Impact of haemoglobin levels on the outcome of cancers treated with chemotherapy.

Anaemia is the most frequently observed haematological abnormality faced by cancer patients. Yet, its impact on tumour biology is not well understood. Several recent retrospective clinical studies showed that anaemia is not only a negative prognostic factor but also, in some situations, a negative predictive parameter in chemotherapy-treated patients with solid tumours or haematological malignancies. These include lymphomas, leukaemias, non-small-cell lung cancer, ovarian cancer, cervical cancer, urothelial and renal cancers, and head and neck carcinoma. The basis for the impact of anaemia on prognosis or outcome of chemotherapy is complex. In vitro and animal models have shown that cellular hypoxia, the consequence of anaemia, may provide a selection pressure for tumour cells with higher rates of mutation, which may ultimately result in increased metastatic potential, increased cellular growth, therapy resistance, and decreased apoptotic potential. There is also evidence to indicate that the anaemia itself may induce a feedback mechanism that results in angiogenesis. Finally, the effect of anaemia on the pharmacokinetics of cytostatics may be an underestimated parameter for therapeutic outcome. The treatment of anaemia in patients with cancer undergoing chemotherapy may improve outcome in terms of both response rate to treatment and survival.