General aspects of leukemia

Many people suffer from leukemia these days. A large number of cases of cancer are identified to be leukemia. Leukemia is a sort of cancer of the blood and marrow. The disease is characterized through the overproducing of immature blood cells (stem cells) that aren’t able to fully develop and to carry out the activities of normal blood cells.

According to their functions and structure, there are three different types of cells within the normal blood: red blood cells, white blood cells and platelets. Through the process of hematopoiesis, these three types of blood cells are developed from a distinctive type of blood cell called stem cell. Stem cells divide and go through several stages of development to finally form a mature blood cell of a particular type, with a certain, distinctive function in the body. The process through which a stem cell morphs into a mature blood cell takes place within the bone marrow.

According to the speed of development and the persistence of the disorder, there are two types of leukemia: acute leukemia and chronic leukemia. Acute leukemia is known to develop very rapidly, while chronic leukemia is developed slowly. According to the types of blood cells affected by the disease, leukemia can either be lymphocytic or myelogenous.

Lymphocytic and myelogenous types of leukemia are developed from different types of cells: the lymphocytic type of leukemia develops from cells called lymphoblasts or lymphocytes in the spongious tissue of the bones, while the myelogenous type of leukemia (sometimes refered to as myeloid and myelocytic leukemia) develops from myeloid cells.

In the case of acute forms of leukemia, the abnormal cells come from early, immature cells. Such forms of the disorder have a very fast rate of development, due to the fact that normal stem cells tend to multiply frequently. Leukemia cells usually don’t divide faster and more frequently than normal stem cells, they simply don’t stop their process of division when they should. Sometimes the numbers of white blood cells are very high, while in other cases they can be normal or low.

Chronic leukemia, apart from its slow development, is different from acute leukemia by the level of maturation that the diseased cells are able to reach. Stem cells affected by chronic leukemia reach a higher level of maturation but they present abnormalities and they can’t act as healthy white blood cells do. Unlike acute leukemia, in the chronic form of the disease the unhealthy cells have much longer periods of life and they tend to accumulate in different parts of the body.

Leukemia affects people of all age groups. While children usually respond better to the treatment for leukemia and sometimes deal well with the disease, adults difficultly cope with this form of cancer.

Regardless of age and sex, many people are diagnosed with forms of leukemia. Children tend to respond better to some types of leukemia, while adults difficultly cope with the disease. The cases of acute leukemia exceed those of chronic leukemia by approximately 10 percent. Older adults seem to be affected the most by acute leukemia. Around two thirds of acute leukemia cases seem to occur after the age of 60.

Understanding chronic leukemia

Leukemia is a disease of the blood and bone marrow that occurs on the background of genetic predispositions to cancer. Leukemia affects the cellular process of maturation, causing the accumulation of immature blood cells in the spinal marrow and bloodstream. In some cases leukemia causes the incomplete cells to multiply very quickly, while in other cases the abnormal blood cells have prolonged periods of life and persist in different places inside the body. Incomplete blood cells can’t substitute for normal blood cells, as they can’t carry out their roles. The cells affected by leukemia are therefore incompatible with the organism and can cause serious damage.

Judging by the speed of development and the persistence of the disorder, there are two types of leukemia: acute leukemia and chronic leukemia. Judging by the types of stem cells affected by the disorder, leukemia can either be lymphocytic or myelogenous.

Acute leukemia is different from chronic leukemia by the levels that stem cells are able to reach in their development (stem cells that present anomalies still manage to partially develop and either resemble immature cells or complete, normal white blood cells).

Acute leukemia is a form of cancer that develops very rapidly. It is manifested through overpopulation of the blood with immature cells that are unable to fulfill the functions of normal blood cells. In the case of acute leukemia, the marrow is unable to produce normal quantities of red blood cells, white blood cells and platelets. Patients who suffer from leukemia also develop anemia, a deficiency of normal red blood cells. Also, a decreased number of white blood cells reduces the body’s ability of overcoming infections, while the lack of platelets facilitates inflammation and bleeding.

Chronic leukemia tends to develop slower than acute leukemia. In the case of chronic leukemia, the body is able to produce blood cells that are more mature than those produced in acute leukemia. Although these cells may appear incomplete, they can’t fulfill their roles inside the organism and tend to cluster at different levels of the body. They also have a longer period of life.

