Chronic lymphocytic leukemia is the most common form of leukemia in adults in most western societies, and is only lethal due to its complications. Therefore, its treatment is tailored according to its effects, balanced with the side effects of the drug in relation to the patient’s condition.
⇒ Some cases do not need treatment at all.
Although the term leukemia is scary, some chronic lymphocytic leukemia patients can live for a decade following their diagnosis. The mere diagnosis of CLL is not enough to initiate treatment, and the presence of other symptoms, complications or markers is necessary before the start of chemotherapy. Among all treatment options, only stem cell transplantation is curative, but we measure treatment efficacy by what we call a “complete response”, which is the absence of signs of the disease, namely: no enlargement of organs -spleen, liver, and lymph nodes-, and normal lab findings including a normal white blood cell count, red blood cell count and normal platelets.
Evidence of rapid progression is necessary before starting treatment. They include massive or progressive enlargement of the spleen, massive or progressive enlargement of the lymph nodes and a group of symptoms called B symptoms, which include a significant weight loss of more than 10% in the past 6 months, night sweats and fever. Another important marker of disease activity is the rapid increase of white blood cell count.
CLL treatment options
Chemotherapy is considered the first-line treatment of chronic lymphocytic leukemia with many drug classes used in combination to achieve optimal results. The overall idea of chemotherapy is to curb the rapid proliferation of the dysfunctional white blood cells, which are immature and immortal leading to the progressive rise of the number of white blood cells.
Chemotherapy regimens include drug classes like nucleoside analogues. These drugs act through disruption of cell division, either by direct action on enzymes involved in the process or through changes in the DNA itself. The DNA is the main code of the cell, used to divide and form proteins. Cancers are formed when such DNA is altered, and these alteration are passed to the next generation of cells through cellular division. When nucleoside analogues incorporate themselves into the DNA of cancer cells, they terminate such processes of division, resulting in cellular death.
Nucleoside analogues include fludarabine, cladribine and pentostatin. The gold standard in the treatment of chronic lymphocytic leukemia is fludarabine, and the most commonly used combination is fludarabine plus cyclophosphamide and rituximab. Other combinations include replacing the fludarabine in the previous regimen with pentostatin, or using the famous CVP regimen which includes cyclophosphamide, vincristine and prednisone.
Cyclophosphamide is the major component of many anti- cancer regimens, including leukemia, and it is an alkylating agent, which means that it acts by directly damaging the DNA of cells through a chemical process called alkylation. The main drawback is that although this process affects cancer cells more than normal cells because cancer cells proliferate at a much higher rate and are more susceptible to DNA damage, normal highly dividing cells like those lining our intestines, those in the testicles and ovaries and our skin cells are also affected, leading to side effects like hair loss, infertility, stomatitis, vomiting, and diarrhea.