Low-risk febrile neutropenia in a medical oncology unit

Prognostic factors for risk stratification of adult cancer patients with chemotherapy-induced febrile neutropenia: a systematic review and meta-analysis

BACKGROUND

Increasing numbers of studies identify new prognostic factors for categorising chemotherapy-induced febrile neutropenia adult cancer patients into high- or low-risk groups for adverse outcomes. These groupings are used to tailor therapy according to level of risk. However many emerging factors with prognostic significance remain controversial, being based on single studies only.

OBJECTIVES

A systematic review was conducted to determine the strength of association of all identified factors associated with the outcomes of chemotherapy-induced febrile neutropenia patients.

INCLUSION CRITERIA

The participants included were adults of 15 years old and above, with a cancer diagnosis and who underwent cancer treatment.The review focused on clinical factors and their association with the outcomes of cancer patients with chemotherapy-induced febrile neutropenia at presentation of fever.All quantitative studies published in English which investigated clinical factors for risk stratification of adult cancer patients with chemotherapy-induced febrile neutropenia were considered.The primary outcome of interest was to identify the clinical factors for risk stratification of adult cancer patients with chemotherapy-induced febrile neutropenia.

SEARCH STRATEGY

Electronic databases searched from their respective inception date up to December 2011 include MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Science-Direct, Scopus and Mednar.

METHODOLOGICAL QUALITY

The quality of the included studies was subjected to assessment by two independent reviewers. The standardised critical appraisal tool from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) was used to assess the following criteria: representativeness of study population; clearly defined prognostic factors and outcomes; whether potential confounders were addressed and appropriate statistical analysis was undertaken for the study design.

DATA COLLECTION

Data extraction was performed using a modified version of the standardised extraction tool from the JBI-MAStARI. Prognostic factors and the accompanying odds ratio reported for the significance of these factors that were identified by multivariate regression, were extracted from each included study.

DATA SYNTHESIS

Studies results were pooled in statistical meta-analysis using Review Manager 5.1. Where statistical pooling was not possible, the findings were presented in narrative form.

RESULTS

Seven studies (four prospective cohort and three retrospective cohort) investigating 22 factors in total were included. Fixed effects meta-analysis showed: hypotension [OR=1.66, 95%CI, 1.14-2.41, p=0.008] and thrombocytopenia [OR=3.92, 95%CI, 2.19-7.01, p<0.00001)] were associated with high-risk of adverse outcomes for febrile neutropenia. Other factors that were statistically significant from single studies included: age of patients, clinical presentation at fever onset, presence or absence of co-morbidities, infections, duration and severity of neutropenia state. Five prognostic factors failed to demonstrate an association between the variables and the outcomes measured and they include: presence of pneumonia, total febrile days, median days to fever, recovery from neutropenia and presence of moderate clinical symptoms in association with Gram-negative bacteraemia.

CONCLUSIONS

Despite the overall limitations identified in the included studies, this review has provided a synthesis of the best available evidence for the prognostic factors used in risk stratification of febrile neutropenia patients. However, the dynamic aspects of prognostic model development, validation and utilisation have not been addressed adequately thus far. Given the findings of this review, it is timely to address these issues and improve the utilisation of prognostic models in the management of febrile neutropenia patients.

IMPLICATIONS FOR PRACTICE

The identified factors are similar to the factors in current prognostic models. However, additional factors that were reported to be statistically significant in this review (thrombocytopenia, presence of central venous catheter, and duration and severity of neutropenia) have not previously been included in prognostic models. This review has found these factors may improve the performance of current models by adding or replacing some of the factors.

IMPLICATIONS FOR RESEARCH

The role of risk stratification of chemotherapy-induced febrile neutropenia patients continues to evolve as the practice of risk-based therapy has been demonstrated to be beneficial to patients, clinicians and health care organisations. Further research to identify new factors /markers is needed to develop a new model which is reliable and accurate for these patients, regardless of cancer types. A robust and well-validated prognostic model is the key to enhance patient safety in the risk-based management of cancer patients with chemotherapy-induced febrile neutropenia.

Prophylactic and therapeutic strategies in chemotherapy-induced neutropenia

INTRODUCTION

Neutropenia poses a serious threat to patients on chemotherapy. It exposes them to the risk of infection--including potentially fatal infections--and also leads to delays in treatment and reductions in dose intensity, which can compromise the possibility of a favorable outcome.

AREAS COVERED

The use of granulocyte colony-stimulating factors (G-CSF) and antibiotics to prevent febrile neutropenia (FN) and to ameliorate cancer chemotherapy-induced myelosuppression is discussed, based on a systematic search of Pubmed for clinical trials, reviews and meta-analysis published in the last 20 years. We consider that the treatment of FN, with the emphasis on careful attention to the patient, prompts antibiotic therapy and good hospital care.

EXPERT OPINION

We would argue that antibiotic prophylaxis should be offered routinely to patients receiving cytotoxic chemotherapy for acute leukemia and for patients with solid tumors and lymphoma receiving high-dose chemotherapy. In patients undergoing cyclical standard-dose myelosuppressive chemotherapy, we believe that prophylaxis is indicated during the first cycle of chemotherapy in which there is an expectation of grade 4 neutropenia (< 500 neutrophils). However, although the use of antibiotics and haematopoietic growth factors may improve quality of life by reducing the risk and consequences of FN, further study of the magnitude of their effects is needed.

