Characterization of therapy-related acute myeloid leukemia: increasing incidence and prognostic implications.

Studies of therapy-related AML (t-AML) are usually performed in selected cohorts and reliable incidence rates are lacking. In this study, we characterized, defined the incidence over time and studied prognostic implications in all t-AML patients diagnosed in Sweden between 1997 and 2015. Data were retrieved from nationwide population-based registries. In total, 6,779 AML patients were included in the study, of whom 686 (10%) had t-AML. The median age for t-AML was 71 years and 392 (57%) patients were females. During the study period, the incidence of t-AML almost doubled with a yearly increase in t-AML of 4.5% (95% confidence interval: 2.8%-6.2%), which contributed significantly to the general increase in AML incidence over the study period. t-AML solidly constituted over 10% of all AML cases during the later period of the study. Primary diagnoses with the largest increase in incidence and decrease in mortality rate during the study period (i.e., breast and prostate cancer) contributed significantly to the increased incidence of t-AML. In multivariable analysis, t-AML was associated with poorer outcome in cytogenetically intermediate- and adverse-risk cases but t-AML had no significant impact on outcome in favorable-risk AML, including core binding leukemias, acute promyelocytic leukemia and AML with mutated NPM1 without FLT3-ITD. We conclude that there is a strong increase in incidence in t-AML over time and that t-AML constitutes a successively larger proportion of the AML cases. Furthermore, we conclude that t-AML confers a poor prognosis in cytogenetically intermediate- and adverse-risk, but not in favorable-risk AML.

Secondary Acute Myeloid Leukemia and the Role of Allogeneic Stem Cell Transplantation in a Population-Based Setting.

Secondary AML (s-AML), including AML with an antecedent hematologic disorder (AHD-AML) and therapy-related AML (t-AML), constitutes a large proportion of patients with AML and is considered to confer a dismal prognosis. The role of allogeneic hematopoietic cell transplantation (HCT) in patients with s-AML and the extent to which HCT is performed in these patients has been little studied to date. We used the population-based Swedish AML Registry comprising 3337 intensively treated adult patients over a 17-year period to study the role of HCT within the group of patients with s-AML as well as compared with patients with de novo AML. HCT was performed in 576 patients (22%) with de novo AML, in 74 patients (17%) with AHD-AML, and in 57 patients (20%) with t-AML. At 5 years after diagnosis, there were no survivors among patients with previous myeloproliferative neoplasms who did not undergo HCT, and corresponding survival for patients with antecedent myelodysplastic syndromes and t-AML was and 2% and 4%, respectively. HCT was compared with chemotherapy consolidation in s-AML using 3 models: (1) a 200-day landmark analysis, in which HCT was favorable compared with conventional consolidation (P = .04, log-rank test); (2) a multivariable Cox regression with HCT as a time-dependent variable, in which the hazard ratio for mortality was 0.73 (95% confidence interval, 0.64 to 0.83) for HCT and favored HCT in all subgroups; and (3) a propensity score matching analysis, in which the 5-year overall survival (OS) and relapse-free survival in patients with s-AML in first complete remission (CR1) was 48% and 43%, respectively, for patients undergoing HCT versus 20% and 21%, respectively, for those receiving chemotherapy consolidation (P = .01 and .02, respectively, log-rank test). Our observational data suggest that HCT improves survival and offers the only realistic curative treatment option in patients with s-AML.

Survival in adult acute lymphoblastic leukaemia (ALL): A report from the Swedish ALL Registry.

OBJECTIVES: As new, effective therapies emerge for acute lymphoblastic leukaemia (ALL), the results of clinical trials need to relate to standard of care. METHODS: We used the population-based Swedish ALL Registry to evaluate characteristics, treatment and long-term outcome in 933 patients with diagnosis between 1997 and 2015. RESULTS: The median age was 53 years. The frequency of Philadelphia (Ph)-positive leukaemia was 34% of examined B-ALL with a peak incidence at 50-59 years. Five-year overall survival (OS) improved between 1997-2006 and 2007-2015; in patients 18-45 years from 50% (95% CI 43-57) to 65% (95% CI 58-72), 46-65 years from 25% (95% CI 18-32) to 46% (95% CI 37-55) and >65 years from 7% (95% CI 2.6-11) to 11% (95% CI 5.9-16) (P < 0.05). Men with Ph-neg B-ALL 46-65 years had inferior OS compared with women (P < 0.01). Standardised mortality ratio was 5.7 (95% CI 5.0-6.3) for patients who survived 5 years from diagnosis. In multivariable analysis, Ph-positive disease was not associated with impaired prognosis but with lower risk of death in 2007-2015. CONCLUSIONS: In a population-based cohort, OS has improved in adult ALL, especially for Ph-positive disease but for middle-aged men with Ph-negative B-ALL outcome was poor. Cure without late toxicity or relapse is still desired.

