Therapy-related AML: A slip of the lip can sink a ship

Myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a family of myeloid cancers with diverse genotypes and phenotypes characterized by ineffective haematopoiesis and risk of transformation to acute myeloid leukaemia (AML). Some epidemiological data indicate that MDS incidence is increasing in resource-rich regions but this is controversial. Most MDS cases are caused by randomly acquired somatic mutations. In some patients, the phenotype and/or genotype of MDS overlaps with that of bone marrow failure disorders such as aplastic anaemia, paroxysmal nocturnal haemoglobinuria (PNH) and AML. Prognostic systems, such as the revised International Prognostic Scoring System (IPSS-R), provide reasonably accurate predictions of survival at the population level. Therapeutic goals in individuals with lower-risk MDS include improving quality of life and minimizing erythrocyte and platelet transfusions. Therapeutic goals in people with higher-risk MDS include decreasing the risk of AML transformation and prolonging survival. Haematopoietic cell transplantation (HCT) can cure MDS, yet fewer than 10% of affected individuals receive this treatment. However, how, when and in which patients with HCT for MDS should be performed remains controversial, with some studies suggesting HCT is preferred in some individuals with higher-risk MDS. Advances in the understanding of MDS biology offer the prospect of new therapeutic approaches.

TP53 mutation defines a unique subgroup within complex karyotype de novo and therapy-related MDS/AML

Among patients with MDS and AML, the presence of TP53 mutation in the context of CK identifies a homogeneously aggressive disease.

TP53 mutation (in particular multihit) identifies an aggressive disease, irrespective of the blast count or therapy-relatedness.

A subset of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) show complex karyotype (CK), and these cases include a relatively high proportion of cases of therapy-related myeloid neoplasms and TP53 mutations. We aimed to evaluate the clinicopathologic features of outcome of 299 AML and MDS patients with CK collected from multiple academic institutions. Mutations were present in 287 patients (96%), and the most common mutation detected was in TP53 gene (247, 83%). A higher frequency of TP53 mutations was present in therapy-related cases (P = .008), with a trend for worse overall survival (OS) in therapy-related patients as compared with de novo disease (P = .08) and within the therapy-related group; the presence of TP53 mutation strongly predicted for worse outcome (P = .0017). However, there was no difference in survival between CK patients based on categorization of AML vs MDS (P = .96) or presence of absence of circulating blasts ≥1% (P = .52). TP53-mutated patients presented with older age (P = .06) and lower hemoglobin levels (P = .004) and marrow blast counts (P = .02) compared with those with CK lacking TP53 mutation. Multivariable analysis identified presence of multihit TP53 mutation as strongest predictor of worse outcome, whereas neither a diagnosis of AML vs MDS nor therapy-relatedness independently influenced OS. Our findings suggest that among patients with MDS and AML, the presence of TP53 mutation (in particular multihit TP53 mutation) in the context of CK identifies a homogeneously aggressive disease, irrespective of the blast count at presentation or therapy-relatedness. The current classification of these cases into different disease categories artificially separates a single biologic disease entity.

Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide

Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.

Clonal evolution in therapy-related neoplasms

Therapy-related myeloid neoplasms (t-MN) may occur as a late effect of cytotoxic therapy for a primary malignancy or autoimmune diseases in susceptible individuals. We studied the development of somatic mutations in t-MN, using a collection of follow-up samples from 14 patients with a primary hematologic malignancy, who developed a secondary leukemia (13 t-MN and 1 t-acute lymphoblastic leukemia), at a median latency of 73 months (range 18-108) from primary cancer diagnosis.

Using Sanger and next generation sequencing (NGS) approaches we identified 8 mutations (IDH1 R132H, ASXL1 Y591*, ASXL1 S689*, ASXL1 R693*, SRSF2 P95H, SF3B1 K700E, SETBP1 G870R and TP53 Y220C) in seven of thirteen t-MN patients (54%), whereas the t-ALL patient had a t(4,11) translocation, resulting in the KMT2A/AFF1 fusion gene. These mutations were then tracked backwards in marrow samples preceding secondary leukemia occurrence, using pyrosequencing and a NGS protocol that allows the detection of low variant allele frequencies (≥0.1%).

Somatic mutations were detectable in the BM harvested at the primary diagnosis, prior to any cytotoxic treatment in three patients, while they were not detectable and apparently acquired by the t-MN clone in five patients.

These data show that clonal evolution in t-MN is heterogeneous, with some somatic mutations preceding cytotoxic treatment and possibly favoring leukemic development.

[Clinical characteristics and prognosis of 35 patients with therapy-related hematological neoplasms]

目的

探讨治疗相关血液肿瘤的临床特征及预后。

方法

采用细胞形态学、流式细胞术、间期荧光原位杂交技术（I-FISH）、染色体核型分析对35例治疗相关血液肿瘤患者进行诊断和分型并回顾性分析其临床特征及预后。

结果

35例患者中，治疗相关急性髓系白血病（t-AML）20例，治疗相关急性淋巴细胞白血病（t-ALL）4例，治疗相关急性混合细胞白血病1例，治疗相关非霍奇金淋巴瘤（t-NHL) 8例，治疗相关骨髓增生异常综合征（t-MDS）2例。第一肿瘤至治疗相关恶性血液肿瘤的中位发病间隔期为29(16~90）个月，中位生存时间14(1~60）个月，3年累积生存率为17.1%。在25例治疗相关性急性白血病患者中，40.0%（10/25）合并复杂核型，36.0%（9/25）合并MLL断裂基因重排，12.0%（3/25）合并AML-ETO融合基因阳性，1例合并NPM1点突变，1例合并P16基因缺失。

结论

治疗相关血液肿瘤患者的预后差。

Therapy-related myelodysplastic syndromes, or are they?

