Anti-anemia drugs shorten survival for some cancer patients

People with cancer may develop a blood problem called anemia, due to the treatment or from the disease itself. They will have very low levels of healthy red blood cells, causing additional health problems. For years, doctors have tried to prevent or treat anemia with injections of erythropoiesis stimulating agents (ESAs) in order to spare cancer patients the many serious harms associated with a red-blood cell transfusion (such as hepatitis, transfusion-related acute lung injury, infection). Earlier reviews of the research showed that ESA treatment reduces the need for transfusion but, in recent years, several studies have shown that ESAs themselves cause harm. The drug may, for example, stimulate tumor growth and cause potentially fatal blood clots. In 2007, new studies reported that ESAs shortens survival in people with breast, non-small cell lung, head and neck, lymphoid and cervical cancers.

A new systematic review was needed to evaluate the old and the new evidence together and determine the impact of ESAs on survival in cancer patients to see if there are groups of patients who are at increased or decreased risk compared to the average. To accomplish this the authors of this meta-analysis conducted an in-depth assessment of the individual patient data generated by the care of nearly 14,000 patients from 53 trials conducted worldwide. Data on each of these patients were provided by three companies that make ESAs: Amgen, Johnson & Johnson, and Roche, and by several independent researchers. (The drug companies, however, had no role in conducting the meta-analysis.) The trials investigated one of two types of ESAs, epoetin or darbepoetin, and compared the use of one of these drugs plus red blood cell transfusion (as needed), with red blood cell transfusion alone (as needed). Most patients were given their treatment while undergoing anti-cancer therapy (chemotherapy and/or radiotherapy); but others received the treatment after they had completed their anti-cancer therapy. Some patients already had anemia; others were treated in order to prevent it. The patients had many different forms of cancer and many different anti-cancer treatments. 

The authors of this new meta-analysis concluded that ESA treatment shortens survival. They could not identify with certainty any subgroup of patients at either increased or decreased risk of dying when taking ESAs. With their doctors' help, cancer patients should consider the risks of taking ESA against the risks of a blood transfusion. Be aware, however, that uncertainties remain about the magnitude of each.

Authors' conclusions: 

ESA treatment in cancer patients increased on study mortality and worsened overall survival. For patients undergoing chemotherapy the increase was less pronounced, but an adverse effect could not be excluded.

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Background: 

Erythropoiesis-stimulating agents (ESAs) reduce anemia in cancer patients and may improve quality of life, but there are concerns that ESAs might increase mortality.

Objectives: 

Our objectives were to examine the effect of ESAs and identify factors that modify the effects of ESAs on overall survival, progression free survival, thromboembolic and cardiovascular events as well as need for transfusions and other important safety and efficacy outcomes in cancer patients.

Search strategy: 

We searched the Cochrane Library, Medline, Embase and conference proceedings for eligible trials. Manufacturers of ESAs were contacted to identify additional trials.

Selection criteria: 

We included randomized controlled trials comparing epoetin or darbepoetin plus red blood cell transfusions (as necessary) versus red blood cell transfusions (as necessary) alone, to prevent or treat anemia in adult or pediatric cancer patients with or without concurrent antineoplastic therapy.

Data collection and analysis: 

We performed a meta-analysis of randomized controlled trials comparing epoetin alpha, epoetin beta or darbepoetin alpha plus red blood cell transfusions versus transfusion alone, for prophylaxis or therapy of anemia while or after receiving anti-cancer treatment. Patient-level data were obtained and analyzed by independent statisticians at two academic departments, using fixed-effects and random-effects meta-analysis. Analyses were according to the intention-to-treat principle. Primary endpoints were on study mortality and overall survival during the longest available follow-up, regardless of anticancer treatment, and in patients receiving chemotherapy. Tests for interactions were used to identify differences in effects of ESAs on mortality across pre-specified subgroups. The present review reports only the results for the primary endpoint.

Main results: 

A total of 13933 cancer patients from 53 trials were analyzed, 1530 patients died on-study and 4993 overall. ESAs increased on study mortality (combined hazard ratio [cHR] 1.17; 95% CI 1.06-1.30) and worsened overall survival (cHR 1.06; 95% CI 1.00-1.12), with little heterogeneity between trials (I2 0%, p=0.87 and I2 7.1%, p=0.33, respectively). Thirty-eight trials enrolled 10441 patients receiving chemotherapy. The cHR for on study mortality was 1.10 (95% CI 0.98-1.24) and 1.04; 95% CI 0.97-1.11) for overall survival. There was little evidence for a difference between trials of patients receiving different cancer treatments (P for interaction=0.42).

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