Autologous bone marrow transplantation versus intensive consolidation chemotherapy for acute myeloid leukemia in childhood. Pediatric Oncology Group

Auto-hematopoietic stem cell transplantation or chemotherapy? Meta-analysis of clinical choice for AML

For patients with acute myeloid leukemia (AML) who are not candidates for allogeneic stem cell transplantation (SCT) or do not have a human leukocyte antigen (HLA)-matched donor, it is unclear whether autologous SCT (ASCT) has a better prognosis after the first complete response (CR1) compared to further chemotherapy treatment. A meta-analysis evaluating ASCT compared to further chemotherapy for AML patients in CR1 was performed. The Medline, Embase, Cochrane Controlled Trials Registry, Cochrane Library, Web of Science, and National Knowledge Infrastructure of China databases were searched for relevant literature as of May 26, 2023. Eligible studies included prospectively enrolled adults with AML and randomized first-time respondent patients who did not have a matched sibling donor. Fourteen randomized controlled trials were identified and included 4281 participants, of which 1499 patients received ASCT and 2782 underwent chemotherapy and continued follow-up. In patients with AML in CR1, a lower relapse rate was associated with ASCT compared to chemotherapy [odds ratio (OR) = 0.49, 95% confidence interval (CI) = 0.41-0.57]. Significant disease-free survival (DFS; OR = 1.37, 95% CI = 1.02-1.84) and relapse-free survival (RFS; OR = 2.78, 95% CI = 1.28-6.02) ASCT benefits were documented, and there was no difference in the overall survival (OS) when the studies were pooled (OR = 1.12, 95% CI = 0.85-1.48). The study results indicated that after the first remission, AML patients receiving autologous stem cell transplantation had higher DFS and RFS, similar OS, and lower relapse compared to patients undergoing chemotherapy treatment. This indicated that autologous stem cell transplantation may have a better prognosis.

Differentiating leukemia subtypes based on metabolic signatures using hyperpolarized 13C NMR

Leukemia is a group of blood cancers that are classified in four major classes. Within these four classes, many different subtypes exists with similar origin, genetic mutations, and level of maturity, which can make them difficult to distinguish. Despite their similarities, they might respond differently to treatment, and therefore distinguishing between them is of crucial importance. A deranged metabolic phenotype (Warburg effect) is often seen in cancer cells, leukemia cells included, and is increasingly a target for improved diagnosis and treatment. In this study, hyperpolarized 13C NMR spectroscopy was used to characterize the metabolic signatures of the six leukemia cell lines ML-1, CCRF-CEM, THP-1, MOLT-4, HL-60, and K562. This was done using [1-13C]pyruvate and [1-13C]alanine as bioprobes for downstream metabolite quantification and kinetic analysis on cultured cells with and without 2-deoxy-D-glucose treatment. The metabolic signatures of similar leukemia subtypes could be readily distinguished. This includes ML-1 and THP-1, which are of the similar M4 and M5 AML subtypes, CCRF-CEM and MOLT-4, which are of the similar T-ALL lineage at different maturation states, and HL-60 and K562, which are of the closely related M1 and M2 AML subtypes. The data presented here demonstrate the potential of hyperpolarized 13C NMR spectroscopy as a method to differentiate between leukemia subtypes of similar origin. Combining this method with bioreactor setups could potentially allow for better leukemia disease management as metabolic signatures could be acquired from a single biopsy through repeated experimentation and intervention.

Advances in the Management of Neuroblastoma

Neuroblastoma is a malignant tumor of neuroblasts, immature nerve cells found in several areas of the body. It usually affects children under age of 5. As usual, the tumor has ability to grow rapidly and to expand vastly which ultimately leads to death. Mostly, management decisions can be drawn by the prediction of the stage of the disease as well as age at the time of its diagnosis. There are four main stages of neuroblastoma, and treatment is according to the low and high risk of the disease. Several cytotoxic agents along with other therapies (antibody therapy, gene therapy, and even immunological therapies, antiangiogenic therapy, etc.) are used. Immunotherapy also has an important treatment option used nowadays for neuroblastoma. The discovery of major neuroblastoma-predisposition gene anaplastic lymphoma kinase cause somatic transformation or gene strengthening in diagnosed neuroblastoma. Promising new antiangiogenic strategies have also been introduced for the treatment of neuroblastoma with multiple mylomas. To manage numerous myelomas and cancers, including neuroblastoma, bone marrow transplantation and peripheral blood stem cell transplantation may be used.

Pediatric Autologous Hematopoietic Stem Cell Transplantation: Safety, Efficacy, and Patient Outcomes. Literature Review

Autologous stem cell transplantation (auto-HSCT) is a part of the therapeutic strategy for various oncohematological diseases. The auto-HSCT procedure enables hematological recovery after high-dose chemotherapy, otherwise not tolerable, by the infusion of autologous hematopoietic stem cells. Unlike allogeneic transplant (allo-HSCT), auto-HSCT has the advantage of lacking acute-graft-versus-host disease (GVHD) and prolonged immunosuppression, however, these advantages are counterbalanced by the absence of graft-versus-leukemia. Moreover, in hematological malignancies, the autologous hematopoietic stem cell source may be contaminated by neoplastic cells, leading to disease reappearance. In recent years, allogeneic transplant-related mortality (TRM) has progressively decreased, almost approaching auto-TRM, and many alternative donor sources are available for the majority of patients eligible for transplant procedures. In adults, the role of auto-HSCT compared to conventional chemotherapy (CT) in hematological malignancies has been well defined in many extended randomized trials; however, such trials are lacking in pediatric cohorts. Therefore, the role of auto-HSCT in pediatric oncohematology is limited, in both first- and second-line therapies and still remains to be defined. Nowadays, the accurate stratification in risk groups, according to the biological characteristics of the tumors and therapy response, and the introduction of new biological therapies, have to be taken into account in order to assign auto-HSCT a precise role in the therapeutic strategies, also considering that in the developmental age, auto-HSCT has a clear advantage over allo-HSCT, in terms of late sequelae, such as organ damage and second neoplasms. The purpose of this review is to report the results obtained with auto-HSCT in the different pediatric oncohematological diseases, focusing on the most significant literature data in the context of the various diseases and discussing this data in the light of the current therapeutic landscape.

