A treatment outline of hairy cell leukemia is given below:

• If a patient is diagnosed in the early stages, the “wait and watch” approach may be used and treatment only started if the blood counts indicate therapy is necessary.
• However, early diagnosis is rare and treatment is often required immediately. In most cases, the treatment is very effective and life expectancy is not significantly shortened. The treatment aims to reduce the number of malignant cells in the bone marrow and restore levels of healthy blood cells.
• The mainstay of treatment is chemotherapy. One of the main drugs used is cladribine, which is given as an intravenous injection every day for seven days. Around 95% of patients respond to this drug and achieve complete remission, meaning the disease cannot be detected in the bone marrow using standard tests. An alternative therapy is pentostatin which is given as an intravenous injection over 3 to 4 months.
• In patients with spleen enlargement, a splenectomy (surgery to remove part or whole of the spleen) may be advised, although this is not usually required because patients respond successfully to chemotherapy.
• A medicine called interferon may be used in combination with chemotherapy. Interferon is classed as an immunotherapy and helps the immune system to destroy malignant cells.
• Cladribine or pentostatin are also effective at treating any instances of disease relapse, although the disease-free remission is usually shorter lived after subsequent treatments.
• A monoclonal antibody may also be used to treat hairy cell leukemia if patients have a poor response to the initial chemotherapy.