COLORADO SPRINGS — Older adolescents and young adults with certain cancers have markedly better outcomes when treated in pediatric centers than in adult oncology centers, based on multiple studies conducted in the United States and Western European countries.
“The cancers that are more pediatric in nature—acute lymphoblastic leukemia, acute myeloid leukemia, bone and soft tissue sarcomas—all have evidence that treatment in pediatric settings yields better results,” said Dr. Stephen P. Hunger professor of pediatrics, director of the center for cancer and blood disorders, and chief of pediatric hematology/oncology/bone marrow transplantation at the University of Colorado at Denver.
Even when adult oncologists employ treatment protocols similar to those used in children's hospitals, the outcomes seem to be better in the pediatric setting. The explanation for the difference in the results remains unclear.
Some adult oncologists argue that they're treating a different population of young people than is encountered in children's hospitals: that is, emancipated youths who are less likely to be treatment compliant than are young patients who are still living with their parents.
Pediatric oncologists counter that their superior outcomes result from their treatment teams' far greater experience with these types of cancers—and a correspondingly greater willingness to treat aggressively, Dr. Hunger explained at the annual conference of the Colorado Academy of Family Physicians.
There are key biologic differences between pediatric and adult cancers. Pediatric cancers such as acute lymphoblastic leukemia (ALL) are typically mesodermal in origin, whereas adult malignancies are generally epithelial. Mendelian genetics and lifestyle risk factors play only a limited role in most childhood tumors, so routine screening and risk reduction efforts aren't emphasized. Pediatric cancers are often microscopically disseminated—rather than localized—at the time of diagnosis, so systemic therapy is almost always required.
Pediatric cancers are more treatment responsive than most adult cancers, and children tolerate intensive systemic therapy far better than adults. Also, cancer patients at a children's hospital are routinely enrolled in a clinical trial under the auspices of the National Cancer Institute–sponsored Children's Oncology Group, with all that implies in terms of state-of-the-art treatment, whereas older adolescents and young adults treated in adult oncology centers are not typically part of a clinical trial, Dr. Hunger continued.
ALL accounts for 80% of all cases of childhood leukemia, and acute leukemia is the most common cause of cancer death before age 35. Outcomes in young adults with ALL have historically been worse than in younger patients with the malignancy. However, a recent Spanish study showed that outcomes in ALL patients (aged 19-30 years) who received the standard pediatric ALL regimen were equal to those in patients aged 15-18 years (J. Clin. Oncol. 2008;26:1843-9).
A retrospective study of 321 ALL patients (aged 16-20 years) who participated in clinical trials conducted by the Children's Cancer Group vs. the adult oncology Cancer and Leukemia Group B showed a 63% event-free survival rate at 7 years for those treated in pediatric centers, compared with just 34% in those treated in adult settings (Blood 2008;112:1646-54).
Similarly, a series of retrospective European studies has shown ALL cure rates to be an absolute 20%-30% higher in older adolescents and young adults treated in pediatric versus adult clinical trials (Hematology January 2006;128-32).
'Treatment in pediatric settings yields better results' in young adults with certain cancers.
Source DR. HUNGER