Chronic leukemia of lymphocytic form is known to affect a type of blood cell called B lymphocyte. The disease weakens the immune system, interferes in the normal activity of the spinal marrow and facilitates the access of harmful cells to body organs. Chronic lymphocytic leukemia first occurs at the levels of the bone marrow, but can quickly spread to different organs and tissue through the bloodstream.

The presence of chronic lymphocytic leukemia is usually revealed by blood tests and careful body examination. Although apparently some people may have no symptoms of the disease, other patients may experience fatigue, lack of concentration, poor balance, memory loss, deterioration of vision and hearing, vertigos, body weakness, joint and bone pains. Just like in other forms of the disease, chronic leukemia requires immediate specific treatment and therapy. The chances of fully overcoming the disease are considerably enhanced if it is discovered quickly.

Different forms of acute leukemia

Leukemia is a disease of the bone marrow and blood that is known to affect normal blood cell production. Normal blood cells have a limited period of life and they need to be constantly replaced by fresh, young cells to carry on their activity. There is a type of cell within the bone marrow (stem cell) that matures into the type of blood cells that the body needs. In normal condition, these stem cells develop either into red blood cells, white blood cells or platelets, into a controlled way. Leukemia perturbs the normal development of blood cells and causes the accumulation of partially developed cells, that aren’t able to fulfill their role inside the organism.

Judging by the speed of development and the persistence of the disorder, there are two types of leukemia: acute leukemia and chronic leukemia. Judging by the types of stem cells affected by the disorder, leukemia can either be lymphocytic or myelogenous.

Acute leukemia differs from chronic leukemia by the levels that stem cells are able to reach in their development (stem cells that present anomalies still manage to partially develop and either resemble immature cells or complete, normal white blood cells).

Inside the body of people who suffer from acute leukemia of myelogenous, the bone marrow produces stem cells which form a kind of partially matured white blood cell called myeloblast. This type of blood cell doesn’t reach a full maturity state and can’t carry out its intended role. Myelogenous cells tend to multiply very fast and exceed the numbers of healthy blood cells, facilitating the occurrence of anemia, infections and weakening the immune system of the body. The diseased cells can also spread to other places of the organism, such as organs.

As statistics indicate, there are lots of annual cases of the disease, acute leukemia of myelogenous form being the most common type of leukemia. Although the disease is known to regress quickly when the appropriate treatment is administered, if left untreated it may cause the death of the affected person. This form of leukemia tends to recidivate and it can redevelop with time.

Regardless of age and sex, many people are diagnosed with forms of leukemia. Children tend to respond better to some types of leukemia, while adults difficultly cope with the disease. The cases of acute leukemia exceed those of chronic leukemia by approximately 10 percent. Older adults seem to be affected the most by acute leukemia. Around two thirds of acute leukemia cases seem to occur after the age of 60. Leukemia is a serious form of cancer and it needs immediate treatment. If treated correctly, especially in its incipient stages, leukemia can be successfully overcome.

Understanding and recognizing leukemia symptoms

Leukemia is a sort of cancer of the blood and marrow. The disease is characterized through the overproducing of immature blood cells (stem cells) that aren’t able to fully develop and carry out the activities of normal blood cells.

Each type of mature blood cells has specific traits and roles inside the body. White blood cells or leukocytes have an important role in the immune system, contributing to overcome infections. White blood cells also help in healing flesh wounds and cuts. Red blood cells or erythrocytes contain hemoglobin, which has a great importance in transporting oxygen to the cells within the organism. Red blood cells are vital for the process of cell respiration, carrying oxygen to cells and removing carbon dioxide from them. Platelets have an important role in repairing damage at the level of blood vessels, accumulating to seal any cuts or tares.

Leukemia leads to the accumulation and crowding of diseased stem cells at the level of the bone marrow, which decreases the normal production of healthy blood cells. The lack of normal blood cells leads to the appearance of leukemia symptoms. It is important to understand that despite the fact that leukemia causes an over production of white blood cells, these cells are immature and can’t substitute for normal blood cells. Due to this, the body is exposed to many forms of infection.

