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| Edited By: Jayadev Calamur |Source: DNA |Updated: Sep 22, 2016, 08:00 AM IST
Until the 1980s, chronic myeloid leukaemia (CML), a type of cancer that affects the blood and bone marrow, was incurable. However, today that isn't the case as a study by the American Cancer Society suggests that 90 per cent of those suffering from CMLs have survived after five years of continuous treatment. Advanced studies and research has also helped developing medicines to treat disease and subside it before it reaches an advanced stage.
Today is World Chronic Myeloid Leukaemia Day and dna called Dr Bhausaheb Bagal, Hematologist, Tata Memorial Hospital and Dr. Santosh Khude, Hemato-Oncologist, Bhaktivedanta Hospital & Research Institute to address the cases of CMLs in India, the work done to treat patients and what the future holds.
The discussions, moderated by dna's Jayadev Calamur threw light on several issues that most people are unaware of. Given below are edited excerpts:
Dr. Khude: It is an uncontrolled proliferation of myeloid-related cells. They start growing uncontrollably in the bone marrow and reach other organs such as the spleen and liver through the blood.
Dr Bagal: The cancer starts with a cell where cell replication goes wrong. In CML cells, a change takes place in the genes between chromosome 22 and chromosome 9. A piece of chromosome 22 breaks off and attaches to the end of chromosome 9 and a piece of chromosome 9 also breaks off and attaches to the end of chromosome 22. This results in shortening of chromosome 22 which is known as the Philadelphia chromosome. The Ph chromosome leads to the formation of too many abnormal white blood cells called leukemia cells inside the bone marrow as discussed earlier.
Dr Khude: Currently, there are four-five patients per one lakh people in India. This is data that we have received from a 2011 study because India doesn't have any organisation or society that enrols CML patients. The data we get is through tertiary care hospitals and therefore the current data we have may be inadequate. Many patients aren't able to reach a tertiary hospital; they are treated in secondary hospitals – maybe even by a primary-level physician. In some cases, patients may not be properly diagnosed. Currently, in Maharashtra only Mumbai provides us with data. We don't receive anything from other cities such as Nagpur or Pune.
Dr Bagal: We don't have population-based registries, which will give exact numbers. This makes us believe that there are a lot of patients we see, but we need to understand that this is what has been reported out of hospital registry. The real picture is probably different from the data we have.
Most of the people will agree that we see much more patient of CML than the western population. But is it because of the share number of our patient – our country's population or is there something to do with our difference in genetic makeup– it's a matter of debate.
Off late, many registries have started showing that now the actual incidence is much less than what it was reported earlier. So we are actually identifying them and diagnosing them correctly. So misclassification has been getting out. And what we feel is that there is no reason to believe that the incidence in India is different from other country.
Dr Khude: There are a group of drugs called tyrosine kinase inhibitors (TKIs) that have been the gold standard of treatment since 2001. There are first-line TKIs, second line TKIs and third line TKIs.
Earlier in 1980/90s, CML cases were fatal. With advancements in medicine, CML also showed how specific targeted therapy or design drugs can work for a particular disease.
Dr Bagal: Bone marrow transplant was picked up in probably 1990s and that probably became the curative option for disease. In this treatment, a marrow from a matched donor was given to the patient with CML. The marrow transplant then helped control the spread of the disease as it identifies the diseased cells as foreign.
To date, bone marrow transplant, it remains the only curative therapy for chronic myeloid leukaemia, but the problem is it's very toxic. So when you have a very good treatment like a first generation or a second generation TKIs for this disease. So we reserve this treatment now for people who are not candidate of the disease or whose outcome is not good with disease or the disease progressing on this drug. So this, sort of, has fallen back. It is a reserved kind of treatment for certain patient with chronic myeloid leukemia.
Dr Khude: In early 1980s the overall survival rate was 38 per cent. Today, the overall survival rate has increased to 95 per cent thanks to drug treatment. So a bone marrow transplant isn't needed
Dr Bagal: The first thing we need to understand is the treatment of cancer is changing very rapidly and it is improving in terms of the results, in terms of its side effects and in terms of its cost. Most of the time there is unnecessary fear about disease and so the expectation has to be based on the thorough assessment and realistic outcome. Also, the physician needs to plan the treatment with the patient so that they can plan their routine accordingly.
Dr Khude: A problem is with the profession as well. While we have several medical courses, oncology isn't one of them. Out of 1,000 doctors, only 10 are oncologists and this becomes problematic because of the number of cancer patients in India.
Dr Bagal: We have seen change what our olden physician use – older physicians used to see CML and their outcome is totally different from what we see, and probably as science is advancing maybe a day will come then, now we say there's functional cure for this diseases. But probably there will be a true cure for diseases some day.
Dr. Bagal: Yeah. So I think the simple and non-complicated answer would be, it doesn't decrease your lifespan, but that is not true for each and every patient. So what we said is 98% of patient would have normal lifespan.
Dr Khude: If you are taking a proper treatment, the rate of success will be 80%, if you are not taking the treatment the rate will be dropping below 50%. So that's why socioeconomic strata will define the disease progression. And because of that patient are not taking treatment properly and because of that they are advancing on a stage like escalated and blast crisis.
Dr. Bagal: Another interesting thing happening about it, this is idea for treatment free remissions, so you keep on treating this patient with drugs and one day the disease goes so low that it is just some cells seen per million cells and very low cell number seen in your blood on blood test. So in this case, we can think of stopping the drug, that's called as treatment free remission.
