Leukemia is a type of blood cancer. All cancer results from uncontrolled growth in a part of your body. In the case of leukemia, this abnormal growth is found in blood cells and bone marrow (the part of your body that makes blood cells).

Leukemia is not a single disease. In fact, there are four major types (acute lymphocytic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, and chronic myelogenous leukemia), as well as a number of rarer varieties. The type of leukemia you have will determine the type of treatment that you receive. Most cases of leukemia are treatable.

The following section will discuss the various types of leukemia in more depth and explain the various signs, symptoms, varieties, and treatments. There is also information on what causes leukemia, life changes that may occur because of this disease, as well as some common myths and misconceptions about leukemia.

The following are the most common signs of leukemia:

• Unexplained fevers, chills, or night sweats
• Swollen lymph nodes (especially in your neck, armpits, and groin)
• Frequent bloody nose
• Unexplained tiredness and a general sense of weakness
• Unexplained bacterial or viral infections
• Unexplained weight loss
• Unexplained bruising
• Changes in skin that include red spots.
• General sense of feeling unwell.

Sometimes, people with leukemia will show no symptoms at all during the first stages of their illness. Others may experience uncommon side effects that are similar to other illnesses.

These are the four main types of leukemia:

• Acute lymphocytic leukemia (ALL) – The word acute means sudden. Any leukemia that is acute develops very rapidly. Acute lymphocytic leukemia is not only a fast-developing cancer but also the most common type of leukemia in people under the age of 18. When a child has leukemia, the chances are good that it will be ALL.
• Acute myeloid leukemia (AML) – Acute myelogenous leukemia is another fast-growing leukemia. While it can occur in children, it is most common among people over the age of 18.
• Chronic lymphocytic leukemia (CLL) - The word chronic means that something develops over time. Chronic lymphocytic leukemia develops gradually. This type of leukemia is primarily found in adults. Some people may have this condition for a few years before they realize they are sick.
• Chronic myelogenous leukemia (CML) – Chronic myelogenous leukemia is another of the slow-forming leukemias. This one also primarily affects adults. People who have this type of cancer often have long periods when they are feeling well and periods when they are feeling very sick.

Besides the “big four” mentioned above, the following are some rarer forms of leukemia:

• Hairy cell leukemia (HCL) – This rare form of leukemia mostly affects adult males. The survival rate is nearly 100%.
• T-cell prolymphocytic leukemia (T-PLL) – T-cell prolymphocytic leukemia involves a type of white blood cell called a T-cell. T-cells are an important part of the immune system. T-PLL almost always affects adults.
• Large granular lymphocytic leukemia (LGL)  – This is a slow-growing (indolent) leukemia that mostly affects adults.
• Adult T-cell leukemia (ATL) – This is a type of leukemia that is caused by a virus. Specifically, it is caused by the HTLV virus.
• Chronic myelomonocytic leukemia (CMML) – This is an extremely rare form of cancer. It only affects about 1,000 people in the world each year.
• Juvenile myelomonocytic leukemia (JMML) – This is also an extremely rare form of cancer. The major difference between this disease from chronic myelomonocytic leukemia is that juvenile myelomonocytic leukemia only affects children.
• Large granular lymphocytic leukemia (LGL) – This form of leukemia primarily affects the lymphocytes, a type of white blood cell that helps fight infection.
• Blastic plasmacytoid dendritic cell neoplasm (BPDCN) – This is a very rare type of cancer that shares common features with another type of blood cancer called lymphoma. In fact, some scientists classify it as lymphoma.
• B-cell prolymphocytic leukemia (B-PLL) – This type of leukemia infects B-cells, a type of white blood cell.
• T-cell prolymphocytic leukemia (T-PLL) – This is a very rare and difficult-to-treat leukemia. It usually affects people over the age of 60.

Most cases of leukemia are idiopathic in nature. This is another way of saying that doctors do not know what caused the illness. There are certain risk factors that make some people more susceptible to developing leukemia. One of these is a genetic predisposition. Having family members who have leukemia increases one’s likelihood of developing this type of cancer. The following genes are associated with an increased risk of developing leukemia: CEBPA, DDX41, RUNX1, ANKRD26, ETV6, GATA2, FANCA-FANCW. People who have Down’s syndrome are also at an increased risk of developing leukemia.

Lifestyle may also play a role. Smoking has been shown to increase one’s risk of developing leukemia. Exposure to certain toxic chemicals, such as benzene, is also known to be a risk factor. Additionally, cancer survivors are at an increased risk, especially those who have received chemotherapy or radiation during their previous cancer treatment.

If you have blood relatives who have developed leukemia, it is advisable to make an appointment with a genetic counselor to assess your risk of developing blood cancer. However, for people without a genetic predisposition, quitting smoking and avoiding carcinogens (chemicals like benzene that cause cancer) and excess radiation will greatly reduce your chances of developing many forms of cancer, including leukemia.

Formulating a risk assessment for developing leukemia will depend on many factors, including age, genetic predisposition, previous cancer history, general health, etc. Making an appointment with a genetic counselor is one way in which you could acquire important data to use in a risk assessment. A genetic counselor is a medical professional who will discuss your health history and arrange for your DNA to be sequenced in order to look for genes that increase your risk for cancer and many other diseases.

If your genetic profile indicates that you have a higher chance than normal of developing a disease, you will likely be referred to another specialist. Many medical centers all over the world have physicians and scientists who specialize in cancer genetics. If you do have a genetic profile that warrants follow-up with one of these specialists, they will give you detailed information about how to monitor your health to look for the signs of leukemia.

Those who have been exposed to large amounts of carcinogens or radiation should gather details about their exposure and present them to their physician in order to get a referral to an oncologist or other specialist.

