Effect of trimethoprim/sulfamethoxazole prophylaxis on outcome of childhood lymphocytic leukemia. A Pediatric Oncology Group Study

Guideline for Antibacterial Prophylaxis Administration in Pediatric Cancer and Hematopoietic Stem Cell Transplantation

Background

Bacteremia and other invasive bacterial infections are common among children with cancer receiving intensive chemotherapy and in pediatric recipients of hematopoietic stem cell transplantation (HSCT). Systemic antibacterial prophylaxis is one approach that can be used to reduce the risk of these infections. Our purpose was to develop a clinical practice guideline (CPG) for systemic antibacterial prophylaxis administration in pediatric patients with cancer and those undergoing HSCT.

Methods

An international and multidisciplinary panel was convened with representation from pediatric hematology/oncology and HSCT, pediatric infectious diseases (including antibiotic stewardship), nursing, pharmacy, a patient advocate, and a CPG methodologist. The panel used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to generate recommendations based on the results of a systematic review of the literature.

Results

The systematic review identified 114 eligible randomized trials of antibiotic prophylaxis. The panel made a weak recommendation for systemic antibacterial prophylaxis for children receiving intensive chemotherapy for acute myeloid leukemia and relapsed acute lymphoblastic leukemia (ALL). Weak recommendations against the routine use of systemic antibacterial prophylaxis were made for children undergoing induction chemotherapy for ALL, autologous HSCT and allogeneic HSCT. A strong recommendation against its routine use was made for children whose therapy is not expected to result in prolonged severe neutropenia. If used, prophylaxis with levofloxacin was recommended during severe neutropenia.

Conclusions

We present a CPG for systemic antibacterial prophylaxis administration in pediatric cancer and HSCT patients. Future research should evaluate the long-term effectiveness and adverse effects of prophylaxis.

Trimethoprim-Sulfamethoxazole Associated Drug-Induced Liver Injury in Pediatrics: A Systematic Review

BACKGROUND

Drug-induced liver injury (DILI) is a rare but known adverse event associated with trimethoprim-sulfamethoxazole (TMP-SMX) in adults. No studies to date have looked at the risk of this association in children. We systematically reviewed the evidence for a potential association between TMP-SMX and DILI in the pediatric population.

METHODS

PubMed, Medline, Embase, Cochrane Database of Systematic Reviews, Scopus and Web of Science was searched using a combination of terms to identify reports of TMP-SMX exposure, liver injury and pediatrics (≤18 years old). We included any studies with hepatic adverse events occurring after exposure to TMP-SMX. Bibliographies were reviewed for additional relevant references. The Narajno scale was used to assess causality in case studies.

RESULTS

A total of 22 studies were identified: 3 randomized trials, 1 prospective observational study, 8 retrospective observational studies and 10 case reports. Among the randomized trials and prospective studies, only mild, transient hepatic function abnormalities were reported. Retrospective observational studies reported 1 fatal DILI and statistically significant increased odds of DILI with TMP-SMX use compared with nonuse. Among the 10 case reports, severe liver outcomes and mild hepatic function abnormalities were both reported. Naranjo scores suggested reported hepatic adverse events were probably because of exposure in 5, possible in 4, and doubtful in 1 case report.

CONCLUSIONS

Evidence regarding DILI associated with TMP-SMX exposure in pediatrics is limited. Observational population studies show mild hepatic abnormalities. Case reports suggest more severe manifestations of DILI. Additional studies may reveal the association between TMP-SMX and DILI in pediatrics.

Effectiveness of antibacterial prophylaxis during induction chemotherapy in children with acute lymphoblastic leukemia

BACKGROUND

Pediatric patients receiving induction chemotherapy for newly diagnosed acute lymphoblastic leukemia (ALL) are at high risk of developing life-threatening infections. We investigated whether uniform antibacterial guidelines, including mandatory antibacterial prophylaxis in afebrile patients during induction, decreases the incidence of microbiologically documented bacteremia.

