When it comes to surviving childhood acute lymphoblastic leukemia (ALL), improving outcomes may come down to an essential directive for patients: Take your medicine.
Although researchers have made great strides toward curing childhood ALL, children of some races or ethnic groups still fare better with the cancer than other children. Now City of Hope scientists have found a likely reason — Latino children are more likely to miss medication doses than are non-Latino white children.
|Smita Bhatia (Photo by Darrin S. Joy)|
Smita Bhatia, M.D., M.P.H., the Ruth Zeigler Chair in Population Sciences, was lead author of the study, which was presented at the 2010 American Society of Hematology Annual Meeting in Orlando, Fla., on Dec. 5, 2010. Bhatia’s team reviewed more than 8,000 cases of ALL in which children received the same therapy — called mercaptopurine, or 6-MP — but experienced different treatment outcomes across various ethnicities.
“Children are required to take an oral medication at home for two years as part of ALL treatment. We hypothesized that nonadherence to oral chemotherapy would increase the risk of relapse, and that sociodemographic determinants of adherence would help explain the ethnic differences in outcome,” said Bhatia, who directs City of Hope’s Center for Cancer Survivorship.
The research team followed 332 Latino and non-Latino white patients under age 21 who were diagnosed with ALL at more than six dozen institutions in the Children’s Oncology Group. Patients received special prescription bottles with microchips in their caps that could track dates and times the bottles were opened. Additionally, patients were monitored monthly to assess levels of chemotherapy in their blood.
Of the 172 Latino patients, about 86 percent adhered to the treatment plan over the six-month course of the study, significantly less than the 93 percent of non-Hispanic white patients who stuck to the treatment plan. Six years later, 81 percent of Latino children and 94 percent of non-Latino white children had no sign of the disease.
Analysis of the data revealed that ethnic differences in survival were associated with non-adherence to the oral 6-MP regimen and patients’ sociodemographic status. The findings stress the importance of developing culturally appropriate tools to help patients stick to their therapy.
“We found that most patients who missed doses said they simply forgot to take them or something interrupted their daily routine and only 5 percent skipped doses because of side effects,” said Bhatia. “We believe that in addition to developing better treatments, we should focus on how to improve adherence to current oral chemotherapy by using a systematic, comprehensive approach that is informed by the results of this study.”
Bhatia also currently is examining adherence in African-American patients, who have the lowest survival outcomes among children with leukemia.
The American Cancer Society estimates that more than 10,700 children in America will be diagnosed with cancer this year, with close to one-third diagnosed with leukemia. While cancer in children is uncommon, it is the second leading cause of death in children, behind accidents. The overall five-year survival rate for childhood leukemia patients is 82 percent.