NT5C2 germline variants alter thiopurine metabolism and are associated with acquired NT5C2 relapse mutations in childhood acute lymphoblastic leukaemia.

The antileukaemic drug 6-mercaptopurine is converted into thioguanine nucleotides (TGN) and incorporated into DNA (DNA-TG), the active end metabolite. In a series of genome-wide association studies, we analysed time-weighted means (wm) of erythrocyte concentrations of TGN (Ery-TGN) and DNA-TG in 1009 patients undergoing maintenance therapy for acute lymphoblastic leukaemia (ALL). In discovery analyses (454 patients), the propensity for DNA-TG incorporation (wmDNA-TG/wmEry-TGN ratio) was significantly associated with three intronic SNPs in NT5C2 (top hit: rs72846714; P = 2.09 × 10-10, minor allele frequency 15%). In validation analyses (555 patients), this association remained significant during both early and late maintenance therapy (P = 8.4 × 10-6 and 1.3 × 10-3, respectively). The association was mostly driven by differences in wmEry-TGN, but in regression analyses adjusted for wmEry-TGN (P < 0.0001), rs72846714-A genotype was also associated with a higher wmDNA-TG (P = 0.029). Targeted sequencing of NT5C2 did not identify any missense variants associated with rs72846714 or wmEry-TGN/wmDNA-TG. rs72846714 was not associated with relapse risk, but in a separate cohort of 180 children with relapsed ALL, rs72846714-A genotype was associated with increased occurrence of relapse-specific NT5C2 gain-of-function mutations that reduce cytosol TGN levels (P = 0.03). These observations highlight the impact of both germline and acquired mutations in drug metabolism and disease trajectory.

Age but not Philadelphia positivity impairs outcome in older/elderly patients with acute lymphoblastic leukemia in Sweden.

OBJECTIVES: Older/elderly patients with acute lymphoblastic leukemia (ALL) are poorly represented in clinical trials. METHODS: Using Swedish national leukemia registries, we investigated disease/patient characteristics, treatment choices, outcome, and the impact of an age-adapted protocol (introduced in 2009) in this population-based study of patients aged 55-85 years, diagnosed with ALL 2005-2012. RESULTS: Of 174 patients, 82% had B-phenotype, 11% Burkitt leukemia (excluded), and 7% T-phenotype. Philadelphia chromosome positivity (Ph+) occurred in 35%. Of the 155 B- and T-ALL patients, 80% were treated with intensive protocols, and 20% with a palliative approach. Higher age and WHO performance status ≥2 influenced the choice of palliation. Intensive, palliative, and both approaches resulted in complete remission rate 83/16/70% and 3-year overall survival (OS) 32/3/26%. The age-adapted protocol did not improve outcome. With intensive treatment, platelet count ≤35×109 /L and age ≥75 years were adverse prognostic factors for OS, Ph+ was not. Male sex was an adverse prognostic factor in the 55-64 year age-group. CONCLUSIONS: We report a high frequency of Ph+ in older/elderly patients, with no evidence of poorer outcome compared to Ph-negative disease. Overall prognosis for elderly patients with ALL remains dismal, despite the use of age-adapted treatment.

Acute de novo Leukemia in Estonia and Western Sweden 1982-2006: Positive Trend in the Survival of Acute Leukemia over 25 Years.

This study focuses on the incidence, treatment, and survival of de novo acute leukemia in a 25-year perspective in western Sweden and Estonia. At the beginning of our study, Estonia was a part of the Eastern bloc with planned economy, but since 1991 it is a member of the European Union and transforming into a market economy. Survival rates have steadily increased in both countries. However, a gap between their survival curves remains. Based on our data, it is difficult to explain the big difference in the 5-year relative survival in favor of western Sweden (55 vs. 22%). In Germany, there was a big difference in overall cancer survival between East and West Germany after the fall of the iron curtain, but today no difference is seen. Differences in survival are probably due to a higher proportion of intense chemotherapy regimens and a higher rate of hematopoietic stem cell transplantations in Sweden. Other important factors might be better supportive care and diagnostics as well as better adjuvant therapy. Better staff training and conditions in wards are also factors that might play an essential role.

Satisfactory outcome after intensive chemotherapy with pragmatic use of minimal residual disease (MRD) monitoring in older patients with Philadelphia-negative B cell precursor acute lymphoblastic leukaemia: a Swedish registry-based study.

