Hematology and Oncology
scanning electron microscopy of erythrocytes
Hematology and Oncology* have traditionally been trotted out in public as siblings, or at least first cousins, something that we probably owe to Sir William Osler, Canadian-American physician who has been called the father of modern medicine. In addition to his central contributions to the creation of the Johns Hopkins School of Medicine, he wrote The Principles and Practice of Medicine, which was first published in 1892 and ended its print run in 2001. In it, the chapter on diseases of the blood divided them into anaemias, leukemias* and Hodgkin disease, a traditional link which has carried over to the 21st century.
*For the purposes of this website, selection of material, and to reduce the potential for confusion by laypersons who might end up here, a separate section, focused on “non-liquid” oncology (solid cancers) alone is in preparation and will appear later this year – author’s note.
The combined field–popularly, hem-onc, has progressed by fits and starts since Anton van Leeuwenhoek, the father of microscopy first described erythrocytes in 1674. The field of haematology spun wheels for the next century until Hewson, the English father of haematology, discovered white cells, fibrinogen, the first anticoagulant, and the basics of coagulation (1770 to 1774).
The 19th century saw an acceleration of haematology discoveries–e.g., that bone marrow plays a central role in haematopoiesis and that platelets play a key role in haemostasis and thrombosis; descriptions–e.g., of Hodgkin disease (see bottom image, which shows a classic Reed-Sternberg mirror cell, dead centre), leukaemia, white cell subtypes, and phagocytosis; and firsts–first successful blood transfusions.
Hodgkin disease, mixed cellularity type with classic Reed-Sternberg cell, dead centre
The early 20th century could be viewed as golden age of haematology, that began with Landsteiner’s discovery of the ABO blood group system, which finally allowed previously elusive safe transfusions. The same era saw the first descriptions of hematologic diseases–sickle cell anaemia, thalassaemia, von Willebrand disease, Fanconi syndrome, and infectious mononucleosis; and first descriptions of newly recognised malignancies–e.g., polycythemia vera, Waldenström’s macroglobulinemia. The first half of the 20th century also saw new tests, including prothrombin time for clotting and the Coombs test to identify incomplete antibodies, and effective therapies–e.g., factor 8 for haemophilia, vitamin B12 for pernicious anaemia, and nitrogen mustard, the first consistently effective agent for managing lymphomas and leukemias.
The latter half of the 20th and 21st centuries have seen massive strides in understanding the pathogenesis of haematologic disorders and development of effective therapies for managing them. Many non-malignant haemopathies respond to simple manoeuvres in the form of supplemental iron (for hypochromic anaemia) and vitamins (B12 for megaloblastic anaemia). Other non-malignant haematologic disorders respond to recombinant products–e.g., erythropoietin, which is used for anaemia from myelodysplastic syndrome, anaemia of prematurity, anaemia associated with chronic renal failure, and factor VIIa, which is used for haemophilia A and B, factor VII deficiency and Glanzmann’s thrombasthenia, blood components–e.g., platelet concentrates for thrombocytopenia and packed red cells for trauma victims.
The newest weapons being brought to bear against haematologic malignancies are stem cells and monoclonal antibodies. The former, if donated–i.e., of non-self origin, carry the risk of graft-versus-host disease (GVHD). The hope is to develop monoclonal antibodies against the donor lymphocytes causing GVHD. On the horizon and in some cases, approved for use in humans, is a growing pipeline of monoclonal antibodies–e.g., obinutuzumab, which may by used in combination with chlorambucil as a first-line therapy or, like alemtuzumab, to manage CLL that is unresponsive to standard chemotherapy.