Leukemia can usually be successfully treated at any stage; however, the earlier it is diagnosed, the more likely it is that you will be cured. Only a physician can diagnose you. Once leukemia is confirmed, your doctor will almost certainly refer you to an oncologist, a physician that specializes in cancer. The oncologist will order a number of tests to determine what stage your cancer is in.

Many people are familiar with the four stages of cancer. Staging leukemia is a bit different than staging other cancers. There are several different staging systems used for the different types of leukemia. For instance, acute myeloid leukemia is staged in the following way:

• M0 – Undifferentiated
• M1 – Acute with minimal maturation
• M2 – Acute with maturation
• M3 – Acute promyelocytic leukemia
• M4 Acute myelomonocytic leukemia
• M4 eos – Acute myelomonocytic leukemia with eosinophilia
• M5Acute monocytic leukemia
• M6Acute erythroid leukemia
• M7Acute megakaryoblast leukemia

People who receive yearly checkups are ordinarily given a series of blood and urine tests to screen for a variety of diseases, including leukemia. However, not all leukemias show up in bloodwork, especially when they are in the early stages. Unless you have a genetic profile that makes you extremely susceptible to developing leukemia, or you have been exposed to carcinogens or radiation, extensive screening for leukemia is rarely carried out.

If you are at high risk of developing leukemia, you will probably be asked to have at least several blood tests per year.

Regular screening is the best way to catch leukemia in its earliest stage. The earlier it is caught, the greater the chances are that it will be cured. And, in most cases, leukemia can be cured.

When you have blood work done and tissue samples taken from your body, a pathology report will be generated. Your pathology report contains your diagnosis. It contains information about which type of cancer you have, and, in many cases, which stage the cancer is in. These reports will be studied in conjunction with PET scans and other tests that your doctor will order. Almost everyone with leukemia has at least one abnormal level on a blood test. For instance, if you do have leukemia, it is very likely that you will have an abnormal white blood cell count (WBC). It is important to discuss the specifics of your lab report with your doctor.

Chemotherapy, radiation, immunotherapy, and bone marrow transplants are the types of treatments used to treat leukemia. You are likely to receive at least one of these. Many patients receive more than one. The type of treatment you get will depend on the type of leukemia you have, the stage of the disease, your age, and your general health.

Chemotherapy – Chemotherapy consists of medicines (chemicals) that are introduced into your body. These medicines kill cancer cells. Chemotherapy has a few side effects, including nausea, tiredness, etc. Medicines are usually given to help alleviate these symptoms. There are numerous different chemotherapeutic agents available for leukemia, some of which have very different side effects. Chemotherapy drugs can be given in an infusion (a process much like receiving blood or IV fluids), pill, or several other methods.

Radiation – Exposing people to high doses of targeted radiation also kills cancer cells. A specialist called a radiation oncologist will usually oversee administering this type of treatment if it is required. Radiation usually produces side effects, including burning of the skin. The amount of radiation you receive is carefully monitored so that the healthy cells in your body receive little to no exposure.

Immunotherapy – Immunotherapy is a new type of treatment. It involves introducing a genetically modified organism or protein into your system. Immunotherapy either attacks the cancer or allows your body’s immune system to recognize cancer cells as dangerous. When the immune system sees cancer cells are an invasive organism, it attacks and kills the cancer as if it were a cold or flu virus.

Bone marrow transplantation – Some leukemia patients will need a bone marrow transplant. In this procedure, a patient’s own bone marrow is destroyed via radiation, and new bone marrow from a donor is given to you. The new bone marrow produces healthy blood cells. If everything goes as planned, the patient is cured.

During treatment, you will have to alter your diet and lifestyle. This is primarily done to make sure that you do not develop an infection.

It should also be noted that many patients may opt to be part of a clinical trial. A clinical trial is an experiment where you are given a drug (or other type of treatment) that has not yet been fully approved by the government. Clinical trials are carefully monitored for safety; however, there are considerable risks. These risks will be explained to you by your physician if you decide to take part in a clinical trial. Many patients, especially those with leukemias that are very difficult or impossible to treat, may wish to ask their doctors if they are a candidate for any clinical trials.

After you complete your treatment, you will continue to be monitored by your oncologist and health care team for several years. This is done to make sure the leukemia does not return and to monitor your overall health. You are likely to experience at least some side effects after you complete treatment, including fatigue and hair loss. Some may be minor; others may be severe. However, most people eventually return to their normal lives after finishing their leukemia treatments. It just takes a little bit of time.

When you become sick with leukemia, interactions with your family and friends will often change. It is important that you talk to the people you know about your leukemia and explain to them that you will be receiving treatment that will probably affect your physical appearance, daily routine, and mood.

Some people may need to avoid sexual relations during the treatment, while others may simply need to take certain precautions. Ask your doctor if you should use condoms or other forms of prophylaxis during sexual encounters. You should also ask them if kissing, hugging, and sleeping in the same bed as one’s partner is advisable during your treatment.

The following are some common myths about leukemia:

• Myth #1 – Leukemia is a death sentence.
  Most leukemia is treatable.
• Myth #2 – Only children get leukemia.
  Leukemia can strike at any age. However, there are some types of leukemia that are far more common in children than adults.
• Myth #3 If you don’t feel sick, you don’t have leukemia.
  Many people with certain types of leukemia feel perfectly healthy. This is especially true in chronic leukemias in the early stages.
• Myth #4 Leukemia is different from cancer.
  Leukemia is cancer. It is cancer of the blood and/or bone marrow.
• Myth #5 Leukemia and lymphoma are the same thing.
  Leukemia and lymphoma are both blood cancers; however, they are different types of blood cancers.
• Myth #6 Only family members can donate bone marrow.
  Bone marrow can be donated by anyone who is a genetic match, including people you are not related to.