The Paradox of Myeloid Leukemia Associated with Down Syndrome

Children with Down syndrome constitute a distinct genetic population who has a greater risk of developing acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) compared to their non-Down syndrome counterparts. The risk for developing solid tumors is also distinct from the non-Down syndrome population. In the case of myeloid leukemias, the process of leukemogenesis in Trisomy 21 begins in early fetal life where genetic drivers including GATA1 mutations lead to the development of the preleukemic condition, transient abnormal myelopoiesis (TAM). Various other mutations in genes encoding cohesin, epigenetic regulators and RAS pathway can result in subsequent progression to Myeloid Leukemia associated with Down Syndrome (ML-DS). The striking paradoxical feature in the Down syndrome population is that even though there is a higher predisposition to developing AML, they are also very sensitive to chemotherapy agents, particularly cytarabine, thus accounting for the very high cure rates for ML-DS compared to AML in children without Down syndrome. Current clinical trials for ML-DS attempt to balance effective curative therapies while trying to reduce treatment-associated toxicities including infections by de-intensifying chemotherapy doses, if possible. The small proportion of patients with relapsed ML-DS have an extremely poor prognosis and require the development of new therapies.

Treatments for children and adolescents with AML

In recent decades, survival rates for childhood acute myeloid leukemia have remarkably improved, owing to chemotherapy intensification, allogeneic hematopoietic stem cell transplantation, and improved supportive care. Furthermore, treatment protocols have evolved and are currently better matched to prognostic factors and treatment responses. Recently, new molecular prognostic factors were discovered via leukemia genomic studies. Moreover, new tumor subtypes with independent gene expression profiles have been characterized. To broaden the therapeutic options for patients with poor prognoses, therapies that target specific candidate mutations are being identified. Additionally, new drugs are undergoing clinical trials, and immunotherapy is attracting significant interest as a treatment option for recurrent or refractory childhood acute myeloid leukemia.

Treatment of Childhood Acute Myeloid Leukemia in Uruguay: Results of 2 Consecutive Protocols Over 20 Years

We evaluated the outcome of 71 children with de novo acute myeloid leukemia enrolled in 2 consecutive protocols in the main pediatric hospital in Uruguay. In the LAM97 protocol (n=34), patients received, as consolidation, autologous or allogeneic hematopoietic stem cell transplantation (HSCT), depending on the availability or not of a matched sibling donor. In the LAM08 protocol (n=37), patients were stratified into risk groups, autologous HSCT was abandoned, and allogeneic HSCT was limited to intermediate-risk patients with matched sibling donor and to all patients who fulfilled the high-risk criteria. Complete remission was achieved in 91% and 92% of patients in LAM97 and LAM08, respectively. Deaths in complete remission were 9.6% and 17.6%, respectively. The incidence of relapse was significantly higher in LAM97, 35.4%, versus 12.5% in LAM08. The 5-year event-free survival and overall survival were 50.0% and 55.9% in LAM97 and 59.9% and 64.8% in LAM08. The 5-year overall survival rates in each of the risk groups were 85.7% and 100% for low risk, 50.0% and 61.2% for intermediate risk, and 42.9% and 50.0% for high risk in LAM97 and LAM08 protocols, respectively. Survival has improved over the last 2 decades, and results are comparable to those published in Europe and North America.

Treatment of pediatric high-grade central nervous system tumors with high-dose methotrexate in combination with multiagent chemotherapy: A single-institution experience

BACKGROUND

Effective treatment for pediatric embryonal brain tumors includes dose-intensive multiagent chemotherapy (DIMAC) followed by high-dose chemotherapy with stem cell rescue (HDCSCR). Use of repeated cycles of DIMAC including high-dose methotrexate (HDMTX) without HDCSCR has not been described.

PROCEDURE

We retrospectively reviewed the responses/toxicities in 13 patients (aged 2-155 months, median 22 months) with central nervous system (CNS) tumors (atypical teratoid rhabdoid tumors, CNS embryonal tumors not otherwise specified, pineoblastoma, embryonal tumor with multilayered rosettes, and CNS sarcoma) treated over a 12-year period with repeated cycles of HDMTX followed by etoposide, cisplatin, cyclophosphamide, and vincristine.

RESULTS

Six patients (46.2%) had disseminated disease at presentation and five (38.5%) had gross total resection. A total of 64 courses of therapy were administered with a median of five courses per patient.  Eight patients (61.5%) received radiation therapy (one at relapse). By completion of therapy, 11 patients (84.6%) achieved a response (six complete, five partial).  Six of the 13 patients (46.2%) remain alive with a median follow-up of 48 months (6-146).  Acute toxicities included fever/neutropenia (70.3%), bacteremia (15.6%), and grade 3 mucositis (18.8%).  Long-term complications included learning disability, seizure disorder, and brain necrosis, without treatment-related deaths.

CONCLUSIONS

DIMAC with HDMTX without HDCSCR may be an effective treatment option for selected patients with embryonal or high-grade CNS tumors.

Comparison of conditioning regimens for autologous stem cell transplantation in children with acute myeloid leukemia: A nationwide retrospective study in Japan

BACKGROUND

Indications for hematopoietic stem cell transplantation (HSCT) have decreased with the improvement in chemotherapy for pediatric acute myeloid leukemia (AML) in the last decade. We conducted reevaluation of autologous HSCT (AHSCT) to compare myeloablative conditioning (MAC) regimens for pediatric AML without the need for consideration of toxicities caused by allogeneic immune reactions.

PROCEDURE

This retrospective study analyzed the clinical outcomes of 220 children with AML who underwent consecutive AHSCT between 1989 and 2002 in Japan by the national prospective registry. The transplantation outcomes of various conditioning regimens were compared.

RESULTS

The median follow-up period of the survivors was 160 months. The clinical outcomes of busulfan + cyclophosphamide ± etoposide or busulfan + melphalan regimens were significantly superior compared with other busulfan-based and total body irradiation-based regimens (leukemia-free survival [LFS]: 68% vs 42% and 55%, P = 0.001; overall survival [OS]: 74% vs 49% and 61%, P < 0.001). Multivariate analysis showed that busulfan + cyclophosphamide ± etoposide and busulfan + melphalan regimens were independent favorable factors for LFS (hazard ratio: 0.46; P < 0.001) and OS (hazard ratio: 0.40; P < 0.001) compared with the other busulfan-based regimen, and both age 2 years or older and advanced stage at AHSCT were independent poor predictors for LFS and OS, simultaneously.

