INTRODUCTION — Anemia is a common complication in patients with malignancy. Anemia can impair the patient's functional status, diminish physiologic reserve, and cause fatigue that can be disabling. (See "Cancer-related fatigue: Prevalence, screening and clinical assessment" and "Cancer-related fatigue: Treatment" and "Hematologic consequences of malignancy: Anemia and bleeding", section on 'Definitions'.)
In addition to causing symptoms, the presence of anemia has been linked to an adverse prognosis in several malignancies. This has been attributed in part to a poorer response to anticancer treatment, since ionizing radiation and some forms of chemotherapy are dependent upon adequate tissue oxygen levels for cytotoxicity. These observations have been used to provide an additional rationale for aggressively treating anemia in patients receiving cancer therapy.
Multiple factors can cause or contribute to anemia in patients with malignancy. (See "Hematologic consequences of malignancy: Anemia and bleeding".)
The definitive therapy for cancer-related anemia is eradication of the underlying malignancy. However, in many cases, this is not possible and short-term red blood cell (RBC) support may be needed.
Erythropoiesis-stimulating agents (ESAs) were initially used to treat anemia in patients with chronic renal failure, including those on hemodialysis. (See "Erythropoietin for the anemia of chronic kidney disease among predialysis and peritoneal dialysis patients" and "Erythropoietin for the anemia of chronic kidney disease in hemodialysis patients".)
Subsequent trials indicated that ESAs were also effective in patients with cancer and cancer treatment-related anemia, but their use has become controversial because of data linking ESA use to an excess of thromboembolic events, inferior survival and worse cancer outcomes.
This topic review will focus primarily on the efficacy and risks associated with the erythropoiesis stimulating agents (ESAs) epoetin alfa and darbepoetin alfa in anemic patients with non-hematologic malignancies. The issues surrounding the use of ESAs for patients with hematologic malignancies such as myelodysplastic syndrome (MDS) are more complex and discussed separately. (See "Treatment of the complications of multiple myeloma", section on 'Anemia' and "Overview of the complications of chronic lymphocytic leukemia", section on 'Chemotherapy induced anemia' and "Prognosis and treatment of primary myelofibrosis" and "Management of the complications of the myelodysplastic syndromes", section on 'Erythropoiesis stimulating agents'.)
OVERVIEW OF TREATMENT OPTIONS FOR ANEMIA IN CANCER PATIENTS — Definitive therapy for cancer-related anemia is eradication of the underlying malignancy. However, in many cases, this is not possible. Successful treatment of the malignancy with combinations of surgery, chemotherapy, and/or radiation therapy (RT) may, in the long term, improve the HGB level. However, short-term red blood cell (RBC) support may be needed.
Transfusion — Red blood cell (RBC) transfusions are almost universally successful in raising HGB levels. Transfusions can often ameliorate the patient's symptoms rapidly and improve health-related QOL. Exceptions include patients unable to be transfused because of the presence of multiple alloantibodies and those who refuse transfusions based on religious beliefs. (See "The approach to the patient who refuses blood transfusion".)
The use of RBC transfusions to treat anemia is discussed in more detail separately. (See "Use of red blood cells for transfusion" and "Indications for red cell transfusion in the adult".)
ESAs: epoetin and darbepoetin — Clinical trials have established that epoetin and darbepoetin are effective in raising HGB levels and decreasing transfusion requirements in a substantial number of patients with chemotherapy-induced anemia. Both ESAs appear to be equivalent with regard to efficacy and safety [6,7]. (See 'ESAs: efficacy, side effects, and clinical use' below.)