The most common leukemia symptoms are: anemia (insufficient number of red blood cells in the bloodstream), risks of bleeding (insufficient number of platelets in the bloodstream), nose bleeding, bleeding of the oral cavity, predisposition to bruising, high exposure to infections due to lack of white blood cells, improper healing.

Other leukemia symptoms may be fatigue, lack of concentration, poor psychical performance, fever, loss of appetite and weight loss.

In the case of chronic leukemia, which facilitates the accumulation of diseased blood cells in different places inside the body, the leukemia symptoms may be migraines, insomnia, decreased vision and hearing, loss of balance, faints and seizures. Some of these leukemia symptoms need immediate medical intervention, as they may lead to further complications.

Sometimes people with leukemia may have enlarged liver and spleen, causing abdominal swelling or enlarged lymph nodes. The body glands of the organism can also be affected by leukemia.

Leukemia symptoms have a non-specific character. This means that they can be misleading in establishing an appropriate diagnose, as they may also occur in the cases of other diseases. Medical professionals are the only persons able to distinguish leukemia from other illnesses with resembling symptoms. Proper diagnose is very important in order to quickly begin the administration of specific treatment. Blood analysis and careful body examinations can reveal the presence of leukemia. Leukemia is considered to have a high rate of mortality and although the disease can be overcome through treatment and therapy, it can cause death if its presence is not noticed in time. Therefore, prompt intervention is required for leukemia, regardless of its type.

Possible leukemia causes and risk factors

Leukemia is a disease that is considered to be life-threatening. It requires prompt intervention when discovered, in order to maximize the chances of recovering through specific treatment and therapy. Leukemia is basically a type of cancer of the bone marrow and blood, caused by inappropriate cellular activity. The disease can be of different forms, according to the types of blood cells that cause its development. Also, if leukemia is developing rapidly, it is called acute leukemia, while if the disease is developing slowly, it is referred to as chronic leukemia.

The direct leukemia causes are still unknown. In present, medical science isn’t able to establish the specific leukemia causes. However, a strong connection between certain genetic factors and the development of the disease has been revealed. Leukemia occurs on the background of genetic failure that causes the excessive production of incomplete, partially matured blood cells. Also, leukemia has a hereditary character, allowing the transmission of genetic predispositions to disease from one generation to another. Although many factors are known to contribute to the development of leukemia, they alone can’t be considered leukemia causes.

Despite the fact that statistics indicate a higher incidence of the disease in people that are exposed to some environmental factors of risk, leukemia doesn’t seem to be caused by neither of them in particular. Among the environmental factors that are thought to be leukemia causes, here are some of the most plausible ones:

- Smoking – smoking is thought to increase the chances of being affected by leukemia. Although statistics show that around 20 percent of acute leukemia cases are related to smoking, leukemia also occurs to people that don’t smoke and therefore it can’t be considered a leukemia cause on itself;

- Prolonged exposure to radiation – Radiation is considered to facilitate the development of leukemia. It is believed that exposure to X-rays can be a leukemia cause;

- Prolonged exposure to benzene – statistics reveal that this is a major factor of risk in some forms of leukemia, such as myelogenous leukemia;

- Chemotherapy and cancer treatment – previous cancer treatments and chemotherapy are known to facilitate the occurrence and development of leukemia and can be considered plausible leukemia causes. Within a few years from the completion of chemotherapy and other treatments for certain forms of cancer, most people can develop leukemia.

Among the genetic factors that are considered to be leukemia causes, the following ones are thought to be the most important:

- chromosome abnormalities – some rare genetic syndromes are known to contribute to leukemia causes;

- Immune system genetic problems - a weak immune system is very likely to facilitate the occurrence of leukemia and therefore can be considered a leukemia cause;

- Down syndrome – children born with this syndrome have a very high risk of developing acute leukemia.

The list of possible leukemia causes can continue further, but these are the most common factors that are considered to be interrelated with leukemia. While some of them can be prevented, others reside within the genes and in present can’t be corrected. In future, however, thanks to medical advance, we will probably be able to prevent leukemia and other forms of cancer.

