Blood counts at time of complete remission provide additional independent prognostic information in acute myeloid leukemia

Association of Platelet Count Detected by Novel Nano Probe with Prognosis After Initial Chemotherapy in Patients with Acute Myeloid Leukemia

Objective: To analyze the correlation between platelet count changing and the newly diagnosed patients with acute myeloid leukemia (AML) after initial induction of chemotherapy for the first time, and to explore the prognostic indicators affecting AML. Methods: 253 AML patients who received explicit diagnosis and treatment as AML. Platelet counts were detected by a near-infrared fluorescence nano probe based upon tirofiban, a clinically approved small-molecule glycoprotein IIb/IIIa inhibitor (GPIIb/IIIa). Results: Hemorrhage, platelet transfusion during chemotherapy and increased the platelet count after a course of treatment are risk factors for complete remission after chemotherapy, in which platelet count detected by nano probe after chemotherapy is an independent risk factor for complete remission in AML patients. Conclusion: Using nano probe to detect platelet by using small-molecule glycoprotein IIb/IIIa inhibitor (GPIIb/IIIa) can significantly improve descision making in AML patient in comparison to other traditional methods. In addition, we found that the prognosis of patients with newly diagnosed AML patients with increased platelet count after induction chemotherapy for the first time is better than no increase.

Dynamic trajectory of platelet counts after the first cycle of induction chemotherapy in AML patients

Background

Platelet counts varied over time after induction chemotherapy. We aimed to investigate the different trajectories of platelet counts after the first cycle of induction chemotherapy in patients newly diagnosed with acute myeloid leukemia.

Methods and results

In total, 149 individuals were included in this study. We identified four distinct trajectories using a group-based trajectory model: low- stability group (n = 27, 18.12%), low-level decrease–medium elevation group (n = 42, 28.19%), low-level decrease–high elevation group (n = 60, 40.27%), and high-level decrease–medium elevation group (n = 20, 13.42%). The baseline characteristics of the high-level decrease–medium elevation group included higher platelet count, lower white blood cell count, lower percentage of bone marrow blasts, and lower rates of complete remission after the first cycle of induction chemotherapy. Compared with the low-stability group, the hazard ratios were 0.32 (95% confidence interval, 0.15–0.68) for the low-level decrease–medium elevation group, 0.31 (95% confidence interval, 0.15–0.63) for the low-level decrease–high elevation group, and 0.35 (95% confidence interval, 0.13–0.89) for the high-level decrease–medium elevation group after adjustment for age and gender by Cox proportional hazard regression. Compared with the low-stability group, the hazard ratios were 0.33 (95% confidence interval, 0.14–0.77) for the low-level decrease–medium elevation group and 0.31 (95% confidence interval, 0.14–0.67) for the low-level decrease–high elevation group after adjustment for age, gender, white blood cell count, and bone marrow blasts. These associations persisted after adjusting for age, gender, white blood cell count, bone marrow blasts, and platelet count.

Conclusion

The dynamic trajectory of platelet counts after the first cycle of induction chemotherapy is a significant predictor of all-cause mortality in patients with acute myeloid leukemia. Timely intervention should be considered for the low-stability group. The low-level decrease–medium elevation and low-level decrease-high elevation groups were independent protective factors for all-cause mortality.

Early platelet elevation after complete remission as a prognostic marker of favourable outcomes in favourable- and intermediate-risk acute myeloid leukaemia: A retrospective study

Objectives

Platelet (PLT) recovery after chemotherapy is associated with the prognosis of patients with acute myeloid leukaemia (AML). This study aimed to explore the prognostic significance of early high PLT values in patients with de novo non‐M3 AML who achieved first complete remission (CR).

Methods

A total of 206 patients with de novo non‐M3 AML were analysed in this retrospective study. A receiver operating characteristic (ROC) curve was used to determine the optimal PLT cut‐off. The overall survival (OS) and relapse‐free survival (RFS) were assessed using Kaplan‐Meier and Cox regression analyses.

Results

312×10⁹/L was confined as the cut‐off of the PLT count. The estimated 3‐year OS of patients with high PLT was higher than that of their counterparts (72.3% vs. 34.6%, p = 0.001). In subgroup analysis, patients with high PLT had better OS in the favourable‐ and intermediate‐risk (non‐adverse‐risk) AML (p = 0.001). The estimated 3‐year RFS for the high and low PLT groups was 75.1% and 45.7% respectively (p = 0.078). Multivariate analyses revealed that high PLT count was an independent favourable variable for OS (HR = 0.264, p < 0.001) and RFS (HR = 0.375, p = 0.011) in the non‐adverse‐risk group.

