By Dr Jasmine Ramiah — Clinical Haematology
Understanding blood cancers and the power of stem cell donation.
Clinical Haematology
The word leukemia may evoke thoughts of terminal, painful cancer and whilst true there are often preconceived misnomers or perceptions of the development and how stem cell donation can essentially save a life. Leukemia stems from the Greek word meaning ‘leukos’ a term which denotes a ‘white blood cell’ and is a malignancy emanating predominately from the bone marrow cavity.
The function of the bone marrow is to produce blood components, each serving a unique biological role; red blood cells transport oxygen, white blood cells combat a multitude of infections, and platelets prevent bleeding. The pathobiology of leukemia involves a genetic basis which disrupts normal haematopoiesis resulting in the uncontrolled proliferation of immature (acute) or mature (chronic) counterparts resulting in leukemia.
These cancerous cells expand within the marrow reserve replacing and displacing residual haematopoietic elements preventing the bone marrow from producing healthy blood cells.
As a result of this dysregulated proliferation, patients often experience symptoms termed ‘bone marrow failure’ such as severe anaemia, frequent infections, unexplained bruising or bleeding, persistent fatigue, bone pain, swollen lymph nodes, or weight loss.
Leukaemia is not one disease but a group of blood cancers, including acute and chronic forms, each requiring different treatment approaches.
Treatment may include several cycles of chemotherapy, targeted therapies (molecular basis), immunotherapy, or stem cell transplantation. Chemotherapy is first administered in a regime termed ‘induction’ followed by ‘consolidation’ and in certain cases ‘maintenance’ phases. The combination and choice of such treatment depends on several factors such as institution factors: availability of drugs, cost etc., patient related factors: preference, fertility, anaphylaxis, co-morbidities etc. and lastly disease related factors such as the rapidity or aggressiveness of the malignancy, the molecular characteristics and other disease related prognostic markers. The response after induction chemotherapy is often prognostic and impacts on the overall survival of the patient. The response is termed measurable residual disease (MRD). For many patients with high-risk or relapsed blood cancers, a stem cell transplant offers the best chance of long-term remission or cure.
A “bone marrow transplant” (BMT) more accurately termed a haematopoietic stem cell transplant may be obtained from a matched related stem cell donor (MRD) or a matched unrelated donor (MUD) or partially matched referred to as a haploidentical donor. A stem cell is unique owing to the ability to differentiate into several types of blood cells.
The process of stem cell transplantation involves obtaining a stem cell donor through a registry in South Africa such as through DKMS or South African Bone Marrow Registry (SABMR). Once identified, the patient receives high doses of chemotherapy and or radiotherapy to ablate the residual remaining bone marrow. The donor is harvested through a peripheral line much like a blood donation. These healthy donated stem cells are then infused into the patient’s bloodstream through an intravenous drip. These cells naturally travel to the bone marrow a process referred to as ‘homing’, where they establish a new niche and proliferate into healthy blood.
A patient may donate their own stem cells referred to as an autologous stem cell transplant which is reserved for curtained haematological conditions such as lymphomas and multiple myeloma, or a patient may receive exogenous stem cells through an allogenic stem cell transplantation.
Despite the life-saving potential of stem cell transplantation, many misconceptions discourage people from becoming donors. One of the most common misconceptions emanates from the fear of invasiveness of the procedure and pain. In reality, approximately 90% of donations today are performed through peripheral blood stem cell donation which is similarly compared to the process of donating blood.
Bone pain may be experienced by the stem cell donor owing to subcutaneous injections of growth factors received for the mobilisation of stem cells over several days prior to the harvest. These growth factors encourage stem cells to proliferated and mobilise from the bone marrow cavity into the peripheral blood where they are then harvested through the process of apheresis.
A stem cell transplant is not always readily available for all demographics owing to the disparities in representation across all ethnicities. Whilst same parentage siblings have a higher chance of being a stem cell match, nearly 70% of patients will require the assistance of an unrelated volunteer donor (MUD), emphasising the urgent need for more individuals to join donor registries, particularly individuals from diverse ethnic backgrounds.
The process of registration is a simple one. Healthy adults who meet eligibility criteria can join organisations such as DKMS Africa by completing a simple 30 second cheek swab. Their tissue type is then added to an international registry, where it may one day match a patient anywhere in the world. This creates an opportunity to save a life, allow someone to celebrate another birthday or simply enjoy more time with loved ones.
Sadly blood cancers do not discriminate affecting both the elderly and young, friends and foe alike. Yet hope exists because of medical advances and the generosity of ordinary people willing to do extraordinary things. A simple cheek swab takes only minutes, but the impact can be life changing. You may never meet the person whose life you save but for them, you could be the miracle they’ve been waiting for.
For more information regarding stem cell donation contact DKMS Africa or SABMR.
One swab can and will save a life.