CONCLUSION

Busulfan + cyclophosphamide ± etoposide and busulfan + melphalan regimens exhibited superior antileukemic effects compared with other BU-based myeloablative regimens.

Down syndrome associated childhood myeloid leukemia with yet unreported acquired chromosomal abnormalities and a new potential adverse marker: dup(1)(q25q44)

Background

Children with constitutional trisomy 21, i.e. Down syndrome (DS, OMIM #190685) have a 10 to 20-fold increased risk for a hematopoietic malignancy. They may suffer from acute lymphoblastic leukemia or acute myeloid leukemia (AML). AML referred to as myeloid leukemia of Down syndrome (ML-DS) is observed especially after birth at an early gestational age and characterized by enhanced white blood cell count, failure of spontaneous remission, liver fibrosis or liver dysfunction, and is significantly associated with early death. There are only few studies yet focusing on the clonal cytogenetic changes during evolution of ML-DS.

Case presentation

In a 1.4-year-old boy with DS an immunophenotype consistent with AML-M1 according to French-American-British (FAB) classification was diagnoses. Cytogenetic and molecular cytogenetic analyses revealed, besides constitutional free trisomy 21, an unbalanced translocation as der(16)t(1;16)(q25.3;q24), plus a balanced translocation t(3;20)(q25;q13.1). A poor clinical outcome was observed here.

Conclusions

To the best of our knowledge, an ML-DS case associated with identical acquired chromosomal abnormalities was not previously reported. Our findings suggest that especially partial trisomy 1q25 to 1q44 may be indicative for a poor prognosis in ML-DS.

Ethnic disparities relative to disease features and outcomes in children with acute myeloid leukemia

Hispanics with acute leukemias have poorer outcomes than non-Hispanic whites (NHWs), despite an increased likelihood of favorable prognostic features. We reviewed medical records from 167 children ages 0-18 years diagnosed with de novo AML over an 18-year period at Texas Children's Cancer Center, among whom 129 self-identified as Hispanic or NHW. Although Hispanics were significantly more likely to have the favorable prognostic cytogenetic feature t(8;21) (P = 0.04), the expected survival benefit was not observed. This lack of survival benefit was primarily due to significantly poorer event-free and overall survival among Hispanics treated with upfront stem cell transplantation after achieving first clinical remission (P = 0.008).

Treatment results in children with myeloid leukemia of Down syndrome in Saudi Arabia: A multicenter SAPHOS leukemia group study

Despite the high incidence of Down syndrome (DS) in Arab countires, the incidence and outcomes of myeloid leukemia of DS (ML-DS) have not been studied. We evaluated 206 pediatric acute myeloid leukemia (AML) patients diagnosed between 2005 and 2012 and identified 31 (15%) ML-DS. The incidence of ML-DS was 48 per 100,000 compared to 0.6 per 100,000 for AML in non-DS children. Thus, patients with DS had 80-fold increased risk of ML-DS compared to AML in non-DS children. The median age at diagnosis was 1.8 years, male/female ratio was 1.2, majority (84%) of patients had FAB-M7 subtype, and the cytogenetic abnormalities were normal karyotype (constitutional trisomy 21) in 48%, additional trisomy in 23%, and other aberrations in 29%. Complete remission, cumulative incidences of relapse (CIR), toxic-death, and 5-year event-free survival (EFS) rates were 96.8%, 19.4%, 13.1%, and 67.7±8.4%; respectively. In the present study, multivariate analysis revealed favorable outcome (5-year EFS 86.7±8.8%) for patients with normal karyotype. The incidence and clinical characteristics of ML-DS in Saudi patients were comparable to other reports. However, there is a need to optimize risk stratification and treatment intensity to reduce CIR and toxic death rates to further improve outcomes of patients with ML-DS.

Treatment of Common Childhood Malignancies

Malignancy is the fourth leading cause of death in persons aged 1 to 19 years. The success of the pediatric oncology cooperative group clinical trials has allowed a systematic approach to the treatment of relatively rare malignancies. Each trial builds on previous results in terms of both survival and toxicity. This article will discuss the current treatment regimens for several of the more common pediatric malignancies and their long-term complications developed through this process.

Different aspects of stem cell procedures in children with poor responding AML: when is HSCT the best answer?

Acute myeloid leukemia in children is a heterogeneous disease with different morphological and cytogenetic features. New diagnostic tools and treatments, improved supportive care and the use of genomic tissue typing in selecting donors for hematopoietic stem cell transplantation (HSCT) adds to increased survival rates. Candidates to HSCT in first complete remission are patients with cytogenetic or molecular unfavorable prognostic markers, or blasts >15% after first induction. The use of minimal residual disease can also identify children benefiting from HSCT in first complete remission and the patients post HSCT with signs of relapse. The outcome and cure rate of acute myeloid leukemia, still remains poor and new diagnostic tools and treatments strategies need to be evaluated. In this management perspective, future management of novel minimal residual disease tools are discussed, conditioning therapies, as well as different transplantation procedures including haplo-transplantation and haplo-identical natural killer cell transplantation, but also altered graft-versus-host-disease treatments.

Survival of Mexican children with acute myeloid leukaemia who received early intensification chemotherapy and an autologous transplant

Background. In Mexico and other developing countries, few reports of the survival of children with acute leukaemia exist. Objective. We aimed at comparing the disease-free survival of children with acute myeloid leukaemia who, in addition to being treated with the Latin American protocol of chemotherapy and an autologous transplant, either underwent early intensified chemotherapy or did not undergo such treatment. Procedure. This was a cohort study with a historical control group, forty patients, less than 16 years old. Group A (20 patients), diagnosed in the period 2005–2007, was treated with the Latin American protocol of chemotherapy with an autologous transplant plus early intensified chemotherapy: high doses of cytarabine and mitoxantrone. Group B (20 patients), diagnosed in the period 1999–2004, was treated as Group A, but without the early intensified chemotherapy. Results. Relapse-free survival for Group A was 90% whereas that for Group B it was 60% (P = 0.041). Overall survival for Group A (18, 90%) was higher than that for Group B (60%). Complete remission continued for two years of follow-up. Conclusions. Relapse-free survival for paediatric patients treated with the Latin American protocol of chemotherapy with an autologous transplant plus early intensified chemotherapy was higher than that for those who did not receive early intensified chemotherapy.