Conclusion

Our results showed that early high PLT count recovery at first CR in non‐adverse‐risk AML patients is a positive prognostic marker for survival outcomes.

Emerging Bone Marrow Microenvironment-Driven Mechanisms of Drug Resistance in Acute Myeloid Leukemia: Tangle or Chance?

Simple Summary

Despite high rates of remission obtained with conventional chemotherapy, the persistence of leukemic cells after treatments, eventually exiting in disease relapse, remains the main challenge in acute myeloid leukemia (AML). Increasing evidence indicates that, besides AML cell mutations, stromal and immune cells, as leukemic microenvironment components, may protect AML cells from therapies. Here, we will recapitulate emerging bone marrow (BM) microenvironment-dependent mechanisms of therapy resistance. The understanding of these processes will help find new drug combinations and conceive novel and more effective treatments.

Abstract

Acute myeloid leukemia (AML) has been considered for a long time exclusively driven by critical mutations in hematopoietic stem cells. Recently, the contribution of further players, such as stromal and immune bone marrow (BM) microenvironment components, to AML onset and progression has been pointed out. In particular, mesenchymal stromal cells (MSCs) steadily remodel the leukemic niche, not only favoring leukemic cell growth and development but also tuning their responsiveness to treatments. The list of mechanisms driven by MSCs to promote a leukemia drug-resistant phenotype has progressively expanded. Moreover, the relative proportion and the activation status of immune cells in the BM leukemic microenvironment may vary by influencing their reactivity against leukemic cells. In that, the capacity of the stroma to re-program immune cells, thus promoting and/or hampering therapeutic efficacy, is emerging as a crucial aspect in AML biology, adding an extra layer of complexity. Current treatments for AML have mainly focused on eradicating leukemia cells, with little consideration for the leukemia-damaged BM niche. Increasing evidence on the contribution of stromal and immune cells in response to therapy underscores the need to hold the mutual interplay, which takes place in the BM. A careful dissection of these interactions will help provide novel applications for drugs already under experimentation and open a wide array of opportunities for new drug discovery.

Combined use of peripheral blood blast count and platelet count during and after induction therapy to predict prognosis in children with acute lymphoblastic leukemia

Several studies have reported an association between the rapidity of reduction in peripheral blood blast count or recovery of normal hematopoiesis and treatment outcome during therapy in children with acute lymphoblastic leukemia (ALL). However, little is known about the impact of both of these aspects on prognosis in pediatric ALL. Accordingly, the purpose of this study was to evaluate whether the combined use of blood blast count and platelet count could predict event-free survival (EFS) and overall survival (OS) when minimal residual disease (MRD) detection was not available.A total of 419 patients aged 0 to 14 years diagnosed and treated for ALL between 2011 and 2015 were enrolled.Patients with a blast count ≥0.1 × 109/L on day 8 exhibited significantly lower survival rates than that in those with blast counts <0.1 × 109/L. The EFS and OS in patients with platelet count ≥100 × 109/L on day 33 were significantly higher than those with platelet counts <100 × 109/L. In univariate and multivariate analyses, patients with low blast count on day 8 and high platelet count on day 33 were significantly associated with better EFS and OS. The combination of blast cell count on day 8 and platelet count on day 33 demonstrated a strong association with MRD-based risk stratification.Complete blood count is an inexpensive, easy to perform, and reliable measurement in children with ALL. The combination of blast count and platelet count during and after induction chemotherapy was a significant and independent prognostic factor for treatment outcome in pediatric ALL.

The complete story of less than complete responses: The evolution and application of acute myeloid leukemia clinical responses

Complete remission (CR) has long been the critical therapeutic response in acute myeloid leukemia (AML). However, "less than CR" responses have been and continue to be proposed to define clinically meaningful post-therapy outcomes. These responses include CR with incomplete recovery (CRi), CR with incomplete platelet recovery (CRp) and, most recently, CR with partial hematologic recovery (CRh), which has been introduced and subsequently used for regulatory approval. However, the clinical benefits associated with "less than CR" responses have primarily been evaluated in the context of intensive therapies. In an era with sophisticated measurable residual disease (MRD) assessments, including flow-based, cytogenetic and molecular techniques, and an increase in "targeted", non-intensive therapies, the clinical value of responses that are "less than CR" must be reevaluated. Improvements in the rate of CR has not always led to improvements in OS among older patients. As such, MRD techniques might help define a more stringent response criterion (MRD-negative CR) that might better correlate with OS and should be incorporated in future clinical trials. Here we discuss the evolution of CR and "less than CR" responses, data regarding their clinical benefits, and considerations relevant to response assessments with newer therapies.