METHODS

Between 2012 and 2015, 230 patients with newly diagnosed ALL (aged 1-21) were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 11-001 (DFCI 11-001). Induction therapy, regardless of risk group, included vincristine, prednisone, doxorubicin, methotrexate, and PEG-asparaginase. Afebrile patients received fluoroquinolone prophylaxis at the initiation of induction and those presenting with fever received broad-spectrum antibiotics; antibiotics were continued until blood count recovery. Rates of documented bacteremias and fungal infections on DFCI 11-001 were compared to those on the predecessor protocol (DFCI 05-001), which included the same induction phase without antibiotic prophylaxis guidelines.

RESULTS

Sixty-six (28.7%) patients received fluoroquinolone prophylaxis, the remaining patients received broad-spectrum antibiotics. Twenty-four (36.4%) patients on prophylaxis developed fever and seven (10.6%) developed bacteremia. The overall rate of infection during induction on DFCI 11-001 was lower than on DFCl 05-001 (14.3% vs. 26.3%, P < 0.0001) due to a decreased rate of bacteremia (10.9% vs. 24.4%, P < 0.0001). The rate of fungal infections (4.8% vs. 3.6%) and induction death (0.9% vs. 2%) was not significantly different.

CONCLUSION

For children with newly diagnosed ALL, uniform antibiotic administration until blood count recovery, including fluoroquinolone prophylaxis for afebrile patients, reduced the incidence of bacteremia during the induction phase. Larger, randomized studies should be performed to confirm these findings.

Maintenance therapy of childhood acute lymphoblastic leukemia revisited-Should drug doses be adjusted by white blood cell, neutrophil, or lymphocyte counts?

BACKGROUND

6-Mercaptopurine (6MP) and methotrexate (MTX) based maintenance therapy is a critical phase of childhood acute lymphoblastic leukemia treatment. Wide interindividual variations in drug disposition warrant frequent doses adjustments, but there is a lack of international consensus on dose adjustment guidelines.

PROCEDURE

To identify relapse predictors, we collected 28,255 data sets on drug doses and blood counts (median: 47/patient) and analyzed erythrocyte (Ery) levels of cytotoxic 6MP/MTX metabolites in 9,182 blood samples (median: 14 samples/patient) from 532 children on MTX/6MP maintenance therapy targeted to a white blood cell count (WBC) of 1.5-3.5 × 10⁹ /l.

RESULTS

After a median follow-up of 13.8 years for patients in remission, stepwise Cox regression analysis did not find age, average doses of 6MP and MTX, hemoglobin, absolute lymphocyte counts, thrombocyte counts, or Ery levels of 6-thioguanine nucleotides or MTX (including its polyglutamates) to be significant relapse predictors. The parameters significantly associated with risk of relapse (N = 83) were male sex (hazard ratio [HR] 2.0 [1.3-3.1], P = 0.003), WBC at diagnosis (HR = 1.04 per 10 × 10⁹ /l rise [1.00-1.09], P = 0.048), the absolute neutrophil count (ANC; HR = 1.7 per 10⁹ /l rise [1.3-2.4], P = 0.0007), and Ery thiopurine methyltransferase activity (HR = 2.7 per IU/ml rise [1.1-6.7], P = 0.03). WBC was significantly related to ANC (Spearman correlation coefficient, r_s  = 0.77; P < 0.001), and only a borderline significant risk factor for relapse (HR = 1.28 [95% CI: 1.00-1.64], P = 0.046) when ANC was excluded from the Cox model.

CONCLUSIONS

This study indicates that a low neutrophil count is likely to be the best hematological target for dose adjustments of maintenance therapy.

Prophylaxis for Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients

BACKGROUND

Pneumocystis pneumonia (PCP) is a disease affecting immunocompromised patients. PCP among these patients is associated with significant morbidity and mortality.

OBJECTIVES

To assess the effectiveness of PCP prophylaxis among non-HIV immunocompromised patients; and to define the type of immunocompromised patient for whom evidence suggests a benefit for PCP prophylaxis.

