Disability, underemployment, and psychosocial challenges are some of the issues that childhood brain cancer survivors grapple with in their daily lives, even decades after treatment, a new study shows. The authors say survivors of pediatric low-grade gliomas-the most common central nervous system (CNS) tumors of childhood-would benefit from ongoing, specialized care throughout adulthood.
The NCI-funded study by researchers from Baylor College of Medicine, Texas Children's Hospital, and St. Jude Children's Research Hospital included 286 individuals-181 survivors of pediatric low-grade glioma and 105 siblings of cancer survivors. All were participants in the Childhood Cancer Survivor Study, according to the data published online in Cancer (2019; doi: 10.1002/cncr.32186). The siblings in the comparison group were not siblings of the survivors in the study, though, the authors noted.
The survivors were a median age of 7 when they were first diagnosed with brain cancer, and a median age of 41 at the time of the follow-up during which time all participants underwent a series of cognitive tests and answered questions about their socioeconomic status.
The scientists reported that the survivors' outcomes were significantly poorer than the siblings' outcomes. Those treated with surgery and radiotherapy scored lower on IQ tests compared with the sibling group. Survivors treated with surgery-only also scored lower on IQ tests.
The surgery and radiotherapy treated group also had lower occupation outcomes compared with survivors who only underwent surgery. They also had lower incomes and less education than the surgery-only group.
Childhood brain cancer survivors diagnosed at younger ages had lower scores on all tests, except for attention/processing speed. Even survivors who had the least malignant types of brain tumors and received the least toxic therapies available at the time had later life effects, said M. Douglas Ris, PhD, Head of the Section of Psychology in the Department of Pediatrics at Baylor College of Medicine, and Chief of the Texas Children's Hospital Psychology Service.
Study co-author Gregory T. Armstrong, MD, a pediatric oncologist in the Department of Epidemiology and Cancer Control in the Division of Neuro-Oncology at St. Jude Children's Research Hospital, said it's difficult to project what today's patients will experience several decades down the road.
"In clinic, parents ask, 'Is my kid going to have Alzheimer's when they're 50?' And with low-grade glioma patients, we just don't know. That's the great unknown."
Up until 5 years ago, the standard treatment for pediatric low-grade glioma was surgery plus or minus radiation, or plus or minus chemotherapy.
"That had been it. In the last 5 years, more targeted agents have also been used, but no one knows the long-term effects," Armstrong said, noting that not just treatment type, but tumor location can play a role in impairment, too.
Jesse Bledsoe, PHD, a clinical neuropsychologist in the Department of Psychiatry and Behavioral Medicine at Seattle Children's, said, "In addition to location and treatment needed, neurological factors such as hydrocephalus, shunts, and surgical side effects such as posterior fossa syndrome are also important factors when predicting long-term cognitive, academic, and social outcomes."
Lifelong Follow-Up & Care
Seventy-five percent of children diagnosed with a CNS tumor will become 5-year survivors, according to the study authors. In 2015, there were approximately 66,798 pediatric CNS tumor survivors.
The authors concluded that even though low-grade glioma survivors are thought to be at lower-risk than survivors of some other pediatric brain tumors, they should receive lifelong monitoring.
"These data show they're not remarkably worse but certainly not better and will probably decline with time," said Armstrong.
His concern is that these patients are spread out across the country and once they leave their pediatric oncology health care providers, they may not receive the care they require. "They are so dispersed geographically. They're in ones or twos all over the country."
While the Children's Oncology Group recommends long-term follow-up for children who've survived cancer and provides primary care physicians with guidelines, it doesn't provide detailed guidance, Armstrong said.
"It says they should have annual follow-up, but it doesn't give a lot of insight on how to follow a 40-year-old pediatric brain cancer survivor. There's no recommendation for following cognitive function in these survivors. They get lost in transition and lost in the medical system and because of their lower cognitive and socioeconomic status, they may not be able to really fight for themselves," he noted.
More research is needed, said Seattle Children's pediatric oncologist Sarah Leary, MD.
"The brain is a truly critical area, and depending on specific factors, brain tumor diagnosis and treatment can affect any function of the brain including cognitive, social, physical, sensory, and hormonal functioning."
Leary said some patients are cured with minimal to no long-term side effects, but she noted, "For others, a cure comes at a very high price that greatly impacts quality of survival. It is critical to support research into better treatments, even for brain tumors with very high cure rates like low-grade glioma."
Mary Brophy Marcus is a contributing writer.