Life-Limiting Conditions in Adult Patients · 3 min read
Leukemia
Definition and Classification
Leukemia is a malignancy of the blood-forming tissues, primarily affecting the bone marrow and lymphatic system. It results from uncontrolled proliferation of abnormal white blood cells that crowd out normal hematopoietic cells. Classification depends on the cell line affected and the rate of disease progression.
Acute leukemias involve immature cells (blasts) that proliferate rapidly and require immediate treatment. Chronic leukemias involve more mature cells, progress slowly, and may remain stable for years before requiring intervention.
The four major types are acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myeloid leukemia (CML). ALL predominantly affects children but can occur in adults, particularly those over 50. AML is the most common acute leukemia in adults. CLL is the most common leukemia in Western countries and typically affects older adults. CML is associated with the Philadelphia chromosome translocation.
Pathophysiology
Leukemia originates from a single mutated hematopoietic stem cell or progenitor cell. Genetic mutations disrupt normal cell differentiation and apoptosis pathways. The malignant clone proliferates uncontrollably, accumulating in bone marrow and eventually spilling into peripheral blood.
Bone marrow failure results from replacement of normal marrow by leukemic cells. This leads to anemia from decreased red blood cell production, thrombocytopenia from decreased platelet production, and neutropenia from decreased functional white blood cell production. Leukemic cells may infiltrate other organs including the liver, spleen, lymph nodes, central nervous system, skin, and gums.
Clinical Manifestations
Patients typically present with symptoms related to bone marrow failure. Fatigue, weakness, pallor, and dyspnea on exertion result from anemia. Easy bruising, petechiae, epistaxis, gingival bleeding, and prolonged bleeding from minor cuts indicate thrombocytopenia. Recurrent infections, fever, and opportunistic infections reflect neutropenia and immune dysfunction.
Additional symptoms include bone pain from marrow expansion, hepatosplenomegaly causing abdominal fullness, lymphadenopathy, weight loss, night sweats, and anorexia. CNS involvement may cause headache, visual changes, cranial nerve palsies, and altered mental status. Gingival hyperplasia is characteristic of certain AML subtypes.
Disease Trajectory and Prognostication
Acute leukemias without treatment progress rapidly to death within weeks to months. With treatment, outcomes vary widely based on patient age, performance status, cytogenetic and molecular features, and response to initial therapy. Cure is possible in some patients, particularly younger individuals with favorable-risk disease.
Chronic leukemias follow a more indolent course. CLL may never require treatment in some patients (watch-and-wait approach), while others progress to aggressive disease. CML has been transformed by tyrosine kinase inhibitors, with many patients achieving long-term disease control. Transformation to acute leukemia (blast crisis) carries a poor prognosis.
Poor prognostic factors include advanced age, poor performance status, high white blood cell count at diagnosis, unfavorable cytogenetics, failure to achieve remission with initial therapy, and relapsed or refractory disease. Median survival after relapse is typically measured in months.
Hospice and Palliative Care Considerations
Patients may transition to hospice when curative therapy is no longer effective or desired, when the patient declines further aggressive treatment, or when comorbidities preclude additional therapy. The decision to pursue hospice care should involve honest discussions about prognosis, treatment burden, and patient goals.
Symptom management focuses on transfusion support for symptomatic anemia and bleeding, infection prevention and treatment, pain control for bone pain, management of tumor lysis syndrome if it occurs, and treatment of treatment-related toxicities.
Transfusion decisions in hospice require careful consideration. Continued transfusions may be appropriate if they significantly improve quality of life and align with patient goals. However, transfusions become less effective over time and may prolong the dying process without improving comfort.
Psychosocial support addresses the often-rapid decline, young age of some patients, impact on family caregivers, and anticipatory grief. Patients may struggle with the transition from aggressive treatment to comfort-focused care.
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