(HealthDay) -- Teenagers and young adults with acute lymphoblastic leukemia, a cancer of the blood and bone marrow, are more likely to relapse and less likely to survive than younger children with the disease, according to a new study.
"This study tells us that the inferior outcome for [adolescent and young adult] patients is the result of more resistant disease, resulting in higher rates of relapse and higher toxicity from treatment," the study's lead author, Dr. Eric Larsen, medical director of the Maine Children's Cancer Program, said in a news release from the American Society of Clinical Oncology.
In conducting the study, the researchers compared four different treatment regimens in a single cancer clinical trial. Of the nearly 2,600 patients involved in the trial, 20 percent were teens and young adults -- more than 500 between 16 and 30 years old.
The researchers found the teen and young-adult patients relapsed more often and had lower overall survival than those who were 1 to 15 years old.
Specifically, 68 percent of the teens and young adults had no evidence of the disease after five years, compared to 80.9 percent of younger patients. Overall survival among the older patients was 79.8 percent, compared to 88.4 percent in the younger patients. The researchers said these differences were statistically very significant.
The study found 21.3 percent of teens and young adults relapsed, compared to 13.4 percent of younger patients. These relapses were due mainly to a higher rate of bone marrow relapse in the older patients, the researchers explained. There was no statistically significant difference in central nervous system relapse between the age groups. Toxic deaths following induction therapy and remission were much higher among the older patients -- 5.5 percent compared to 2.1 percent in the younger patients.
The study is scheduled for presentation Saturday at the American Society of Clinical Oncology annual meeting in Chicago.
Data and conclusions presented at meetings should be considered preliminary until published in a peer-reviewed medical journal.
More information: The U.S. National Cancer Institute provides more information on leukemia.