Particularities of different types of leukemia

Leukemia is a form of cancer that occurs at the level of the spinal marrow. Inside the spinal marrow there is a type of immature blood cells that are called stem cells. These cells have a neutral initial state and later develop into different types of blood cells (white blood cells, red blood cells and platelets). Leukemia interferes in the normal process of cell maturation, leading to an accumulation of partially developed blood cells in the marrow, blood and later in body organs. Most of these resulted cells are inefficient inside the organism, as they can’t carry out the activity of normal blood cells.

Depending on to the rate of development, the disease can either be acute leukemia (developing very rapidly), or chronic leukemia (slow developing).

Particular to acute leukemia is the inability of stem cells (immature cells that can be found within the bone marrow) to reach the state of maturity. These immature blood cells tend to continuously divide and they accumulate in the bloodstream. Acute leukemia develops very rapidly and people who suffer from it need immediate treatment and specific therapy. If mistreated or ignored, acute leukemia causes the death of affected patients within a few months. While certain forms of acute leukemia are usually successfully treated, other forms don’t respond well to the specific treatment.

A characteristic of the chronic type of leukemia is that the diseased cells usually come from more mature cells, but in most cases they aren’t developed normally. The leukemia cells have long periods of life and they tend to accumulate within the bloodstream. Although normal people have between 5000 and 10000 white blood cells in their body, people who suffer from chronic leukemia may have more than 100000.

Lymphocytic and myelogenous types of leukemia are developed from different types of cells: the lymphocytic type of leukemia develops from cells called lymphoblasts or lymphocytes in the spongious tissue of the bones, while the myelogenous type of leukemia (sometimes refered to as myeloid and myelocytic leukemia) develops from myeloid cells. Judging by the types of cells involved in the development of leukemia and by the rate of cellular division specific to each form of the disease, the main types of leukemia are: acute myelogenous leukemia (AML), chronic myelogenous leukemia (CML), acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL).

In addition to the common forms of chronic leukemia, there are also some rare types. Hairy cell leukemia (HCL), just like chronic lymphocytic leukemia, has a slow progression. The cells of hairy cell leukemia are different from other diseased cells mainly through their aspect. Hairy cell leukemia doesn’t usually respond well to treatment. Prolymphocytic leukemia is a very rare and unusual form of chronic lymphocytic leukemia.

Some cancers, called lymphomas, are caused by abnormal blood cells that are present in the lymph nodes, liver, spleen or other organs. These particular types of cancer don’t occur at the levels of the bone marrow and have a development that is not characteristic to most forms of lymphocytic leukemia.

Cancer therapies right on target

Cancer has always been synonymous with loss and fear. With today's new advancements in prevention, detection and treatment, a diagnosis of cancer no longer necessarily means facing a terminal disease. Rather, as new advances provide more treatment options, cancer increasingly takes on the shape of a chronic condition.

Recently, the National Cancer Institute (NCI) announced that leading cancer organizations report that Americans' risk of dying from cancer continues to decline, indicating that progress in prevention, early detection, and newer treatments appear to be helping in the fight against this disease.

The next revolution in cancer therapy will likely find its roots in the ongoing Cancer Genome Atlas (TCGA), a pilot project initiated by the National Cancer Institute (NCI) and the National Human Genome Research Institute (NHGRI). Scientists have begun to discover that numerous genes play a role in cancer, but they have only uncovered a small portion of these genes. The Cancer Genome Atlas is aimed at helping to accelerate the understanding of the genetic make-up of cancer. Researchers hope that a better understanding of how cancer develops and spreads, will lead to new tests to detect cancer in its early, most treatable stages; new therapies to target cancer; and, ultimately, new strategies to prevent cancer.

Understanding of the genetic basis for cancer has already allowed researchers to develop the first drugs that target faulty genes, which are making a difference in the lives of patients. Just ask Bob Ferber. In July of 1999, the Los Angeles attorney was diagnosed with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML), a malignant cancer of the bone marrow and blood.

Ferber tried many futile attempts at treatment before entering a clinical trial for a drug now called Gleevec (imatinib mesylate) tablets to help fight his disease. Gleevec, approved by the FDA in 2001, is one of the first "targeted therapies" and works by turning off the specific cause of Ph+ CML, something The Cancer Genome Atlas hopes to make possible for many more cancers. Within months, Ferber's white blood cell counts were within normal range and his disease was in remission.

