For most people, the word cancer implies that there’s a tumor or mass growing somewhere in the body. However, contrary to popular belief, not all cancers form tumors.

While many cancer patients are likely to hear the word tumor when they are diagnosed, that might not be the case for the more than 4,700 Texans expected to be diagnosed with leukemia this year.

What is leukemia?
Unlike most cancers, which occur when abnormal cells multiply to form masses, leukemia occurs when abnormal blood cells are generated within the bone marrow, multiply, and spread throughout the body, crowding out platelets and healthy white and red blood cells. These abnormal cells make it difficult for normal blood cells and platelets to function properly within the body, making a person prone to infection, anemia, bruising, and bleeding.

• Acute lymphocytic leukemia (ALL)
• Acute myeloid leukemia (AML)
• Chronic lymphocytic leukemia (CLL)
• Chronic myeloid leukemia (CML)

Acute leukemia is characterized by rapidly growing cells and quickly diminishes a person's health, and chronic leukemia develops and progresses slowly over time.

For most cancer types, the stage of the cancer is based on the size and spread of the primary tumor. However, leukemia staging is determined based on blood cell counts and the accumulation of leukemia cells in organs like the liver and spleen. First, the leukemia subtype is determined using cytologic (cellular) tests, flow cytometry, or other lab tests. Then, each leukemia subtype is staged using a specific system which may include molecular testing results for determining the level of risk:

• ALL looks at the type of lymphocyte and the maturity of the cells.
• AML considers the number of healthy blood cells, size and number of the leukemia cells, changes in the chromosomes of the leukemia cells, and other genetic abnormalities.
• CLL uses the number of lymphocytes in the blood; the degree of lymph node, spleen, or liver enlargement; and the presence of anemia or thrombocytopenia.
• CML measures the number of diseased cells found in blood and bone marrow tests.

Treatment for leukemia varies depending on the type and stage of leukemia, as well as the patient’s age, medical history, general health, and treatment goals. However, patients with acute leukemia must start treatment immediately due to the rapid progression of the disease. Treatment options for leukemia can include:

• Blood and bone marrow transplant
• CAR-T therapy
• Chemotherapy
• Immunotherapy
• Monoclonal antibodies
• Palliative medicine
• Radiation therapy
• Surgery
• Surveillance
• Targeted therapy

Although leukemia is the most common childhood cancer, most cases are in adults over 55. It is also slightly more common in men than women, but everyone should be aware of the signs and symptoms associated with this cancer type, which include swollen lymph nodes, frequent fevers or night sweats, weakness, shortness of breath, and reoccurring infections, among other symptoms.

Thanks to ongoing research and clinical trials, medical advancements have improved survival rates for many types of leukemia. For example, the survival rate for chronic myelogenous leukemia is now 70% — three times higher than it was in the 1970s.

September is Blood Cancer Awareness Month, and while leukemia accounts for only 3.2% of new cancer diagnoses nationally, for the more than 62,770 people who will be diagnosed this year, understanding the potential risk factors, symptoms, and unique characteristics of this disease is crucially important.