The bone marrow, peripheral blood or umbilical cord blood transplant
A hematopoietic transplant is another form of treatment which can be used in certain cases. The bone marrow of the patient (which produces the malign cells), is destroyed by administering a high dosage of medication and radiotherapy, and replacing it with a healthy bone marrow. The latter option can be carried out using a donor (allogeneic transplant) or the patient themselves (autologous transplant).
Although hematopoietic transplants were traditionally carried out using hematopoietic stem cells from the bone marrow (bone marrow transplant), nowadays they are usually performed with the stem cells from the venous blood. This is made possible after stimulating the passage of hematopoietic stem cells from the bone marrow. Another possible source is from the umbilical cord blood (which is rich in hematopoietic stem cells and obtained in the moment of delivery).
Read online the Patients' bone marrow transplantation guide (available in Spanish)
What diseases might require a transplant from an unrelated donor?
The bone marrow transplant is one of the selected treatments in many different leukaemia cases but leukaemia is not the only disease which can be cured through this process. With this document we want to inform you of the range of diseases that can be cured thanks to an allogeneic bone marrow transplant (using a donor, which could be a family member or a stranger) (1).
The acute leukaemias (acute lymphoblastic leukaemia – ALL and acute myeloid leukaemia) make up the majority of cases for the Bone Marrow Donor's Registry (REDMO) in the search for non-related donors. For example, in 2012, both of these leukaemias made up more than 45% of the searches initiated by REDMO (2).
Leukaemia consists of the uncontrolled proliferation of an abnormal number of blood cells. These abnormal cells infiltrate the bone marrow, impeding the healthy cells and invading the blood and other organs.
Normally, the acute leukaemias are the most likely to require a bone marrow transplant. In many cases, the chronic leukaemias can be controlled with medication.
The leukaemias which are most likely to require the patient to undergo a hematopoietic transplant are: acute lymphoblastic leukaemia, acute myeloid leukaemia, acute post myelodysplastic leukaemia, acute secondary leukaemia, and chronic lymphocytic leukaemia.
What proportion of patients with leukaemia require a transplant?
Not all patients with leukaemia need of an allogenic transplant (from a donor) from hematopoietic progenitors. For example, only 10% of children with acute lymphoblastic leukaemia (ALL) must undergo this intervention. Furthermore, patients with certain acute leukemias, for example, acute promyelocytic leukaemia, do not need, currently, allogenic transplants. This is also the case of most chronic leukemias, such as chronic myeloid leukemia. Considering this and that patients over 65 years, a priori, can't undergo a transplant of this kind, we can say that 20% of patients with acute leukaemia require an allogeneic transplant.
The lymphomas are a group of neoplastic diseases (cancers) that develop in the lymphatic system, which forms part of the immune system of the human body. There are two main types of leukaemia: Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). It is not common for the patients of Hodgkin's lymphoma to undergo a transplant now that this disease can be controlled with chemotherapy treatment and/or and autologous bone marrow transplant. However, in cases where the aforementioned treatments are not enough a transplant from donor (family member or unrelated) could be used. In 2012, patients diagnosed with Hodgkin's lymphoma made up 5% of the searches started by REDMO. (2)
In the non-Hodgkin's lymphomas, a certain type of lymphocyte is reproduced at an uncontrollable rate, with time causing the growth of the organ in which they are produced. Given that lymphatic tissue is found all around the body, the lymphomas can appear in any part of the organism and disseminate in the liver and other organs and tissues. There are many sub-types of non-Hodgkin's lymphoma and some require an allogeneic transplant of hematopoietic progenitors. The sub-types of non-Hodgkin's lymphoma which are most frequently treated through a transplant are: B, T, or NK cell lymphoma, follicular lymphoma, MALT lymphoma, lymphoplasmacytoid lymphoma, large cell diffused lymphoma, mantle cell lymphoma, Burkitt's lymphoma, anaplastic lymphoma, peripheral T-cell lymphoma, fungoid mycosis or Sézary syndrome and the hepatosplenic lymphoma.