However, use of these agents in patients with cancer has become controversial because of data linking ESA use to an excess of thromboembolic events, inferior survival (particularly when used in patients whose anemia is unrelated to chemotherapy) and worse cancer outcomes. While there is general agreement that ESAs are not indicated in anemic cancer patients who are not receiving chemotherapy (with the exception of lower-risk myelodysplastic syndromes and those patients with coexistent renal failure), whether ESAs should be avoided in patients who are receiving myelosuppressive chemotherapy with the intent of cure remains controversial. (See 'Effect on disease control and survival' below and 'Thromboembolic risk' below and "Erythropoietin for the anemia of chronic kidney disease among predialysis and peritoneal dialysis patients" and "Erythropoietin for the anemia of chronic kidney disease in hemodialysis patients".)
ESAs versus transfusion — For patients with symptomatic anemia induced by chemotherapy HGB levels can be raised with either ESAs or RBC transfusions. In addition to the issues raised above, many other factors influence the choice of one or the other of these approaches, including the following:
The relative risks and benefits of ESAs versus RBC transfusion in patients undergoing cancer chemotherapy are outlined in the table (table 2).
Androgens — Androgen use (eg, testosterone, fluoxymesterone) for the treatment of anemia has declined markedly since ESAs became available; androgens are now rarely used to treat cancer-related anemia. Side effects which have limited the application of androgens include acne, virilization in women, priapism in men, peliosis hepatis, liver enzyme abnormalities, an elevated risk of hepatocellular carcinoma, and stimulation of the growth of prostate cancer. (See "Non-iron pharmacologic adjuvants to erythropoiesis stimulating agent therapy in dialysis patients", section on 'Androgens'.)
ESAS: EFFICACY, SIDE EFFECTS, AND CLINICAL USE — Randomized clinical trials have consistently demonstrated that use of ESAs raises HGB levels and reduces the frequency of red blood cell transfusions in anemic cancer patients who are receiving chemotherapy [10,11]. With few exceptions [12,13], most of these trials have not shown that ESAs prolong survival, or improve quality of life (QOL) or patient-reported outcomes (PRO), including fatigue. Furthermore, these trials have also raised questions about serious side effects, including an increased incidence of thromboembolic events and the possibility of adverse cancer outcomes.
Meta-analyses — Multiple meta-analyses have addressed issues of benefit and adverse effects from ESAs [10,14-19]. Key findings have included the following:
Thromboembolic risk — As noted above, randomized trials and systematic reviews demonstrate a significantly increased risk of thromboembolism in patients receiving ESAs.
In two separate meta-analyses, the relative risk (RR) for VTE in patients who received versus did not receive an ESA was approximately 1.57 and 1.69, respectively [15,20]. The pooled event rates of thromboembolic events were 7 (range 1 to 30 percent) versus 4 (range 0 to 23) percent for epoetin and controls, respectively, whereas the rates were 5 versus 3 percent in one published darbepoetin trial [20].
Specific risk factors for thromboembolism have not been defined in these trials, and clinicians must use caution and clinical judgment when considering the use of one of these agents. Established general risk factors for thromboembolism include a history of thromboses, surgery, and prolonged periods of immobilization or limited activity. Some disease and treatment regimens have also been associated with a higher risk of thromboembolic events (eg, multiple myeloma treated with thalidomide or lenalidomide and doxorubicin or corticosteroids). (See "Drug-induced thrombosis and vascular disease in patients with malignancy".)
Effect on disease control and survival — The presence of anemia has been linked to shortened survival in a variety of solid tumors [21-25], an effect attributed, in part, to a poorer response to anticancer treatments dependent upon oxygen delivery for their cytotoxicity (eg, ionizing radiation and some forms of chemotherapy). It was hypothesized that normalizing HGB levels through the use of ESAs might reduce the degree of tumor hypoxia, thus improving the response to chemotherapy and/or RT and prolonging disease-free and overall survival.
This hypothesis was generally supported by observational studies, which suggested that raising HGB levels to >12 or >14.5 g/dL improved survival in non-small cell lung cancer and head and neck cancer, respectively [26,27]. (See "Methods to overcome radiation resistance in head and neck cancer".)
However, several trials using this approach in various solid tumors have raised concerns about possible increased mortality with ESAs:
Target HGB levels were supraphysiologic in all of these trials. The risks of shortened survival and inferior tumor control have neither been excluded nor confirmed when ESAs are dosed to a target HGB value <12 g/dL.
