Chronic lymphocytic leukemia (CLL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell). Early on, there are typically no symptoms. Later, non-painful lymph node swelling, feeling tired, fever, night sweats, or weight loss for no clear reason may occur. Enlargement of the spleen and low red blood cells (anemia) may also occur. It typically worsens gradually over years. Risk factors include having a family history of the disease, with 10% of those who develop CLL having such ancestry. Exposure to Agent Orange, certain insecticides, sun exposure, exposure to hepatitis C virus, and common infections are also considered risk factors. CLL results in the buildup of B cell lymphocytes in the bone marrow, lymph nodes, and blood. These cells do not function well and crowd out healthy blood cells. CLL is divided into two main types: Those with a mutated IGHV gene Those without. Diagnosis is typically based on blood tests finding high numbers of mature lymphocytes and smudge cells. Early-stage CLL in asymptomatic cases responds better to careful observation, as there is no evidence that early intervention treatment can alter the course of the disease. Immune defects occur early in the course of CLL and these increase the risk of developing serious infection, which should be treated appropriately with antibiotics. In those with significant symptoms, chemotherapy, immunotherapy, or chemoimmunotherapy may be used. Depending on the individual's age, physical condition, and whether they have the del(17p) or TP53 mutation, different first line treatments may be offered. As of 2021, BTK inhibitors such as ibrutinib and acalabrutinib are often recommended for first line treatment of CLL. The medications fludarabine, cyclophosphamide, and rituximab were previously the initial treatment in those who are otherwise healthy. CLL affected about 904,000 people globally in 2015 and resulted in 60,700 deaths. In 2021, the estimated incidence of CLL in the United States is 21,250 new cases and 4,320 deaths. The disease most commonly occurs in people over the age of 65, due to the accumulation of genetic mutations that occur over time. Men are diagnosed around twice as often as women (6.8 to 3.5 ratio). It is much less common in people from Asia. Five-year survival following diagnosis is approximately 83% in the United States. It represents less than 1% of deaths from cancer.

Reference
Wiki: Chronic lymphocytic leukemia