Hematopoietic cell transplantation and cellular therapeutics in the treatment of childhood malignancies

Hematopoietic cell transplantation (HCT) represents the most common and effective form of immunotherapy for childhood malignancies. The role of the graft-versus-leukemia effect in allogeneic HCT has been well established in childhood malignancies, but is also associated with short-term and long-term morbidity. HCT may be ineffective in some settings at obtaining control of the malignancy, and as such, cannot be used as a universal cancer immunotherapy. Novel therapies using dendritic cell vaccinations, tumor-infiltrating lymphocytes, and chimeric antigen receptor T cells are being evaluated as potential adjuvants to HCT.

Pediatric acute myeloid leukemia: biology and therapeutic implications of genomic variants

Acute myeloid leukemia (AML) is a molecularly heterogeneous disease and age-associated molecular alterations result in younger children harboring a distinct signature from older children and adolescents. Pediatric AML has a genetic and epigenetic profile with significant differences compared to adult AML. Somatic and epigenetic alterations contribute to myeloid leukemogenesis and can evolve from diagnosis to relapse. Cytogenetic alterations, somatic mutations and response to induction therapy are important in informing risk stratification and appropriate therapy allocation. Next-generation sequencing technologies are providing novel insights into the biology of AML and have the ability to identify potential targets for therapeutic intervention.

Down syndrome preleukemia and leukemia

Children with Down syndrome (DS) and acute leukemias acute have unique biological, cytogenetic, and intrinsic factors that affect their treatment and outcome. Myeloid leukemia of Down syndrome (ML-DS) is associated with high event-free survival (EFS) rates and frequently preceded by a preleukemia condition, the transient abnormal hematopoiesis (TAM) present at birth. For acute lymphoblastic leukemia (ALL), their EFS and overall survival are poorer than non-DS ALL, it is important to enroll them on therapeutic trials, including relapse trials; investigate new agents that could potentially improve their leukemia-free survival; and strive to maximize the supportive care these patients need.

Therapy-induced secondary acute myeloid leukemia with t(11;19)(q23;p13.1) in a pediatric patient with relapsed acute promyelocytic leukemia

Acute myeloid leukemia is classified based upon recurrent cytogenetic abnormalities. The t(15;17)(q24.1;q21.1) abnormality is found in 5% to 8% of de novo acute myeloid leukemia and is diagnostic of acute promyelocytic leukemia (APL). The translocation results in fusion of the retinoic acid receptor-α (RARA) gene at 17q21.1 and the promyelocytic leukemia (PML) gene at 15q24.1. Standard APL therapy is a combination of all-trans retinoic acid and anthracycline-based chemotherapy. Anthracycline treatment is associated with secondary clonal chromosomal aberrations that can lead to therapy-related secondary myeloid neoplasms. We present a pediatric case of relapsed APL coexistent with treatment-associated secondary myeloid neoplasm with t(11;19)(q23;p13.1).

Optimal dose and schedule of consolidation in AML: is there a standard?

Approximately 35%-40% of younger adults with acute myeloid leukemia (AML) can be cured using higher doses of cytosine arabinoside (ara-C) as post remission consolidation. Earlier studies focused on higher doses of 3 gms/m(2), but since then numerous studies evaluating differences in dose, schedule, number of courses, and the addition of other agents, suggest that an intermediate-dose of ara-C may offer the greatest benefit to most patients with less toxicity than with higher dose regimens. In retrospect, this was predictable by the cellular pharmacology of ara-C. Perhaps most importantly, the overall outcome has not changed in the past 2-3 decades, indicating that the limits of available chemotherapy have been defined for AML. This review examines studies that have established the various dosing options and considers whether there is a true standard for post remission therapy for patients with AML.

A critical review of which children with acute myeloid leukaemia need stem cell procedures

The last decades have seen parallel improvements in chemotherapy-based and haematopoietic stem cell transplantation (HSCT) regimens for acute myeloid leukaemia (AML) in children. There has been no consensus on indication for HSCT. Reserving HSCT for high-risk and relapsed patients spare many patients from the long-term toxicity of this treatment. The results of matched unrelated donor HSCT equal family donor transplantation and the presence of a matched sibling should no longer be a transplant indication. Minimal residual disease measured by flow cytometry may identify poor responders benefitting from HSCT in first complete remission (CR1) and those with a favourable response to induction therapy who do not need HSCT even with adverse cytogenetic aberrations. FLT3-internal tandem duplication without NPM1 mutation has a very high relapse rate despite favourable response and HSCT is indicated in CR1 in these cases. Finding the optimal indications for HSCT is a delicate balance between risk of relapse and late effects.

Outcome of pediatric patients with acute myeloid leukemia (AML) and -5/5q- abnormalities from five pediatric AML treatment protocols: a report from the Children's Oncology Group

BACKGROUND

Abnormalities of chromosome 5q (-5/5q-) are associated with poor prognosis in adults with acute myeloid leukemia (AML). However, there are no large studies on outcomes of children with -5/5q- AML. To determine the disease correlates of this group, we retrospectively analyzed cytogenetic data from five studies of childhood AML.

PROCEDURE

Data from patients whose cytogenetic clones included -5/5q-, with the exception of those with acute promyelocytic leukemia or Down syndrome, were included.

RESULTS

Of the 2,240 patients with cytogenetic data available, 26 (1.2%) had -5 or 5q-. A significant number of these patients were age 11-21 (61.5%, P = 0.031) and had M0 morphology compared with patients without -5/5q- (24.0% vs. 2.8%, P < 0.001). Twenty-two of the 26 patients had a complete remission (CR) response to induction chemotherapy. The 5-year overall survival (OS) from the time of diagnosis for the -5/5q- patients was significantly lower than for patients without -5/5q- (27 ± 17% vs. 50 ± 2%, P = 0.027). Similarly, from induction CR, patients with -5/5q- had significantly worse disease free survival, OS and relapse risk than those without this abnormality (27 ± 19% vs. 46 ± 2%, P = 0.035, 32 ± 20% vs. 57 ± 2%, P = 0.025, 68 ± 21% vs. 45 ± 2%, P = 0.01, respectively).

