Oncology Flashcards
MC form of cancer in children (30%)
Leukemia
What are the types of Leukemia?
Types:
o Acute lymphoblastic leukemia (ALL): MC
o Acute myelogenous leukemia (AML)
o Chronic myelogenous leukemia (CML)
o Juvenile myelomonocytic leukemia (JMML)
What is Acute Lymphoblastic Leukemia?
ACUTE LYMPHOBLASTIC LEUKEMIA (ALL)
Etiopatho
- Malignant proliferation of lymphoblasts
- Peak at 2-6yo, M>F
- Etiology unknown
- RF: down syndrome, Neurofibromatosis type I,
exposure to medical diagnostic radiation in utero and
in childhood, drugs (alkylating agents, benzene
exposure, advanced maternal age)
Patho
- Multifactorial: infection, genetics, environmental exposure –> disruption in the regulation and
proliferation of lymphoid precursor cells in BM –> excessive production of immature blast cells and drop
in RBCs, WBCs, plt
What are the clinical manifestations?
CM
1. Acute onset (<4wks duration of sx)
2. Anorexia, irritability, lethargy, fatigue, - MC
3. Anemia, bleeding, purpuric/petechial lesions, LG fever
– signs of BM failure. MC presenting sx. Results from
clonal proliferation of leukemic blasts in the BM,
preventing normal BM production of RBCS, plt, neu
4. Persistent bone and joint pain, Limp, back pain,
lymphadenopathy, hepatosplenomegaly – signs of
infiltration
5. Weight loss, headache, pallor, dyspnea on exertion,
pallor, dizziness, near syncope
6. Concomitant infections – fever, RTI
7. Dyspnea on exertion, SOB, tachypnea, orthopnea,
stridor – consider anterior mediastinal mass (T-cell ALL)
Oncologic emergencies
Oncologic Emergencies:
1. Hyperleukocytosis – WBC>100,000/uL. Large number of
blasts cause leukostasis –> precipitates dec tissue perfusion
–> neuro and pulmo sequelae.
- CNS: headache, confusion, lethargy, dizziness, BOV,
ataxia, papilledema, retinal hemorrhage, CNS hemorrhage
- Pulmo: tachypnea, hypoxia, CXR infiltrates, Respi
failure, ARDS
- Vasc: peripheral vascular occlusion, thrombosis
- Coagulation: DIC, elev PT and PTT, dec fibrinogen
- Mgt: IV dextrose 5% half-normal saline at 125 ml/m2/h
(no K in IVF). Allopurinol. Rasburicase. plt transfusion.
FFP, cryoprecipitate if with DIC
2. Tumor lysis syndrome (TLS) – metabolic complications that
may occur after the tx of neoplastic disorders
- Hyperphosphatemia, hypocalcemia (caused by
precipitation of Ca phosphate), hyperuricemia, hyperkalemia
- Intracellular contents of malignant cells being spilled
into the circulation –> overwhelm kidney from inc
nucleic acids, K, Ph –> arrhythmia, renal failure
- Laboratory TLS: at least 2 metabolic abN
- Clinical TLS: laboratory TLS + inc crea, sz, cardiac
dysrhythmia, death
- Mgt: hydration, allopurinol, hemodialysis (severe)
Diagnostics
Dx
1. BM aspiration biopsy – definitive dx test. >25% of BM
cells are homogenous population of lymphoblasts
2. CBC – anemia, thrombocytopenia, atypical
lymphocytes, hyperleukocytosis (some, WBC
>100x109/L), neutropenia. Usually more than 1 cell
line affected.
3. PBS – blasts
4. PT, PTT, fibrinogen, LFT, BUN, Crea, Cx
5. Infection evaluation
6. CXR – mediastinal mass (T cell immunophenotype)
7. CSF – if with CNS involvement (lymphoblasts)
8. Immunophenotyping (flow cytometry) and
electrophoresis – required for accurate dx. guide
selection of chemo protocol
What are the differences between the STANDARD and HIGH RISK?
—–STANDARD—– (good prognosis)
Age: >1yr old and <10yrs old
WBC at diagnosis: <50 x 10^9/L
Immunophenotype: Pre B-cell
CNS involvement: Negative
Response to steroids: Day 7 absence of blast on PBS
—–HIGH RISK—–
Age: <1yr old and >10yrs old
WBC at diagnosis: >50 x 10^9/L
Immunophenotype: T-cell, mature B, biphenotypic
CNS involvement: Positive
Response to steroids: Day 7 presence of blast on PBS
Management
Mgt
1) Refer to Hema-Onco for mgt
The single most impt prognostic factor for ALL is receiving
treatment
2) Standard tx: multiagent chemotherapy for 2-3 yrs with goal of eradicating detectable leukemia cells or remission:
c. BMA blast cell count <5% (remission)
d. Return of neutrophil and plt counts to near-
N levels
Phases of chemo:
1. Remission induction – eradicate leukemic cells from
the BM: vincristine, prednisone, cyclophosphamide,
doxorubicin, L-asparaginase x 4-6wks
- Consolidation – focuses on intensive CNS tx in
combination with continued intensive systemic tx:
cytarabine, MTX - Intensification – phase of aggressive tx as well as
relatively non-toxic phase of tx depending on risk
stratification: Vincristine, asparaginase,
cyclophosphamide, MTX - Maintenance – given to maintain px on remission: 6-
mercaptopurine, MTX, CS, vincristine
3) Bone marrow transplantation – for pxs with poor prognostic
features: high incidence of relapse, induction failure, extreme
hypodiploidy
4) Pneumocystis carinii PN prophylaxis – TMP-SMX 5-10 mkd
q12 x 3 consecutive days/week
What is AML?
relative frequency of AML increases in adolescence
CM: signs of marrow failure, subcutaneous nodules or “blueberry muffin” lesions, gingival infiltration, DIC, chloromas
Diagnosis: >20% of bone marrow cells consist of homogenous population of blast cells
Management: Chemo, stem cell transplantation
What is CML?
CML
-associated with Philadelphia chromosome translocation resulting in BCR-ABL fusion protein gene
CM: nonspecific symptoms, splenomegaly, initial chronic phase (3-4yrs) with mild anemia and thrombocytosis; after chronic phase, moves into accelerated or blast crisis phase with course similar to acute leukemia
Dx: high WBC count with myeloid cells at all stages of differentiation in the PBS and BM (usually the same appearance under the microscope)
Management: Imatinib, Dasatinib, (BCR-ABL tyrosine inase inhibitor)
Hydroxyurea
What is JMML?
typically affects <2yrs
CM: rashes, lymphadenopathy, splenomegaly, hemorrhage
Dx: luekocytosis with increased monocytes, thrombocytopenia, anemia with erythroblasts, myelodysplastic pattern in BM
Management: Stem cell transplantation
AML worse prognosis than ALL