The incidence of therapy-related myelodysplastic syndromes (t-MDS) is increasing as the number of cancer survivors is increasing. While t-MDS is currently defined descriptively by prior receipt of chemotherapy and/or radiotherapy, some forms of MDS that occur post localized radiation monotherapy, biologically and clinically resemble de novo (d)-MDS more than t-MDS, and therefore may not be truly therapy-related. Although patients with t-MDS, as a group, fare worse than patients with d-MDS, a variation in individual outcomes of patients with t-MDS has increasingly been appreciated. As such, accurate risk stratification is important for counseling of patients and for clinical decision making. Most of the current clinical tools used for prognostication in t-MDS were developed for d-MDS and were not specifically validated in patients with t-MDS. The management of patients with t-MDS remains challenging, highlighting the importance of developing effective prevention strategies as well as newer, targeted, and rationally-designed therapeutic interventions.

Therapy-related myeloid neoplasms: what's in a name?

PURPOSE OF REVIEW

Therapy-related myeloid neoplasms (tMN) are increasingly recognized and studied diseases which have traditionally been defined clinically. With advances in methods used to study the genetics of aging and myeloid disease biology, novel insights are emerging which are expected to improve our understanding of the genetics and pathogenesis of tMN.

RECENT FINDINGS

Clinical outcomes in tMN and de novo MDS/AML appear to be largely determined by genetics, and data are emerging to show how DNA mutations may enhance tMN risk stratification. The discovery of skewed hematopoieses and mutations in healthy older adults suggests an alternate predisposition mechanism for the genesis of tMN. Patients with tMN do respond to standard therapy and can benefit from allogeneic transplant in a manner similar to their genetically matched de novo counterpart.

SUMMARY

De novo MDS/AML and tMN have shared genetic features, and tMN clinical outcomes may depend more on the genetics at presentation than the clinical history of an antecedent malignancy. Acquired somatic mutations in genes such as TP53 and myeloid skewing with associated mutations in cancer-free older adults may predispose such individuals to tMN under the influence of myelosuppressive therapy, and this may be a route to the development of a subset of tMN.

Novel Therapeutics for Therapy-Related Acute Myeloid Leukemia: 2014

Effective treatment options for adults with therapy-related AML continues to be an area of unmet need. Genetic and molecular changes within these leukemias confer resistance to standard chemotherapy regimens. Emerging developmental therapeutics in this area has focused on several approaches. These include; novel delivery of chemotherapy as well as newer DNA-damaging agents delivered through antibody-drug conjugates, increased use of hypomethylating agents, and molecularly-directed small molecules against specific mutations commonly occurring in secondary AML. Results of this efforts are encouraging, but to date, no clear improvements have been demonstrated in this most difficult to treat population.

Defining AML and MDS second cancer risk dynamics after diagnoses of first cancers treated or not with radiation

Risks of acute myeloid leukemia (AML) and/or myelodysplastic syndromes (MDS) are known to increase after cancer treatments. Their rise-and-fall dynamics and their associations with radiation have, however, not been fully characterized. To improve risk definition we developed SEERaBomb R software for Surveillance, Epidemiology and End Results second cancer analyses. Resulting high-resolution relative risk (RR) time courses were compared, where possible, to results of A-bomb survivor analyses. We found: (1) persons with prostate cancer receiving radiation therapy have increased RR of AML and MDS that peak in 1.5-2.5 years; (2) persons with non-Hodgkin lymphoma (NHL), lung and breast first cancers have the highest RR for AML and MDS over the next 1-12 years. These increased RR are radiation specific for lung and breast cancer but not for NHL; (3) AML latencies were brief compared to those of A-bomb survivors; and (4) there was a marked excess risk of acute promyelocytic leukemia in persons receiving radiation therapy. Knowing the type of first cancer, if it was treated with radiation, the interval from first cancer diagnosis to developing AML or MDS, and the type of AML, can improve estimates of whether AML or MDS cases developing in this setting are due to background versus other processes.

Therapy-Related Myeloid Neoplasms

OBJECTIVES

In the 2008 World Health Organization classification, cases of acute myeloid leukemia (AML) and myelodysplastic syndrome that arise after chemotherapy or radiation therapy for a primary neoplasm are considered together as therapy-related myeloid neoplasms (TR-MNs). This concept, however, is not universally accepted since there are confounding variables in attributing myeloid neoplasms to earlier therapies.

METHODS

Cases in session 6 of the 2013 Workshop of the Society for Hematopathology/European Association for Haematopathology illustrated myeloid neoplasms thought likely to be TR-MNs, and discussed the differences and biologic similarities with de novo myeloid neoplasms.

RESULTS

We reviewed data showing that diagnosis of TR-MN alters patient outcome only in specific subsets. The session also included examples of therapy-related AML with recurrent genetic abnormalities, such as t(15;17), inv(16), and t(8;21), and reports were highlighted showing that patients with these neoplasms have clinical outcomes similar to patients with their de novo counterparts.

CONCLUSIONS

The study of TR-MNs will likely provide insight into the pathogenesis of de novo myeloid disease and may explain why some patients with cancer develop TR-MN and evidently have a higher genetic susceptibility, whereas most patients treated with the same agents do not. These studies will also result in critical reappraisal of current concepts related to TR-MNs.