SEARCH METHODS

Electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 1), MEDLINE and EMBASE (to March 2014), LILACS (to March 2014), relevant conference proceedings; and references of identified trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing prophylaxis with an antibiotic effective against PCP versus placebo, no intervention, or antibiotic(s) with no activity against PCP; and trials comparing different antibiotics effective against PCP among immunocompromised non-HIV patients. We only included trials in which Pneumocystis infections were available as an outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias in each trial and extracted data from the included trials. We contacted authors of the included trials to obtain missing data. The primary outcome was documented PCP infections. Risk ratios (RR) with 95% confidence intervals (CI) were estimated and pooled using the random-effects model.

MAIN RESULTS

Thirteen trials performed between the years 1974 and 2008 were included, involving 1412 patients. Four trials included 520 children with acute lymphoblastic leukemia and the remaining trials included adults with acute leukemia, solid organ transplantation or autologous bone marrow transplantation. Compared to no treatment or treatment with fluoroquinolones (inactive against Pneumocystis), there was an 85% reduction in the occurrence of PCP in patients receiving prophylaxis with trimethoprim/sulfamethoxazole, RR of 0.15 (95% CI 0.04 to 0.62; 10 trials, 1000 patients). The evidence was graded as moderate due to possible risk of bias. PCP-related mortality was also significantly reduced, RR of 0.17 (95% CI 0.03 to 0.94; nine trials, 886 patients) (low quality of evidence due to possible risk of bias and imprecision), but in trials comparing PCP prophylaxis against placebo or no treatment there was no significant effect on all-cause mortality (low quality of evidence due to imprecision). Occurrence of leukopenia or neutropenia and their duration were not reported consistently. No significant differences in overall adverse events or events requiring discontinuation were seen comparing trimethoprim/sulfamethoxazole to no treatment or placebo (four trials, 470 patients, moderate quality evidence). No differences between once daily versus thrice weekly trimethoprim/sulfamethoxazole were seen (two trials, 207 patients).

AUTHORS' CONCLUSIONS

Given an event rate of 6.2% in the control groups of the included trials, prophylaxis for PCP using trimethoprim/sulfamethoxazole is highly effective among non-HIV immunocompromised patients, with a number needed to treat to prevent PCP of 19 patients (95% CI 17 to 42). Prophylaxis should be considered for patients with a similar baseline risk of PCP.

Antibiotic prophylaxis in children with cancer or who have undergone hematopoietic cell transplantation

Bacterial infections are common in children with cancer and can lead to life-threatening complications. Infections in these patients mainly occur during neutropenic periods, and may be caused by Gram-positive or Gram-negative bacteria. The patients at highest risk of serious infections include those with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML), and those undergoing myeloablative hematopoietic cell transplantation (HCT). This is a review with the main aim of making a critical appraisal of the literature, and summarising what is currently known and can be recommended. The most significant studies support the use of floroquinolones (mainly ciprofloxacin) as the most rational approach to treat pediatric patients with probably long-lasting neutropenia, although trimetoprim-sulphametoxazole and amoxicillin/clavulanate may theoretically be valid alternatives. No prophylaxis seems to be needed for children with cancer without severe neutropenia. However, a global evaluation of the studies of antibiotic prophylaxis in children with cancer indicates that there are not enough data to prepare definite guidelines for its use or avoidance in pediatric oncology, and so further studies are needed. It is not only important to define the best antibiotic regimens for the children in whom such prophylaxis is useful, but also to identify precisely those who do not need it. This would avoid the antibiotic misuse that probably occurs at the moment because many low-risk children with cancer are treated. As prophylaxis against infections requires long-term adherence to an antibiotic regimen, the attitudes and beliefs of stakeholders need to be fully considered.

Prevention of bacterial infection in pediatric oncology: what do we know, what can we learn?

