HEMATOLOGICAL ABNORMALITIES OF DISSEMINATED CANCER

The hematological malignancies, that is, leukemia and lymphoma, have hematological abnormalities as a central part of the disease process. Thus, deficiency of host defense and hemorrhagic diathesis are the most prominent complications.4 For other types of disseminated cancer, hematological abnormalities may affect any of the three formed elements of the blood; red celis, white cells, or platelets.’ For red cells, extensive metastases to the bone marrow can result in myelophthisic anemia. This form of anemia is characterized by a very disturbed red cell maturation, resulting in a high proportion of nucleated red cells circulating in the blood. This hematologic abnormality should lead to bone marrow examination to confirm metastatic disease of the bone marrow. Management, of course, depends on control of the metastatic disease and replacement transfusion with allogeneic red cells. The commonest form of anemia associated with metastatic disease results from blood loss when metastases occur on surfaces which result in bleeding, particularly in the gastrointestinal tract. Hemolytic anemia is characteristically associated with lymphomas and leukemias and rarely seen with other kinds of malignancies. A deficiency of platelets can occur with wide spread metastatic disease of the bone marrow, although this is not very common. Any disorders resulting in splenomegaly will be associated with a lowered concentration of platelets in the blood, but generally not symptomatic. Hematological malignancies like polycythemia vera and chronic granulocytic leukemia can result in thrombocytosis. In the presence of wide spread metastases, a syndrome of disseminated intravascular coagulation can occur. This is most common in acute promyelocytic leukemia; however, it has been observed rarely in other disseminated malignancies, particularly from such primaries as prostate and lung. A lowering of platelets associated with a low fibrinogen concentration of the plasma and an increased level of fibrin split products is diagnostic. A syndrome can be controlled acutely with heparin; however, control of the progress of the disease is fundamental to treatment. Platelet replacement transfusion is not useful in this circumstance because of the very short intravascular life span. With wide spread metastatic bone marrow involvement, a decrease in concentration of granulocytes can be observed rarely: this results in an increased susceptibility to infection. Characteristic of far advanced disseminated malignancy is a progressive decrease in circulating lymphocytes, associated with a progressive loss of immunocompetence. The treatment of disseminated cancer generally requires systemic chemotherapy with adjuvant surgery or radiation therapy for major sites of involvement or for palliation. A limiting side effect of treatment for cancer is toxicity to the rapidly turning over bone marrow stem cells; thus, bone marrow failure is a common side effect in treatment of advanced cancer. Therefore, management of bone marrow failure has become an essential part of the treatment of metastatic disease. Replacement transfusion therapy;* i.e. replacement of red cells by transfusion, is a well