The influence of chronic anaemia on the radiosensitivity of two mouse tumours

Erythropoietin or darbepoetin for patients with cancer

BACKGROUND

Anaemia associated with cancer and cancer therapy is an important clinical factor in the treatment of malignant diseases. Therapeutic alternatives are recombinant human erythropoiesis stimulating agents (ESAs) and red blood cell transfusions.

OBJECTIVES

To assess the effects of ESAs to either prevent or treat anaemia in cancer patients.

SEARCH METHODS

This is an update of a Cochrane review first published in 2004. We searched the Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE and other databases. Searches were done for the periods 01/1985 to 12/2001 for the first review, 1/2002 to 04/2005 for the first update and to November 2011 for the current update. We also contacted experts in the field and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials on managing anaemia in cancer patients receiving or not receiving anti-cancer therapy that compared the use of ESAs (plus transfusion if needed).

DATA COLLECTION AND ANALYSIS

Several review authors assessed trial quality and extracted data. One review author assessed quality assessment and extracted data, a second review author checked for correctness.

MAIN RESULTS

This update of the systematic review includes a total of 91 trials with 20,102 participants. Use of ESAs significantly reduced the relative risk of red blood cell transfusions (risk ratio (RR) 0.65; 95% confidence interval (CI) 0.62 to 0.68, 70 trials, N = 16,093). On average, participants in the ESAs group received one unit of blood less than the control group (mean difference (MD) -0.98; 95% CI -1.17 to -0.78, 19 trials, N = 4,715). Haematological response was observed more often in participants receiving ESAs (RR 3.93; 95% CI 3.10 to 3.71, 31 trials, N = 6,413). There was suggestive evidence that ESAs may improve Quality of Life (QoL). There was strong evidence that ESAs increase mortality during active study period (hazard ratio (HR) 1.17; 95% CI 1.06 to 1.29, 70 trials, N = 15,935) and some evidence that ESAs decrease overall survival (HR 1.05; 95% CI 1.00 to 1.11, 78 trials, N = 19,003). The risk ratio for thromboembolic complications was increased in patients receiving ESAs compared to controls (RR 1.52, 95% CI 1.34 to 1.74; 57 trials, N = 15,498). ESAs may also increase the risk for hypertension (fixed-effect model: RR 1.30; 95% CI 1.08 to 1.56; random-effects model: RR 1.12; 95% CI 0.94 to 1.33, 31 trials, N = 7,228) and thrombocytopenia/haemorrhage (RR 1.21; 95% CI 1.04 to 1.42; 21 trials, N = 4,507). There was insufficient evidence to support an effect of ESA on tumour response (fixed-effect RR 1.02; 95% CI 0.98 to 1.06, 15 trials, N = 5,012).

AUTHORS' CONCLUSIONS

ESAs reduce the need for red blood cell transfusions but increase the risk for thromboembolic events and deaths. There is suggestive evidence that ESAs may improve QoL. Whether and how ESAs affects tumour control remains uncertain. The increased risk of death and thromboembolic events should be balanced against the potential benefits of ESA treatment taking into account each patient's clinical circumstances and preferences. More data are needed for the effect of these drugs on quality of life and tumour progression. Further research is needed to clarify cellular and molecular mechanisms and pathways of the effects of ESAs on thrombogenesis and their potential effects on tumour growth.

The importance of haemoglobin level and effect of transfusion in HNSCC patients treated with radiotherapy--results from the randomized DAHANCA 5 study

BACKGROUND AND PURPOSE

Patients with head and neck squamous cell carcinoma (HNSCC) and a low level of haemoglobin (Hb) often have a poor response to radiation which may be related to hypoxia induced radioresistance. The aim of the study was to evaluate the prognostic significance of low Hb level and its modification by transfusion in HNSCC patients treated with radiotherapy. The study was performed as a subrandomization in the DAHANCA 5 trial.

MATERIAL AND METHODS

Patients were randomized to treatment with the hypoxic radiosensitizer nimorazole or placebo, and in addition, patients with "low" pre-irradiation Hb values (females<13 g/dL; males<14.5 g/dL) were subrandomized to plus or minus transfusion. Transfusion was given with packed red blood cells with the aim to achieve a Hb level in the "high" value range.

RESULTS

A total of 414 patients were included, 243 patients had high Hb levels and 171 patients had low Hb levels. Of the low Hb patients, 82 were randomized to receive transfusion and 89 not to receive transfusion. The treatment arms were well balanced. In the majority of patients, transfusion resulted in increased Hb levels although this tended to decline throughout treatment. Patients with high Hb levels had a significantly better probability of locoregional control, disease-specific survival and overall survival compared to 'low Hb no transfusion' patients. In the low Hb group, transfusion did not improve the outcome in locoregional control, disease-specific survival or overall survival. In multivariate analyses, T and N classifications were significant for all outcome measures, whereas there was no significant influence of transfusion or Hb level on endpoints.

CONCLUSION

The univariate prognostic significance of high Hb level was demonstrated in patients with HNSCC treated with radiotherapy; however, transfusion prior to and during treatment did not improve the outcome in patients with low Hb values.

