Daily Facts

Symptoms

Damage to the bone marrow, by way of displacing the normal bone marrow cells with higher numbers of immature white blood cells, results in a lack of blood platelets, which are important in the blood clotting process. This means people with leukemia may become bruised, bleed excessively, or develop pinprick bleeds (petechiae).

White blood cells, which are involved in fighting pathogens, may be suppressed or dysfunctional. This could cause the patient’s immune system (white blood cells etc.) to start attacking other body cells.

Finally, the red blood cell deficiency leads to anemia, which may cause dyspnea. All symptoms can be attributed to other diseases; for diagnosis, blood tests and a bone marrow examination are required.

Some other related symptoms

* Fever, chills, night sweats and other flu-like symptoms
* Weakness and fatigue
* Loss of appetite and/or weight
* Swollen or bleeding gums
* Excess bleeding (from minor cut)
* Neurological symptoms (headache)
* Enlarged liver and spleen
* Easy Bruising
* Frequent Infection
* Bone Pain
* Joint Pain
* Swollen Tonsils

The word leukemia, which means ‘white blood,’ is derived from the disease’s namesake high white blood cell counts that most leukemia patients have before treatment. The high number of white blood cells are apparent when a blood sample is viewed under a microscope. Frequently, these extra white blood cells are immature or dysfunctional. The excessive number of cells can also interfere with the normal function of other cells.

Some leukemia patients do not have high white blood cell counts visible during a regular blood count. This less-common condition is called aleukemia. The bone marrow still contains cancerous white blood cells, and they are disrupting the normal production of blood cells. However, they are staying in the marrow instead of entering the bloodstream, where they would be visible in a blood test. For an aleukemic patient, the white blood cell counts in the bloodstream can be normal or low. Aleukemia can occur in any of the four major types of leukemia, and is particularly common in hairy cell leukemia.

Four major types

Leukemia is a broad term covering a spectrum of diseases.

Leukemia is clinically and pathologically split into its acute and chronic forms.

* Acute leukemia is characterized by the rapid proliferation of immature blood cells. This crowding makes the bone marrow unable to produce healthy blood cells. Acute forms of leukemia can occur in children and young adults. (In fact, it is a more common cause of death for children in the US than any other type of malignant disease). Immediate treatment is required in acute leukemias due to the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. However, CNS involvement is uncommon, though the disease occasionally causes cranial nerve palsies.

* Chronic leukemia is distinguished by the excessive build up of relatively mature, but still abnormal, blood cells. Typically taking months to years to progress, the cells are produced at a much higher rate than normal cells, resulting in many abnormal white blood cells in the blood. Chronic leukemia mostly occurs in older people, but can theoretically occur in any age group. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy.

Furthermore, the diseases are classified according to the type of abnormal cell found most in the blood (lymphoid cells vs. myeloid cells).

Causes and risk factors

There is no single known cause for all of the different types of leukemia. The different leukemias likely have different causes, and very little is certain about what causes them. Researchers have strong suspicions about four possible causes:

* natural or artificial ionizing radiation
* certain kinds of chemicals
* some viruses
* genetic predispositions

Leukemia, like other cancers, result from somatic mutations in the DNA which activate oncogenes or deactivate tumor suppressor genes, and disrupt the regulation of cell death, differentiation or division. These mutations may occur spontaneously or as a result of exposure to radiation or carcinogenic substances and are likely to be influenced by genetic factors. Cohort and case-control studies have linked exposure to petrochemicals, such as benzene, and hair dyes to the development of some forms of leukemia.

Viruses have also been linked to some forms of leukemia. For example, certain cases of ALL are associated with viral infections by either the human immunodeficiency virus (HIV, responsible for AIDS) or human T-lymphotropic virus (HTLV-1 and -2, causing adult T-cell leukemia/lymphoma).

Fanconi anemia is also a risk factor for developing acute myelogenous leukemia.