The introduction of minimal residual disease (MRD) monitoring, in the Swedish national guidelines for acute lymphoblastic leukaemia, was evaluated in 35 patients aged 46-79 years (median 61), who were diagnosed from 2007 to 2011 and treated with high-intensity, block-based chemotherapy (ABCDV/VABA induction). Both a high complete remission rate (91 %) and acceptable overall survival (OS) rate (47 %) at 5 years were achieved. MRD by flow cytometry was measured in 73 % of the patients reaching complete remission after the first course, but was omitted by the clinicians for eight patients who were either over 70 years of age or already met conventional high-risk criteria. Factors negatively influencing OS were age over 65 years and WHO status ≥2. MRD < 0.1 % after induction had positive impact on continuous complete remission but not on OS. Only five patients were allocated to allogeneic haematopoietic stem cell transplantation in first remission, mainly due to conventional high risk factors. Thus, use of intensive remission induction therapy is effective in a selection of older patients. In a population for whom the possibilities of treatment escalation are limited, the optimal role of MRD monitoring remains to be determined.

Characterization and prognostic features of secondary acute myeloid leukemia in a population-based setting: a report from the Swedish Acute Leukemia Registry.

Patients with secondary acute myeloid leukemia (AML) often escape inclusion in clinical trials and thus, population-based studies are crucial for its accurate characterization. In this first large population-based study on secondary AML, we studied AML with an antecedent hematological disease (AHD-AML) or therapy-related AML (t-AML) in the population-based Swedish Acute Leukemia Registry. The study included 3,363 adult patients of which 2,474 (73.6%) had de novo AML, 630 (18.7%) AHD-AML, and 259 (7.7%) t-AML. Secondary AML differed significantly compared to de novo AML with respect to age, gender, and cytogenetic risk. Complete remission (CR) rates were significantly lower but early death rates similar in secondary AML. In a multivariable analysis, AHD-AML (HR 1.51; 95% CI 1.26-1.79) and t-AML (1.72; 1.38-2.15) were independent risk factors for poor survival. The negative impact of AHD-AML and t-AML on survival was highly age dependent with a considerable impact in younger patients, but without independent prognostic value in the elderly. Although patients with secondary leukemia did poorly with intensive treatment, early death rates and survival were significantly worse with palliative treatment. We conclude that secondary AML in a population-based setting has a striking impact on survival in younger AML patients, whereas it lacks prognostic value among the elderly patients.

High relapse rate of T cell acute lymphoblastic leukemia in adults treated with Hyper-CVAD chemotherapy in Sweden.

BACKGROUND: Hyper-CVAD is widely used to treat acute lymphoblastic leukemia (ALL) and aggressive lymphomas. This multicenter, population-based study assessed the efficacy of Hyper-CVAD as first-line therapy in patients with T-cell ALL (T-ALL). PATIENTS AND METHODS: Between October 2002 and September 2006, 24 patients were diagnosed with T-ALL in Sweden; 19 were eligible for treatment with the protocol. RESULTS: The median age was 32 yr (range 18-72 yr). Complete remission (CR) was obtained in 17 of 19 (89%) patients, and the treatment was relatively well tolerated. Allogeneic stem cell transplantation (SCT) was recommended in high-risk disease and was performed in four patients upfront. Two- and 5-yr leukemia-free survivals (LFS) in 17 patients with CR achievement were identical, at 29% (95% confidence interval [CI]: 8-51). Two- and 5-yr overall survival (OS) in whole cohort was 63% (95% CI: 42-85) and 47% (95% CI: 26-69), respectively. The 5-yr LFS for 15 patients who did not receive allogeneic SCT upfront were 20% (95% CI: 0-40), although 14 of 15 completed the protocol (eight cycles). Relapse occurred in 2 of 4 upfront-transplanted patients and in 12 of 15 patients treated with chemotherapy alone, six of whom received allogeneic SCT in CR2. Age ≥35 yr influenced OS negatively in univariate analysis (HR 5.1, 95% CI: 1.55-16.7). CONCLUSIONS: Hyper-CVAD treatment resulted in a high CR rate and appeared safe, but it showed poor efficacy at preventing relapse. Therefore, this treatment is no longer recommended for adults with T-ALL in Sweden.

Risk group assignment differs for children and adults 1-45 yr with acute lymphoblastic leukemia treated by the NOPHO ALL-2008 protocol.