The results of meta-analyses examining the survival impact of ESA use are described above. In the most influential of these, when the analysis was restricted to patients receiving chemotherapy, there was only a nonstatistically significant trend toward higher on study (10 percent) and overall mortality (4 percent, 95% CI -3 to 11 percent) [17]. (See 'Meta-analyses' above.)
Potential mechanisms — The reasons for poorer outcomes in cancer patients receiving ESA treatment are unclear. One potential mechanism by which ESA therapy might result in negative outcomes is through promotion of thromboembolic events [41]. However, in the trials described above, the incidence of thromboembolic and other adverse events was only minimally elevated and insufficient to explain the observed differences in survival [32,42]. In addition, the events would not explain the reduction in survival related to enhanced tumor progression in some of the studies. (See 'Thromboembolic risk' above.)
Another proposed potential mechanism to explain more rapid disease progression and shortened survival following treatment with ESAs is the presence of erythropoietin receptors (EPO-Rs) on the surface of tumor cells, which may promote angiogenesis, tumor growth, tumor cell survival, and/or resistance to treatment [43-48]. A possible stimulatory effect of ESAs on tumor growth has been suggested [34], particularly since, in one of the trials, the worse outcomes were limited to epoetin-treated patients whose tumors expressed the erythropoietin receptor (EPO-R) [49].
However, other laboratory and clinical results raise questions about the significance of these observations [41]:
For these reasons, the clinical significance of tumor cell expression of EPO-R in patients receiving ESAs remains uncertain and this issue requires further evaluation [41,46].
Finally, there is some evidence that indirect, non-EPO-R-mediated effects of ESAs may contribute to mechanisms of tumor regulation (including endothelial cell and platelet activation and resulting neovasculogenesis) [56-61]. However, the role that neovascularization plays in tumor progression during ESA therapy remains to be determined [41].
Use in patients treated with curative intent: recommendations of EMA, FDA, ASCO/ASH, and NCCN — Preliminary results from many of the trials described above led the European Medicines Agency to recommend in June 2008 that blood transfusions are preferred over ESAs in cancer patients who have chemotherapy-related anemia and a "reasonably long life expectancy" [62].
Review of the same data also led the US Food and Drug Administration (FDA) to mandate a label change for ESAs, stating that their use was not indicated in patients receiving myelosuppressive chemotherapy when the anticipated outcome was cure [63]. However, they did not restrict this recommendation to patients being treated for breast, head and neck, or cervical cancer. (See 'United States FDA' below.)
Furthermore, to ensure that patients receiving ESAs in the setting of cancer are informed about the risks before they begin treatment, regardless of the intent of therapy, the US FDA has mandated a risk evaluation and mitigation strategy (REMS) risk management program, termed APPRISE (Assisting Provides and Cancer Patients with Risk Information for the Safe Use of ESAs) for use of ESAs in patients with cancer [64]. (See 'APPRISE: the US FDA Risk Evaluation and Mitigation Strategy program' below.)
Despite these mandates, whether use of ESAs should be avoided in patients receiving myelosuppressive chemotherapy with the intent of cure remains controversial, particularly in view of the 2009 pooled analysis that failed to find an adverse impact of darbepoetin on death or disease progression in patients with chemotherapy induced anemia [17], and the fact that no study has evaluated outcomes of ESA therapy by subgroups defined by chemotherapy intent. Furthermore, determination of the goal of treatment requires clinical judgment of an individual patient’s circumstances. (See 'Summary: patient selection for ESAs' below and 'Meta-analyses' above.)
While the most recent NCCN guidelines for cancer and chemotherapy-related anemia state that ESAs are not indicated in patients for whom the cancer treatment goal is cure [30], updated guidelines for the use of ESAs from the American Society of Hematology/American Society of Clinical Oncology (ASH/ASCO) do not differentiate between patients receiving potentially curative cancer therapy and those undergoing palliative cancer treatment [6,7]. (See 'Recommendations from expert groups' below.)
