Fever and granulocytopenia in children with acute Lymphoblastic Leukemia under induction therapy

Infection is one of the most serious complications of cancer therapy. The rationale of using broad spectrum antibiotics prophylactically has led to a great change in the causative organisms. The aim of the present study is to review retrospectively the type and sequence of infectious complications among Saudi children with acute lymphoblastic leukemia. A total of 233 febrile episodes were observed in 137 children with acute lymphoblastic leukemia under induction therapy using modified BFM protocol were studied. Profound neutropenia [Absolute Neutrophil count < 100/mm3] was encountered in 72 episodes [31%]. Clinical signs and symptoms suggestive of infection were evident in 39% of the neutropenic episodes. The respiratory system was the most frequently affected site encountered in 17% of the episodes. Microbiologically documented infection was recorded in 59% [n=137] of the fever and granulocytopenia episodes. In 96 episodes [41%], there was neither clinical nor microbiological evidence of infection fever of unknown origin. Out of the 932 cultures, positive isolates were detected in 346 cultures [37%]. Gram positive cocci were the most frequently organisms [54%] followed by gram negative bacilli [39%]. In the current study, 7 patients [3%] died because of direct or indirect consequences of infection. The current study stresses the importance of frequent reviewing of the type, frequency, severity and outcome of infection complications over years to detect changing epidemiological patterns

Radiotherapeutic implications of genetic instability of tumor cells

A mathematical model was used to explore the radiotherapeutic implications of genetic instability. The model included two populations whose different radiosensitivity was represented by different values of alpha parameter of linear quadratic model. It was shown that the presence of a small fraction of mutants may profoundly affect an optimal treatment schedule structure, especially for radiosensitive tumors currently deemed suitable for treatment by hyperfractionation. In some cases, the analysis favors hypofractionation or hybrid schedules composed of hyperfractionated and hypofractionated phases