Acute Lymphoblastic Leukemia (ALL)

Definition malignancy of lymphoid cells, affecting either B or T lymphocyte cell lines arrest maturation & promote uncontrolled proliferation of immature blast cells, with bone marrow failure & tissue infiltration

Etiology genetic susceptibility (translocations, gains, losses of whole chromosomes) + environmental trigger- ionizing radiation(eg. x-ray during pregnancy)- Down's syndrome CNS involvement is common

Epidemiologycommonest cancer of childhood

Signs & Symptoms marrow failure- anemia d/t decreased Hb- bleeding d/t decreased platelets- infections d/t decreased WCC infiltration- hepato- & splenomegaly- lymphadenopathy (superficial or mediastinal)- orchidomegaly- CNS involvement common infections- esp. chest, mouth, perianal, skin- bacterial septicemia, zoster, CMV, measles, candidiasis, PCP

Investigation results characteristic blast cells on blood film & bone marrow CXR, CT: mediastinal & abdominal lymphadenopathy LP: CNS involvement

Treatment educate & motivate support- blood, platelet transfusion- IV fluids- allopurinol prevents tumor lysis syndrome- insert subcutaneous port/Hickman line for IV access infections*dangerous d/t neutropenic status d/t Rx/disease- immediate IV Abx- neutropenic regimen + prophylactic antivirals, antifungals, antibiotics*co-trimoxazole can prevent PCP but can worsen neutropenia chemotherapy- enter into national clinical trials1. remission induction2. consolidation3. CNS prophylaxis4. maintenance matched related allogeneic marrow transplant- once in 1st remission (young patients)*Hematological remission: no evidence of leukemia in blood, a normal or recovering blood count, & <5% blasts in normal regenerating marrow

Prognosis  70-90% cure rates for children, 40% for adults (higher if imatinib used) poor prognosis if- adult- male- Ph+- presentation w CNS signs- Hb low or WCC high (>100x10^9/L) or B-cell ALL

Classification morphological- FAB, 3 types (L1, L2, L3)- by microscopic appearance immunological- by surface markers- precursor B-cell ALL, T-cell ALL, B-cell ALL cytogenetic- chromosomal analysis- useful for predicting prognosis & detecting disease recurrence

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