Bacterial sepsis continues to be a leading cause of morbidity and toxic death in children receiving intensive therapy for cancer. Empiric therapy for suspected infections and treatment of documented infections are well-established standards of care. The routine use of prophylactic strategies is much less common in pediatric oncology. This paper will review the current literature on the use and risks of antimicrobial prophylaxis as well as non-pharmacological methods for infection prevention and will address areas in need of further research.

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.

Infections during induction therapy for children with acute lymphoblastic leukemia. the role of sulfamethoxazole-trimethoprim (SMX-TMP) prophylaxis

BACKGROUND

Bacteremias are frequent during induction therapy for acute lymphoblastic leukemia (ALL) in children. Antibacterial prophylaxis therapy may thus be warranted. The purpose of this study was to analyze the rate of infections during induction therapy in two cohorts of children with ALL where one cohort received prophylactic sulfamethoxazole-trimethoprim (SMX-TMP).

PROCEDURE

All infections were registered through a retrospective non-randomized review of medical records of 171 consecutive children newly diagnosed with ALL below 15 years of age at diagnosis. A total of 85 children treated from 1992 to 2000 did not receive SMX-TMP, whereas 86 children treated from 2000 to 2008 received SMX-TMP 20 mg/kg in one daily oral dose during induction therapy.

RESULTS

A total of 26% of all children had no febrile episodes during induction. Infections were more frequent in children below 5 years of age. Significantly fewer children receiving SMX-TMP developed fever (17% vs. 34%, P = 0.02) and bacteremia (20% vs. 45%, P = 0.0003). Especially children with non-high risk criteria had fewer infections when receiving prophylaxis. When adjusting for age, type of catheter, and SMX-TMP prophylaxis on the risk of bacteremia by a multiple Cox regression analysis, we found that age and prophylaxis, but not the type of catheter, were associated with a significantly reduced risk of bacteremia.

CONCLUSION

Children with ALL receiving SMX-TMP prophylaxis during induction therapy experienced fewer febrile episodes, fewer days with fever demanding intravenous antibiotic treatment, and fewer episodes of bacteremia. Both SMX-TMP prophylaxis and age played significant independent roles for the occurrence of bacteremia.

Outcomes of patients who participate in randomized controlled trials compared to similar patients receiving similar interventions who do not participate

BACKGROUND

Some people believe that patients who take part in randomised controlled trials (RCTs) face risks that they would not face if they opted for non-trial treatment. Others think that trial participation is beneficial and the best way to ensure access to the most up-to-date physicians and treatments. This is an updated version of the original Cochrane review published in Issue 1, 2005.

OBJECTIVES

To assess the effects of patient participation in RCTs ('trial effects') independent both of the effects of the clinical treatments being compared ('treatment effects') and any differences between patients who participated in RCTs and those who did not. We aimed to compare similar patients receiving similar treatment inside and outside of RCTs.

SEARCH STRATEGY

In March 2007, we searched The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, The Cochrane Methodology Register, SciSearch and PsycINFO for potentially relevant studies. Our search yielded 7586 new references. In addition, we reviewed the reference lists of relevant articles.

SELECTION CRITERIA

Randomized studies and cohort studies with data on clinical outcomes of RCT participants and similar patients who received similar treatment outside of RCTs.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed studies for inclusion, assessed study quality and extracted data.

MAIN RESULTS

We identified 30 new non-randomized cohort studies (45 comparisons): no new RCTs were found. This update now includes five RCTs (yielding 6 comparisons) and 80 non-randomized cohort studies (130 comparisons), with 86,640 patients treated in RCTs and 57,205 patients treated outside RCTs. In the randomised studies, patients were invited to participate in an RCT or not; these comparisons provided limited information because of small sample sizes (a total of 412 patients) and the nature of the questions they addressed. When the results of RCTs and non-randomized cohorts that reported dichotomous outcomes were combined, there were 98 comparisons; there was also heterogeneity (P < 0.00001, I(2) = 42.2%) between studies. No statistical significant differences were found for 85 of the 98 comparisons. Eight comparisons reported statistically significant better outcomes for patients treated within RCTs, and five comparisons reported statistically significant worse outcomes for patients treated within RCTs. There was significant heterogeneity (P < 0.00001, I(2) = 58.2%) among the 38 continuous outcome comparisons. No statistically significant differences were found for 30 of the 38 comparisons. Three comparisons reported statistically significant better outcomes for patients treated within RCTs, and five comparisons reported statistically significant worse outcomes for patients treated within RCTs.

