Oral drug treatment for cancer

Thanks to a giant leap in treatment and prognosis of Chronic Myeloid Leukemia, it has now become a disease like hypertension or diabetes with the discovery of orally administered effective drugs. These drugs have minimal side-effects compared to traditional cancer therapies like chemotherapy

Chronic Myeloid Leukaemia (CML) is one of a kind of blood cancer. It usually affects people after the age of 40s though it can also occur earlier even in children. Human blood is composed of various types of cells that perform vital functions like carrying oxygen (red blood cells), fight infections (white blood cells) and help prevent bleeding (platelets). These cells have a limited life and die once they become older.

Whenever the blood cells are produced in excess or do not die as programmed, their numbers increase dramatically. These ineffective cells soon start taking over the entire body and the normal functions of the body are impaired. Such a condition is known as blood cancer.

CML, which is expanded as The cause of CML is a change in the structure of genes that constitute the building blocks of life. The initial stage of CML is known as chronic phase. It may progress and become more advanced to phases called the accelerated phase and blast crisis.

Diagnostic methods

The most common test is a complete blood count which will typically show low hemoglobin, low or high platelets and very high white blood cells(normally white cells are four thousand to eleven thousand in CML, they can be in lakhs). Earlier diagnosis only included complete blood count (CBC). Recent development in diagnosis for CML involves more sensitive tests such as standard cytogenetic, fluorescent in-situ etc.

The confirmatory test is detection of the abnormal bcr-abl (two genes) DNA rearrangement by a test known as PCR. This test not only gives us the diagnosis of CML but is also a way to check the response to treatment. Sometimes, the doctor might do a bone marrow test which consists of taking a small piece of bone tissue from the back bone. This test is repeated during treatment to check the efficacy of the drugs used.

The specialist doctors for treatment of CML are medical oncologists. It is best to take the treatment at a specialised cancer centre rather than any clinic or hospital.

Orally drugs for CML treatment

There has been a giant leap in treatment and prognosis of CML over the past few years. It has become a truly chronic disease like hypertension or diabetes with the discovery of orally administered effective drugs. These drugs have minimal side-effects compared to traditional cancer therapies like chemotherapy. The drugs which are being used in CML attack the gene rearrangement and are known as tyrosine kinase inhibitors. The first of these drugs is called Imatinib.

Over the past 10 years, it has been shown that up to 60 per cent of patients with CML have had their disease successfully under control with imatinib alone for more than 10 years. Moreover, there has been a drastic reduction in price of the drug by almost 95 per cent and it is freely available in India. Despite this encouraging progress, there are some patients who will have progression of disease due to inherent resistance to imatinib.

The good news is that there are two new drugs called dasatinib and nilotinib which are considered more effective than imatinib. These drugs too are widely available in India.

There are still around 10-20 per cent patients or to put it in another way, 1-2 out of every 10 patients who do not have an adequate response with the TKIs. These patients require a much more expensive and aggressive form of treatment known as stem cell therapy for management. The other issues in CML include the cost of long term therapy and the necessity of blood testing.

A patient with CML is checked by doing blood tests at intervals of one to two months initially and later at three monthly intervals. In case the disease becomes resistant to one kind of TKI, treatment can be changed to the newer TKIs. The patients taking treatment have to be careful in taking the medicines on time as advised by their doctors. They should immediately contact the doctor in case of any complications like fever, bleeding, chest pain or persistent body pains.

Overall ML has become a more manageable disease and we are seeing the possibility of cure and long term survival of more than 10 years. In addition, there is a lot of research going on and there is every hope that newer drugs with even greater effectiveness can be discovered in the near future.

(Consultant Medical Oncologist and Hematologist Yashoda Hospitals, Secunderabad Ph: 9959778112)

Did you Know?

• That the annual incidence of CML ranges from 0.8–2.2/100,000 population in males and 0.6–1.6/100,000 population in females.
• That radiation exposure too can increase the risk of developing CML. However, it takes many years to develop leukemia from radiation exposure.

Symptoms

• Weakness
• Frequent feeling of fatigue
• Stomach pain, especially in the left upper side
• Feel a lump in the stomach
• Rarely have bleeding
• Many patients do not have specific complaints, but are diagnosed of CML when they get their blood checked for any other reason.