What is an MPN Diagnosis
Myeloproliferative Neoplasms (MPN)
The term myeloproliferative neoplasms (MPN) is a group of rare, malignant diseases of the bone marrow in which too many red blood cells, white blood cells and / or platelets are formed. MPN are chronic diseases that can currently only be cured by a stem cell transplant. On the basis of more recent research results, drugs are currently being sought that can permanently inhibit the reproduction of the diseased cells.
Myeloproliferative neoplasms (MPN) - also called chronic myeloproliferative diseases (CMPE) - are a group of various chronic diseases of the blood-forming cells in the bone marrow. What they all have in common is that a certain blood cell is produced in excess. This can affect the red blood cells (erythrocytes), certain white blood cells or platelets (thrombocytes). Sometimes different types of blood cells are also produced in excess. The massive formation of properly functioning blood cells can subsequently cause various complications such as blood clots, vascular occlusions or an increased tendency to bleed.
The most common forms of MPN include essential thrombocythemia (ET), Polycythemia vera (PV), primary myelofibrosis (PMF) and chronic myeloid leukemia (CML). A specific genetic change, the Philadelphia chromosome, can be detected in almost all CML patients. Because of this change, CML has a special role with regard to the course of the disease and treatment and is described elsewhere. ET, PV and PMF, which, in contrast to CML, are collectively referred to as Philadelphia-negative MPN, have a lot in common and can merge into one another in individual cases.
Causes and frequency
The Philadelphia-negative MPN, like other forms of cancer, are neither contagious nor can they be passed on to other people. The cause of MPN are malignant, genetic changes (mutations) of the blood-forming cells in the bone marrow, which are acquired accidentally in the course of life, due to certain genetic predispositions or through environmental influences. The majority of MPN patients may have a mutation of the Janus kinase 2 (JAK2). Kinases are proteins that regulate cell division, for example, and can be switched on or off by the cell as required. Due to the mutation, JAK2 can no longer be switched off and the affected cell begins to divide unchecked. The JAK2 mutation mainly affects patients with polycythemia vera, but can also be detected in around half of patients with essential thrombocythemia and primary myelofibrosis. There are also many other mutations.
Myeloproliferative neoplasms are rare diseases. Only about 1 to 2 new cases per 100,000 population are diagnosed each year. MPN can affect all ages, but is most common in adults in their 60s. Men get sick a little more often than women.
The symptoms of MPN usually develop very slowly. Therefore, it often happens that the diseases are discovered as an incidental finding during a routine examination before the first clear signs of the disease. Symptoms are caused by excessively high numbers of red blood cells, white blood cells, or platelets:
- Tiredness, exhaustion
- Circulatory disorders in the hands and feet
- Dizziness, headache and blurred vision
- increased bleeding tendency (small punctiform skin bleeding (petechiae), bruises, nosebleeds, prolonged bleeding e.g. after a visit to the dentist or after injuries, prolonged menstrual bleeding in women)
- in advanced disease: feeling of pressure in the left upper abdomen due to an enlarged spleen
Many patients also lose their appetite and lose weight. Other patients suffer from night sweats, leg cramps and pain in the legs, ringing in the ears, tinnitus (ringing in the ears), tingling in the tips of the fingers or toes. In addition, PV patients often experience severe itching.
All symptoms described also occur in the context of other, comparatively harmless diseases and in most cases have nothing to do with MPN. However, if the symptoms persist, it is advisable to have the cause clarified by a doctor.
Diagnosis of myeloproliferative neoplasms
The diagnosis of MPN is often made by chance as part of a routine blood test by the family doctor / internist. You will notice increased or decreased levels of red blood cells, white blood cells or platelets. At the latest when the doctor detects an enlarged spleen (splenomegaly) in an ultrasound examination and / or the changed blood values are confirmed during a follow-up examination, a referral should be made to a specialist in leukemia (hematologist). This can make an exact diagnosis through further special examinations.
With the help of molecular genetic laboratory tests of the blood, changes (mutations) in the JAK2 gene that are characteristic of the presence of an MPN are searched for. They occur in over 90% of patients with PV and around half of patients with ET and PMF. A JAK2 mutation or other less frequent genetic changes can confirm the diagnosis of MPN.
Usually the bone marrow is also examined. For this purpose, bone marrow is removed from the hipbone or sternum (bone marrow puncture) with a syringe under local anesthesia. This short, outpatient procedure can be a little uncomfortable for the patient as it takes a few minutes for the bone marrow to get into the syringe. The bone marrow obtained is examined under the microscope with regard to the appearance and number of the various bone marrow cells (cytomorphology). An experienced doctor can thus obtain further information on the form of the disease.
Forms of myeloproliferative neoplasms
In patients with myeloproliferative neoplasia, the body makes too many red blood cells, certain white blood cells, or platelets. Sometimes different types of blood cells are also overproduced. The classification of an MPN depends on which type of blood cells is most affected. Myeloproliferative neoplasms include
- chronic myeloid leukemia (CML)
- Polycythemia vera (PV)
- essential thrombocythemia (ET)
- primary myelofibrosis (PMF) (also chronic idiopathic myelofibrosis or osteomyelofibrosis)
- systemic mastocytosis
- chronic neutrophil leukemia
- chronic eosinophilic leukemia (CEL) (also called hypereosinophilic syndrome)
It is often difficult to distinguish between the various forms, especially in the early stages. In individual cases, the diseases can also merge.