Until the cause or causes of leukemia are found, there is no way to prevent the disease. Even when the causes become known, they may prove to be things which are not readily controllable, such as naturally occurring background radiation, and therefore not especially helpful for prevention purposes.

Treatment options for leukemia by type

Acute Myelogenous Leukemia (AML)

It is most common for adults; more men than women are affected. Many different chemotherapeutic plans are available for the treatment of AML. Overall, the strategy is to control bone marrow and systemic (whole-body) disease while offering specific treatment for the central nervous system (CNS), if involved. In general, most oncologists rely on combinations of drugs for the initial, induction phase of chemotherapy. Such combination chemotherapy usually offers the benefits of early remission (lessening of the disease) and a lower risk of disease resistance. Consolidation or “maintenance” treatments may be given to prevent disease recurrence once remission has been achieved. Consolidation treatment often entails a repetition of induction chemotherapy or the intensification chemotherapy with added drugs. By contrast, maintenance treatment involves drug doses that are lower than those administered during the induction phase.

In addition, specific treatment plans may be used, depending on the type of leukemia that has been diagnosed. Whatever the plan, it is important for the patient to understand the treatment that is being given and the decision-making process behind the choice.

Initial treatment of AML

Initial treatment of AML usually begins with induction chemotherapy using a combination of drugs such as daunorubicin (DNR), cytarabine (ara-C), idarubicin, thioguanine, etoposide, or mitoxantrone, anabolic steroids.

Follow-up treatment

Follow-up therapy for such patients may involve:

* supportive care, such as intravenous nutrition and treatment with oral antibiotics (e.g., ofloxacin, rifampin), especially in patients who have prolonged granulocytopenia; that is too few mature granulocytes (neutrophils), the bacteria-destroying white blood cells that contain small particles, or granules (< 100 granulocytes per cubic millimeter for 2 weeks)
* injection with colony-stimulating factors such as granulocyte colony-stimulating factor (G-CSF), which may help to shorten the period of granulocytopenia that results from induction therapy
* transfusions with red blood cells and platelets

Patients with newly diagnosed disease also may be considered for stem cell transplantation (SCT), either from the bone marrow or other sources. Allogeneic bone marrow transplant (alloBMT) is reserved primarily for patients under 55 years of age who have a compatible family donor. Approximately half of newly diagnosed AML patients are in this age group, with 75% achieving a complete remission (CR) after induction and consolidation therapy. Allogeneic bone marrow transplant is available for about 15% of all patients with AML. Unfortunately, it is estimated that only 7% of all AML patients will be cured using this procedure.

People who receive stem cell transplantation (SCT, alloBMT) require protective isolation in the hospital, including filtered air, sterile food, and sterilization of the microorganisms in the gut, until their total white blood cell (WBC) count is above 500.

Treatment of central nervous system leukemia, if present, may involve injection of chemotherapeutic drugs (e.g., cytarabine or ara-C, methotrexate) into the areas around the brain and spinal cord.

Consolidation or maintenance therapy

Once the patient is in remission, he or she will receive consolidation or maintenance therapy, for example, consolidation therapy with high-dose ara-C (HDAC) with/without anthracycline drugs).

If, however, the AML patient has resistant disease (about 15%) or relapses (about 70%), second remissions sometimes are achieved by treating them with:

* conventional induction chemotherapy
* high-dose ara-C (HDAC), with/without other drugs
* etoposide or other single chemotherapeutic agents

Elderly AML patients have special treatment concerns. They may be less able to tolerate the septicemia (blood poisoning) associated with granulocytopenia, and they often have higher rates of myelodysplastic (’preleukemia’) syndrome (MDS). Individuals who are over age 75 or who have significant medical conditions can be treated effectively with low-dose ara-C. High-dose post-induction chemotherapy is unlikely to be tolerated by elderly patients.