"My CML diagnosis was a real scare. But, I'm grateful now. I'm grateful for every new day I have."

Sadly, not everyone's story is as positive as Ferber's. Hopefully, with the continued advancement of cancer awareness and research, preventative treatment and The Cancer Genome Atlas, cancer patients will one day be able to breathe a sigh of relief and agree with Ferber when he says, "Every time I challenge this cancer, emotionally or physically-and survive-that's a victory for me."

Researchers have developed the first cancer-fighting drugs that target faulty genes.

Note to Editors: About Gleevec Tablets: Gleevec (imatinib mesylate) tablets are indicated for the treatment of newly diagnosed adult patients with Philadelphia chromosome−positive (Ph+) chronic myeloid leukemia (CML) in chronic phase. Follow-up is limited. Gleevec tablets are also indicated for the treatment of patients with Ph+ CML in blast crisis, in accelerated phase or in chronic phase after failure of interferon-alpha (IFN-a) therapy.

Important Safety Information1: Severe (NCI Grades 3/4) neutropenia (3%−48%), anemia (<1%−42%), thrombocytopenia (<1%−33%), hemorrhage (1%−19%), fluid retention (<1%−8%) (eg, pleural effusion, pulmonary edema, and ascites) and superficial edema (1%−6%), musculoskeletal pain (1%−9%), and hepatotoxicity (3%−8%) were reported among Gleevec® recipients. Patients should be weighed and monitored regularly for signs and symptoms of edema, which can be serious or life-threatening. There have also been reports, including fatalities, of cardiac tamponade, cerebral edema, increased intracranial pressure, papilledema, and gastrointestinal perforation. Bullous dermatologic reactions (eg, erythema multiforme and Stevens-Johnson syndrome) have also been reported. In some cases, the reaction recurred upon rechallenge. Several foreign postmarketing cases note a resolution or improvement of bullous reaction following dose reduction with or without supportive care. Dose adjustments may be necessary due to hepatotoxicity, other nonhematologic adverse events, or hematologic adverse events. Therapy with Gleevec was discontinued for adverse events in 3% to 5% of patients. Patients with severe hepatic impairment should be treated at a starting dose of 300mg/day and should be closely monitored. Gleevec is metabolized by the CYP3A4 isoenzyme and is an inhibitor of CYP3A4, CYP2D6, and CYP2C9. Dosage of Gleevec Tablets should increase by at least 50% and clinical response should be carefully monitored in patients receiving Gleevec Tablets with a potent CYP3A4 inducer such as rifampin or phenytoin. Examples of commonly used drugs that may significantly interact with Gleevec include acetaminophen, warfarin, erythromycin, and phenytoin. Please see enclosed full prescribing information for other potential drug interactions. For daily dosing of 800mg and above, dosing should be accomplished using the 400mg tablets to reduce exposure to iron. Use of Gleevec Tablets is contraindicated in patients with hypersensitivity to imatinib or to any other component of Gleevec Tablets. Women of childbearing potential should be advised to avoid becoming pregnant while taking Gleevec Tablets. Because of the potential for serious adverse reactions in nursing infants, women should be advised to avoid breast-feeding while taking Gleevec Tablets.

Common Side Effects of Gleevec Tablets1: The majority of the approximately 1700 adult patients who received Gleevec in clinical studies experienced adverse events at some time, but most were mild to moderate in severity. The most frequently reported adverse events were superficial edema (58%−81%), nausea (47%−74%), diarrhea (39%−70%), muscle cramps (28%−62%), vomiting (21%−58%), rash (36%−53%), fatigue (30%−53%), musculoskeletal pain (30%−49%), and abdominal pain (30%−40%).* Supportive care may help management of most mild-to-moderate adverse events so that prescribed dose can be maintained whenever possible. Gleevec tablets should be taken with food and a large glass of water to minimize gastrointestinal (GI) irritation. Gleevec tablets should not be taken with grapefruit juice.

1 Gleevec® (imatinib mesylate) tablets prescribing information. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2005.

* Numbers indicate the range of percentages in 4 studies among adult patients with Ph+ CML in blast crisis, accelerated phase, and chronic phase.