AUTHORS' CONCLUSIONS

This review indicates that participation in RCTs is associated with similar outcomes to receiving the same treatment outside RCTs. These results challenge the assertion that the results of RCTs are not applicable to usual practice.

Prophylaxis of Pneumocystis pneumonia in immunocompromised non-HIV-infected patients: systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To assess the efficacy of prophylaxis for Pneumocystis pneumonia (PCP), caused by Pneumocystis jirovecii (formerly Pneumocystis carinii), for immunocompromised non-HIV-infected patients by conducting a systematic review and meta-analysis.

METHODS

We searched for randomized controlled trials that compared prophylaxis using antibiotics effective against P jirovecii, given orally or intravenously, vs placebo, no intervention, or antibiotics with no activity against P jirovecii. In addition, we included trials that compared different PCP prophylactic regimens or administration schedules. The search included the Cochrane Central Register of Controlled Trials, PubMed, Latin American and Caribbean Health Sciences Literature, and conference proceedings. No language, year, or publication restrictions were applied. Two reviewers (H.G. and M.P.) independently searched, selected trials, extracted data, and performed methodological quality assessment. Relative risks (RRs) with 95% confidence intervals (CIs) are reported. Meta-analysis was performed using the random-effects model.

RESULTS

Twelve randomized trials were identified, including 1245 patients (50% children) who had undergone autologous bone marrow or solid organ transplant or who had hematologic cancer. When trimethoprim-sulfamethoxazole was administered, a 91% reduction was observed in the occurrence of PCP (RR, 0.09; 95% CI, 0.02-0.32); the number needed to treat was 15 (95% CI, 13-20) patients, with no heterogeneity. Pneumocystis pneumonia-related mortality was significantly reduced (RR, 0.17; 95% CI, 0.03-0.94), whereas all-cause mortality did not differ significantly (RR, 0.79; 95% CI, 0.18-3.46). Adverse events that required discontinuation occurred in 3.1% of adults and none of the children, and all were reversible. No differences between once-daily and thrice-weekly administration schedules were found.

CONCLUSION

Balanced against severe adverse events, PCP prophylaxis is warranted when the risk for PCP is higher than 3.5% for adults. Adverse events are less frequent in children, for whom prophylaxis might be warranted at lower PCP incidence rates.

Prophylaxis for Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients

BACKGROUND

Pneumocystis pneumonia (PCP) is a disease affecting immunocompromised patients. PCP among these patients is associated with significant morbidity and mortality.

OBJECTIVES

To assess the effectiveness of PCP prophylaxis among non-HIV immunocompromised patients. To define the type of immunocompromised patients for whom evidence suggests a benefit for PCP prophylaxis.

SEARCH STRATEGY

Electronic searches of The Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 1, 2007), PubMed (March 2007), LILACS (March 2007), relevant conference proceedings; references of identified trials; the first author of each included trial was contacted.

SELECTION CRITERIA

RCTs or quasi- RCTs comparing prophylaxis with an antibiotic effective against Pneumocystis versus placebo, no intervention, an antibiotic/s with no activity against Pneumocystis or another antibiotic effective against Pneumocystis for immune-compromised non-HIV patients. Only trials pre-defining Pneumocystis infections as an outcome were included.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from included trials. Relative risks (RR), with 95% confidence intervals (CI) were estimated and pooled using the random effects model.