Essential thrombocytemia is characterized by a slow but progressive increase in blood platelets (thrombocytes). Platelets play an important role in clotting, which in healthy people is triggered by injuries and which leads to the rapid closure of wounds. Due to the greatly increased platelet count, the cells in the blood vessels clump together in ET without any injury. As a result, circulatory disorders or vascular occlusions (thromboses) can occur. Essential thrombocythemia has the most favorable outcome among MPN, so patients usually have a normal life expectancy.
In PV, the number of red blood cells and, as a result, the value of the red blood pigment (hemoglobin) is greatly increased. As a result, the blood becomes thick and viscous, which can lead to circulatory disorders in the arms and legs. However, the fact that the blood platelets and white blood cells are sometimes very high often makes it difficult to distinguish them from the other MPNs. Patients with PV can sometimes have a normal life expectancy. In rare individual cases, the disease can develop into acute myeloid leukemia after years or decades.
Primary myelofibrosis (PMF)
In PMF, at the beginning of the disease, the focus is on the increase in blood platelets and white blood cells. At the same time, there is an increased formation of new connective tissue in the bone marrow (fibrosis), which can be thought of as scarring and which can gradually lead to failure of the bone marrow. The blood formation shifts in the course to other organs such as the spleen or liver. Myelofibrosis can occur primarily, i.e. as an independent disease (PMF), or develop from ET or PV. Within the myeloproliferative neoplasia, PMF has the most unfavorable prognosis, even if the course of the disease can be very different in individual cases. Factors such as the age of the patient, the nature of the symptoms and the blood counts are used to assess the individual risk and help in the selection of a suitable treatment.
Myeloproliferative neoplasms are chronic diseases that cannot currently be cured with drugs. The aim of therapy is to improve the patient's quality of life and prevent serious complications. For many MPN patients, it is often sufficient at the beginning to monitor the disease closely (blood values and examination of the spleen) and observe it. This procedure is known as watch and wait. Only when symptoms or changes show up is action taken. The treatment methods should always be based on the respective disease situation of each individual patient. Possible risks and side effects should be weighed against the individual benefit. Since the course of the disease can be very different, there is no standardized therapeutic approach.
Platelet aggregation inhibitors prevent blood platelets (thrombocytes) from clumping together and thus prevent circulatory disorders. The most frequently prescribed active ingredient is acetylsalicylic acid (ASA), which is also used in higher concentrations as a pain reliever (e.g. headaches).
One of the most effective therapies for PV is bloodletting. A larger amount of blood (up to 500 mL) is taken from the patient in order to reduce the number of red blood cells and to normalize the blood flow. Depending on the blood count, it may be necessary at the beginning to perform several bloodletting with only a few days apart. Later on, the gaps get bigger. In addition to the immediate lowering of the hematocrit value (amount of all cells in the blood), bloodletting causes a welcome iron deficiency in the long term, which also inhibits the production of new red blood cells.
Medicinal reduction in cell numbers
Strongly increased cell numbers can also be reduced through the use of various drugs. These include cell poisons (cytostatics) such as Hydroxyurea or Anagrelidethat inhibit the formation of new blood cells in the bone marrow. While hydroxyurea decreases the production of platelets, red and white blood cells, anagrelide has specific effects on the production of platelets. Alternatively, treatment with the hormone-like messenger substance can also be used Interferon alpha come into question, which, like hydroxyurea, has a reducing effect on all three types of blood cells.
Stem cell transplant
The only curative (curative) treatment for patients with MPN is a stem cell transplant. This is a stressful and risky procedure in which the diseased bone marrow is replaced by healthy ones. Contrary to what the name suggests, a stem cell transplant is not an operation. The patient receives the purified blood stem cells from a suitable donor by means of an infusion. For a successful therapy, all of the patient's diseased bone marrow cells must first be killed. This is achieved through strong (intensive) chemotherapy and radiation, which destroys both the diseased and the healthy cells in the bone marrow. The risk of a stem cell transplant is great. Therefore, this treatment is only suitable for patients with advanced disease.
In Germany, many MPN patients are treated as part of therapy studies. Here, the patient has access to the latest scientific findings and is treated with innovative drugs and correspondingly up-to-date treatment strategies. Participation in a study does not mean that the use of the drugs used is experimental. Rather, the goal is to improve the treatment strategies of MPN in the future. The decision about which study is suitable for a patient must be made together with the attending physician. Various criteria play a role, e.g. disease characteristics, disease phase, pretreatment, age and risk factors. However, the ultimate decision to participate in the study is always made by the patient himself.
Many clinics throughout Germany participate in the studies of the study group for MPN. The current studies of these study groups can be found in the German Leukemia Study Register.
You can easily download these patient brochures or order them by email or post:
mpn network e. V.
c / o German Leukemia and Lymphoma Aid e. V. (DLH)
Created by: Hehn (Information Center) on July 25, 2014, last change: November 24, 2016
more on the subject
Current studies on MPN in the German Leukemia Study Register
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