Studies Split on Childhood Leukemia Survival Rates by Race
Dramatically different conclusions on how children of different races and ethnicities fare
TUESDAY, Oct. 14, 2003 (HealthDayNews) -- Two new studies have come to drastically different conclusions on how children of different races and ethnicities fare after treatment for acute lymphoblastic leukemia.
The first study, conducted at one medical institution, found black and white children had essentially the same survival rates five years after diagnosis.
The other study, which looked at patients across the United States, found that white children did better than black, Hispanic and American Indian/Alaska Native children.
Both studies appear in the Oct. 15 issue of the Journal of the American Medical Association.
The differences in the conclusions may be explained by different study designs, and may also offer clues as to how to eliminate the gap in survival rates between the races and ethnic groups.
"There's no question that across the country black children have inferior outcomes than whites, although the majority are being cured," says pediatric cancer expert Dr. William L. Carroll, author of an accompanying editorial in the same issue of the journal. "The question is why and what can we do about it."
Acute lymphoblastic leukemia, or ALL, is the most common cancer among American children, accounting for almost a third of all pediatric cancers. While this malignancy used to be almost always fatal, today the likelihood of surviving five years after diagnosis is 80 percent. The medical literature offers conflicting information on how different races and ethnicities fare.
The first study looked at 412 children and teens who had participated in clinical trials during the 1990s at the renowned St. Jude Children's Research Hospital in Memphis, Tenn. Sixty-eight of the children were black, 338 were white and six were "other race." Therapy was based on age and white blood cell counts at the time of diagnosis.
The five-year survival rates for black and white children were almost the same: 86.2 percent for blacks and 85 percent for whites. This held true, despite the fact that the black children were much more likely to have cancer with high-risk features, such as high white blood cell counts.
The second study involved a number of different treatment facilities throughout the United States, and looked at 4,952 children 19 years old or younger. Although all groups did better with more modern treatments, racial/ethnic differences persisted across the board.
The five-year survival rate for white children was 84 percent; for Asian/Pacific Islanders, it was 81 percent; for black children, 75 percent; and for both Native American and Hispanic children it was 72 percent. The largest difference by race and/or ethnicity was observed among children diagnosed between the ages of 1 and 9, the authors write.
There could be a number of reasons for the discrepancies between the two studies.
"We have a more precise risk classification so that we have identified the high-risk patients to give them more intensive therapy," says Dr. Ching-Hon Pui, director of St. Jude's leukemia lymphoma division and lead author of the first paper. "Everybody knows that African-American children tend to have more high-risk leukemia, so therefore they would benefit from more intensive therapy."
Also, says Carroll, children who participate in clinical trials tend to have better outcomes and black children tend to participate less in the trials.
There's also a question of parental motivation. St. Jude's is well-known for its work in pediatric oncology. Parents motivated enough to take their child there may also be motivated enough to make sure the child follows through with all treatment requirements, Carroll says.
So, should race be considered when weighing treatment options?
No, Carroll says.
For one thing, he says, "race and ethnicity are difficult to define. They're not exact." Instead, he says, "All children need to go on a protocol where they're guaranteed the best therapy."
This means that biological differences in the cancers need to be noted, but not necessarily the racial or ethnic differences of the patients. It so happens that biological differences often coincide with ethnic and racial ones, he says.
"You have to pay attention to the additional markers," Carroll says. "There are probably scores of different diseases that we label as acute lymphoblastic leukemia. We should not intensify therapy globally because intensified therapy has side effects. That tells us not go into this blind and apply treatments to everybody, but with great care."