblastoma, a forum for parents who want to share their knowledge and experience. “I had heard about a clinical trial of direct infusion of chemotherapy into the fourth ventricle around the time Riley had the stem cell transplant in 2013,” she says. “After her oncologist told us her body wouldn’t tolerate any more systemic chemo, I started looking for other options. I was fortunate to find another parent on the Facebook page whose child had just finished the clinical trial in Houston.”
Through Parents of Kids with Medulloblastoma, Melissa connected with Marcia Kerr, RN, CCRC, research coordinator for pediatric neuroscience at McGovern Medical School at UTHealth.

Among the trials Kerr coordinates is one led by David I. Sandberg, M.D., FAANS, FACS, FAAP, director of pediatric neurosurgery at Children’s Memorial Hermann Hospital, Memorial Hermann Mischer Neuroscience Institute, and McGovern Medical School.

Prior to his arrival in Houston in 2012, Dr. Sandberg conducted translational studies that demonstrated the safety of infusing chemotherapeutic agents directly into the fourth ventricle to treat children with recurrent malignant brain tumors in this location. The promising results of those studies led to a pilot clinical trial completed in August 2015 and a new methotrexate dose-escalation study available only at Children’s Memorial Hermann Hospital in collaboration with Mischer Neuroscience Institute.

“This radically new approach to chemotherapy delivers agents directly to the site of disease, which minimizes the side effects for children like Riley by decreasing systemic drug exposure,” says Dr. Sandberg, an associate professor with dual appointments in the Vivian L. Smith Department of Neurosurgery and the department of Pediatric Surgery at McGovern Medical School. “After we determined that methotrexate can be infused into the fourth ventricle without causing neurological toxicity, and that some patients with recurrent medulloblastoma experience a beneficial anti-tumor effect both within the fourth ventricle and at distant sites, our next step was a dose-escalation study to determine the optimum dose of the agent.”

“This radically new approach to chemotherapy delivers agents directly to the site of disease, which minimizes the side effects for children like Riley by decreasing systemic drug exposure.”

- David I. Sandberg, M.D., FAANS, FACS , FAAP

Riley was among the first participants enrolled in the clinical trial at Children’s Memorial Hermann Hospital, the only such study under way in the world. In a surgery that took place on Nov. 3, 2015, Dr. Sandberg removed as much of the tumor as possible and placed a reservoir for the direct delivery of chemotherapy – a catheter and plastic disk covered by a rubber balloon underneath the skin at the back of Riley’s neck.

Riley and other children who participate in the trial undergo three cycles of chemotherapy and an MRI before and after treatment. Each cycle includes an infusion on Monday and Thursday for three weeks, followed by a rest week.
“Once we’ve shown that the treatment is safe and the child is responding to it, we’re happy if we can find a pediatric oncologist to continue it,” Dr. Sandberg says. “Riley came to us from Arkansas and had a dramatic response. Her parents are unbelievably dedicated, leaving no stone unturned to help their daughter, including making the 16-hour round-trip drive to Houston twice a week. We’re thrilled to get this kind of positive response to the treatment without the toxicity of systemic chemotherapy, and we’re grateful to Riley’s oncologist for continuing the treatment in Little Rock.”