Hemoblastosis are bone marrow and extra-bone marrow neoplastic processes represented by two groups of diseases – myeloproliferative (leukemia) and lymphoproliferative (hematosarcoma). Hyperplastic, intoxication, hemorrhagic, anemic, immunodeficiency syndromes are common for all forms. Diagnosis includes a general blood test; sternal puncture, trepanobiopsy, lymph node biopsy with examination of the material; instrumental studies (ultrasound, radiography). Treatment of hemoblastosis, mainly chemoradiotherapy; in some cases, bone marrow transplantation may be indicated.
Hemoblastosis are malignant tumor diseases characterized by primary lesions of hematopoietic and lymphatic tissues. Over the past decades, the frequency has been steadily increasing: 7-11 cases of hematopoietic tissue tumors per 100 thousand population are registered annually in Russia, Western European countries and the USA. In the structure of oncological morbidity, among malignant tumors of other localizations, hemoblastosis occupy 5-6 place. It has been noticed that men suffer from hemoblastosis more often than women, and rural residents are less likely than the urban population. Acute lymphoblastic leukemia prevails with absolute frequency in children of the first 5 years of life, chronic myeloid leukemia prevails in people aged 20-45 years. The search for adequate ways of prevention, early detection and effective treatment is an acute problem of hematology.
Classification of hemoblastosis
In the structure of hemoblastosis, myeloproliferative and lymphoproliferative diseases are distinguished. The first are represented by leukemias –leukemia) – malignant tumors of hematopoietic tissue with primary bone marrow damage; the second – hematosarcomas, or lymphomas – extra-medullary volumetric formations with primary local growth, mainly in lymph nodes.
At the same time, as they progress, leukemias and hematosarcomas can transform into each other. Thus, with leukemia, tumor cells may metastasize into the pleura, peritoneum, testicles, lymph nodes, and meninges. At the same time, at a certain stage of the development of hematosarcoma, the bone marrow may be involved in pathological processes, i.e. leukemia may occur with the development of blood changes characteristic of leukemia. In some cases, hemoblastosis initially develops as lymphoma-leukemia – a disease that combines signs of bone marrow and extra-bone marrow lesions.
Based on the morphological differences of the cells forming the tumor substrate, leukemias are divided into acute and chronic. The basis of acute leukemia is the proliferation of blast cells, chronic – mainly mature and intermediate cells. The main clinical and hematological forms of acute leukemia are represented by: O. lymphoblastic leukemia of children and adults, O. myeloblastic, O. monoblastic, O. myelomonoblastic, O. megakaryoblastic and other leukemias.
Chronic leukemias are divided into myeloproliferative and lymphoproliferative. These include the following types: chronic myeloid leukemia, chronic lymphocytic leukemia, chronic erythromyelosis, polycythemia, myeloma, etc. Another group of hematoblastoses – hematosarcomas are represented by lymphogranulomatosis (Hodgkin’s lymphoma) and non-lymphogranulomatous/non-Hodgkin’s lymphomas.
Causes of hemoblastosis
Hemoblastosis belong to diseases of a polyethological nature with definitively unexplained causes. Nevertheless, some carcinogenic factors that increase the risk of hematoblastosis have been established for certain. First of all, these are radiation effects on the body of various origins: ultraviolet and ionizing radiation, radiation and radioisotope diagnostics, radiation therapy for other oncological diseases.
Chemical substances (benzene), many drugs (chloramphenicol, phenylbutazone, etc.), including cytostatics (methotrexate, cyclophosphane, chlorambucil, etc.) have a mutagenic effect on cells. This explains the fact that cancer patients receiving chemoradiotherapy for a primary malignant tumor often develop secondary hemoblastosis.
The increased probability of leukemic transformation of myeloid or lymphoid cells is predetermined by certain chromosomal defects, in particular, Down syndrome, Louis-Bar syndrome, Fanconi anemia, Klinefelter syndrome, etc. The etiological role of viral factors (Epstein-Barr virus, retroviruses) and metabolic disorders (disorders of tryptophan and tyrosine metabolism) in the origin of hemoblastosis has been proven.