Prognostic value of platelet recovery degree before and after achieving minimal residual disease negative complete remission in acute myeloid leukemia patients

Background

Risk stratification and prognosis prediction of acute myeloid leukemia (AML) are largely dependent on pre-treatment information. However, post-treatment data also provides much useful information. In this retrospective study, we explored whether the level of blood count recovery before and after the first minimal residual disease (MRD) negative complete remission (CR) is relevant to clinical outcomes of AML patients.

Methods

For each included patient, peripheral platelet counts were measured on the day before initial treatment (PLT_pre), whereas platelet peak values (PLT_peak) were recorded after marrow recovery following the chemotherapy course inducing the first MRD-negative CR. The difference (D_PLT) between these two values (D_PLT = PLT_peak−PLT_pre) was calculated. X-tile software was utilized to establish the optimal cut-point for D_PLT, which was expected to distinguish CR patients with different clinical outcomes. A cross validation analysis was conducted to confirm the robustness of the established cut-point. The results were further tested by a Cox multivariate analysis.

Results

The optimal cut-point of D_PLT was determined as 212 × 10⁹/L. Patients in high D_PLT group were observed to have a significantly better PFS (p = 0.016) and a better OS (without statistical significance, p = 0.106). Cox multivariate analysis showed that higher D_PLT was associated with longer PFS (HR = 2.894, 95% CI: 1.320–6.345, p = 0.008) and longer OS (HR = 3.077, 95% CI: 1.130–8.376, p = 0.028).

Conclusion

Platelet recovery degree before and after achieving MRD-negative CR (D_PLT) is a potential predictor of clinical outcomes in CR patients. Higher D_PLT value is associated with longer PFS and OS. Our findings may help to develop simple methods for AML prognosis evaluation.

The comparison of bone marrow kinetics between patients with acute myeloid leukemia and acute promyelocytic leukemia after induction chemotherapy

Background and Aim: Recently, acute promyelocytic leukemia (APL) has shifted from the most hazardous to the best curable type of acute myeloid leukemia. Anthracyclines, all-trans retinoic acid (ATRA) and arsenic derivatives are the most important developments for the treatment of APL. ATRA promotes the terminal differentiation of malignant promyelocytes to mature neutrophils. We aimed to compare platelet and neutrophil recovery time after induction chemotherapy in patients with acute myeloid leukemia (AML) and APL.Materials and Methods: Two hundred and fifteen patients with AML and APL, who were diagnosed and treated in our tertiary care center between the years of 2001 and 2018 were evaluated.Results: One hundred and eighty one AML patients (84.2%) and 34 (15.8%) APL patients were included in this study. The time between neutrophil nadir after induction chemotherapy and neutrophil recovery was longer in APL patients than in AML patients [30.5 (4-52) vs. 20 (5-58), p < 0.001]. The time between platelet nadir after induction chemotherapy and platelet recovery was longer in APL patients than in AML patients [21.5 (4-42) vs. 17 (4-45), p = 0.02].Conclusion: Neutrophil and platelet recovery times were longer in APL patients than in AML patients in our present study. In 60 days, mortality rate was higher in APL patients than AML patients. Non-relapse mortality (NRM) rate was similar between two groups. There was a significant difference between two groups in terms of NRM causes. Platelet and neutrophil recovery time is very important because infection is the most important cause of NRM.

The Impact of Early Versus Late Platelet and Neutrophil Recovery after Induction Chemotherapy on Survival Outcomes of Patients with Acute Myeloid Leukemia

Objective:

The prognosis of patients with acute myeloid leukemia (AML) is affected by factors that are both patient- and disease-specific. The aim of this study is to evaluate the impact of early versus late platelet and neutrophil recovery after induction chemotherapy on survival outcomes of AML patients.