Threshold and target hemoglobin levels — An excessively high hemoglobin level, either prior to treatment with an ESA or as an ESA treatment target, may have contributed to adverse outcomes in the above clinical trials, either by increasing the incidence of thromboembolic events or by accelerating tumor growth [32,36,65-67]. In many of these trials, HGB target levels were in the range of 13 to 15 g/dL.
When ESAs are used in patients with end-stage renal disease (ESRD), higher target HGB levels increase the incidence of thrombotic and vascular events. Studies evaluating target HGB levels in patients with ESRD are discussed separately. (See "Anemia of chronic kidney disease: Target hemoglobin/hematocrit for patients treated with erythropoietic agents", section on 'Target levels'.)
The data in anemic cancer patients are less extensive, and the relationship between baseline and target HGB levels and the incidence of thrombotic and vascular events remains uncertain [68,69]:
In its 2010 updated guidelines for use of ESAs in adult patients with cancer, the ASCO/ASH expert panel concluded that the use of ESAs to decrease transfusions is recommended for patients with chemotherapy induced anemia and a hemoglobin concentration that has decreased to <10 g/dL; the optimal level at which to initiate ESA therapy in patients with anemia and a HGB level between 10 and 12 g/dL cannot be determined from the available data [6,7]. Furthermore, given that an optimal target HGB could not be definitively determined from the available literature, the panel recommended that HGB should be increased to the lowest concentration needed to avoid transfusion, a level that may vary by patient and condition. (See 'Recommendations from expert groups' below.)
Use in patients not receiving chemotherapy — Off-label use of ESAs in cancer patients not receiving chemotherapy was frequent in the past [71]. However, results from large clinical trials suggest that ESAs are not beneficial in this setting, and may be harmful [67,72,73].
The largest was a double-blind phase III trial, in which 989 patients with nonmyeloid malignancy and anemia were randomly assigned to receive either darbepoetin (6.75 microg/kg every four weeks) or placebo for 16 weeks [72]. All patients had a HGB ≤11 g/dL and were not receiving chemotherapy. Treatment was withheld if the HGB level was >13 g/dL, and reinstated with a 25 percent dose reduction once the HGB was <12 g/dL.
Key findings included the following:
Based upon these results, ESAs are NOT recommended for the treatment of anemia that is unrelated to chemotherapy in patients with malignancy. Use of ESAs in patients with lower-risk myelodysplastic syndromes to avoid transfusion is an exception to this recommendation [6,7]. (See 'United States FDA' below and 'ASH/ASCO guidelines' below and "Management of the complications of the myelodysplastic syndromes", section on 'Erythropoiesis stimulating agents'.)
Variability in and predictors of response to ESAs — Not all patients with chemotherapy-induced anemia benefit from use of an ESA. Up to 15 to 20 percent still require RBC transfusions, and only 50 to 70 percent have a HGB increment of ≥1 g/dL after 8 to 12 weeks of ESA therapy [73,74].
There are a number of other settings in which ESAs may not be effective, including:
The ASCO/ASH expert panel on use of ESAs in adult patients with cancer concluded that starting doses and dose modifications of ESAs after response or nonresponse should follow the US FDA-approved labeling guidelines (table 3), and that ESAs should be discontinued after eight weeks in nonresponders (ie, a <1 to 2 g/dL increase in HGB, or no diminution of transfusion requirements) [6,7]. (See 'Threshold and target hemoglobin levels' above and 'United States FDA' below.)
INDICATIONS FOR ESA THERAPY
Recommendations from expert groups
ASH/ASCO guidelines — Clinical practice guidelines for use of ESAs from the American Society of Hematology (ASH) and the American Society of Clinical Oncology (ASCO) were updated in 2010 [6,7]: (See 'Use in patients not receiving chemotherapy' above and "Management of the complications of the myelodysplastic syndromes", section on 'Erythropoiesis stimulating agents'.)
