Oncology - Leukaemia Flashcards
Definition
Acute lymphoblastic leukaemia = proliferation of lymphoblasts, most commonly of the B cell lineage.
- MC cancer in children and associated with Down Syndrome
- t(12;21) MC cytogenic abnormality in children
Epidemiology
- Bimodal age distribution: 4-5 years and 50 +
- Previous chemotherapy
- Radiation exposure
- Down syndrome: X 20
- Benzene exposure: painters, petroleum, rubber, manufacturers
- Family history
Pathophysiology
Genetic aberrations result in the excessive proliferation of lymphoblasts which accumulate in the bone marrow leading to bone marrow failure, with subsequent anaemia and thrombocytopenia . Lymphoblasts ‘leak’ into the blood and can invade a number of tissues, including the testicles, meninges, and kidneys.
Signs
- Lymphadenopathy
- Hepatosplenomegaly
- Pallor
- Flow murmur due to anaemia
- Parotid infiltration
- Testicular swelling: due to testicular involvement
- Central nervous system (CNS) involvement e.g. meningism, and cranial nerve palsy
Symptoms
- Fatigue
- Loss of appetite
- Easy bruising, prolonged bleeding and mucosal bleeding: due to thrombocytopaenia
- Bone pain: due to bone marrow infiltration
- Weight loss
- Recurrent infections: due to neutropaenia
- Fever: present in half of patients
Treatment
Pre-phase: 5 - 7 days of treatment shortly after diagnosis
- Treat with corticosteroids +/- additional chemotherapy agent
Induction: 4 - 8 week therapy to induce remission, defined as < 5% blast cells in bone marrow
- e.g. corticosteroids , vincristine or doxorubicin (chemotherapy)
- + Imatinib if Philadelphia chromosome-positive
- Intrathecal therapy if there is CNS involvement
Consolidation: Up to 1 year of high-dose chemotherapy , which is started after complete remission
- The aim of treatment is to eliminate clinically undetectable residual leukaemia, hence preventing relapse
Maintenance:
- 2 years of mercaptopurine and methotrexate therapy
- The aim of treatment is to eliminate minimal residual disease (leukemic cells not present on microscopy but cell surface markers still present)
Treatment Second Line
Bone marrow transplantation: may be used as consolidation therapy in people at high risk of relapse, or for treating relapse when it occurs
Complications
2’ to chemo:
- Myelosuppression and neutropaenic sepsis
- Tumour lysis syndrome
2’ to ALL
- Myelosupression and neutropaenic sepsis
- Extramedullary involvement: CNS, testicular and renal involvement
- Infertility: due to lymphoblastic invasion