CONCLUSIONS

Pediatric patients with AML and -5/5q- had a very poor outcome. These findings support the need for new or novel therapies for these patients.

Results of the AIEOP AML 2002/01 multicenter prospective trial for the treatment of children with acute myeloid leukemia

Risk-adapted therapy and broad use of HSCT resulted in a significant improvement in outcome. AUTO- or ALLO-HSCT in high-risk patients resulted in a cumulative incidence of leukemia relapse superimposable to that of SR.

Role of autologous hematopoietic stem cell transplantation according to the NPM1/FLT3-ITD molecular status for cytogenetically normal AML patients: a GOELAMS study

The choice of postremission therapy for acute myeloid leukemia (AML) patients is now based on the blasts' cytogenetic and molecular profile. However, the potential benefit of autologous hematopoietic stem cell transplantation (auto-HSCT) according to the NPM1/FLT3-ITD status has been poorly studied in AML patients with a normal karyotype (NK). Therefore, we evaluated the NPM1/FLT3-ITD molecular status in 135 NK-AML patients treated by allogeneic HSCT (allo-HSCT), auto-HSCT, or chemotherapy as consolidation therapy within the GOELAMS LAM-2001 trial. In univariate analyzes, 4-year leukemia-free survival (LFS) and overall survival (OS) were significantly higher for NPM1+/FLT3-ITD- patients compared with patients presenting another molecular profile (61 vs. 43% and 72 vs. 48%, P = 0.02 and P = 0.01, respectively). In the NPM1+/FLT3-ITD- subgroup, there was no benefit for allo-HSCT or auto-HSCT vs. chemotherapy (4-year LFS: 71, 56, and 60%; 4-year OS: 73, 71, and 60%, respectively; P = NS). For patients with other NPM1/FLT3-ITD molecular profiles, allo-HSCT was found to be the best consolidation therapy, whereas auto-HSCT was associated with a better outcome when compared with chemotherapy (allo-HSCT-, auto-HSCT-, and chemotherapy-related 4-year LFS: 68, 44, and 36%, P = 0.004; 4-year OS: 68, 52, and 29%, respectively, P = 0.02). Our study indicates that allo-HSCT and auto-HSCT provide similar outcomes compared with chemotherapy as consolidation for NPM1+/FLT3-ITD- NK-AML patients. For NK-AML patients with an adverse molecular profile, auto-HSCT could represent an alternative therapeutic approach when no human leukocyte antigen-matched allogeneic donor is available.

Diagnosis and management of acute myeloid leukemia in children and adolescents: recommendations from an international expert panel

Despite major improvements in outcome over the past decades, acute myeloid leukemia (AML) remains a life-threatening malignancy in children, with current survival rates of ∼70%. State-of-the-art recommendations in adult AML have recently been published in this journal by Döhner et al. The primary goal of an international expert panel of the International BFM Study Group AML Committee was to set standards for the management, diagnosis, response assessment, and treatment in childhood AML. This paper aims to discuss differences between childhood and adult AML, and to highlight recommendations that are specific to children. The particular relevance of new diagnostic and prognostic molecular markers in pediatric AML is presented. The general management of pediatric AML, the management of specific pediatric AML cohorts (such as infants) or subtypes of the disease occurring in children (such as Down syndrome related AML), as well as new therapeutic approaches, and the role of supportive care are discussed.

Pediatric acute myeloid leukemia

Pediatric acute myeloid leukemia (AML) is currently associated with survival rates as high as 70%. However, many events still occur, side effects are significant, and late effects occur and can even be life-threatening. Thus, the treatment of pediatric AML still needs further improvement. While most study groups agree on several principles of AML treatment, many unanswered questions and even controversies remain, which will be the topic of this review. Relapsed AML, the most frequent event in children, will also be discussed. The controversies justify future clinical studies. Fortunately, biotechnical developments provide novel treatment targets and targeted drugs, and will enable minimal residual disease-driven tailored therapy. Moreover, a wide range of new drugs is being developed. International collaboration is required to perform randomized, or even single-arm clinical studies, in this setting of subgroup-directed therapy, and fortunately is being accomplished. Therefore, optimism is justified and the treatment of pediatric AML will continue to improve.

Is there a role for autologous stem cell transplantation for patients with acute myelogenous leukemia? A retrospective analysis

For patients with acute myelogenous leukemia (AML) who are unable to secure an acceptable HLA donor, the role of autologous stem cell transplantation (auto-SCT) has remained controversial. Its effectiveness remains unclear as, when analyzed on intention-to-treat strategies, a significant number do not undergo the procedure, whereas others seem to fail therapy from pretransplant recurrences. To improve our counseling to our patients on these 2 therapeutic options, we compared the outcome of patients in first remission of AML who actually underwent autologous or allogeneic transplantation. The choice for the type of graft was based on availability of HLA identical siblings. Patients received myeloablative conditioning followed by allogeneic or autologous cytokine mobilized peripheral blood stem cell transplantation. For prophylaxis of graft-versus-host disease (GVHD), grafts were incubated ex vivo with anti-CD52 antibodies and patients were prescribed cyclosporin until day 90. Patients were stratified by clinical and laboratory factors as well as cytogenetic risk. The endpoints were treatment-related mortality (TRM), disease-free survival (DFS), and overall survival (OS). The median presentation age for both transplant groups was 35 (14-60) years. Of the 112 consecutive patients achieving remission, autologous or allogeneic grafts were transplanted to 43 and 32 patients, respectively. There was no significant difference in the presentation clinical features, laboratory parameters, marrow morphology, or proportion of low and intermediate cytogenetic risk for both transplant options. Treatment mortality as well as relapse rate was similar (14% and 15%; 39% and 27%, respectively). At a median of 1609 and 1819 posttransplant days, 56% and 63% in each group survived. In univariate analysis performance status, cytogenetic risk, morphologic features of dysplasia, blast count, and lactate dehydrogenase (LDH) were significant factors for survival. Although for the entire group there was no difference in survival between both modalities, all patients with unfavorable cytogenetics receiving an autologous graft died of disease recurrence (3-year survival 35% versus 0%; P = .05). We conclude that patients with AML who have low or intermediate cytogenetic risk undergoing myeloablative conditioning followed by autologous or allogeneic T cell-depleted stem cell transplantation appeared to have similar outcome. However, those with unfavorable karyotype are unlikely to be cured with autologous grafts and are candidates for experimental modalities.