NCCN guidelines — The most recent update of indications for ESAs in the management of cancer and chemotherapy-related anemia from the National Comprehensive Cancer Network (NCCN) can be summarized as follows [30]:
Regulatory and fiscal policies
United States FDA — In 2007 and 2008, the results of various trials led the US Food and Drug Administration (FDA) to clarify several aspects of the usage of ESAs in patients with cancer.
The safety and efficacy of ESA use within these confines was shown in a small randomized trial in which 186 patients receiving chemotherapy for lung or gynecological cancer who had a hemoglobin ≤10g/dL were randomly assigned to ESA use (epoetin beta 36,000 units or placebo weekly for 12 weeks) with weekly doses held for hemoglobin levels >10 g/dL and sustained levels >12 g/dL avoided [84]. Transfusions were significantly less common in the ESA group (5 versus 20 percent of patients), and the incidence of thromboembolic events was similar, as was the one-year overall survival. While this trial provides some reassurance that the risk of thromboembolic events is not increased when ESAs are dosed according to established guidelines, it was not adequately powered to detect the magnitude of differences in survival or disease progression that have been noted with ESAs in much larger trials.
European Medicines Agency — The same data that led the United States FDA to restrict approval for ESAs to palliative settings prompted the European Medicines Agency to recommend in June 2008 that blood transfusions are preferred over ESAs in cancer patients who have chemotherapy-related anemia and a "reasonably long life expectancy" (otherwise not defined) [62].
Medicare and Medicaid — CMS has restricted its coverage for ESAs in response to the controversies and safety concerns surrounding their use in patients with cancer. ESA use is currently limited to patients with chemotherapy-induced anemia whose hemoglobin level is <10 g/dL. Furthermore, treatment with ESAs is not reimbursed once the hemoglobin level has risen to ≥10 g/dL. CMS left coverage decisions about ESA use in MDS up to regional carriers, so there is geographic variability in reimbursement policies for ESA use in patients with MDS.
APPRISE: the US FDA Risk Evaluation and Mitigation Strategy program — To ensure that patients receiving ESAs in the setting of cancer (regardless of the intent of therapy) are informed about the risks before they begin treatment, the US FDA approved a Risk Evaluation and Mitigation Strategy (REMS) risk management program, termed APPRISE (Assisting Provides and Cancer Patients with Risk Information for the Safe Use of ESAs) on February 16, 2010 [64]. The program requires hospitals and physicians prescribing ESAs for cancer patients to register and maintain enrollment in the REMS program, complete training on the use of ESAs in patients with cancer, and provide written documentation of the discussion with patients as to the risks of stroke, heart attack, blood clots, heart failure, tumor progression, and death, prior to instituting ESAs. Enrollment began March 24, 2010.
In addition to providing the FDA-approved medication guide [85,86], ASCO/ASH guidelines suggest that health care providers discuss specific issues with patients considering ESA therapy, as outlined in the table (table 5) [6,7].
Summary: patient selection for ESAs
Minimum requirements — ESAs are indicated for the treatment of anemia in patients with non-myeloid malignancies when the anemia is due to chemotherapy. In keeping with guidelines from ASH/ASCO, cancer patients with anemia should meet all of the following criteria before being treated with an ESA:
Intent of therapy — FDA-mandated labeling changes for ESAs in July 2008 state that these drugs are not indicated for patients receiving myelosuppressive chemotherapy when the anticipated outcome is cure [63]. This decision was based upon data from randomized trials suggesting worse outcomes in patients with early, potentially curable breast, head and neck, and cervical cancer who received ESAs compared to those who did not receive ESAs. In all of the trials, target hemoglobin levels were ≥12 g/dL. Furthermore, a meta-analysis found no association between darbepoetin use and risk of death or disease progression in patients with chemotherapy-induced anemia, the approved indication for ESAs [87]. (See 'Effect on disease control and survival' above.)
