Overview

Leukemia and myelodysplastic syndromes (MDS) are malignant disorders of normal hematopoiesis. The complications of leukemia or MDS are due to either the excess accumulation of morphologically immature cells (blasts) or the reduced or absent production of leukocytes, red blood cells, or platelets, i.e., pancytopenia. Myeloproliferative disorders (MPD) are distinct disorders of hematopoiesis that initially involve excess production of mature blood cells. Table 39.1 summarizes the estimated incidence, median survival, and likelihood of cure with contemporary treatment. Untreated leukemia is uniformly and rapidly fatal due to the infectious or hemorrhagic complications of the pancytopenia. Treatment produces a relatively modest prolongation of life for the majority of patients with leukemia. The prolonged median survival of certain subtypes of MDS and MPD is due to their relatively benign behaviors. However, except for the uncommon individual cured of the disease or who dies of unrelated causes, patients with leukemia, MDS, or MPD will succumb to complications of progressive pancytopenia either due to leukemia refractory to chemotherapy or marrow fibrosis. The complications are enumerated in the section entitled “Caring for the individual with advanced leukemia.”

We define the term, advanced leukemia, as the phase of the disease when the likelihood of benefit from conventional therapy does not justify the potential toxicity of therapy. The likelihood of benefit is influenced by factors such as age, overall health, characteristics of the disease, and whether the disease is newly diagnosed or recurrent.