Until recently, the treatment plans and responses of children with AML did not differ much from those of adults. Yet new, more intensive induction and consolidation treatments have resulted in higher remission rates and prolonged survivals. Many induction trials have produced good results using combinations of cytarabine (ara-C) plus an anthracycline (e.g., daunorubicin, doxorubicin). In children under 3 years of age, the anthracycline used for induction should be chosen with care, since doxorubicin produces more toxicity and related deaths than daunorubicin.

Consolidation therapy is complex, but it should include at least two courses of high-dose ara-C (HDAC). Children who have hyperleukocytosis (too many white blood cells), especially monocytic M5 leukemia, have a poor prognosis.

Chronic Myelogenous Leukemia (CML)

The challenge of treating newly diagnosed CML is to determine the best overall strategy to control the disease. General strategies for management include a variety of options:

Leukapheresis, also known as a peripheral blood stem cell transplant, with stem cell cryopreservation (frozen storage) prior to any other treatment. The patient’s blood is passed through a machine that removes the stem cells and then returns the blood to the patient. Leukapheresis usually takes 3 or 4 hours to complete. The stem cells may or may not be treated with drugs to kill any cancer cells. The stem cells then are stored until they are transplanted back into the patient.
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What is cancer?

Cancer is a group of many related diseases that begin in cells, the body’s basic building blocks. To understand cancer, it is helpful to know what happens when normal cells become cancerous.

The body is made up of many types of cells. Normally, cells grow and divide to produce more cells as they are needed to keep the body healthy. Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. The extra cells form a mass of tissue called a growth or tumor. Not all tumors are cancerous; tumors can be benign or malignant.

Benign tumors are not cancer. They can often be removed and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely a threat to life.

Malignant tumors are cancer. Cells in malignant tumors are abnormal and divide without control or order. Cancer cells invade and destroy the tissue around them. Cancer cells can also break away from a malignant tumor and enter the bloodstream or lymphatic system.

Blood vessels include a network of arteries, capillaries, and veins through which the blood circulates in the body. The lymphatic system carries lymph and white blood cells through lymphatic vessels (thin tubes) to all the tissues of the body. By moving through the bloodstream or lymphatic system, cancer can spread from the primary (original) cancer site to form new tumors in other organs. The spread of cancer is called metastasis.
What causes cancer?

Scientists have learned that cancer is caused by changes in genes that normally control the growth and death of cells. Certain lifestyle and environmental factors can change some normal genes into genes that allow the growth of cancer. Many gene changes that lead to cancer are the result of tobacco use, diet, exposure to ultraviolet (UV) radiation from the sun, or exposure to carcinogens (cancer-causing substances) in the workplace or in the environment. Some gene alterations are inherited (from one or both parents). However, having an inherited gene alteration does not always mean that the person will develop cancer; it only means that the chance of getting cancer is increased. Scientists continue to examine the factors that may increase or decrease a person’s chance of developing cancer.

Although being infected with certain viruses, such as the human papillomavirus (HPV), hepatitis B and C (HepB and HepC), and human immunodeficiency virus (HIV), increases the risk of some types of cancer, cancer itself is not contagious. A person cannot catch cancer from someone who has this disease. Scientists also know that an injury or bruise does not cause cancer.
Can cancer be prevented?

Although there is no guaranteed way to prevent cancer, people can reduce their risk (chance) of developing cancer by:

* not using tobacco products
* choosing foods with less fat and eating more vegetables, fruits, and whole grains
* exercising regularly and maintaining a lean weight
* avoiding the harmful rays of the sun, using sunscreen, and wearing clothing that protects the skin
* talking with a doctor about the possible benefits of drugs proven to reduce the risk of certain cancers

Although many risk factors can be avoided, some, such as inherited conditions, are unavoidable. Still, it is helpful to be aware of them. It is also important to keep in mind that not everyone with a particular risk factor for cancer actually gets the disease; in fact, most do not. People who have an increased likelihood of developing cancer can help protect themselves by avoiding risk factors (see Question 2) whenever possible and by getting regular checkups so that, if cancer develops, it is likely to be found and treated early. Treatment is often more effective when cancer is detected early. Screening exams, such as sigmoidoscopy or the fecal occult blood test, mammography, and the Pap test, can detect precancerous conditions (which can be treated before they turn into cancer) and early-stage cancer.