MAIN RESULTS

Eleven trials including 1155 patients (520 children), performed between the years 1974 and 1997, were included. Compared to no treatment or treatment with fluoroquinolones (inactive against Pneumocystis), there was a 91% reduction in the occurrence of PCP in patients receiving prophylaxis with trimethoprim/sulfamethoxazole, RR 0.09 (95% CI 0.02 to 0.32), eight trials, 821 patients. No significant difference was encountered in all cause mortality, RR 0.81 (95% CI 0.27 to 2.37), five trials, 509 patients, while PCP-related mortality was significantly reduced, RR 0.17 (95% CI 0.03 to 0.94), seven trials, 701 patients. Occurrence of leukopenia, neutropenia and their duration were not reported consistently. No significant difference in any adverse event was seen comparing trimethoprim/sulfamethoxazole to no treatment/ placebo (four trials, 470 patients). No differences between once daily versus thrice weekly trimethoprim/sulfamethoxazole were seen (two trials, 207 patients).

AUTHORS' CONCLUSIONS

Given an event rate of 7.5% as in included trials' control group, prophylaxis for PCP using TMP/SMX is highly effective among non-HIV patients, with a number needed to treat of 15 patients (95% CI 13 to 20). Prophylaxis should be considered for the types of patients with hematological malignancies, bone marrow transplantation and solid organ transplantation included in these trials.

Outcomes of patients who participate in randomised controlled trials compared to similar patients receiving similar interventions who do not participate

BACKGROUND

Some people believe that patients who take part in randomised controlled trials (RCTs) face risks that they would not face if they opted for non-trial treatment. Others think that trial participation is beneficial and the best way to ensure access to the most up to date physicians and treatments.

OBJECTIVES

To assess the effects of patient participation in RCTs ('trial effects') independent both of the effects of the clinical treatments being compared ('treatment effects') and any differences between patients who participated in RCTs and those who did not.

SEARCH STRATEGY

In May 2001, we searched The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, The Cochrane Methodology Register, SciSearch and PsycINFO for potentially relevant studies. Our search yielded over 10,000 references. In addition, we reviewed the reference lists of relevant articles and wrote to over 250 investigators to try to obtain further information.

SELECTION CRITERIA

Randomised studies and cohort studies with data on clinical outcomes of RCT participants and similar patients who received similar treatment outside of RCTs.

DATA COLLECTION AND ANALYSIS

At least two reviewers independently assessed studies for inclusion, assessed study quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

We included five randomised studies (yielding 6 comparisons) and 50 non-randomised cohort studies (85 comparisons), with 31,140 patients treated in RCTs and 20,380 patients treated outside RCTs. In the randomised studies, patients were invited to participate in an RCT or not; these comparisons provided limited information because of small sample sizes (a total of 412 patients) and the nature of the questions they addressed. There was statistically significant heterogeneity (P < 0.002, I(2) = 36.2%) among the 73 dichotomous outcome comparisons; none of the potential explanatory factors we investigated helped to explain this heterogeneity. No statistically significant differences were found for 63 of the 73 comparisons. Eight comparisons reported statistically significant better outcomes for patients treated within RCTs, and two comparisons reported statistically significant worse outcomes for patients treated within RCTs. There were no statistically significant differences in heterogeneity (P = 0.53, I(2) = 0%) or in outcomes (SMD 0.01, 95% CI -0.10 to 0.12) of patients treated within and outside RCTs in the 18 comparisons which had used continuous outcomes.

AUTHORS' CONCLUSIONS

This review indicates that participation in RCTs is not associated with greater risks than receiving the same treatment outside RCTs. These results challenge the assertion that the results of RCTs are not applicable to usual practice.

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.

