What is considered a poor prognostic factor of acute lymphoblastic leukemia (ALL)?

CSF involvement is indeed considered a poor prognostic factor in acute lymphoblastic leukemia (ALL). When leukemic cells are found in the cerebrospinal fluid (CSF), it indicates central nervous system (CNS) involvement, which complicates the disease's management and is associated with a higher risk of relapse. This involvement suggests a more aggressive form of the disease and typically requires additional treatment strategies, such as intrathecal chemotherapy.

In contrast, while elevated white blood cell count, patient gender, and age at diagnosis can provide insight into prognosis, they do not carry the same weight as CSF involvement in terms of indicating a poor outcome. For instance, an elevated white blood cell count can have different implications depending on the overall clinical picture and the patient’s response to treatment, and while certain ages (very young or older children) may correlate with prognosis, they are not as definitive in prognosticating a poor outcome as CNS involvement. Thus, CSF involvement is a critical factor to consider when assessing prognosis in ALL.