Materials and Methods:

A total of 181 patients with AML who were treated in our tertiary center between 2001 and 2018 were evaluated. Neutrophil and platelet recovery times were accepted as the periods from the beginning of induction chemotherapy to a neutrophil count of ≥0.5x10⁹/L and a platelet count of ≥20x10⁹/L 3 days in a row, respectively. The median time to platelet recovery was 25 days (range=12-52) for all patients. Therefore, platelet recovery in the first 25 days was defined as early platelet recovery (EPR) and at ≥26 days it was defined as late platelet recovery (LPR). The median time to neutrophil recovery was 28 days (range=13-51) for all patients. Therefore, neutrophil recovery in the first 28 days was defined as early neutrophil recovery, and at ≥29 days it was defined as late neutrophil recovery.

Results:

The 5-year overall survival (OS) rates for patients who had EPR and LPR after induction chemotherapy were 62% and 23%, respectively (p<0.001). The 5-year disease-free survival (DFS) rates for patients who had EPR and LPR after induction chemotherapy were 57% and 15%, respectively (p<0.001).

Conclusion:

Short bone marrow recovery time may indicate better healthy hematopoiesis and marrow capacity associated with longer OS and DFS.

Early recovery of the platelet count after decitabine-based induction chemotherapy is a prognostic marker of superior response in elderly patients with newly diagnosed acute myeloid leukaemia

BACKGROUND

Definite prognostic clinical factors of benefit for decitabine-based induction chemotherapy in elderly patients newly diagnosed with acute myeloid leukaemia (AML) are not identified. This study was designed to explore the potential biomarker, especially regeneration of haematopoiesis, of treatment response and survival in elderly patients with newly diagnosed AML.

METHOD

We analysed the clinical data of 117 elderly AML patients who were treated with a decitabine dose of 15 mg/m² for 5 days, granulocyte colony-stimulating factor of 300 μg/d for priming, plus cytarabine 10 mg/m² q12h for 7 days and aclarubicin 10 mg/d for 4 days (D-CAG).

RESULTS

After initial induction chemotherapy, the overall response rate and complete remission (CR) were 71.8% and 58.1%, respectively. Patients responding to the D-CAG regimen achieved higher platelet counts on day 14 after initial treatment (p < 0.001). Median counts were 59.5 × 10⁹/L in the CR group, 37 × 10⁹/L in the partial remission group and 28 × 10⁹/L in the non-responsive group. We then classified patients into those who achieved platelet counts≥60 × 10⁹/L or 100 × 10⁹/L on day 14 after D-CAG vs. those who did not. Platelet counts≥60 × 10⁹/L or 100 × 10⁹/L on day 14 were significantly associated with superior CR, overall survival and disease-free survival (80.9% vs. 45.3% p < 0.001,16.5 vs. 9.1 months p = 0.009 and 16.3 vs. 7.4 months p = 0.024; 85.2% vs. 50% p = 0.001, 31 vs. 10.1 months p = 0.003 and 16.9 vs. 8.9 months p = 0.006). Multivariate analysis confirmed that poor cytogenetics (p = 0.010) and FLT3-ITD mutation (p = 0.007) were identified as independent factors of OS, but not platelet count (p = 0.091). However, platelet count≥100 × 10⁹/L on day 14 was an independent prognostic factor of CR and DFS.

CONCLUSION

Platelet count recovery on day 14 after D-CAG induction chemotherapy is associated with response.

TRIAL REGISTRATION

D-CAG regimen was registered on ChicTR with number 11001700 .

Clinical value of the quantitation of average daily platelet increase during the recovery period in childhood acute lymphoblastic leukaemia

The time to platelet recovery (TPR) is becoming a predicting factor during the treatment of childhood acute leukaemia. However, the initial pre-treatment platelet count (PPC) could interfere with TPR. Here, we integrated both TPR and PPC as the average daily platelet amount increase (Ap) to predict the prognosis in childhood B-ALL during the recovery period.148 patients were enrolled. The relationship between the Ap and MRD was evaluated, and Multivariate analysis was performed to evaluate whether Ap was independently associated with a better EFS. The PPC was inversely correlated with TPR (rs = -0.519, P = 0.021). Patients in Ap >3.9 × 10⁹/L group had better EFS (x² = 3.109, P = 0.028) than TPR ≤ 16d. Multivariate analysis indicated that Ap > 3.9 × 10⁹/L was independently associated with a longer EFS (RR = 3.468; 95%CI: 1.037-11.597, P = 0.043). However, when introducing both MRD and Ap > 3.9 × 10⁹/L as candidate variables, the Ap > 3.9 × 10⁹/L lost its independent effect (P = 0.081). The strong association between MRD on treatment day 33 and Ap > 3.9 × 10⁹/L (x² = 148.00, P = 0.000) was responsible for this phenomenon. Ap could be a valuable prognostic indicator in childhood B-ALL.