In our view, whether ESAs should be avoided in patients receiving chemotherapy for a potentially curable cancer remains controversial. Updated guidelines for the use of ESAs from ASH/ASCO do not differentiate between patients receiving potentially curative cancer therapy and those undergoing palliative cancer treatment, stating that no study has evaluated outcomes of ESA therapy by subgroups defined by chemotherapy intent [6,7]. Given the general uncertainty about outcomes in patients being treated for cancer, whether individuals are receiving curative or palliative-intent therapy is not always a clear distinction.
The FDA mandate neither prohibits nor prevents health care providers from prescribing ESAs in this situation. We suggest that the benefits and risks of ESAs be discussed with patients who meet the minimum requirements as outlined above regardless of the intent of therapy. If after discussion with a well-informed patient, the risks are felt to be counterbalanced by the benefits of avoiding transfusion or reducing the chemotherapy dose(s), then use of ESAs is appropriate.
ESA FORMULATIONS AND DOSING
Epoetin alfa — When epoetin alfa was initially approved for patients with chemotherapy-associated anemia, a starting dose of 100 to 150 units/kg administered subcutaneously (SC) was recommended three times weekly along with supplemental oral iron. Responders were expected to show an increase in the reticulocyte count within one week and a rise in the hemoglobin concentration of at least 0.5 g/dL by two to four weeks [88,89].
However, a subsequent meta-analysis of data from four randomized trials in 604 patients with non-myeloid malignancies concluded that up to 46 percent of those without a rise in hemoglobin by two to four weeks ultimately respond to ESA therapy [78]. Accordingly, most patients are treated for 8 to 12 weeks before treatment is considered a failure.
The FDA-approved starting dose for epoetin is 150 U/kg three times weekly or 40,000 U weekly (table 3). When a weekly single dose schedule was employed in anemic patients, results were similar to three times weekly administration, with an increase in mean hemoglobin concentration, a reduction in transfusion requirement, and an improvement in quality of life measures for patients receiving chemotherapy [90] or chemoradiotherapy [91].
Less frequent administration of higher doses of epoetin is similarly effective but more convenient. Alternative schedules include:
If hemoglobin levels have not increased by six to eight weeks in the setting of adequate iron stores, the schedule can be intensified or the dose raised (table 3). FDA-approved labeling guidelines suggest not continuing ESAs beyond eight weeks in the absence of a response (a <1 to 2 g/dL increase in HGB or no diminution in transfusion requirements). (See 'Iron monitoring and supplementation' below.)
Darbepoetin — Darbepoetin is indicated for the treatment of chemotherapy-induced anemia in non-myeloid malignancies. Darbepoetin is effective when given as infrequently as once every three to four weeks [93-96].
Darbepoetin is a biochemically distinct form of erythropoietin that is produced in Chinese hamster ovary cells using recombinant DNA technology. Darbepoetin has a longer in vivo half-life than erythropoietin and a modestly lower EPO-R binding activity (figure 1). These properties are due to an altered glycosylation pattern compared to native erythropoietin, while the protein sequence of darbepoetin is the same as that of epoetin. (See "Darbepoetin alfa for the management of anemia in chronic kidney disease".)
The activity of darbepoetin in patients with chemotherapy-induced anemia was illustrated by a double-blind trial in 314 anemic patients (hemoglobin ≤11.0 g/dL) receiving chemotherapy for lung cancer [97]. Patients were randomly assigned to weekly darbepoetin (initial dose 2.25 microg/kg SC) or placebo. Key findings included the following:
The FDA-approved starting dose for darbepoetin is 2.25 microgram/kg weekly or 500 micrograms every three weeks [95], subcutaneously (table 3). Other guidelines for the use of darbepoetin in patients with chemotherapy-induced anemia recommend an initial dose of 200 micrograms every two weeks, a dose and schedule that is included in NCCN guidelines [30]. Three randomized trials for the treatment of chemotherapy-induced anemia in patients with breast, lung, or gynecologic malignancy found this dose and schedule for darbepoetin achieved comparable clinical and hematologic outcomes compared to epoetin given at a dose of 40,000 units once per week [73,98,99].
