Introduction
Patients with cancer frequently experience chemotherapy-induced or cancer-related anaemia and iron deficiency (ID) [
1,
2]. Anaemia adds a substantial burden to these patients already affected by cancer and its treatment [
1‐
3]. ID is a major component in the pathogenesis of anaemia in cancer patients [
4] and has been estimated to affect 19–63 % of patients with different tumour types [
5]. The prevalence of ID increases with progression of the disease and correlates with the prevalence of anaemia [
2].
Impaired iron homeostasis (a common feature in chronic disease), chronic blood loss and nutritional deficiencies (e.g. cancer-induced anorexia) are the main causes of ID in cancer patients [
5]. Early diagnosis and management of ID is important to reduce the risk of anaemia and improve patient care. Biological iron status markers include serum ferritin, which reflects storage iron under non-inflammatory conditions, and transferrin saturation (TSAT), reflecting circulating iron that is available for erythropoiesis. A low TSAT is related to both absolute and functional iron deficiency [
6]. In absolute ID, iron stores are depleted (serum ferritin ≤100 ng/mL in patients with inflammation, including cancer) [
5,
6]. Functional ID is characterised by a lack of available iron (TSAT ≤20 %) despite normal or elevated serum ferritin [
5‐
7]. Most iron-deficient cancer patients present with functional ID [
2].
Historically, anaemia in cancer patients was treated with red blood cell (RBC) transfusions or erythropoiesis-stimulating agents (ESAs). However, a substantial proportion of anaemic cancer patients remain unresponsive to ESA treatment [
8‐
10], and over recent years, evidence has accumulated that RBC transfusions, as well as ESA use outside the current label and guidelines, can increase all-cause mortality [
11‐
13]. Current guidelines therefore recommend preventing RBC transfusions and using ESAs with the lowest effective dose and in approved indications only [
14‐
20].
In ESA-treated patients with functional ID, concomitant administration of intravenous (i.v.) iron should be considered [
14]. Several controlled clinical trials have shown that i.v. iron supplementation of ESA therapy enhances haematological response and may be effective in reducing ESA doses and transfusion requirements [
21‐
26]. In contrast, administration of oral iron showed less or no effect in comparative trials [
21,
25].
This cross-sectional study evaluated the routine practice in the diagnosis and treatment of anaemia and ID in patients with chemotherapy-induced anaemia (CIA) and the implementation of anaemia treatment guidelines into practical management.
Materials and methods
Study populations
Oncologist, haematologist and onco-haematologist (managing mainly solid or mainly haematological tumours), in the manuscript collectively referred to as medical oncologists and/or haematologists, were selected at random from nine European countries. They reported data on their last five cancer patients treated for CIA within the preceding 6 months. Patients who had not received any chemotherapy in the last 3 months and patients with myelodysplastic syndromes were excluded. Eligible medical oncologists and/or haematologists had to spend >50 % of their working time on patient care and personally see and treat more than five cancer patients with CIA per month.
Details on patients were collected from patient records in two surveys: from June to September 2009 in France (FR), Germany (DE), Spain (ES), Switzerland (CH) and United Kingdom (UK) (survey 1) and from August to September 2010 in Austria (AT), Italy (IT), the Netherlands (NL) and Sweden (SE) (survey 2).
An additional data set was collected in survey 1 countries about 2 years after the first survey (June to August 2011). This data set was only used for comparison with the corresponding data set from 2009, to assess potential changes in routine practice over time. It was not included in the main analysis.
Data collected in patient record forms
Collected patient demographics included gender, age, weight, height, dietary habits, comorbidities, type and TNM stage of cancer. Data on anaemia management included a list of haematological tests performed at diagnosis of anaemia, levels of Hb and iron status parameters (serum ferritin, TSAT) and prescribed anaemia treatment. For all iron-treated patients, information on the iron administration route (oral, i.v., intra-muscular) and the type of specialist that initiated the treatment were collected. Additional details, which were recorded during survey 1 only, included reasons for prescription of i.v. or oral iron as well as anaemia-related symptoms. In survey 2, RBC transfusions were evaluated in more detail.