Absolute lymphocyte counts at end of induction correlate with distinct immune cell compartments in pediatric B cell precursor acute lymphoblastic leukemia

Several retrospective studies in children with B cell precursor (BCP) acute lymphoblastic leukemia (ALL) provided clinical evidence that higher absolute lymphocyte counts (ALC) early into treatment significantly correlated with improved relapse-free and overall survival. It still remains unknown, however, whether the predictive role of higher ALCs reflects general bone marrow recovery or a more specific attribute of immune function. To investigate this question, we implemented a prospective observational cohort study in 20 children with BCP ALL on day 29 (D29) of induction chemotherapy and immunophenotyped their lymphoid (T, B and natural killer cells) and myeloid (neutrophils, monocytes, dendritic cells) compartments. In a first evaluation of a cohort treated with Children's Oncology Group-based induction chemotherapy, the immune cell compartments were differentially depleted at D29. Neither gender, risk status, minimal residual disease, nor bone marrow recovery markers correlated with D29 ALC. In contrast, both CD3+ T cell and dendritic cell compartments, which did not correlate with age, significantly correlated with D29 ALC (p < 0.0001). In addition, subset complexity of cellular immune compartments was preserved at D29. This study reveals that D29 ALC significantly correlates with distinct immune cell compartments but not with bone marrow recovery markers, suggesting that higher D29 ALCs may contribute to leukemia control by inducing specific host immune activity.

Bone marrow evaluation for diagnosis and monitoring of acute myeloid leukemia

The diagnosis of acute myeloid leukemia (AML) can be made based on peripheral blood or bone marrow blasts. In this review, we will discuss the role of bone marrow evaluation and peripheral blood monitoring in the diagnosis, management, and follow up of AML patients. For patients with circulating blasts, it is reasonable to perform the necessary studies needed for diagnosis and risk stratification, including multiparametric flow cytometry, cytogenetics, and molecular analysis, on a peripheral blood specimen. The day 14 marrow is used to document hypocellularity in response to induction chemotherapy, but it is unclear if that assessment is necessary as it often does not affect immediate management. Currently, response assessments performed at count recovery for evaluation of remission and measurable residual disease rely on bone marrow sampling. For monitoring of relapse, peripheral blood evaluation may be adequate, but the sensitivity of bone marrow testing is in some cases superior. While bone marrow evaluation can certainly be avoided in particular situations, this cumbersome and uncomfortable procedure currently remains the de facto standard for response assessment.

Hyper-recovery of platelets after induction therapy is a predictor of relapse-free survival in acute myeloid leukemia

We verified the association between standard clinical and laboratory variables and the risk of relapse in acute myeloid leukemia (AML), which led us to retrospectively examine the effect of regeneration of hematopoiesis in patients with newly diagnosed AML. We used data from 230 patients who obtained remission after cytarabine-based induction chemotherapy. Platelet counts ≥500 × 10⁹/L and hemoglobin levels ≥9 g/dL on day 28 after treatment initiation were significantly associated with relapse-free survival (RFS) rate, conferring respective multivariate risk ratios of 0.38 (95% CI: 0.18-0.79) and 0.60 (95% CI: 0.40-0.89) for the occurrence of relapse or death. No disease relapse occurred in core binding factor leukemia patients whose platelet counts recovered ≥500 × 10⁹/L at 28 days after therapy initiation. We conclude that regeneration of hematopoiesis, especially platelet hyper-recovery, after induction chemotherapy is a significant predictor of RFS in patients with AML.

Absolute Lymphocyte Count Recovery Independently Predicts Outcome in Childhood Acute Lymphoblastic Leukemia: Experience From a Tertiary Care Cancer Center of a Developing Country

BACKGROUND

Accurate risk stratification is essential for successful treatment outcome in childhood acute lymphoblastic leukemia. Early recovery of absolute lymphocyte count (ALC) during induction therapy is emerging as a reliable favorable prognostic indicator that may hold its relevance in resource-constraint settings.

MATERIALS AND METHODS

This is a retrospective chart review of medical records of 212 patients of acute lymphoblastic leukemia, aged less than 18 years, treated between January 1996 and December 2009. Time to lymphocyte recovery was analyzed with respect to various prognostic factors and survival and Martingale residuals were used to define ALC cut-offs.

