Mathematical model personalizes treatment.

• Position: Chemotherapy

Cancer chemotherapy can be a lifesaver, but it is fraught with severe side effects, among them an increased risk of infection. Until now, the major criterion for assessing this risk has been the blood cell count: if the number of white blood cells falls below a critical threshold, the risk of infection is thought to be high. A new model built by mathematicians at the Weizmann Institute of Science, Rehovot, Israel, in collaboration with physicians from the Meir Medical Center in Kfar Saba, Israel, and the Hoffmann-La Roche research center in Basel, Switzerland, suggests that, for proper risk assessment, it is essential to evaluate not only the quantity of these blood cells, but their quality, which varies from one person to another.

This research may represent an important step in the emerging field of personalized medicine, leading to a more individualized approach to chemotherapy. In particular, better precautions might need to be taken to prevent infection in high-risk patients whereas those at a low risk could be spared unnecessary preventive treatments.

The model reveals how the immune system functions under conditions of neutropenia--a dangerously how level of white blood cells, mainly neutrophils. In this condition, which often emerges after chemotherapy or a bone marrow transplant, severe infections can develop if the immune system fails to perform the crucial function of devouring and...