Children who develop problems with memory, attention and behavior after cancer treatment may gain some long-term benefit from a medication commonly used for attention-deficit hyperactivity disorder (ADHD), a small clinical trial suggests.

It's well known that children who undergo radiation and chemotherapy that target the central nervous system can develop long-term problems with thinking, memory and attention span, as well as behavior and school performance.

Methylphenidate, sold under brand-names like Ritalin and Concerta, can improve such symptoms in children diagnosed with ADHD and is the most commonly prescribed drug for them. But until now, only a few, very short-term studies had looked at the drug's effects in child cancer survivors.

The new research, published in the Journal of Clinical Oncology, included 122 children who had developed attention and learning problems after successful treatment for brain cancer or acute lymphoblastic leukemia (ALL), a cancer of the white blood cells.

Researchers found that those who were given methylphenidate for a year showed a greater improvement in attention, behavioral problems and social skills than those who did not take the medication.

That does not mean methylphenidate can help all children with cognitive and behavioral issues after cancer treatment. Nor is it clear how the drug may ultimately affect their school performance.

The evidence does suggest that methylphenidate improves attention, behavioral problems and social skills in about half of the child cancer survivors who take it, according to Dr. Heather M. Conklin, a pediatric neuropsychologist at St. Jude Children's Research Hospital in Memphis and the lead researcher on the new study.

As far as academics, Conklin and her colleagues found that children on the drug showed no greater improvement in tests of reading, spelling and math skills than those in the control group.

But that is consistent with what studies have shown in children with ADHD, Conklin told Reuters Health in an e-mail.

Methylphenidate has mainly been found to improve children's performance on measures of attention, concentration and ability to process information -- with less evidence that it affects specific academic skills.

Anecdotally, Conklin said, some parents in her study said their children's grades improved, and that appeared to be related to improvements in the kids' ability to finish their homework and study for tests. She said future studies should assess such executive aspects of school performance, rather than only looking at specific math or reading abilities.

For the current study, Conklin's team used a standard battery of tests that gauge a person's capacity for sustained attention. They also had parents and teachers rate the children's attention and hyperactivity symptoms; parents completed additional questionnaires on behavioral issues and social skills.

Overall, children on methylphenidate showed a statistically significant improvement on the sustained-attention tests, in parent and teacher ratings of attention, and in parent ratings of behavior and social skills.

In most of those areas, Conklin said, the children's average scores improved to the levels seen among healthy children the same age.

In contrast, children in the control group showed improvements only in parent ratings of attention and social skills.

According to Conklin, the findings suggest that methylphenidate can be considered an option for child cancer survivors.

She said that in her practice, she discusses it with parents. But she also pointed out that the drug would typically be just one element of a strategy that includes certain school accommodations -- like seating the child in the front of the classroom and giving him or her shorter homework assignments - and teaching kids tactics for making schoolwork and test-taking easier -- such as studying in quiet settings, with frequent breaks.

Right now, there are few research-based alternatives for improving child cancer survivors' cognitive and behavioral problems. A recent study found that a so-called cognitive remediation program -- which includes giving kids practical strategies and helping them view their struggles in a more positive light -- can boost academic abilities.

But, Conklin noted, the improvements were modest and the time investment large (20 two-hour, one-on-one sessions with a clinician).

She said there remains a clear need for non-drug treatments that are feasible, acceptable and affordable.

As for the safety of methylphenidate, the most common side effects of the drug in children with ADHD include appetite problems, insomnia, headaches, dizziness and stomachaches. So far, research suggests that child cancer survivors do not suffer greater or more severe side effects. But further work is still needed.

The current study had some limitations, including the fact that the children were not randomly assigned to the treatment and control groups. Those in the methylphenidate group had all responded to the drug in an initial three-week study, during which they spent part of the time on methylphenidate and part of the time on a placebo.

The children used in the control group for the year-long study had all qualified for the earlier, three-week trial, but in most cases had not participated because their parents did not want them taking the medication. Some had taken part in the early trial, but either did not respond to the drug or did not want to take it longer term.

In addition, 91 children were originally in the methylphenidate group for the year-long study, but 23 -- or one-quarter - of them dropped out. In eight cases, adverse drug effects were given as the reason.

The study was funded by the National Cancer Institute and the American Lebanese Syrian Associated Charities. One of the co-researchers on the work has served as a consultant to Shire Pharmaceuticals, maker of a methylphenidate product for ADHD sold only in Europe.