Blood count test may predict prognosis in leukemia

A multi-institutional group of researchers have zeroed in on a more accurate way to decipher treatment outcomes in young leukemia patients using information from a simple complete blood count test.

The minimal residual disease indicator and the absolute lymphocyte count (ALC) from the CBC test enabled the physicians to better predict which patients with acute lymphocytic leukemia (ALL) will remain disease free and who is most likely to relapse.

For several years minimal residual disease (MRD) has been the best prognostic tool used to predict patients' risk of relapse.

"MRD is an important tool for predicting prognosis," said lead author Patrick Zweidler-McKay, MD, PhD, an assistant professor at the Children's Cancer Hospital, at M.D. Anderson Cancer Center, "but it misses a subgroup of patients who, despite having low MRD, still are at high risk of relapse. Using the ALC information, we can define which patients fall into this category. Down the line, we hope this information will allow us to alter treatment to help prevent these patients from relapsing."

Dr. Zweidler-McKay and colleagues found absolute lymphocyte count was just as powerful as minimal residual disease, if not more, in predicting prognosis. By using the two together though, they defined a subgroup of patients who are more prone to relapse but originally overlooked based on using minimal residual disease alone.

After a month of treatment, 171 patients who were positive for MRD and had a low ALC had an event-free survival rate of 33% and an overall five-year survival outcome of 41%.

However, patients who were positive for minimal residual disease and had a high absolute lymphocyte count had an event-free survival rate of 69% and an overall five-year survival of 92%.

The most positive outcomes, 99% overall five-year survival, came in patients who were negative for minimal residual disease and had a high absolute lymphocyte count, the authors reported (2010 American Society of Pediatric Hematology Oncology platform session 303c).

"Our ultimate goal is to use these prognostic tools in the future to guide treatments for our patients," Dr. Zweidler-McKay said. "If we know that a patient is at high-risk for relapse from the beginning, then potentially we can adjust their treatment plan to a more aggressive therapy."

Collaborators on this study were Karen R. Rabin, MD, M. Monica Gramatges, MD, Xiadong Shi, MD, and Judith Margolin from the Texas Children's Cancer Center in Houston; Michael J. Borowitz, MD, PhD, from Johns Hopkins University in Baltimore, and Shana L. Palla from M.D. Anderson.