Infections in neutropenic patients. II: Management

Antibiotic prophylaxis for bacterial infections in afebrile neutropenic patients following chemotherapy

BACKGROUND

Bacterial infections are a major cause of morbidity and mortality in patients who are neutropenic following chemotherapy for malignancy. Trials have shown the efficacy of antibiotic prophylaxis in reducing the incidence of bacterial infections but not in reducing mortality rates. Our systematic review from 2006 also showed a reduction in mortality.

OBJECTIVES

This updated review aimed to evaluate whether there is still a benefit of reduction in mortality when compared to placebo or no intervention.

SEARCH METHODS

We searched the Cochrane Cancer Network Register of Trials (2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2011), MEDLINE (1966 to March 2011), EMBASE (1980 to March 2011), abstracts of conference proceedings and the references of identified studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing different types of antibiotic prophylaxis with placebo or no intervention, or another antibiotic, to prevent bacterial infections in afebrile neutropenic patients.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from the included trials. Analyses were performed using RevMan 5.1 software.

MAIN RESULTS

One-hundred and nine trials (involving 13,579 patients) that were conducted between the years 1973 to 2010 met the inclusion criteria. When compared with placebo or no intervention, antibiotic prophylaxis significantly reduced the risk of death from all causes (46 trials, 5635 participants; risk ratio (RR) 0.66, 95% CI 0.55 to 0.79) and the risk of infection-related death (43 trials, 5777 participants; RR 0.61, 95% CI 0.48 to 0.77). The estimated number needed to treat (NNT) to prevent one death was 34 (all-cause mortality) and 48 (infection-related mortality).Prophylaxis also significantly reduced the occurrence of fever (54 trials, 6658 participants; RR 0.80, 95% CI 0.74 to 0.87), clinically documented infection (48 trials, 5758 participants; RR 0.65, 95% CI 0.56 to 0.76), microbiologically documented infection (53 trials, 6383 participants; RR 0.51, 95% CI 0.42 to 0.62) and other indicators of infection.There were no significant differences between quinolone prophylaxis and TMP-SMZ prophylaxis with regard to death from all causes or infection, however, quinolone prophylaxis was associated with fewer side effects leading to discontinuation (seven trials, 850 participants; RR 0.37, 95% CI 0.16 to 0.87) and less resistance to the drugs thereafter (six trials, 366 participants; RR 0.45, 95% CI 0.27 to 0.74).

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis in afebrile neutropenic patients significantly reduced all-cause mortality. In our review, the most significant reduction in mortality was observed in trials assessing prophylaxis with quinolones. The benefits of antibiotic prophylaxis outweighed the harm such as adverse effects and the development of resistance since all-cause mortality was reduced. As most trials in our review were of patients with haematologic cancer, we strongly recommend antibiotic prophylaxis for these patients, preferably with a quinolone. Prophylaxis may also be considered for patients with solid tumours or lymphoma.

Antibiotic prophylaxis for bacterial infections in afebrile neutropenic patients following chemotherapy

BACKGROUND

Bacterial infections are a major cause of morbidity and mortality in neutropenic patients following chemotherapy for malignancy. Trials have shown the efficacy of antibiotic prophylaxis in decreasing the incidence of bacterial infections, but not in reducing mortality rates.

OBJECTIVES

This review aimed to evaluate whether antibiotic prophylaxis in afebrile neutropenic patients reduced mortality when compared to placebo or no intervention.

SEARCH STRATEGY

Electronic searches on The Cochrane Cancer Network Register of Trials (2004), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to 2004) and EMBASE (1980 to 2004) and abstracts of conference proceedings; references of identified studies; the first author of each included trial was contacted.

SELECTION CRITERIA

RCTs or quasi-RCTs comparing different types of antibiotic prophylaxis with placebo or no intervention, or another antibiotic to prevent bacterial infections in afebrile neutropenic patients.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from the included trials. Relative risks (RR) or average differences, with their 95% confidence intervals (CI) were estimated.

MAIN RESULTS

One hundred trials (10,274 patients) performed between the years 1973 to 2004 met inclusion criteria. Antibiotic prophylaxis significantly decreased the risk for death when compared with placebo or no intervention (RR, 0.66 [95% CI 0.54 to 0.81]). The authors estimated the number needed to treat (NNT) in order to prevent 1 death from all causes as 60 (95% CI 34 to 268). Prophylaxis resulted in a significant decrease in the risk of infection-related death, RR 0.58 (95% CI 0.45 to 0.74) and in the occurrence of fever, RR 0.78 (95% CI 0.75 to 0.82). A reduction in mortality was also evident when the more recently conducted quinolone trials were analysed separately. Quinolone prophylaxis reduced the risk for all-cause mortality, RR 0.52 (95% CI, 0.37 to 0.84).

AUTHORS' CONCLUSIONS

Our review demonstrated that prophylaxis significantly reduced all-cause mortality. The most significant reduction in mortality was observed in trials assessing prophylaxis with quinolones. The benefit demonstrated in our review outweighs harm, such as adverse effects, and development of resistance, since all-cause mortality is reduced. Since most trials in our review were of patients with haematologic cancer, prophylaxis, preferably with a quinolone, should be considered for these patients.

Alterations in adhesion molecule (CD11b/CD18 and CD62L) expression on granulocytes after chemotherapy

BACKGROUND

Infections during chemotherapy-induced granulocytopenia constitute a major threat to patients with malignant disorders. The aim of this study was to evaluate whether circulating granulocytes after chemotherapy have a normal expression of adhesion molecules or if the granulocytes, in addition to being present in low number, also present signs of qualitative alterations.

METHODS

We have investigated the time course of adhesion molecule expression (CD11b/CD18 and CD62L) and in vitro mobilization [responsiveness against N-formyl-methionyl-leucyl-phenylalanine (fMLP) for CD11b/CD18] by flow cytometry in circulating granulocytes after chemotherapy in 12 patients with haematological malignancies. Blood samples for analysis were drawn before chemotherapy and at time points when granulocyte counts were < 0.5, 0.5-1.0 and > 1.0 x 109 L-1.

RESULTS

The quantitative level, expressed as mean fluorescence intensity (MFI), of CD11b/CD18 was significantly higher and of CD62L significantly lower at granulocyte nadir than before chemotherapy. The in vitro responsiveness to fMLP was significantly reduced at the same time point. These alterations were restored to pretreatment values at the time of granulocyte count recovery. Granulocytes from patients with bacteraemia (n = 6) exhibited lower CD11b/CD18 MFI values after fMLP stimulation than non-bacteraemic patients after granulocyte count recovery. In addition, the MFI of CD62L was significantly lower both before chemotherapy and after granulocyte recovery in the bacteraemic group.

CONCLUSION

Chemotherapy induces qualitative alterations in circulating granulocytes with respect to adhesion molecule expression and mobilization, and these alterations are more pronounced in patients with accompanying bacteraemia.