A review on allogeneic stem cell transplantation for newly diagnosed pediatric acute myeloid leukemia

Survival of pediatric acute myeloid leukemia (AML) has improved considerably over the past decades. Since 1985, allogeneic stem cell transplantation (allo-SCT) is widely recommended for patients who have a matched sibling donor. However, it remains controversial whether allo-SCT is superior to chemotherapy for children with newly diagnosed AML. This review summarizes phase 3 clinical trials that compared allo-SCT with chemotherapy (including autologous SCT) in pediatric AML, excluding studies that did not use the intention-to-treat analysis or correct for time-to-transplantation. Although allo-SCT might prevent more relapses than chemotherapy, the number needed for transplantation (with allo-SCT) to prevent one relapse is in the order of 10 patients. Moreover, overall survival is similar with both methods in most recent studies, apparently because of increased salvagability of a relapse when initial therapy concerned chemotherapy only, and because of a higher treatment-related mortality with allo-SCT. Because allo-SCT also gives more severe side effects and results more often in secondary malignancies than chemotherapy, we do not recommend allo-SCT in first remission for pediatric AML in general. Further research should focus on the possibility that subgroups might benefit from allo-SCT, aiming at further improvements in the prognosis of pediatric AML.

High transcript level of FLT3 associated with high risk of relapse in pediatric acute myeloid leukemia

Identification of prognostic factors and risk-based post-remission therapy was proposed to improve the outcomes of acute myeloid leukemia (AML) and a mutation of FLT3 has been reported to be a risk factor, especially for pediatric patients. Recently, FLT3 expression level was implicated to have prognostic significance in adults, but little is known for childhood AML. To define the prognostic significance, transcript level of FLT3 was analyzed in 52 pediatric AML patients. The median copy number of FLT3 was 4.6x10(3) (40-5.9x10(7) copies)/1.0x10(6) GAPDH copy, and the relapse free survival of patients with high transcript level of FLT3 (>10(6) copy number) (0%) was significantly lower than that of the others (53.2%). High transcript level of FLT3 was associated with a markedly high risk of relapse. The development of new therapeutic scheme such as a frontline allogeneic stem cell transplantation or administration of FLT3 inhibitor is needed to improve outcomes.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Hematopoietic stem cell transplantation for leukemia

Leukemia represents the most common pediatric malignancy, accounting for approximately 30% of all cancers in children less than 20 years of age. Most children diagnosed with leukemia are cured without hematopoietic stem cell transplantation (HSCT), but for some high-risk subgroups, allogeneic HSCT plays an important role in their therapeutic approach. The characteristics of these high-risk subgroups and the role of HSCT in childhood leukemias are discussed.

Idarubicin plus behenoyl cytarabine and 6-thioguanine compares favorably with idarubicin plus cytarabine-based regimen for children with previously untreated acute myeloid leukemia: 10-year retrospective, multicenter study in Korea

We investigated the outcome of idarubicin plus N(4)-behenoyl-1-beta-D-arabinofuranosyl cytosine (BHAC)-based chemotherapy (BHAC group, n=149) compared to idarubicin plus cytarabine-based chemotherapy (cytarabine group, n=191) for childhood acute myeloid leukemia (AML). Between January 1996 and December 2005, 340 children with AML from 5 university hospitals in Korea received the BHAC-based or cytarabine-based chemotherapy, with or without hematopoietic stem cell transplantation. After induction therapy, 264 (77.6%) of 340 children achieved a complete remission (CR) and 43 (12%) achieved a partial remission (PR). The CR rate in the BHAC group was higher than in the cytarabine group (85.2% vs. 71.7%, P=0.004). However, the overall response rate (CR+PR) was not different between the two groups (93.3% vs. 87.9%, P=0.139). The 5-yr estimates of overall survival (OS) of children in the two groups were similar (54.9% for the BHAC group vs. 52.4% for the cytarabine group, P=0.281). Although the results were analyzed according to the treatment type and cytogenetic risk, the OS showed no significant difference between the BHAC group and the cytarabine group. In the present study, the clinical outcomes of the BHAC-based chemotherapy, consisting of BHAC, idarubicin, and 6-TG, are comparable to that of the cytarabine-based chemotherapy for childhood AML.

Treatment of children with acute promyelocytic leukemia: results of the first North American Intergroup trial INT0129

BACKGROUND

This report focuses on the children enrolled on the first North American Intergroup study of APL (INT0129). This study was designed to compare the rates of CR, disease-free survival (DFS), overall survival (OS) and toxicity of therapy with all-trans-retinoic acid (ATRA) for remission induction and/or maintenance compared to conventional chemotherapy in patients with previously untreated APL.

PROCEDURE

Fifty-three patients who were documented to have the t(15;17) translocation were able to be evaluated for toxicity of treatment, outcome of induction, and survival.

RESULTS

The overall CR rate was 81%. The estimated 5-year DFS from time of CR was 41% for all patients. The estimated 5-year OS for all patients from entry into the study was 69%. The 5-year DFS from time of CR for patients who were randomized to ATRA for induction or maintenance or both was 48% compared to 0% for patients who never received ATRA (P < 0.0001).

CONCLUSIONS

The most important finding of our study is that a significant DFS advantage exists for children with APL who received ATRA during induction or maintenance or both compared to children who received no ATRA. Furthermore, remissions in these children appear durable as the OS rates are stable at 10 years.

