In summary

In patients with blood cancer, there is an abnormal development of blood cells or cells that make up the bone marrow. Today, more than 50% of affected patients are elderly, while the rests are children or young adults. They can develop three primary forms of blood cancer: myeloma, lymphoma, or leukemia. Treatment of the disease depends on the type of cancer, its degree of aggressiveness, and its stage of progression. It is mainly based on chemotherapy, radiotherapy, bone marrow cell transplantation, and targeted therapies.

Definition of blood cancer

Blood cancers, or hematological cancers, are also qualified as malignant hematopathies. While other cancers appear in an organ, blood cancers originate in the bone marrow. The latter produces and renews hematopoietic stem cells at the origin of all blood cells, namely red blood cells (oxygen transport), white blood cells (body defense), and platelets (coagulation). In patients with hematological cancer, an abnormality is expressed at a certain stage of maturation of these stem cells. Generally, the earlier it appears in the process, the more aggressive the cancer is. Today we know three main categories of blood cancers :


  • Leukemias: localized in the bone marrow and the blood, associated with an abnormal overproduction of white blood cells; these are the most frequent pediatric cancers. There are tricholeukocyte leukemias (rare), acute, lymphoblastic or myeloblastic leukemias, and chronic leukemias, such as Waldenström’s disease, chronic lymphoid leukemias or chronic myeloid leukemias ;


  • Lymphomas: 5th of the most frequent cancers, they concern the lymphatic system, and the tumors are localized in the nodes. There are two primary forms of it: Hodgkin’s lymphomas and non-Hodgkin’s lymphomas (90% of lymphomas, including diffuse large cell B lymphomas, T lymphomas, or follicular lymphomas) ;


  • Multiple myelomas (or Kahler’s disease): in the bone marrow, they are formed by malignant plasma cells.


It should be noted that other bone marrow diseases exist outside these three categories and are considered hematological cancers. These are essentially myeloproliferative syndromes (including Vaquez’s disease and thrombocythemia, linked to mutations that block the proper production of blood stem cells in the bone marrow) and myeloproliferative neoplasms, which involve excessive production of blood cells. The course of the disease, the prognosis, the symptoms, and the treatments vary greatly depending on the type of blood cancer and the patient.


Symptoms of blood cancer

There is significant variability in blood cancers. The symptoms can differ significantly From one patient to another. Sometimes the clinical signs are very pronounced, while in some people, they go unnoticed and are less severe (loss of appetite, general fatigue, etc.). In patients with acute leukemia, the clinical signs arrive suddenly, sometimes within a few days. We most often notice: anemia (decrease in red blood cells in the blood), pallor, fatigue, rapid heartbeat, shortness of breath, bleeding (gums, nose) related to thrombocytopenia (decrease in platelets), unexplained hematomas, and leukopenia (white blood cells decrease in the blood) associated with an increased risk of infection.


Other, less frequent signs may appear: an increase in the size of the nodes, spleen, or liver (most often painless symptoms), swollen and painful gums, and minor skin lesions (leukemides). In patients with chronic leukemia, the disease remains silent and symptom-free for a long time. It can be discovered by chance during a routine blood test (patients have an abnormally high level of lymphocytes). Patients suffering from lymphomas may present with: fever, itching, night sweats, unexplained fatigue, swollen lymph nodes, or a persistent cough. Finally, myelomas essentially involve a substantial weakening of the bones and a significant risk of fractures.


Causes of blood cancer

There is great diversity in blood cancers. Each has different risk factors and is more or less known. The factors highlighted by the research are multiple:


  • age: for example, if leukemia can occur at any age, it is the first childhood cancer. In addition, blood cancers affect more than 50% of cases in elderly individuals;
  • sex ;
  • the ethnic origin ;
  • overweight ;
  • smoking: Tobacco consumption increases the risks of cancers, in particular, blood cancers ;
  • genetic predispositions and family history (with or without a clearly identified gene): this is the case for several blood cancers, and in particular for chronic myeloid leukemia, which involves the Philadelphia chromosome ;
  • exposure to certain substances: benzene and ionizing radiation are involved in leukemia, while non-Hodgkin’s lymphoma is common in farmers regularly exposed to plant protection products ;
  • contact with certain viruses: for example, the Epstein-Barr virus or hepatitis C ;
  • a history of cancer: which required chemotherapy or radiation therapy ;
  • a weakened immune system: by an immunosuppressive treatment, an HIV infection, or a pathology related to immunity.


Blood cancer: when to consult?

Some blood cancers gradually settle down and remain silent for a long time. The patients do not present significant symptoms and discover their pathology by chance during a blood test for a completely different reason. In other patients, the clinical signs are not specific and do not cause concern (loss of appetite, fatigue, minor skin lesions, etc.). But as with any cancer, the success of the treatment lies essentially on the precocity of the diagnosis. Individuals who, as part of their profession, come into contact with substances at risk (pesticides, benzene, ionizing radiation, etc.) must carry out regular control checks. More generally, specific symptoms should prompt a doctor to be consulted: unexplained fever, anemia, pallor, abnormal shortness of breath, repeated fractures or infections, abnormally large nodes, etc.


Examinations and diagnostics of blood cancer

Each form of blood cancer has its symptoms and diagnostic path. In the case of leukemia, the diagnosis is initially based on the blood test, according to the Foundation for Cancer Research. Doctors may suspect this cancer in the case of abnormal NFS (blood count) and excessive white blood cell levels. In case of doubt, the patient is referred to a specialized hematology center to confirm the diagnosis via a myelogram. This painful examination is essential to make a reliable diagnosis of acute leukemia. It consists of taking a bone marrow sample under local anesthesia by puncture in the pelvic bone or the sternum. Once the diagnosis has been confirmed, doctors can carry out other complementary examinations (such as studying chromosomes at the level of abnormal cells) to refine it and choose an appropriate treatment.


Chronic leukemias are diagnosed thanks to the NFS, associated with a clinical examination and immunophenotyping of the cells. The latter is essential to determine the stage of cancer progress (stage A, B, or C). In addition to the blood test and the myelogram, the diagnosis of other blood cancers may involve several other examinations:


Karyotype of the cells: in the case of chronic myeloid leukemia, to highlight the presence of the Philadelphia chromosome ;

removal of tissue from the nodes.


Blood cancer treatments

Once the diagnosis of blood cancer has been made and refined, doctors can develop an adapted treatment strategy, depending on the patient, the type of cancer, its level of aggressiveness, or its progress. Care related to blood cancers can involve :


  • Chemotherapy: the destruction of abnormal cells ;
  • Targeted therapies, alone or combined with other treatments: treatments that target cancer cells and block their proliferation, particularly suitable for lymphomas and certain forms of leukemia ;
  • A blood or marrow cell transplant: the destruction of all abnormal bone marrow cells by chemotherapy, then replacement by healthy cells (coming from a donor by allograft or from the patient by autograft) ;
  • Radiation therapy: use of ionizing radiation that attacks abnormal cells ;
  • A treatment with CAR-T cells (Chimeric antigenic receptor T): an innovative form of immunotherapy based on genetically manipulated autologous cells used to treat certain lymphomas and certain leukemias.


How to prevent blood cancer?

To date, there is no method for screening for blood cancer. Moreover, many risk factors remain poorly known or uncontrollable. Ideally, avoiding exposure to certain harmful substances, such as pesticides or benzene, is recommended. The professionals who are exposed to it must take care to respect the safety and hygiene instructions scrupulously. More generally, adopting a healthy lifestyle based on a good diet and stopping smoking is vital.