Erythropoietin or darbepoetin for patients with cancer

BACKGROUND

Anaemia associated with cancer and cancer therapy is an important clinical factor in the treatment of malignant diseases. Therapeutic alternatives are recombinant human erythropoietin (Epo), darbepoetin (Darbepo) and red blood cell transfusions.

OBJECTIVES

The aim of this systematic review was to assess the effects of Epo or Darbepo to either prevent or treat anaemia in cancer patients.

SEARCH STRATEGY

We searched the Central Register of Controlled Trials, MEDLINE and EMBASE and other data bases. Searches were done for the periods 01/1985 to 12/2001 for the first review and 1/2002 to 04/2005 for the update. We also contacted experts in the field and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials on managing anaemia in cancer patients that compared the use of Epo/Darbepo (plus transfusion if needed) with observation until red blood cell transfusion was required.

DATA COLLECTION AND ANALYSIS

Several reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

This update of the systematic review included a total of 57 trials with 9,353 patients. Of these, 27 trials with 3,287 adults were also included in the first Cochrane Review. Thirty trials with 6,066 patients were added during the update process. Use of Epo/Darbepo significantly reduced the relative risk of red blood cell transfusions (RR 0.64; 95% CI 0.60 to 0.68, 42 trials, n = 6,510). On average participants in the Epo/Darbepo group received one unit of blood less than the control group (WMD -1.05; 95% CI -1.32 to -0.78, 14 trials, n = 2,353). For participants with baseline haemoglobin below 12 g/dL haematological response was observed more often in participants receiving Epo/Darbepo (RR 3.43; 95% CI 3.07 to 3.84, 22 trials, n = 4,307). There was suggestive evidence that Epo/Darbepo may improve Quality of Life (QoL). The relative risk for thrombo embolic complications was increased in patients receiving Epo/Darbepo compared to controls (RR 1.67, 95% CI 1.35 to 2.06; 35 trials, n = 6,769). Uncertainties remain whether and how Epo/Darbepo effects tumour response (fixed effect RR 1.12; 95% CI 1.01 to 1.23, 13 trials, n = 2,833; random effects: RR 1.09; 95% CI 0.94 to 1.26) or overall survival (unadjusted and adjusted data: HR 1.08; 95% CI 0.99 to 1.18; 42 trials, n = 8,167).

AUTHORS' CONCLUSIONS

There is consistent evidence that administration of Epo/Darbepo reduces the relative risk for blood transfusions and the number of units transfused in cancer patients. For patients with baseline haemoglobin below 12 g/dL (mild anaemia) there is strong evidence that Epo/Darbepo improves haematological response. There is suggestive evidence that Epo/Darbepo may improve QoL. However, there is strong evidence that Epo/Darbepo increases the relative risk for thrombo embolic complications. Whether and how Epo/Darbepo effects tumour response and overall survival remains uncertain.

Reduced progression of atherosclerosis in apolipoprotein E-deficient mice with phenylhydrazine-induced anemia

Epidemiological and experimental studies suggest that circulating erythrocytes play a role in the incidence of coronary heart disease. We investigated the influence of phenylhydrazine (PHZ)-induced anemia on the formation of atherosclerotic lesions in apo E-deficient mice on regular chow and on a high-fat, high-cholesterol diet during 10 weeks. The repeated doses of PHZ caused sustained anemia throughout the study, changes in the physical characteristics of erythrocytes and increased reticulocyte count. The lesions of the anemic animals were smaller than in the controls and this was even more evident in mice fed with the atherogenic diet. A positive correlation was found between circulating red blood cells at the end of the experiment and the area of aortic lesion. There was also a negative association between the lesion and the reticulocyte count. This reduced progression of atherosclerotic lesions is independent of nutritional status or the lipoprotein cholesterol distribution. The results suggest that mechanisms related to the number of circulating red blood cells may have a significant influence on the development of atherosclerosis.

The effect of recombinant human erythropoietin treatment on tumour radiosensitivity and cancer-associated anaemia in the mouse

Recombinant human erythropoietin (rHuEpo) has recently become available for the treatment of chronic anaemia, including that associated with cancer. Carcinoma NT in CBA mice causes a progressive anaemia which can be overcome by daily injections of recombinant human erythropoietin (rHuEpo). This model was used to study the effect of haematocrit on tumour blood flow, growth rate and radiosensitivity, in mice with haematocrits ranging from approximately 38% (control) to 65% (20 U/day rHuEpo). Tumours showed a small but significant slowing in growth rate with higher haematocrit. In vitro studies showed rHuEpo had no direct effect on the growth of NT cells. Tumour blood flow was measured by two methods in each mouse (133Xe clearance and 86Rubidium uptake). Blood flow showed a tendency to decrease with increasing blood viscosity although this effect was not significant despite the large differences in haematocrit. Although tumour doubling time was prolonged despite the large differences in haematocrit. Although tumour doubling time was prolonged with increasing radiation dose, from 0 (sham irradiated) to 35 Gy, haematocrit was not found to influence the growth delay. This was attributed to adaptation of the tumour during the relatively slow change in the haematocrit. rHuEpo is being considered for clinical use in anaemic cancer patients. Our data suggest that this treatment will correct haematocrit with no effect on tumour radiosensitivity.