The NCI is conducting many cancer prevention studies to explore ways to reduce the risk of developing cancer. These studies are evaluating dietary supplements, chemopreventive agents, nutrition, personal behaviors, and other factors that may prevent cancer. More information about cancer prevention trials is available in the following NCI resources:

What are some of the common signs and symptoms of cancer?

Cancer can cause a variety of symptoms. Possible signs of cancer include the following:

* new thickening or lump in the breast or any other part of the body
* new mole or an obvious change in the appearance of an existing wart or mole
* a sore that does not heal
* nagging cough or hoarseness
* changes in bowel or bladder habits
* persistent indigestion or difficulty swallowing
* unexplained changes in weight
* unusual bleeding or discharge

When these or other symptoms occur, they are not always caused by cancer. They can be caused by infections, benign tumors, or other problems. It is important to see a doctor about any of these symptoms or about other physical changes. Only a doctor can make a diagnosis. A person with these or other symptoms should not wait to feel pain because early cancer usually does not cause pain.

If symptoms occur, the doctor may perform a physical examination, order blood work and other tests, and/or recommend a biopsy. In most cases, a biopsy is the only way to know for certain whether cancer is present. During a biopsy, the doctor removes a sample of tissue from the abnormal area. A pathologist studies the tissue under a microscope to identify cancer cells.
How is cancer treated?

Cancer treatment can include surgery, radiation therapy, chemotherapy, hormone therapy, and biological therapy. The doctor may use one method or a combination of methods, depending on the type and location of the cancer, whether the disease has spread, the patient’s age and general health, and other factors. Because treatment for cancer can also damage healthy cells and tissues, it often causes side effects. Some patients may worry that the side effects of treatment are worse than the disease. However, patients and doctors generally discuss the treatment options, weighing the likely benefits of killing cancer cells and the risks of possible side effects. Doctors can suggest ways to reduce or eliminate problems that may occur during and after treatment.

Surgery is an operation to remove cancer. The side effects of surgery depend on many factors, including the size and location of the tumor, the type of operation, and the patient’s general health. Patients have some pain after surgery, but this pain can be controlled with medicine. It is also common for patients to feel tired or weak for a while after surgery.

Patients may worry that having a biopsy or other type of surgery for cancer will spread the disease. This is a very rare occurrence because surgeons take special precautions to prevent cancer from spreading during surgery. Also, exposing cancer to air during surgery does not cause the disease to spread.

Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells in a targeted area. Radiation can be given externally by a machine that aims radiation at the tumor area. It can also be given internally; needles, seeds, wires, or catheters containing a radioactive substance are placed directly in or near the tumor. Radiation treatments are painless. The side effects are usually temporary, and most can be treated or controlled. Patients are likely to feel very tired, especially in the later weeks of treatment. Radiation therapy may also cause a decrease in the number of white blood cells, which help protect the body against infection. With external radiation, it is also common to have temporary hair loss in the treated area and for the skin to become red, dry, tender, and itchy.

There is no risk of radiation exposure from coming in contact with a patient undergoing external radiation therapy. External radiation does not cause the body to become radioactive. With internal radiation (also called implant radiation), a patient may need to stay in the hospital, away from other people, while the radiation level is highest. Implants may be permanent or temporary. The amount of radiation in a permanent implant goes down to a safe level before the person leaves the hospital. With a temporary implant, there is no radioactivity left in the body after the implant is removed.

