Blood Cancers: Investigations and Treatment
For hematologic malignancies, initiate diagnostic workup with bone marrow aspiration for myeloid neoplasms, acute leukemias, and myeloma, or peripheral blood for lymphoproliferative disorders like CLL, combined with comprehensive cytogenomic analysis including chromosome banding and FISH, followed by next-generation sequencing to identify actionable molecular targets that directly guide selection of targeted therapies.
Diagnostic Investigations
Sample Selection by Disease Type
The tissue choice is disease-specific and critical for accurate diagnosis 1:
Myeloid neoplasms, acute leukemias, and myeloma: Bone marrow is essential (0.5-1 ml minimum, first draw preferred to avoid hemodilution). Peripheral blood is only acceptable if significant circulating disease is present 1.
Lymphoproliferative disorders (CLL): Peripheral blood is preferred, with bone marrow as alternative if infiltrated 1.
Lymphomas: Lymph node or primary site biopsy is required. Bone marrow or peripheral blood analysis is inappropriate unless morphological/immunophenotypic evidence of infiltration exists 1.
Core Cytogenomic Testing
All samples require comprehensive cytogenomic analysis with at least two independent analysts 1:
- Chromosome banding analysis with at least two different culture conditions
- FISH (fluorescence in situ hybridization) on bone marrow/peripheral blood smears
- Molecular profiling using next-generation sequencing (NGS), whole-exome sequencing (WES), and RNA sequencing 2
Advanced Molecular Diagnostics
Next-generation sequencing panels are now standard of care in England and should identify disease-specific molecular targets 3:
- AML: FLT3, IDH1/2, NPM1, CEBPA mutations
- ALL: Philadelphia chromosome (BCR-ABL1), Ph-like subtypes
- CML: BCR-ABL1 kinase domain mutations
- CLL: TP53, IGHV mutation status, del(17p), del(11q)
- DLBCL: Cell-of-origin subtypes (GCB vs ABC), MYC/BCL2/BCL6 rearrangements
- Multiple Myeloma: Cytogenetic risk stratification including t(4;14), t(14;16), del(17p)
Germline Testing Considerations
When somatic NGS identifies potential germline variants, particularly in TP53, DDX41, RUNX1, CEBPA, ETV6, ANKRD26, or GATA2, immediate germline confirmation testing is required 3, 4. This is especially critical before allogeneic transplantation to avoid using affected family donors 4.
Monitoring Technologies
- Minimal residual disease (MRD) monitoring using flow cytometry or molecular methods for treatment response assessment 2
- Liquid biopsy for non-invasive disease monitoring 2
- PET/CT imaging for staging and response assessment in lymphomas and selected cases 5
Treatment Strategies
Targeted Therapy Selection Based on Molecular Profile
Treatment must be molecularly directed rather than empiric 6:
AML-Specific Targets
- FLT3-ITD or TKD mutations: FLT3 inhibitors (midostaurin, gilteritinib)
- IDH1 mutations: Ivosidenib
- IDH2 mutations: Enasidenib
- BCL-2 overexpression: Venetoclax combinations 6
CLL-Specific Targets
- BTK inhibitors (ibrutinib, acalabrutinib) for first-line or relapsed disease
- BCL-2 inhibitors (venetoclax) particularly for del(17p) or TP53-mutated disease 6
CML
- BCR-ABL1 tyrosine kinase inhibitors: Imatinib first-line, with second/third-generation TKIs (dasatinib, nilotinib, bosutinib, ponatinib) for resistance mutations 6
Lymphomas
- CD20-positive B-cell lymphomas: Rituximab or obinutuzumab-based regimens
- Bispecific antibodies for relapsed/refractory disease 6
Immunotherapy Approaches
CAR T-cell therapy has demonstrated efficacy in relapsed/refractory leukemia and lymphoma, particularly:
Common pitfall: CAR-T therapy carries risks of cytokine release syndrome and neurotoxicity requiring specialized monitoring and management capabilities.
Therapeutic Drug Monitoring
For drugs with narrow therapeutic windows, therapeutic drug monitoring (TDM) should guide dose adjustments 7:
- Established TDM: Methotrexate, cyclosporine, antifungals, antibiotics
- Emerging TDM applications: BCL-2 inhibitors, BCR-ABL TKIs, FLT3 inhibitors, BTK inhibitors
- 71% of clinicians modify treatment based on TDM results, with faster turnaround times strongly associated with clinical action 7
Allogeneic Transplantation Considerations
When germline predisposition is identified (DDX41, ETV6, CEBPA, RUNX1, ANKRD26, GATA2), urgent multidisciplinary evaluation is required involving hematologists, clinical geneticists, and laboratory geneticists to:
- Confirm germline status
- Screen potential family donors for the same variant
- Consider unrelated or haploidentical donors if family members are affected 4
Critical Implementation Points
Quality Assurance Requirements
- Laboratories must comply with ISO-15189 standards
- Written protocols for all pre-analytical, analytical, and post-analytical procedures
- Participation in appropriate external quality assessments 1
- At least two independent analysts for all cytogenomic analysis 1
Common Pitfalls to Avoid
Sample quality: Using hemodiluted bone marrow samples reduces diagnostic yield—always request first draw 1
Tissue mismatch: Analyzing peripheral blood for lymphomas without documented infiltration leads to false-negative results 1
Incomplete molecular profiling: Failing to perform NGS in 2025 misses actionable targets that could change treatment selection 2, 3
Ignoring germline implications: Not recognizing potential germline variants before transplant donor selection can lead to using affected donors 4
Delayed turnaround: Slow TDM reporting reduces clinical utility—faster results correlate with treatment modifications 7
Integration Barriers
Despite advances, high costs, access disparities, lack of standardization, and integration barriers in clinical practice remain significant challenges 2. However, precision medicine approaches driven by molecular diagnostics continue to refine individualized treatment strategies and improve outcomes across all hematologic malignancies 2, 6.