RESULTS

High-risk disease characteristics including older age (10 y and older), National Cancer Institute high risk, and central nervous system disease at diagnosis were associated with delayed lymphocyte recovery. The 5-year event-free, relapse-free, and overall survival of patients with day 15 ALC of ≥ 500 cells/µL and day 29 ALC of ≥ 1000 cells/µL was 81.7% ± 4%, 86.4% ± 2.8%, 91.0% ± 3%, respectively, compared with those with delayed recovery (16.6% ± 5.6%, 19.3% ± 6.4%, 32.8% ± 7.2%, P < 0.001). In multivariate analysis both these ALC cut-offs retained their significance as prognostic variables of survival.

CONCLUSION

Our analysis revealed ALC to be an important independent predictor of treatment outcome and may provide key prognostic information in settings where minimal residual disease-based risk stratification is not feasible.

Absolute lymphocyte count is associated with minimal residual disease level in childhood B-cell precursor acute lymphoblastic leukemia

The prognostic value of absolute lymphocyte count (ALC) has been a recent matter of debate in childhood acute lymphoblastic leukemia (ALL). In the current study, ALCs at the time of diagnosis (ALC-0), after 7 days of initial therapy (ALC-8) and at interim of the induction therapy (ALC-22) were examined in Chinese children with B-cell precursor (BCP) ALL and correlated with the level of minimal residual disease (MRD) at day 22 of induction therapy. Medical and laboratory records of 140 patients diagnosed with childhood BCP ALL were retrieved and analyzed. ALC-22 is significantly correlated with MRD level at day 22 of therapy and can be a good prognostic factor for childhood BCP-ALL. Furthermore, lymphocyte count at initial diagnosis is correlated with MRD level at day 22 in childhood BCP-ALL with the immnunophenotype of CD19(pos)/CD10(pos)/CD34(pos)/CD45(neg) and role as a new prognostic factor was determined.

Acute myeloid leukemia with normal cytogenetics

Acute myeloid leukemia (AML) is proving to be a heterogeneous disease process that is driven by various genetic mutations and aberrant protein expression. As our population ages, the incidence of AML is likely to increase, with approximately a third of adult cases categorized with normal cytogenetics. Advances in technology are now allowing us to explore the genetic expression and protein transcription patterns of AML, providing more information that must find its place in the prognosis and the therapeutic algorithm of this disease. As we learn more, we hope to further categorize patients with normal karyotype AML into discrete risk categories that will help in treatment decision making and further elucidate the necessity for hematopoietic cell transplantation. However, at this time, many of the identified mutations and expression patterns are still experimental, requiring further analysis to determine their exact role in AML.

Absolute lymphocyte counts refine minimal residual disease-based risk stratification in childhood acute lymphoblastic leukemia

BACKGROUND

Several studies have demonstrated the prognostic utility of absolute lymphocyte count (ALC) during therapy for a range of malignancies, with low ALC associated with adverse outcome. Here we investigated whether ALC retained independent prognostic significance with respect to minimal residual disease (MRD) status in children with acute lymphoblastic leukemia (ALL).

PROCEDURE

We reviewed 171 cases of pediatric ALL treated on the Children's Oncology Group P9900 series of treatment trials. Variables analyzed included ALC at several time points during Induction, age at diagnosis, cytogenetics, initial white blood cell count, and MRD status at Day 29 of Induction (MRD-29).

RESULTS

We found high ALC at Induction Day 29 (ALC-29) to be an independent, clinically significant predictor of improved relapse-free and overall survival (OS). Patients with ALC-29 >1,500 cells/µl had a superior 6-year relapse-free survival (80 ± 4% vs. 62 ± 8%, P = 0.018) and overall survival (96 ± 2% vs. 74 ± 8%, P = 0.001). Moreover, ALC-29 identified distinct prognostic subgroups within cases stratified by MRD-29. In subjects with >0.01% MRD, ALC-29 > or <1,500 cells/µl had a significant 51% difference in 6-year OS (92 ± 7% vs. 41 ± 16%, P = 0.0001).

CONCLUSIONS

ALC, a readily obtainable test, constitutes a significant and independent prognostic factor in childhood ALL that may refine current MRD-based risk stratification algorithms and provide key prognostic information in settings where MRD determination is not feasible.