Chemotherapy is the use of drugs that kill cancer cells throughout the body. Healthy cells can also be harmed, especially those that divide quickly. The doctor may use one drug or a combination of drugs. The side effects of chemotherapy depend mainly on the drug(s) and the dose(s) the patient receives. Hair loss is a common side effect of chemotherapy; however, not all anticancer drugs cause loss of hair. Anticancer drugs may also cause temporary fatigue, poor appetite, nausea and vomiting, diarrhea, and mouth and lip sores. Drugs that prevent or reduce nausea and vomiting can help with some of these side effects. Normal cells usually recover when chemotherapy is over, so most side effects gradually go away after treatment ends.

Hormone therapy is used to treat certain cancers that depend on hormones for their growth. It works by keeping cancer cells from getting or using the hormones they need to grow. This treatment may include the use of drugs that stop the production of certain hormones or that change the way hormones work. Another type of hormone therapy is surgery to remove organs that make hormones. For example, the ovaries may be removed to treat breast cancer, or the testicles may be removed to treat prostate cancer.

Hormone therapy can cause a number of side effects. Patients may feel tired, or have fluid retention, weight gain, hot flashes, nausea and vomiting, changes in appetite, and, in some cases, blood clots. Hormone therapy may also cause bone loss in premenopausal women. Depending on the type of hormone therapy used, these side effects may be temporary, long lasting, or permanent.

Biological therapy uses the body’s immune system, directly or indirectly, to fight disease and to lessen some of the side effects of cancer treatment. Monoclonal antibodies, interferon, interleukin-2, and colony-stimulating factors are some types of biological therapy.

The side effects caused by biological therapy vary with the specific treatment. In general, these treatments tend to cause flu-like symptoms, such as chills, fever, muscle aches, weakness, loss of appetite, nausea, vomiting, and diarrhea. Patients also may bleed or bruise easily, get a skin rash, or have swelling. These problems can be severe, but they go away after the treatment stops.
Are clinical trials (research studies) available? Where can people get more information about clinical trials?

Yes. Clinical trials are an important treatment option for many cancer patients. To develop new, more effective treatments, and better ways to use current treatments, the NCI is sponsoring clinical trials in many hospitals and cancer centers around the country. Clinical trials are a critical step in the development of new methods of treatment. Before any new treatment can be recommended for general use, doctors conduct clinical trials to find out whether the treatment is safe for patients and effective against the disease.

People interested in taking part in a clinical trial should talk with their doctor. Information about clinical trials is available from the NCI’s Cancer Information Service (CIS) (see below) at 1–800–4–CANCER and in the NCI booklet Taking Part in Clinical Trials: What Cancer Patients Need To Know, which is available at http://www.cancer.gov/publications on the Internet. This booklet describes how research studies are carried out and explains their possible benefits and risks. Further information about clinical trials is available at http://www.cancer.gov/clinicaltrials on the NCI’s Web site. The Web site offers detailed information about specific ongoing treatment trials as well as trials focused on prevention, screening, and diagnosis by linking to PDQ®, the NCI’s comprehensive cancer information database. The CIS also provides information from PDQ.
Does cancer always cause pain?

Having cancer does not always mean having pain. Whether a patient has pain may depend on the type of cancer, the extent of the disease, and the patient’s tolerance for pain. Most pain occurs when the cancer grows and presses against bones, organs, or nerves. Pain may also be a side effect of treatment. However, pain can generally be relieved or reduced with prescription medicines or over-the-counter drugs recommended by the doctor. Other ways to reduce pain, such as relaxation exercises, may also be useful. Pain should not be accepted as an unavoidable part of having cancer. It is important for patients to talk about pain so steps can be taken to help relieve it. The fear of addiction or “losing control” should not stop patients from taking pain medication. Patients who take medications for cancer pain, as prescribed by their doctor, rarely become addicted to them. In addition, changing the dose or type of medication can usually help if the patient has troublesome side effects.

Daily Facts