What proportion of lymphoma patients require a transplant?
Lymphomas and, in general, lymphoproliferative syndromes, are currently the most common cause of autologous transplants from hematopoietic progenitors. In the case of Diffuse Large Cell B Lymphoma (the most common histological type of lymphoma), the standard procedure accepted by most transplant organizations and scientific societies include performing transplants in patients after a first relapse, which happens in almost 50% of patients with this subtype of lymphoma. In the rest of histologic subtypes, the procedure depends on multiple factors, and therefore, the decision to transplant must, in many cases, must be individualized and considered in the context of each patient.
In the myelodysplastic síndromes (MDS), the blood stem cells produced by the bone marrow and charged with the development of all the blood cells, do not mature properly and therefore, are not converted into healthy red blood cells, white blood cells or platelets.
In general, less severe cases of MDS do not require any treatment and remain stable for many years. The only definitive cure for MDS is a bone marrow transplant. However, the advanced age of many patients and the toxicity of the aforementioned procedure limit the use of this treatment to younger patients with a poor prognosis, who have a compatible donor available.
Patients with myelodysplastic syndromes most likely to need an allogeneic bone marrow transplant are: refractory anaemia with excess blasts, cytopenia refractory with multilineage dysplasia, chronic myelomonocytic leukaemia, and myelodysplastic syndromes with difficult classifications.
What proportion of patients with myelodysplastic syndromes require a transplant?
Currently a minority of patients with myelodysplastic syndromes require an allogenic transplant and it is only indicated for patients at high risk, young patients with available donors, which happens in 1 of every 4 cases.
*Bone marrow aplasia
Bone marrow aplasia (BMA) is the disappearance of bone marrow stem cells charged with the production of all the blood cells. Patients with a less severe form of aplasia can be practically symptomless and not need any treatment. The method of treatment for more severe forms of bone marrow aplasia in younger patients is a bone marrow transplant.
*Congenital erythrocyturia abnormalities
The erythrocytes (also called red blood cells or haematids) are the most numerous elements in the blood. The haemoglobin is one of its main components, and its objective is to transport oxygen to the different tissues around the body. The congenital abnormalities of the erythrocytes which can cause the patient to undergo a bone marrow transplant in search of a cure are: Fanconi's anaemia, alpha thalassemia, beta thalassemia intermedia, drepanocytosis and sideroblastic anaemia.
*Alterations of the plasma cells
Alterations of the plasma cells or monoclonal gammapathies are a group of illnesses that include diverse haematological malignancies which are characterized by a disorder in the plasma cells and the immunoglobulins.
What proportion of patients with monoclonal gammopathy require a transplant?
Approximately one third of patients with multiple myeloma will require an autologous transplant, 20% of patients with amyloidosis and 10% of those with Waldenström's disease.
Immunodeficiencies are a state in which the immune system does not fulfill its protective role which thus leaves the organism vulnerable to infections. Congenital immunodeficiencies manifest (apart from a few exceptions) from infancy and are due to defects which impede the correct functioning of the immune system.
There are different types of congenital immunodeficiencies but they are nonetheless extremely rare. Perhaps severe combined immunodeficiency (SCID) would be the most common of the diseases within this group. An allogeneic bone marrow transplant is the most effective form of treatment.
We could list many more illnesses where a transplant of haematopoietic progenitors, is often the only opportunity for a cure. However, many of them are very rare diseases such as other neoplasias like primary myelofibrosis; histiocytosis, metabolic disorders and other non-neoplasm diseases.
What proportion of patients with chronic myeloproliferative disorders such as myelofibrosis require a transplant?
The role of allogenic transplants from hematopoietic progenitors in patients with chronic myeloproliferative syndromes is very minor.
(1) Evidentally this information is not provided as a replacement for a consultation with a specialist doctor. The haematologist of a patient is who decides which intervention is adequate in relation to the age of the patient, their physical condition and the level of the disease.
(2) Source: 2012 REDMO annual report