Leukemia Is Most Common Form of Childhood Cancer : Disease: Experts say the illness can cause death within weeks. It remains unclear if early diagnosis could have saved Julio Cano’s life.

The disease that apparently led to the death of 12-year-old Julio Cano is the most common form of childhood cancer, sometimes leading to aggressive infections and causing death in a matter of months or even weeks, medical experts said Wednesday.

But whether his life might have been saved by a diagnosis of acute leukemia just a few days earlier remains uncertain.

Childhood leukemia experts said Wednesday that they would need to know much more about the boy’s case--including his precise history and which type of leukemia he had--before reaching a conclusion on whether his death was preventable.

Generally speaking, treatment of acute leukemia in children--even in its late stages--has a significant chance of success, said Dr. Stuart Siegel, head of the division of hematology/oncology at Childrens Hospital in Los Angeles.

A cancer of the bone marrow and blood, acute leukemia involves the rampant growth of abnormal white blood cells, which essentially crowd out normal blood cells and invade body organs, Siegel said. The cause is uncertain, but it is not believed to be hereditary. It might involve some sort of genetic mutation, Siegel said.

In Julio’s case, the disease had affected his spleen, brain, kidney and liver, said Lt. Dan Martini of the Orange County sheriff-coroner’s office.

It was not known how long he had the disease, but one official said it could have been weeks or months. More tests are needed to determine how fast the disease progressed.

The disease takes two basic forms. One type, called acute lymphoblastic leukemia, has a survival or cure rate of about 70% after five years if treated, Siegel said. The other type, non-lymphoblastic leukemia, is more difficult to treat and has a 40% to 50% survival rate, he said.

The chances of successfully treating both forms are reasonably good even if the disease is diagnosed in its late stages, Siegel said. Both forms are treated with chemotherapy, although non-lymphoblastic leukemia also may require a bone marrow transplant.

Symptoms of acute leukemia may include paleness caused by anemia, fever, bruising easily, bone pain, skin rashes and an enlarged liver or spleen. The disease might develop for a period of months, Siegel said, but symptoms can “come on very quickly. . . . It could happen within a period of a week.”

Because symptoms often occur late, many patients do not to seek early treatment, he said.

A parent might initially mistake some symptoms for the flu, except that the condition does not go away, he said.

Dr. Alexis Thompson, assistant professor of pediatric hematology and oncology at the UCLA School of Medicine, said an alert general practitioner usually will be able to detect signs of the disease. It is diagnosed using blood tests and bone marrow biopsies.

“There are children who die under the best of circumstances,” she said, even with relatively prompt treatment. She said an aggressive infection--which Julio may have suffered--can overwhelm a child “even before we’re able to give adequate chemotherapy.”

Times medical writer Thomas H. Maugh II contributed to this report.