One simple blood test could predict relapse or survival for children and young adults with acute leukemias, researchers from the Children's Cancer Hospital at The University of Texas M. D. Anderson Cancer Center reported at the American Society of Pediatric Hematology Oncology's annual meeting Saturday, May 5.
A review of young leukemia patients over the past decade has shown that the absolute lymphocyte count (ALC), a measure of normal immune cells found on every complete blood count report, is a powerful predictor of survival for young patients with leukemia.
According to the American Cancer Society, the average rate of survival for pediatric patients with acute myelogenous leukemia (AML) is close to 50 percent. However, researchers have found that using the ALC count on day 15 after initial chemotherapy treatment can significantly predict which patients are likely to relapse and those who will not.
This prediction may help physicians decide how aggressively to treat a leukemia patient. In addition, it may direct researchers in developing therapies to increase a patient's ability to battle the leukemia cells.
"Possibly by tweaking the immune system through chemotherapy, immune modulators or oral supplements, we could help a patient's body better fight leukemia," says Guillermo De Angulo, M.D., researcher and fellow at the Children's Cancer Hospital at M. D. Anderson. "This ALC test could also help us identify patients who would benefit from less chemotherapy."
The report studied 171 patients with either AML or acute lymphocytic leukemia (ALL), 21 years or younger, who had begun treatment at M. D. Anderson between 1995 and 2005. The statistics showed significant differences in survival rates in multiple analyses.
The results from the study showed that AML patients who had a low lymphocyte count on day 15 of treatment had a five-year overall survival chance of only 28 percent. However, patients with higher lymphocytes on day 15 had a much better overall survival rate of 85 percent.
For patients with ALL, the most common form of childhood leukemia, researchers found that those children and young adults with a high ALC count on day 15 had an 87 percent six-year overall survival rate while those with a low lymphocyte count had a 55 percent overall survival rate.
Researchers at the Children's Cancer Hospital plan to continue their study by following newly diagnosed patients and have begun a new study that analyzes the subsets of lymphocytes to see which ones have the most impact on prognosis. They hope their findings will be used to help physicians worldwide make decisions on how aggressively to treat their patients.
"Many developing countries lack the latest technologies and treatment options that we have here in the United States," says senior author Patrick Zweidler-McKay, M.D., Ph.D., assistant professor of pediatrics. "A complete blood count test is a universal, inexpensive test. There is the potential for physicians worldwide to look at the ALC count to help determine whether the patient needs additional treatment options that aren't available in every center."