Neutropenia: Etiology and Pathogenesis

Neutropenia is defined as an absolute neutrophil count <1500 cells/mm(3) and can be graded as mild (1000-1500 cells/mm(3)), moderate (500-1000 cells/mm(3)), or severe (<500 cells/mm(3)). Neutropenia can develop as a result of > or =1 pathologic mechanism, including decreased bone marrow production, the sequestering of neutrophils, and increased destruction of neutrophils in the peripheral blood. The clinical result is increased risk for infection. This risk is directly proportional to the severity and duration of neutropenia. Neutropenia is classified according to the etiology as congenital or acquired, with the latter further defined according to the etiology or pathology. Febrile neutropenia is associated with substantial morbidity and even mortality.

Risk models for predicting chemotherapy-induced neutropenia

Neutropenia and its complications, including febrile neutropenia, are major dose-limiting toxicities of systemic cancer chemotherapy. A number of studies have attempted to identify risk factors for neutropenia and its consequences to develop predictive models capable of identifying patients at greater risk for such complications and to guide more effective and cost-effective applications of the colony-stimulating factors. A systematic review of the literature showed that age, performance status, nutritional status, chemotherapy dose intensity, and low baseline blood cell counts were associated with the risk of severe and febrile neutropenia or reduced chemotherapy dose intensity in multivariate analysis in two or more studies. Similarly, age, diagnosis of leukemia or lymphoma, high temperature or low blood pressure at admission, and i.v. site infection along with low blood cell counts and organ dysfunction were associated with serious medical complications of febrile neutropenia, including bacteremia and death. The available risk model studies, however, had several limitations, including retrospective analyses of small study populations lacking independent validation, frequent missing values, and differences in the predictive factors considered. To overcome the limitations of previous studies, efforts are under way to develop and validate risk models based on large prospective studies in representative populations of patients receiving systemic chemotherapy.

Randomized placebo-controlled trial of oral antibiotics in pediatric oncology patients at low-risk with fever and neutropenia

PURPOSE

Fever combined with neutropenia in pediatric oncology patients has traditionally been managed in the hospital with broad-spectrum intravenous antibiotics until there is documented neutrophil recovery. Recent evidence has suggested that patients at "low-risk" can be discharged from the hospital before neutrophil recovery. Whether oral antibiotics are required at the time of discharge is not known.

PATIENTS AND METHODS

Using a randomized, double-blind, placebo-controlled study design, 73 patients at low-risk with episodes of fever and neutropenia were discharged home while still neutropenic: 37 administered with oral cloxacillin and cefixime and 36 administered with corresponding placebos. Low-risk criteria included: afebrile for more than 24 hours, negative blood culture results at 48 hours, absence of clinical sepsis, cancer in bone marrow remission, and absence of comorbid conditions.

RESULTS

Five patients (14%; 95% confidence interval [CI]; 2%-25%) in the antibiotic arm and two patients (6%; 95% CI; 0%-13%) in the placebo arm were readmitted to the hospital with recurrent fever while still neutropenic (P = 0.43). One patient randomized to the placebo arm had a positive blood culture result on readmission, which responded to appropriate intravenous antibiotics. All of the readmissions were uneventful and there were no fatalities. The average cost per episode of fever and neutropenia was $1,821 Canadian dollars with only minimal incremental cost to the antibiotic arm.

CONCLUSION

This study supports the discontinuation of antibiotics in pediatric oncology patients at low-risk who still have neutropenia at the time of discharge from the hospital.

"Low-risk" prediction rule for pediatric oncology patients presenting with fever and neutropenia

PURPOSE

To prospectively derive and validate a clinical prediction rule to allow a more tailored approach to the management of pediatric oncology outpatients presenting with fever and neutropenia.

PATIENTS AND METHODS

The clinical prediction rule was derived over a 1-year period and then validated over the following 8 months in a new set of fever and neutropenia episodes. Patients were excluded if they presented with comorbidity or an abnormal chest x-ray (CXR).

RESULTS

Significant bacterial infection (SBI; defined as any blood or urine culture positive for bacteria, interstitial or lobar consolidation on CXR, or unexpected death from infection) was documented in 43 of the 227 episodes. Multivariate analysis found four significant factors: bone marrow disease, general appearance unwell on initial examination, monocyte count less than 0.1 x 10(9)/L, and peak oral or oral equivalent temperature greater than 39 degrees C. Only the monocyte count contributed to determining a low-risk group, excluding SBI with 84% sensitivity (95% confidence interval [CI], 61% to 100%), 42% specificity (95% CI, 38% to 46%), and a negative predictive value of 92% (95% CI, 76% to 100%). If the monocyte count was >/= 0.1 x 10(9)/L at the time of presentation (low risk), the incidences of SBI and bacteremia were 8% and 5%, respectively, versus 25% and 17% in the high-risk group. When validated in a new population of 136 episodes of fever and neutropenia, the incidences of SBI and bacteremia in the low-risk group were 12% and 5%, respectively, and 25% and 19% in the high-risk group.

CONCLUSION

Pediatric oncology outpatients with fever and neutropenia who present with an initial monocyte count of >/= 0.1 x 10(9)/L and do not have comorbidity or an abnormal CXR at the time of presentation are at lower risk for SBI and can be considered for less aggressive initial therapy.