Building the Knowledge Base
January 01, 2016
New Children’s Oncology Group study provides important insights on adolescent boys with malignant testicular germ cell tumors
As rare as malignant germ cell tumors are, data on how adolescent boys fare with these cancers is rarer still. “If you look at testicular tumors in children, there are really two separate groups,” says Jonathan Ross, MD, Division Chief, Pediatric Urology, UH Rainbow Babies & Children’s Hospital Professor of Urology and Pediatrics, Case Western Reserve University School of Medicine. “There are little kids, maybe 2 or 3 years old, and the others are teenagers. The problem is that there are very few studies of adolescent testicular cancer. Most pediatric studies exclude them, and most adult studies start including patients at age 18.”
However, Dr. Ross and his fellow members of the Children’s Oncology Group’s (COG) committee on germ cell tumors are working to change that. They’ve recently published study results including a wider population of testicular cancer patients, ranging in age from infancy to age 15. Their findings, published recently in the Journal of Pediatric Surgery, show markedly different outcomes between children and teenagers after orchiectomy for stage I testicular cancer.
“What we found is that these patients generally do well, but the older kids don’t do nearly as well as the younger kids,” Dr. Ross says. For patients under age 11, event-free survival (lack of recurrence) at four years after surgery was 80 percent. For patients age 11 and older, the same metric was only 48 percent.
Histological differences between the tumor types can explain much of this disparity, Dr. Ross says. “Pediatric tumors are almost all pure yolk-sac tumors, whereas adolescents are more likely to have mixed histology with different types of cells in it, which is also more typical of adult tumors.”
One potential prognostic factor to emerge from the recent study is lymphovascular invasion – a measure of how aggressive the tumor is locally. For patients without lymphovascular invasion, the recurrence four years after surgery was 16 percent. For those with lymphovascular invasion, the recurrence rate was 38 percent.
“Lymphovascular invasion has been shown in adults to have some predictive value,” Dr. Ross says. “In this study, it seemed to correlate, but there were so few patients to analyze, we need to investigate further.”
Dr. Ross has served as pediatric urologist on the COG’s Germ Cell Tumor Committee for the past 15 years. Going forward, he and other committee members are planning new studies to further develop the knowledge base on these tumors.
“We’re working to include all adolescents in future studies, without that age 15 cut-off,” he says. “There’s so little data about adolescents. My guess is that they’ll behave like adult patients, but we don’t have a lot of evidence to know for sure. This work dovetails nicely with Rainbow’s emphasis on tumors in adolescents and young adults through the Angie Fowler Adolescent & Young Adult Cancer Institute.”
The hope is to provide more definitive information about the prognostic factors that matter most for boys and teens with these tumors.
“Going forward, we’re going to be able to answer more questions by including more patients,” Dr. Ross says. “Our current study wasn’t designed to ask the question of whether lymphovascular invasion mattered or not. But now that we have data suggesting that it might be a factor, we can look at it intentionally.”
For more information about this study or other COG projects under way at the Angie Fowler Adolescent & Young Adult Cancer Institute at UH Rainbow Babies & Children’s Hospital, email Peds.Innovations@UHhospitals.org.