Down syndrome and malignancies: a unique clinical relationship: a paper from the 2008 william beaumont hospital symposium on molecular pathology

The patterns of malignancies in Down syndrome (DS) are unique and highlight the relationship between chromosome 21 and cancer. DS children have a approximately 10- to 20-fold higher risk for developing acute lymphoblastic leukemia and acute myeloid leukemia (AML), as compared with non-DS children, although they do not have a uniformly increased risk of developing solid tumors. DS children with acute lymphoblastic leukemia frequently experience higher levels of treatment-related toxicity and inferior event-free survival rates, as compared with non-DS children. DS children also develop AML with unique features and have a 500-fold increased risk of developing the AML subtype, acute megakaryocytic leukemia (AMkL; M7). Nearly 10% of DS newborns are diagnosed with a variant of AMkL, the transient myeloproliferative disorder, which can resolve spontaneously without treatment; event-free survival rates for DS patients with AMkL ranges from 80% to 100%, in comparison with <30% for non-DS children with AMkL. In addition, somatic mutations of the GATA1 gene have been detected in nearly all DS TMD and AMkL cases and not in leukemia cases in non-DS children. GATA1 mutations are key factors linked to both leukemogenesis and the high cure rates of DS AMkL patients. Identifying the mechanisms that account for the high event-free survival rates of DS AMkL patients may ultimately improve AML treatment as well. Examining leukemogenesis in DS children may identify factors linked to the general development of childhood leukemia and lead to potential new therapeutic strategies to fight this disease.

RUNX1 regulates phosphoinositide 3-kinase/AKT pathway: role in chemotherapy sensitivity in acute megakaryocytic leukemia

RUNX1 (AML1) encodes the core binding factor alpha subunit of a heterodimeric transcription factor complex which plays critical roles in normal hematopoiesis. Translocations or down-regulation of RUNX1 have been linked to favorable clinical outcomes in acute leukemias, suggesting that RUNX1 may also play critical roles in chemotherapy responses in acute leukemias; however, the molecular mechanisms remain unclear. The median level of RUNX1b transcripts in Down syndrome (DS) children with acute megakaryocytic leukemia (AMkL) were 4.4-fold (P < .001) lower than that in non-DS AMkL cases. Short hairpin RNA knockdown of RUNX1 in a non-DS AMkL cell line, Meg-01, resulted in significantly increased sensitivity to cytosine arabinoside, accompanied by significantly decreased expression of PIK3CD, which encodes the delta catalytic subunit of the survival kinase, phosphoinositide 3 (PI3)-kinase. Transcriptional regulation of PIK3CD by RUNX1 was further confirmed by chromatin immunoprecipitation and promoter reporter gene assays. Further, a PI3-kinase inhibitor, LY294002, and cytosine arabinoside synergized in antileukemia effects on Meg-01 and primary pediatric AMkL cells. Our results suggest that RUNX1 may play a critical role in chemotherapy response in AMkL by regulating the PI3-kinase/Akt pathway. Thus, the treatment of AMkL may be improved by integrating PI3-kinase or Akt inhibitors into the chemotherapy of this disease.

Risk-stratified therapy and the intensive use of cytarabine improves the outcome in childhood acute myeloid leukemia: the AML99 trial from the Japanese Childhood AML Cooperative Study Group

PURPOSE

To improve the prognosis in children with newly diagnosed acute myeloid leukemia (AML) by introducing a dose-dense intensive chemotherapy regimen and an appropriate risk stratification system.

PATIENTS AND METHODS

Two hundred forty children with de novo AML were treated with continuous cytarabine-based induction therapy and stratified to three risk groups based on the initial treatment response, age, and WBC at diagnosis and cytogenetics. All of the patients were treated with intensive consolidation chemotherapy including three or four courses of high-dose cytarabine. Allogeneic hematopoietic stem-cell transplantation (HSCT) was indicated for only the intermediate-risk patients with matched related donors and for all the high-risk subsets.

RESULTS

Two hundred twenty-seven children (94.6%) achieved a complete remission (CR). Four children demonstrated induction death. The median follow-up of the live patients was 55 months (range, 37 to 73 months). The 5-year overall survival of all 240 children was 75.6% (95% CI, 70.3% to 81.4%) and event-free survival was 61.6% (95% CI, 55.8% to 68.1%). The 5-year disease-free survival in each risk group were 71.3% (95% CI, 63.4% to 80.2%) in the low-risk group (n = 112), 59.8% (95% CI, 50.6% to 70.7%) in the intermediate-risk group (n = 92), and 56.5% (95% CI, 39.5% to 80.9%) in the high-risk group (n = 23). Eight children died during the first CR, including four after HSCT.

CONCLUSION

A high survival rate, 75.6% at 5 years, was achieved for childhood with de novo AML in the AML99 trial. The treatment strategy was well tolerated with only 1.7% induction death rate and 3.5% remission death rate. Low-risk children were successfully treated with chemotherapy alone.

Postremission therapy for acute myeloid leukemia in the first remission

The medical records of 99 patients with acute myeloid leukemia (AML; except AML, M3) in the first remission from 1995 to 2004 were retrospectively reviewed. When they achieved complete remission, at first complete remission (CR1), patients received allogeneic (n = 23), autologous hematopoietic stem cell transplantation (HSCT) (n = 35), or intensive chemotherapy (n = 41) according to prognostic factors and donor availability. There was an advantage in terms of event-free survival (EFS, p = 0.0001) and overall survival (OS, p = 0.0002) with HSCT as compared to those of intensive chemotherapy. However, the EFS and OS were not different between allogeneic HSCT and autologous HSCT. In high-risk patients, the EFS and OS of allogenic or autologous HSCT group were higher compared with those in the intensive chemotherapy group (p < 0.01). However, there was no difference between allogeneic HSCT and autologous HSCT in terms of EFS and OS. In the intermediate- or low-risk group, there was no significant difference in the outcome according to the postremission modalities.

Treatment strategies for pediatric acute myeloid leukemia

Therapeutic strategies utilized in recently completed Phase III clinical trials in children with de novo acute myeloid leukemia have led to long-term disease-free survival in 50 - 60% of children. This review describes the contributions from early intensification of therapy and postremission intensification using highly myelosuppressive chemotherapy strategies and discusses the controversial roles of allogeneic bone marrow transplantation, maintenance therapy and CNS irradiation. Current strategies focusing on the identification of critical biologic features and measurements of early response to therapy allow for greatly improved risk group stratification. Future improvements in the treatment of children with acute myeloid leukemia will depend on a better understanding of the biology of the disease, targeted therapeutic approaches directed to specific biologic targets, selective use of allogeneic transplantation and innovative clinical trial designs that will allow for the testing of an increasing number of new agents in increasingly small numbers of patients in defined risk groups.