Hemoblastosis are accompanied by numerous local and systemic manifestations. The manifestation of hemoblastosis can be acute, resembling an acute respiratory viral infection clinic, or slow, latent. The most typical for various forms of hemoblastosis are intoxication, proliferative (hyperplastic), hemorrhagic, anemic syndromes and infectious complications syndrome.
In most cases, the first signs of hemoblastosis are nonspecific symptoms of general intoxication – prolonged unmotivated fever, fatigue, sweating, asthenization. Hyperplastic syndrome in hemoblastosis is characterized by generalized lymphadenopathy (enlargement of the cervical, axillary, inguinal lymph nodes), hepatomegaly and splenomegaly. Ossalgia caused by an increase in bone marrow volume is typical. As a result of compression of the superior vena cava by enlarged intra-thoracic lymph nodes, swelling of the face, neck, upper extremities, shortness of breath (so-called superior vena cava syndrome).
Hemorrhagic manifestations of hemoblastosis include an increased tendency to the formation of subcutaneous and submucosal hemorrhages, the occurrence of gingival, nasal, gastrointestinal bleeding, DIC syndrome. Due to secondary immunodeficiency, resistance to infections decreases in patients with hemoblastosis, so they easily develop pneumonia, septicemia, nosocomial infections, which can have a lightning course and end fatally.
During hemoblastosis, there are stages of exacerbation and remission (complete and incomplete). Complete remission is indicated in the absence of clinical signs of hemoblastosis within a month, normalization of the blood picture, determination of less than 5% of blast cells in the myelogram.
Diagnosis of hemoblastosis
The basis for suspicion of hemoblastosis (except for the clinical picture of the disease) are changes in the hemogram (the number of red blood cells and platelets, the number and morphology of leukocytes, lymphocytes). These deviations from the norm can be different, depending on the form and type of hemoblastosis. All patients with abnormalities in the general blood test should be referred to a hematologist to clarify the diagnosis.
At the next diagnostic stage, a sternal puncture or trepanobiopsy, puncture or open biopsy of lymph nodes is performed to assess hematopoiesis and determine the nature of hemoblastosis. The resulting material is subjected to cytochemical, cytogenetic, histological studies. According to the indications, ultrasound of the liver and spleen, radiography and MSCT of the chest, radiography of the skull, ribs, spine, pelvic bones are performed. Differential diagnosis is required mainly between different forms of hemoblastosis.
Treatment of hemoblastosis is carried out for a long time and in stages: first in a specialized department of the hospital, then in the hematology office of the polyclinic. Standardized treatment programs have been developed for various types of hemoblastosis. The general principles include placing the patient in aseptic conditions (isolated wards with an increased level of protection against infection), conducting therapy aimed at induction and consolidation of remission.
Usually, high-dose mono- or polychemotherapy with cytostatic drugs is chosen as the first line of therapy for hemoblastosis. When positive dynamics is achieved according to the results of the myelogram, the dosage of chemotherapy drugs is reduced to maintenance. In order to correct the blood picture, replacement hemotransfusion therapy (transfusion of erythro-, thrombomass) is carried out. Prevention of infectious complications involves the appointment of antibacterial and antimycotic drugs. In addition to cytostatic therapy, hormone therapy, local irradiation of lymph nodes, spleen, splenectomy may be indicated.
Drug therapy of hemoblastosis can be complicated by cytostatic disease, including agranulocytosis, septicemia, necrotic enteropathy; serum hepatitis, dystrophic liver changes, aplastic anemia, etc. Bone marrow transplantation is an effective and promising method of treating hemoblastosis, but the main difficulty of this procedure lies in the selection of an HLA-compatible donor.
Prognosis and prevention
The prognosis depends on the form of hemoblastosis, the timeliness, correctness and completeness of the treatment courses. Thus, with lymphogranulomatosis, complete remission can be achieved in more than 90% of patients, with acute leukemia – in 60-70%, which allows prolonging the life of patients for years. Many patients with hemoblastosis manage to overcome the 5-year survival threshold and even achieve a full recovery. Meanwhile, the analysis of epidemiological data over the past decades makes it possible to predict an increase in the number of cases of hemoblastosis in the near future.
The prevention of hemoblastosis can be discussed only from the position of reducing contact with potentially dangerous factors – sources of ionizing radiation, chemicals, viral agents. Practically healthy people are recommended to take a general blood test every year.