As with epoetin, if there is no increase in the hemoglobin concentration after four weeks in the setting of adequate iron stores, the dose can be increased (table 3) [6,7]. Guidelines from ASCO/ASH recommend not continuing ESAs beyond eight weeks in the absence of a response (a <1 to 2 g/dL increase in HGB or no diminution in transfusion requirements) [6,7].
Iron monitoring and supplementation — As noted above, the availability of iron can limit the hemoglobin response following treatment with ESAs in patients with cancer-related anemia as well as in those with renal failure. (See 'Variability in and predictors of response to ESAs' above.)
Iron deficiency may develop quickly in treated patients who have borderline iron levels at the onset of therapy. Furthermore, even normal subjects and cancer patients with adequate iron stores may have difficulty adequately mobilizing iron to respond to erythropoietin therapy, a phenomenon which has been termed "functional iron deficiency" or iron-restricted erythropoiesis [100-105]. Anemic cancer patients treated with ESAs may have additional difficulties with iron mobilization, due to cytokine-mediated inhibition of the transfer of iron from macrophages to the developing erythron. (See "Anemia of chronic disease (anemia of chronic inflammation)", section on 'Pathogenesis'.)
The most widely available markers reflecting functional iron status of the body are transferrin saturation (serum iron divided by the total iron binding capacity [TIBC, transferrin]) and serum ferritin, although transferrin saturation is strongly influenced by daily variations in serum iron, and ferritin is an acute phase protein that may be increased during acute inflammation [104].
Nevertheless, these are the best markers of iron stores that are currently available, and serum iron, TIBC, and serum ferritin should be assayed at baseline in all anemic patients who are being considered for an ESA and in patients who fail to respond to ESA therapy within six to eight weeks. Iron should be given during ESA therapy, if necessary, in order to maintain a transferrin saturation of ≥20 percent and a serum ferritin level of ≥100 ng/mL.
Oral versus parenteral — Although some cancer patients will respond to the use of oral iron, such replacement has not been demonstrated to be consistently effective in patients receiving ESAs [75,76]. Parenteral iron, although less convenient for both the patient and staff, may augment erythropoiesis by providing iron in a more rapidly bioavailable form. (See "Iron balance in predialysis, peritoneal dialysis, and home hemodialysis patients" and "Use of iron preparations in hemodialysis patients".)
Multiple randomized trials in patients with chemotherapy-induced anemia have shown that parenteral iron supplementation (compared to either oral iron or no iron) increases the proportion of patients achieving an adequate hemoglobin response to ESA therapy and decreases the percentage of patients requiring transfusion [75,76,102,106,107]. This benefit has been seen both in iron-deficient and iron-replete patients. However, the benefit of parenteral as compared to oral iron has been called into question by the following results:
Two trials, including the largest randomized trial to date of ESA with or without parenteral iron conducted in 502 patients receiving chemotherapy who had a hemoglobin <11 g/dL, failed to show any benefit with the intravenous iron preparation compared to oral iron [108,109] or oral placebo [108].
A meta-analysis of eight trials comparing parenteral iron versus no iron or oral iron in anemic chemotherapy patients receiving ESAs (including the two negative trials cited above) concluded that the use of parenteral iron significantly reduced the risk of transfusion compared to no iron (relative risk 0.77, 95% CI 0.62-0.97), but the difference was not statistically significant when parenteral iron was compared to oral iron (RR 0.68, 95% CI 0.44-1.05) [110].
Widespread adoption of parenteral iron in patients receiving ESAs has been slow. In the past, anaphylactic reactions have been a major problem for IV iron administration, particularly with high-molecular weight iron dextran preparations (eg, ImFeron, which is no longer available, and DexFerrum, which is available). This problem has been reduced but not eliminated with the introduction of ferric gluconate (Ferrlecit), and iron sucrose (Venofer), and perhaps to a lesser extent, low molecular weight iron dextran (InFed). There appears to be little difference among these agents in terms of efficacy, although low molecular weight iron dextran is less costly.
