Cancer chemotherapy will kill about 99.99 % of cells. So the 0.01% of cell will always survive as it will hide somewhere. This is relevant because the cancer arose in the first place because that 0.01 became 0.1 then 1 and then 10%.
Shahid Akhter, editor, ETHealthworld spoke to Dr Tarun Verma, Sr Consultant Haematology and BMT programme, HCG APEX Cancer Centre, Mumbai, to figure out the trends and techniques in bone marrow transplant.
Need for bone marrow transplant
When we talk about bone marrow transplant, essentially it implies replacing a diseased bone marrow with a healthy one. With this you are able to at least potentially eliminate the disease. In the sense you are able to offer the patient a prospect of cure. Be it a blood cancer, blood production disorder a hemoglobinopathy such as thalassemia, autoimmune disorder, metabolic disorder or even an immune deficiency disorder. The very fact that you are able to eliminate the disease altogether is a very exciting prospect. For example, let us talk about blood cancer for a while. When we talk about cancer chemotherapy and its effectiveness, the best drugs that we use, they are able to kill a certain fraction of the cells. We talk in terms of long kill. For example, the cancer chemotherapy will kill about 99.99 % of cells. So the 0.01% of cell will always survive as it will hide somewhere. This is relevant because the cancer arose in the first place because that 0.01 became 0.1 then 1 and then 10%. It was able to escape the body immune system at overpower the other cells, thereby the patient got the cancer in the first place. So no matter how good your cancer chemotherapy, that cell is always going to hide somewhere in the body. Eventually the cancer will raise its head once more, when it does it will be smarter than before and maybe very difficult to treat. Therefore you need a continuous system of surveillance and a fight against cancer which basically a bone marrow transplant can give you.
Impact of bone marrow transplant
Thalassemia is a condition in which the body does not produce the blood hemoglobin and the patient needs to get lifelong blood transfusions. With transfusion comes the problem of Iron which accumulates in different tissues. Not only does it damage the liver and pancreas but also the presence of excess iron in the blood itself which is like an invitation card to all infections. So from childhood to adulthood to old age the person is dependent on blood. Just imagine the stress of the family, always having to search for donors, having to buy drugs to remove iron. In one stroke a bone marrow transplant can get a rid of all these problems, it can transform the disease completely.
Let’s talk about immune deficiency disease where the patient is born or he inherits some defect of immunity meaning he has risk of certain type of infection be it viruses, bacteria, fungus or may be a combination of all of them. Basic problem of him is his body does not produce the required immunity to cover these bugs. What he needs is somebody’s immune system, bone marrow and a bone marrow transplant can possibly transform his life and give him a fresh, complete robust immunity all by itself. Similarly with autoimmune inflammatory conditions SLE, rheumatoid arthritis, so many autoimmune disease exist for which basically the body develops an immune responsiveness against its own either cells, tissues etc. So basically the body begins to perceive parts of it as foreign and mount an immune attack. We give drugs to suppress the immunity including steroids. So these drugs will suppress the immunity, control the disease very well for years together but you are not answering the basic question that the body has which is that it has still perceived itself as foreign and is attacking its own tissues. A bone marrow transplant can achieve this, it can make the body forget its own anti-self nature. It can make the body forget that it is attacking its own tissues and reset the immunological mechanism. It can give a patient, years of freedom from the procedure.
Trends in transplant techniques
Today many transplant centres are coming up all across India and 10 years back we used to believe that we would only do bone marrow transplant in cases of blood cancer whose outcome was so dismal that it was worthwhile taking the risk of a very intensive procedure like bone marrow transplant because the risk of the patient dying from chemotherapy alone was too high. Basically the risk was justified, but now transplant techniques have refined so much. Now outcomes have improved to such an extent: the preparatory phase, the supportive care, the post transplant care which we are able to give to the patient has become so sophisticated that today we talk about transplant as it was just similar to chemotherapy means we are able to give much better results and we are not anticipating very great complications. In thalassemia, the basic bottom line is that when we talk about transplant, the donor who can donate stem cells has to be a HLA matched sibling meaning it has to be a real brother, real sister who is HLA rather immunological profile matches from the patient, so that they are less likely of complications which we call graft versus host disease.
Today we have such a range of options because of improvements in our transplant techniques. We can find a donor who does not match completely; we can find a donor who matches completely but lives in another part of the world- matched unrelated donor. His stem cells can collected, flown across the India and transplant can be performed. We can do haploidentical transplant. Though we get a lot of complications but such is the power of the refinement and techniques. We are able to sequentially give chemotherapy which knocks out the cells which are likely to cause complications. The way I see the future evolving is that possibly a time will come when no patient is denied a transplant just for want to have a suitable donor.
Traditionally transplant used to be done on relatively younger group of patient. Now by modifying and reducing our chemotherapy doses, we are able to now offer this transplant to many more people that are as old as 60-65 or even older by using something we call as Reduced Intensity Conditioning (RIC).So effectively what the world has achieved in the last decade is to grossly widen the range of transplant, widen the range of patients who can be taken up for transplant including so many diseases.
10 years back nobody would even think of doing transplants for rheumatoid arthritis because the results were so abysmal but now transplant techniques have refined, they have found out that every disease has its own requirements. We need to handle the transplants for every condition differently and basically you need a centre which has the experience to do transplant for that particular disease.
Current scenario is that India has a very exciting future. A lot of centres are coming up and they are all doing quality work. Essentially we have the lab back up, blood bank back up and we can collect, modify our components required for a large scale transplant programme. HCG as chain is devoted to cancer care and one of the components of cancer care is bone marrow transplant. So we are able to offer bone marrow transplant to a wide variety of malignant and non malignant conditions and because we are in this business we are able to provide most of the facilities in-house and provide comprehensive diagnosis for follow up and treatment to cancer transplant requiring patients.