Prevention of infection in children with acute leukaemia. No major difference between total and selective bowel decontamination

To evaluate the effect of total bowel decontamination (TD) and selective bowel decontamination (SD) in a non-protective environment clinical and laboratory data of children treated for acute leukaemia between 1983 and 1991 were analysed retrospectively. From 1983 until 1989 34 patients [18 acute non-lymphoblastic leukaemia (ANLL) patients, 16 acute lymphoblastic leukaemia (ALL) patients] received TD and 31 patients (8 ANLL patients, 23 ALL patients) received SD from 1987 until 1991. TD consisted of colistin sulphate, neomycin, cephaloridine and amphotericin B orally as well as Orabase and sterilized food, while the patients were nursed in a single room. SD consisted of oral colistin sulphate, neomycin and amphotericin B. Those patients with ANLL were nursed in a single room; patients with ALL were nursed in a single room during remission induction therapy only. All patients except those with ANLL receiving TD received Pneumocystis carinii pneumonia prophylaxis with cotrimoxazole. Because the two groups were heterogeneous for diagnosis and chemotherapy the occurrence of fever (central body temperature at least 38.5 degrees C) and major infections (septicaemia of infections of the deep tissues or organs) were registered during periods of neutropenia (neutrophilic granulocytes < or = 500/mm3 for at least 8 days). Patients on TD had 55 periods of neutropenia, patients on SD 80. Patients on TD had 89.1 periods of fever/100 periods of neutropenia whereas patients on SD had 56.3. Also patients on TD had 27.3 major infections/100 periods of neutropenia whereas patients on SD had 11.3. Major infections predominantly consisted of septicaemia caused by gram-positive bacteria. We conclude that, in this study, TD in a non-protective environment does not offer better protection against major infections that SD in patients with ALL or ANLL.

Treatment intensity and outcome for children with acute lymphocytic leukemia of standard risk. A Pediatric Oncology Group Study

Four hundred thirty-four children, with good-risk acute lymphocytic leukemia (ALL), were assigned randomly to receive intensive or less intensive maintenance therapy with 6-mercaptopurine and methotrexate, plus vincristine and prednisone pulses in such a way that patients on treatment 1 had their leukocyte counts maintained between 1500 and 3000/mm3. Patients on treatment 2 had leukocyte counts maintained between 3000 and 4500/mm3. Absolute granulocyte counts were maintained above 500/mm3 on both groups. All children received induction treatment with vincristine, prednisone and L-asparaginase and had central nervous system (CNS) prophylaxis with cranial irradiation and intrathecal methotrexate. The overall remission rate was 94%. Event-free survival at 8 years was 44% (SE, 5.6%). There was no significant difference in outcome between treatments 1 and 2 (P = 0.83). The incidence of infection was similar overall and not significantly different between treatment arms.

A comparison of two regimens for high-risk acute lymphocytic leukemia in childhood. A Pediatric Oncology Group Study

Four hundred thirty patients with high-risk acute lymphoid leukemia were entered on the acute leukemia in childhood protocol (AlinC 12) of the Pediatric Division of the Southwest Oncology Group (now the Pediatric Oncology Group) between 1976 and 1979. This study was a prospective randomized comparison of two regimens that had as their primary differences: (1) an intensification period with Cytoxan (cyclophosphamide) and asparaginase after induction; (2) a period of intravenous methotrexate before initiating maintenance; and (3) in the regimen that had those two additions, triple-drug chemoprophylaxis of the central nervous system (CNS) using methotrexate, hydrocortisone, and cytosine arabinoside as compared to cranial irradiation and intrathecal methotrexate. All patients received vincristine and prednisone induction, 6-mercaptopurine and methotrexate maintenance, and vincristine and prednisone pulse intensification. There was no significant difference in the rate of bone marrow relapse. However, overall disease-free survival favored the arm with intensification and chemoprophylaxis because of a lesser incidence of extramedullary relapse. Thus, for treatment 1 versus treatment 3 the two-sided P values were for overall disease-free survival 0.16; bone marrow relapses 0.13; all CNS relapses 0.04; and all extramedullary disease relapses 0.013. It is concluded that intensification as delivered in this protocol protects against testicular relapse and that chemoprophylaxis is adequate prophylaxis against isolated CNS relapse.