Some questions were stated in a slightly different way in survey 2 to avoid ambiguity that had been observed among responses to these questions in the first survey and to better reflect the time frames physicians referred to when asked for given treatments. The question for “current” anaemia treatment (survey 1) was extended to “current or last treatment” in survey 2, and the question on whether a patient had “ever” received an RBC transfusion (survey 1) was limited to “during the last 12 months” in survey 2.
Data collected in physician self-reporting section
In survey 1, participating medical oncologists and/or haematologists were asked to disclose the trigger points (Hb levels) they used for starting treatment in male/female patients and minimal target Hb levels.
Data analysis
Results are presented for all nine countries combined and as range of overall data in the individual countries (shown in square brackets). Alternatively, data from survey 1 or survey 2 countries only were combined, as indicated. Patients without current anaemia treatment (only in survey 1) were excluded from the analysis for better comparability of the results of the two surveys. Collected data were verified by plausibility checks and phone interviews of 10 % of participants.
Due to the low number of patients receiving i.v. iron, information on the reasons for prescribing i.v. iron was gathered from an extended patient sample, for which each participating physician provided data from up to two additional i.v. iron-treated patients. The extended patient sample was not used in any of the other analyses.
Discussion
This study on cancer patients treated for CIA revealed substantial variations in routine diagnosis and treatment approaches across Europe. A high proportion of patients had moderate to severe anaemia (Hb ≤10 g/dL) and a considerable percentage presented with ID (ferritin ≤100 ng/mL or TSAT ≤20 %) at the time of diagnosis of anaemia. The most commonly used anaemia therapy was administration of an ESA but also RBC transfusions were frequently given. About a third of patients received iron supplementation but only a minority of iron-treated patients received i.v. iron, despite clinical evidence for its efficacy [
21‐
26] and recommendations in guidelines to consider its use [
5,
14,
15,
17‐
19].
While current treatment guidelines recommend baseline and periodic assessment of iron status [
5,
16,
20], at least a third of patients in this study had no iron status assessed at diagnosis of anaemia. If assessed, diagnosis was mainly based on serum ferritin measurements whereas TSAT was underused as a diagnostic marker. Ferritin is an acute phase protein and often does not accurately reflect iron stores in cancer patients. Although TSAT is to some extend also affected by inflammatory cytokines, it is accepted as a relevant marker of ID and a TSAT value <20 % is a feature of both absolute and functional ID [
5].
The survey data demonstrate that the management of ID in patients with CIA continues to rely on oral iron preparations. Also in the subgroup of ESA-treated patients, concomitant iron supplementation consisted mainly of oral iron. Although oral iron may be used in cancer patients with absolute ID who do not receive any ESA and do not have active inflammation [
14], several randomised trials showed superiority of i.v. iron over oral iron in iron-deficient patients scheduled for initial or ongoing ESA-treatment (Table
3) [
14,
15,
17‐
19]. Intravenous iron supplementation resulted in increased haematological response, reduced need for transfusions and faster correction of anaemia [
21‐
28]. In contrast, oral iron did not improve response vs. no iron in ESA-treated cancer patients [
21,
25]. Side effects were similar in study treatment groups, confirming that only very few clinically relevant adverse events are observed with the new formulations of i.v. iron [
29,
30]. Good tolerability of i.v. iron has been shown not only in cancer patients [
5] but also in other patient populations with chronic conditions, such as chronic heart failure (FAIR-HF) [
31] or chronic kidney disease [
32]. Since cancer patients frequently present with multiple comorbidities and cancer therapies are often cardio- and/or nephrotoxic, these are important considerations [
33].
Table. 3
Randomised controlled trials on i.v. iron compared to oral or no iron supplementation of ESAs in cancer patients
| i.v. iron | 68* |
oral iron | 36 |
no iron | 25 |
| i.v. iron | 87* |
no iron | 53 |
| i.v. iron | 53* |
oral iron | 36 |
no iron | 36 |
| i.v. iron | 86* |
standard | 73 |
| i.v. iron | 77* |
no iron | 62 |
| i.v. iron | 82* |
no iron | 63 |
| i.v. iron | 70 (80 %)b
|
oral iron | 67 |
no iron | 65 |
| i.v. iron | 100* |
no iron | 79 |
Interestingly, 22 % of iron-treated patients in this study received iron as monotherapy (5 % i.v.; 17 % oral). Data from a recently published large prospective observational study indicate that i.v. iron as sole therapy of anaemia in cancer can increase Hb levels even without concomitant ESA [
35]. This data is supported by the results of four smaller randomised studies [
36‐
39], yet further studies are warranted.
