Fr child survivrs of a blood cancer called acute lymphocytic leukemia (ALL), two years of follow-up medications help assure that the cancer doesn't return.

But a new study finds that a quarter of these young cancer survivrs aren't taking the potentially lifesaving drugs.

A prime reason fr the lapse: frgetfulness.

"One in four children in remission from ALL does not take the medicine needed to remain cancer-free and, in an overwhelming majrity, the primary reason why is that they frget to take their pills each day," study senir authr Dr. Smita Bhatia, of City of Hope in Duarte, Calif., said in a news release from the American Society of Hematology.

ALL is a cancer of the white blood cells, but the advent of new drugs means that most children with ALL go into remission within a month after beginning their cancer treatment.

However, one in five of these children will relapse. To prevent the cancer from coming back, children with ALL must take a chemotherapy pill, called 6-mercaptopurine (6MP), daily fr two years.

Although 6MP has been proven effective, previous studies found that children may have trouble taking the drug on a regular basis. Since there are racial differences in survival rates fr ALL, the researchers took a closer look at patterns in adherence to 6MP treatment plans.

"While we don't yet know why children of different races have significantly different survival rates fr ALL, we know that their adherence to their maintenance medication is a critical factr in their survival," explained Bhatia.

Back in 2012, the researchers found that Hispanic children were less likely to follow their 6MP maintenance regimen as regularly as non-Hispanic white children.

Explring the issue further, Bhatia's team tracked how well almost 300 black, Asian and non-Hispanic white children in remission from ALL kept up with their daily dose of 6MP.

Levels of the drug were tracked in the children's bloodstream. The researchers also placed an electronic microprocessr chip in the cap of each child's pill bottle. This chip recrded every date the bottle was opened fr a period of six months.

The study, published online recently in Blood, revealed that black and Asian children were less likely than white children to stick to their treatment regimen. The researchers found that 46 percent of black children and 28 percent of Asian children were not taking enough 6MP to prevent their cancer from returning. The same was true fr 14 percent of white children.

Asian and black children who came from homes in which their mother was their full-time caregiver and treatment supervisr were mre likely to take their medication properly. In turn, the black children who had a mother with less education r lived in a home with one parent and multiple children were less likely to take their medication as prescribed.

Certain interventions might raise the numbers of ALL survivrs who stick to the 6MP regimen, Bhatia said.

Further studies, could "examine how physicians can successfully intervene, using technology, fr example, to ensure that children do not experience an increased risk of relapse because they did not take their [pills]," she said.