BACKGROUND: The prognosis of acute lymphoblastic leukemia is poorer in adults than in children. Studies have indicated that young adults benefit from pediatric treatment, although no upper age limit has been defined. DESIGN AND METHODS: We analyzed 749 patients aged 1-45 yr treated by the NOPHO ALL-2008 protocol. Minimal residual disease (MRD) on days 29 and 79, immunophenotype, white blood cell count (WBC), and cytogenetics were used to stratify patients to standard-, intermediate-, or high-risk treatment with or without hematopoietic stem cell transplantation. RESULTS: Adults aged 18-45 had significantly lower WBCs at diagnosis compared with children aged 1-9 and 10-17 yr, but significantly more adults were stratified to high-risk chemotherapy (8%, 14%, 17%; P < 0.0001) or high-risk chemotherapy with transplantation (4%, 13%, 19%; P < 0.0001). This age-dependent skewing of risk grouping reflected more T-ALL (11%, 27%, 33%, P < 0.0001), poorer MRD response day 29 (MRD < 0.1%: 75%, 61%, 52%; P < 0.0001), and more MLL gene rearrangements (3%, 3%, 10%; P = 0.005) in older patients. CONCLUSIONS: Even if identical diagnostics, treatment, and risk stratification are implemented, more adults will be stratified to high-risk therapy, which should be considered when comparing pediatric and adult outcomes.

Sequential population-based studies over 25 years on the incidence and survival of acute de novo leukemias in Estonia and in a well-defined region of western Sweden during 1982-2006: a survey of patients aged ≥65 years.

Estonia regained independence in 1991 after five decades of occupation by the Soviet Union. The present population-based survey was carried out over five consecutive 5-year study periods (1982-2006) on the incidence and survival of de novo acute leukemia patients aged ≥65 years at diagnosis in Estonia and in a well-defined area in western Sweden. During the study period of retrospective work (1982-1996), the first 10 years were carried out while Estonia was still under the mentorship of the Soviet Union. Over these years, Estonian hematologists did not have access to therapeutic measures readily available to Swedish hematologists, and the results for survival for western Swedish patients with acute myeloid leukemia (AML) far exceeded those of their Estonian counterparts. However, the results for acute lymphoblastic leukemia were equally dismal in the two countries. Subsequent prospective population-based studies were carried out during the years 1997-2006. A gradual improvement as to long-term relative survival of the Estonian AML patients was observed. When studying 2002-2006, no difference as regards relative survival at 5 years was anymore present between the two countries. Over the first 20 years of our population-based studies, it was repeatedly observed that the age-standardized incidence rate particularly for de novo AML was considerably higher for the western Swedish as compared to the Estonian cohorts. During the last 5-year study period (2002-2006), no such difference between the two countries was present, indicating that some true changes in the reporting procedure in Estonia had occurred.

High curability via intensive reinduction chemotherapy and stem cell transplantation in young adults with relapsed acute lymphoblastic leukemia in Sweden 2003-2007.

BACKGROUND: A minority of patients with adult acute lymphoblastic leukemia who relapse are rescued. The aim of this population-based study was to assess the results of reinduction treatment and allogeneic stem cell transplantation in patients in second complete remission. DESIGN AND METHODS: Between 2003-2007, 76 adults (<66 years) with relapsed acute lymphoblastic leukemia (Burkitt's leukemia excluded) were prospectively reported to The Swedish Adult Acute Leukemia Registry and later evaluated. RESULTS: Reinduction with: (i) mitoxantrone, etoposide, and cytarabine (MEA); (ii) fludarabine, cytarabine, pegylated-asparaginase plus granulocyte colony-stimulating factor (FLAG-Asp); and (iii) cytarabine, betamethasone, cyclophosphamide, daunorubicin, and vincristine (ABCDV) resulted in complete remission in 6/9 (67%), 10/16 (63%) and 9/21 (43%) of the patients, respectively. Allogeneic stem cell transplantation was performed during second complete remission in 29 patients. Multivariate analysis regarding overall survival after relapse revealed that age over 35 years at diagnosis and relapse within 18 months were negative prognostic factors. Overall survival rates at 3 and 5 years were 22% (95% CI: 13-32) and 15% (95% CI: 7-24). Of 19 patients less than 35 years at diagnosis who underwent allogeneic stem cell transplantation in second remission, ten (53%) are still alive at a median of 5.5 years (range, 4.2-8.3) after relapse, whereas all patients over 35 years old at diagnosis have died. CONCLUSIONS: Allogeneic stem cell transplantation remains the treatment of choice for young adults with relapsed acute lymphoblastic leukemia. Both (i) mitoxantrone, etoposide, and cytarabine and (ii) fludarabine, cytarabine, pegylated-asparaginase plus granulocyte colony-stimulating factor seem effective as reinduction treatments and should be further evaluated. New salvage strategies are needed, especially for patients over 35 years old at diagnosis.