More than half of all patients in this study received RBC transfusions. Further inquiries revealed that transfusions were given on a regular basis, and not only as rescue therapy, possibly reflecting suboptimal results obtained with ESA alone or in combination with oral iron. The frequent use of transfusions in patients with CIA is surprising, considering the health risks associated with this treatment. Possible complications of RBC transfusions include transfusion reactions, alloimmunisation, transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO), increased risk of infections, thromboembolic complications and transfusion-transmitted infections [
12,
40]. Although safety measures have reduced the incidence of transfusion-transmitted HIV, HCV and HBV infections, newly emerging and several re-emerging pathogens that are currently not tested for remain a risk [
41]. In many studies, an adverse clinical outcome (higher local tumour recurrence rate or shorter survival time) has been shown for cancer patients receiving transfusions [
13]. In addition, there are several procedural problems associated with RBCs (e.g. transfusion of RBC to ABO-incompatible recipients, availability of sufficient blood donations and quality issues). Guidelines therefore recommend preventing RBC transfusions by timely recognition and appropriate treatment of anaemia [
14‐
16].
Findings strikingly similar to this study’s were reported in a retrospective observational study in France (
N = 276) and a recent cross-sectional survey in Germany (
N = 3,867) [
42,
43]. Both studies showed frequent use of RBC transfusions in anaemic cancer patients and disregard of available treatment options for iron deficiency. Among iron-treated patients, iron therapy mainly consisted of oral iron. The authors concluded that routine treatment practice did not reflect current guidelines which recommend prevention of RBC transfusions and the i.v. route for iron supplementation, based on evidence that oral iron is ineffective in cancer-associated anaemia [
21,
25].
Our follow-up survey, 2 years after the first one, revealed only minor changes in management practices. Notably, there was an increase in the use of TSAT as a diagnostic marker. In addition, in year 2011, Hb levels at diagnosis of anaemia were slightly lower, possibly reflecting a general reservation regarding the use of ESA as a consequence of discussions about its safety [
11]. However, a 2-year interval may not be long enough for significant changes in management practices.
The majority of patients in this study population had already reached a moderate or severe stage of anaemia at the time of anaemia diagnosis. A possible reason for this may be that diagnostic tests and treatment were only initiated when anaemia symptoms were noticed.
Some caution is required in generalising the results of this study. The study was designed to capture diagnosis and treatment of CIA in routine practice in cancer patients who have already been treated for CIA. Among those, analysis was limited to the last five patients treated by each participating physician. Only limited information such as the presence of comorbidities was obtained, but no detailed data on the clinical history and the specific cause(s) of anaemia were collected. While the majority of cancer patients undergoing chemotherapy become anaemic, the cause of anaemia often is multifactorial and treatment decisions should be based on its underlying aetiology. Therefore, iron status should carefully be assessed, in addition to haemoglobin levels, when use of iron replacement therapy is considered in CIA patients. The significant variability in anaemia management observed in this study may not only reflect differences in appraisal of treatment benefits and insufficient concordance with treatment recommendations but also country-specific differences in reimbursement policies. The low utilisation of ESAs in the UK for instance may mainly be due to guidance against ESA use by the National Institute of Clinical Excellence (NICE).
Although some statistically significant differences in the use of diagnostic tests and anaemia treatment options were observed between entirely hospital-based and at least partially office-based medical oncologists and/or haematologists, these were of small magnitude, particularly in comparison to inter-country differences. The wide variation in diagnostic approaches seen between the countries is one of the main findings of this study, indicating the heterogeneity of patient management across Europe, and probably also between centres/practices within individual countries.
Acknowledgments
Preparation and conduct of the study have been sponsored by Vifor Pharma, Switzerland. The first and second surveys were conducted by A+A Healthcare Market Research, UK. The follow-up survey was conducted by EUMARA AG, Germany. Medical writing support in the preparation of the manuscript was provided by Bettina Dümmler, SFL Regulatory Affairs & Scientific Communication, Switzerland and funded by Vifor Pharma.