Pregledni rad
Hypoxia in solid tumors
Miroslav Banović
; Department of Transfusion Medicine and Hemostasis, University Hospital for Tumors, Zagreb, Croatia
Irena Veliki
; Cand. Med., School of Medicine, Zagreb University, Croatia
Mladen Stanec
; Department of Surgical Oncology, University Hospital for Tumors, Zagreb, Croatia
Miroslav Lesar
; Department of Surgical Oncology, University Hospital for Tumors, Zagreb, Croatia
Sažetak
Anemia is the main cause of hypoxia in tumor patients. Hemoglobin (Hb) at concentration of 150 g/L, 100% saturated, carries about 200 mL O2/L blood, while Hb 75 g/L carries about 100 mL O2/L. Under normal conditions, O2 extraction ratio (O2ER) is 0.25, meaning that Hb 150 g/L releases 50 mL O2/L in tissues, and Hb 75 g/L releases 25 mL O2/L (hypoxia). In healthy persons, compensatory mechanisms may increase O2ER to the borderline value of 0.50. In tumor patients, Hb concentration should be carefully monitored as their compensatory mechanisms for O2 delivery to cells are disordered. Under anaerobic conditions (without O2), from 1 mol glucose only 5% of necessary energy is released, requiring anemia correction in tumor patients. Hypoxia promotes malignant tumor progression and reduces the sensitivity of tumor cells to radio- and chemotherapy. Despite the fact that some patients survived surgery with Hb 50 g/L, and that, for economic benefits, the aim is to lower a transfusion trigger or erythropoietin Hb < 80 g/L, the verified borderlines of Hb 100 g/L and hematocrit 0.300 are still considered to be safe. It has been known that patients with higher Hb concentration respond better to surgery, chemotherapy and radiotherapy, having a better quality of life and longer survival time.
Ključne riječi
cancer; anemia; hypoxia; oxygen extraction ratio; transfusion trigger
Hrčak ID:
281802
URI
Datum izdavanja:
3.12.2003.
Posjeta: 838 *