Although nausea and vomiting are common in children undergoing chemotherapy, few quality studies identify absolutely the best way to prevent and treat this problem in kids, said Robert Phillips, M.D., lead author of a new Cochrane review. Phillips, a pediatric oncologist at St. James's Hospital in Leeds, England, said the main finding is the paucity of data that he and his colleagues uncovered.
While childhood cancers are rare, affecting less than 1 percent of all new cancer diagnoses, that 1 percent represents more than 10,000 young people under 15 in the United States, and many more worldwide. The second-most important finding of this study, Phillips said, is that a class of drugs called 5-HT3 antagonists appear to be the most effective anti-nausea agents.
"We think these drugs put a damper on nerves, calming receptors in the brain and gut, so they don't respond so strongly to chemo," he said. The drugs ondansetron, granisetron and tropisetron belong to this drug class.
"We are not surprised by these findings — which are blindingly obvious for clinicians — because this is a superb class of drugs," said Phillips. "It used to be that kids were stuck in wards for five, six, seven days after chemo. Now we are sending them home, because their vomiting is controlled."
Doctors often give 5-HT3 antagonists along with steroids such as dexamethasone. According to Phillips, there must be "small magic fairies inside steroids, because they are excellent anti-sickness agents." Some investigators question whether steroids might reduce one's sensitivity to chemo. No evidence-based studies exist, however, that show worsened outcomes.
The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.
For this review, Phillips said, "We expected there to be more studies doing the same comparisons. We selected 28 trials with 1,719 patients undergoing 2,226 rounds of chemo. These randomized controlled trials looked at 23 drug combinations — all different. One study reporting on the same drug combination might be true, but 10 or 15 studies would be so much more convincing."