Research Gives Children Life After Leukemia
The 6-year-old complains of tiredness and achy joints. His fever just won't go away. Time for his parents to take the pale little guy to his pediatrician.
"The majority of the time, it's flu or a cold," reassures John Perentesis, MD, director of the oncology program at Cincinnati Children's. But for a tiny percentage of patients, the diagnosis is leukemia.
Today genetic research at Cincinnati Children's is helping to transform the treatment – and the outlook – for these children.
Blood Cells Under Attack
The most common childhood leukemia is acute lymphoblastic leukemia (ALL), a fast-growing cancer of the white blood cells that usually strikes children ages 1 to 10. Bone marrow makes unformed cells called blasts that normally develop into lymphocytes, which fight infections. In ALL, however, the blasts are abnormal, allowing leukemia cells to grow quickly and crowd out the normal red and white blood cells and platelets the body needs.
Each year, about 5,000 new cases of ALL arise in North America, and Cincinnati Children's sees "between 70 and 90 new diagnoses and relapses," Dr. Perentesis says. Patients are identified by a blood test, followed by a marrow sample drawn from the hip bone.
Still Searching for the Cause
Researchers have yet to pinpoint the cause. Studies so far have ruled out factors such as parents' occupations and exposures to radon, electromagnetic fields, pesticides and household cleaners. Scientists speculate that some aspect of a child's lymphatic system goes awry during development.
"The positive news is the dramatic improvements in childhood cancer cure rates," Dr. Perentesis says. "In the past 50 years, we've gone from childhood cancer being a uniformly fatal disease to an 80 percent cure rate. It's probably the biggest medical advance in the last half century."
This is heartening for parents and patients, who have intensive treatment ahead. Because ALL is fast-growing, chemotherapy begins immediately, usually as outpatient treatment. Few patients require bone marrow transplants or radiation.
Teamwork Advances Treatment
"For those who need radiation, we understand how to target it so much better than when it was first used 40 years ago," Dr. Perentesis says.
"Pediatric cancer is a remarkably collaborative field. In the 1950s, the National Cancer Institute and pediatric cancer experts formed a national cooperative research group to test new therapies. Now we have 240 centers in North America, including Cincinnati Children's.
"Each year, these medical professionals pushed the cure rate up a few points, and now we build on their success."
The Cancer Center at Cincinnati Children's is a major referral and clinical research program for children with leukemia. Center staff are pursuing the most comprehensive research to date analyzing genetic variation and childhood leukemia.
"There is a lot of variability between patients, and that affects their chances of cure and the risk of side effects," Dr. Perentesis says. "Using a patient's DNA, our goal is to learn how to dose drugs for them individually at the start of treatment."
Additional research here explores how to administer current drugs more effectively. Other studies seek to target leukemia cells with "magic bullets," small molecules that zero in on specific cancer-related pathways.
"This is an extraordinarily optimistic time with pediatric cancers," Dr. Perentesis says. "The big federal investment to study cancer genomics is paying off. We're learning how leukemia cells differ from other cells, how they grow and how designer drugs can be created to target them. The biggest advances are coming soon."