Comparable outcomes of HLA-matched unrelated and HLA-identical sibling donor bone marrow transplantation for childhood acute myeloid leukemia in first remission

We retrospectively investigated the outcomes of HLA-matched unrelated BMT (MU-BMT, n = 13) and HLA-identical sibling donor BMT (MS-BMT, n = 17) for childhood AML in CR1 between June 2002 and August 2005. Engraftment of neutrophil and platelet did not differ between the two transplant groups. The cumulative incidence of grade II-IV acute GVHD and any chronic GVHD at three yr was not different between MS-BMT and MU-BMT. Of the 30 patients, four patients experienced relapses (three with MS-BMT, one with MU-BMT) and four patients died of transplant-related complications (two with MS-BMT, two with MU-BMT). A total of 23 patients survived with a median follow-up of 43.2 months. The Kaplan-Meier estimates for EFS rates at three yr were 71% and 77% for MS-BMT and MU-BMT, respectively, and the OS rates were 76% and 77% for MS-BMT and MU-BMT, respectively. The outcome of HLA-matched unrelated BMT is comparable to that of HLA-identical sibling BMT for childhood AML in CR1. HLA-matched unrelated BMT may be recommended for patients who have AML in CR1 without an HLA-matched sibling donor.

Malignancy in children with trisomy 21

Patients with Down syndrome (DS) display a unique spectrum of malignancies, with a 10- to 20-fold higher risk of acute leukemias, and a markedly lower incidence of solid tumors. This review discusses the current understanding of the basis for this distinctive pattern of cancer incidence and the clinical and biologic features of the malignant disorders most frequent in DS individuals: transient myeloproliferative disease, acute megakaryoblastic leukemia, and acute lymphoblastic leukemia. We also review distinctive pharmacogenetic issues, highlighting the differential chemosensitivity and toxicity profiles of DS patients compared with the general population, and epidemiologic studies of protective and adverse environmental risk factors for the development of leukemia.

Clinical management of primary non-acute promyelocytic leukemia acute myeloid leukemia: Practice Guidelines by the Italian Society of Hematology, the Italian Society of Experimental Hematology, and the Italian Group for Bone Marrow Transplantation

As many options are now available to treat patients with de novo acute myeloid leukemia, the Italian Society of Hematology and two affiliated societies (SIES and GITMO) commissioned project to an Expert Panel aimed at developing clinical practice guidelines for acute myeloid leukemia treatment. After systematic comprehensive literature review, the Expert Panel formulated recommendations for the management of primary acute myeloid leukemia (with the exception of acute promyelocytic leukemia) and graded them according to the supporting evidence. When evidence was lacking, consensus-based statements have been added. First-line therapy for all newly diagnosed patients eligible for intensive treatment should include one cycle of induction with standard dose cytarabine and an anthracycline. After achieving complete remission, patients aged less than 60 years should receive consolidation therapy including high-dose cytarabine. Myeloablative allogeneic stem cell transplantation from an HLA-compatible sibling should be performed in first complete remission: 1) in children with intermediate-high risk cytogenetics or who achieved first complete remission after the second course of therapy; 2) in adults less than 40 years with an intermediate-risk; in those aged less than 55 years with either high-risk cytogenetics or who achieved first complete remission after the second course of therapy. Stem cell transplantation from an unrelated donor is recommended to be performed in first complete remission in adults 30 years old or younger, and in children with very high-risk disease lacking a sibling donor. Alternative donor stem cell transplantation is an option in high-risk patients without a matched donor who urgently need transplantation. Patients aged less than 60 years, who either are not candidate for allogeneic stem cell transplantation or lack a donor, are candidates for autologous stem cell transplantation. We describe the results of a systematic literature review and an explicit approach to consensus techniques, which resulted in recommendations for the management of primary non-APL acute myeloid leukemia.

Impact of disease risk on efficacy of matched related bone marrow transplantation for pediatric acute myeloid leukemia: the Children's Oncology Group

PURPOSE

There is considerable variation in the use of HLA-matched related bone marrow transplantation (BMT) for the treatment of pediatric patients with newly diagnosed acute myeloid leukemia (AML). Some oncologists have argued that BMT should be offered to most patients in first complete remission (CR). Others have maintained that transplantation in first remission should be reserved for patients with high-risk disease. We performed this study to determine how disease risk influences the efficacy of BMT.

METHODS

We combined data from four cooperative group clinical trials: Pediatric Oncology Group 8821, Children's Cancer Group (CCG) 2891, CCG 2961, and Medical Research Council 10. Using cytogenetics and the percentage of marrow blasts after the first course of chemotherapy, patients were stratified into favorable, intermediate, and poor-risk disease groups. Patients who could not be risk classified were analyzed separately. Outcomes for patients assigned to BMT and for patients assigned to chemotherapy alone were compared.

RESULTS

The data set included 1,373 pediatric patients with AML in first CR. In the intermediate-risk group, the estimated disease-free survival at 8 years for patients who did not undergo transplantation was 39% +/- 5% (2 SE), whereas it was 58% +/- 7% for BMT patients. The estimated overall survival for patients who did not undergo transplantation was 51% +/- 5%, whereas it was 62% +/- 7% for BMT patients. Both differences were significant (P < .01). There were no significant differences for survival in the other two risk groups or in the non-risk-stratified patients.

CONCLUSION

Our study indicates that HLA-matched related BMT is an effective treatment for pediatric patients with intermediate-risk AML in first CR.

Host factors and consequence of chemotherapy in pediatric cancer patients

The 5-year survival rates for childhood ALL are approaching 80%, but therapy-related toxicities are common. One of the challenges in this population is determining the most efficacious therapeutic regimens for these individuals. Factors such as drug metabolism, genetics, and concomitant disease affect drug efficacy and may be important in determining therapeutic outcomes in these patients. This review will focus on these factors in the treatment of childhood ALL.

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.