**5.4 Approach to AML diagnostic algorithms**

500 Advances in Cancer Therapy

prognostic value of quantitative PCR in MRD diagnostics in these subgroups was demonstrated in several studies. Patients with an MRD level<1% after induction chemotherapy in relation to initial diagnosis had a relapse rate of 8% in contrast to 91% in the patients with MRD levels of ≥1% in the investigation on the CBF-leukemias by Krauter et al.,2003. Marcucci et al, 2000, were able to define a distinct transcript copy number in inv(16)/CBFB/ MYH11 below which relapse was unlikely and above which relapse occurred with high probability. A Gruppo Italiano Malattie Ematologiche Maligne dell' Adulto (GIMEMA) trial showed that molecular switch from CR to PML/RAR positivity was followed by hematologic relapse after a median time of 3 months in 95% of all APL cases (Diverio et al. 1998). Data from different studies indicate that of all AML subtypes, quantitative PCR monitoring could be best established for the reciprocal gene fusions. Molecular analyses enabled 23.7% of the cases of our study to be classified in the adequate genetic entities of AML with different prognosis requiring different therapeutically

**5.3 Analyses of the clinical characteristics of the patients in the era of modern** 

Several studies support the use of the ECOG performance status as a measure of physical functioning and prognosis in patients with AML (Oken et al. 1982). A retrospective study of data from five Southwestern Oncology Group (SWOG) trials that included 968 patients with AML found that the mortality rate within 30 days of initiation of induction therapy is dependent upon both the patient's age and ECOG performance status at diagnosis. A second retrospective analysis of 998 patients age 65 or greater (range 65 to 89; median 71 years) who underwent intensive induction chemotherapy reported eight-week mortality rates of 23, 40, and 72 percent for patients with ECOG PS of zero to 1, 2, and 3 to 4, respectively. One-year overall survival rates for the same groups were 35, 25, and 7 percent, respectively. A third retrospective study of 2767 patients with non-APL AML from the Swedish acute leukemia registry also reported that older patients with an ECOG PS of zero to 1 had 30 day death rates after intensive chemotherapy of less than 15 percent, while patients with a PS of 3 or 4 had higher early death rates regardless of patient age ranging from 26 to 36 percent. Seventy percent of patients up to age 80 years had a PS of zero to 2. A prospective trial of induction chemotherapy with cytarabine plus daunorubicin in 811 older adults (median age 67 years, range 60 to 83 years) with ECOG PS of zero to 2 reported a 30 day mortality rate of 11 percent (Appelbaum et al, 2006). We used the EKOG performance status score in initial randomization of our AML patients for different induction and consolidation approaches, in order to avoid intensive induction and consolidation treatment for patient with EKOG performance status higher than 2. Only 8 (12.5%) patients from our study group have EKOG performance status higher than 2, but only 3 of those patients were

Comorbidity is an also a distinct additional clinical entity that exists or may occur during the clinical course of patient with a primary disease (i.e. AML). Comorbid conditions are poor prognostic factors especially in older patients with AML. Patients with age-related

approach.

**diagnosis of AML** 

younger than 60 years of age.

**5.3.2 Analyses of the comorbidities** 

**5.3.1 Analyses of the EKOG performance status** 

Modern diagnostic approaches in the AML should be created as integral and basic parts of optimized treatment concepts for the benefit of the each individual patient. The ultimate test of any disease diagnostic algorithm approach is its usefulness in guiding the selection of effective treatment strategies. Algorithms that provide a basis for risk-adapted therapeutic choices may include immunological markers, cytogenetic factors, molecular markers as well as clinical parameters (e.g., age, attainment of an early or late complete remission) and hematological determinants (e.g., secondary AML, white blood cell count at diagnosis) (Haferlach et al., 2007).

A comprehensive approach in diagnosis, classification, and treatment follow-up in patients with acute leukemias can, therefore, be suggested by diagnostic algorithms, which also show the relationship and the hierarchy between single methods. These standard guidelines for AML mostly result from a combination of different methods and intend to add prognostic information (Lowenberg 2008).

Our diagnostic algorithm for AML (as shown in Fig. 8) starts with cytomorphology and cytochemistry. These methods should be performed in combination: cytomorphology and cytochemistry allow rapid classification of the acute leukemias and further enables the choice of the antibody panel for flow cytometric analyses. In case cytomorphology gives indices for characteristic aberrations—in the FAB subtypes M3/M3v for t(15;17)/PML/ RAR, in FAB M4eo for inv(16)/CBF/MYH11, or in M1/2 with the characteristic long Auer rods for the t(8;21)/AML1/ETO, PCR analyses for these rearrangements should be promptly applied.

Especially in case of suspicion for APL due to clinical symptoms or due to the morphological findings, RT-PCR for PML/RARshould be initiated as soon as possible (Schoch et al., 2002). We think that, regardless of the morphological, cytochemical and immunological futures of the blast cells, RT-PCR for the fusion oncogene PML/RARare recommendable in all AML cases. The RT- PCR method is the most sensitive and rapid technique for detection of this oncogene and provides an optimal basis for MRD analyses. Further we suggest all AML cases which are PML/RARnegative to be tested for the presence of the reciprocal fusions genes that describe CBF-AML, AML1/ETO and CBF/MYH11.Those analyses provides the basis for sub-classification of the AML cases in prognostically relevant subclasses. This is the prerequisite for adequate individual clinical risk stratification and therapeutic decisions.

Moreover, we correlated the obtained result for the applied multimodal diagnostic approach with the patient age, EKOG performance status and comorbidities, which allowed us to optimize the individual risk stratification for each AML patient.

Immunophenotyping of the Blast Cells in Correlations with

requiring different therapeutical approach.

stratification in treatment protocols of the patients.

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The applied multimodal diagnostic approach consisted of minimal number of cytomorphological, cytochemistry, immunological and molecular analyses enables improved and more precise diagnosis and clinical stratification in 38.2% acute leukemia patients from our study. Moreover, when we correlate those results with the results obtained from the analyses of the EKOG performance status and the incidence of the serious comborbidities in our study group, an additional 12.5% of the patients were stratified to a different risk adapted therapy. Our initial results are consistent with literature data and indicate that our applied multimodal diagnostic approach improved the diagnosis of the specific genetic entities of AML in which specific treatment approach is indicated and allows individual clinical

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Fig. 8. Diagnostic algorithm and algorithm for risk adapted therapy in AML patients