Another issue is that in the United States, Medicare rules do not allow the administration of an ESA and parenteral iron on the same day.
NCCN guidelines recommend use of low molecular weight iron dextran (INfed) for the treatment of iron deficiency in patients intolerant or unresponsive to oral iron therapy and for cancer patients who are receiving ESAs [30]. However, in our view, this recommendation is surprising in view of the data on the better safety profile of Ferrlecit (ferric gluconate) and Venofer (iron sucrose). Furthermore, the newest preparation, ferumoxytol, allows for the infusion of 510 mg of IV iron as a single push infusion, in contrast to the limit of 125 mg for Ferrlecit and Venofer. The use of these agents is discussed separately. (See "Treatment of anemia due to iron deficiency", section on 'Intravenous iron'.)
Even with the availability of safer parenteral agents, whether all patients receiving ESAs require IV iron remains controversial, and clinical practice varies. Randomized trials suggest that 50 to 70 percent of patients will respond to ESAs alone or with the addition of oral iron. Given this fact, some clinicians reserve IV iron for patients who fail to respond to an ESA within five to six weeks. On the other hand, particularly in patients with marginal or low iron stores, use of IV iron could be considered a faster way to ensure adequate iron stores than oral iron, and this might lead to the lowest possible dose of an ESA. NCCN guidelines suggest IV iron in this setting, as long as active infection is excluded [30].
Updated guidelines from the ASH/ASCO expert panel state that the evidence is inadequate to consider IV iron as the standard of care in patients with chemotherapy-associated anemia [6,7]. They cite the heterogeneity across the trials in patient population, use of concomitant chemotherapy, ESA and iron formulations and schedules, control groups, and reported primary outcomes, the lack of standardization of transfusion use, the lack of blinding, and imbalances between the experimental and control groups (eg, more women with breast and gynecologic cancers), which could have led to greater degrees of iron deficiency in the groups receiving IV iron.
In our view, the observed increase in erythropoiesis seen when using ESAs in combination with parenteral iron needs to be balanced against the increased cost, need for a several hour visit to an infusion center, small risk of an adverse reaction to the parenteral iron preparation and the very small potential risk of aggravating total body iron overload. Other potential long-term biologic effects of iron overload remain largely undefined, but concerns for promotion of tumor growth, enhanced oxidative stress, and exacerbation of infection have been voiced [104].
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SUMMARY AND RECOMMENDATIONS — Anemia in cancer patients may be due to the malignancy itself, myelosuppressive chemotherapy or radiation therapy, or any of the other causes of anemia that affect patients without cancer. (See "Hematologic consequences of malignancy: Anemia and bleeding".)
In the patient with cancer and chemotherapy-related anemia, erythropoiesis-stimulating agents (ESAs) may be used to reduce the need for red blood cell (RBC) transfusions. There is no clear evidence that these agents relieve the symptoms of anemia or improve QOL. Transfusion is a reasonable alternative, particularly if a rapid increase in hemoglobin (HGB) is needed. (See 'ESAs: efficacy, side effects, and clinical use' above and 'ESAs versus transfusion' above.)
The use of ESAs has been associated with an increased incidence of thromboembolic events and shortened survival, particularly when used in patients whose anemia is not due to myelosuppressive chemotherapy. Furthermore, randomized trials conducted in patients with potentially curable breast, head and neck, and cervical cancer raise the possibility that the use of ESAs might compromise tumor control and survival. In all of these trials, the target HGB level was >12 g/dL. (See 'Thromboembolic risk' above and 'Effect on disease control and survival' above.)
The following recommendations are for the use of ESAs in adult patients with non-hematologic malignancy.
Indications
Choice of agent, dose titration, and supplemental iron
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