Hairy cell leukemia is a rare, slow growing blood cancer in which there is excessive production of immature and non-functional B lymphocytes. The condition is named after hairy appearance of these cells when viewed under a microscope. These abnormal cells are known as leukemic cells. Hairy cell leukemia gets worse slowly or does not get worse at all. It affects all blood cells including red blood cells, white blood cells and platelets as these leukemic cells build up in bone marrow and blood leading to anemia, thrombocytopenia and leucopenia. Pancytopenia may lead to increased susceptibility to infection, anemia and easy bleeding.
The etiology of hairy cell leukemia is still unknown, but it has been linked to genetic mutation. Men in the age group of 40 to 70 are five times more susceptible to this type of blood cancer. They may present with signs of infection, fatigue, pain below the ribs, abdominal pain (due to splenomegaly), frequent fever, shortness of breath, unexplained weight loss, easy satiety, lumps in neck, axilla, stomach or groin and easy bruising/bleeding.
Can Hairy Cell Leukemia Be Cured?
Although, hairy cell leukemia is a rare condition, it is a successfully treated disease with very good prognosis and excellent survival rate of about 10 years after remission of the disease. After remission, the patients live a healthy normal life with regular monitoring of the condition. Since hairy cell leukemia is a very rare condition, it is not extensively studied, so currently there is no permanent cure for it; however, the current treatment aims at controlling the disease progression with increased survival rate of the patients.
Hairy cell leukemia is diagnosed with the help of blood test or bone marrow test along with ultrasound or CT scan to look for involvement of any other body parts. After diagnosis, immediate treatment is not required in all the patients and these patients can be monitored until treatment is needed. Symptomatic treatment is given to patients suffering from the disease. Often treatment is required for frequent infections along with fever due to decrease in white blood cell count.
For the last three decades, purine analogues (pentostatin and cladribine) have been the cornerstone of hairy cell leukemia treatment. They are highly effective at controlling the disease and inducing 90-95% complete remission rate and a survival rate of about 10 years.
Pentostatin is administered intravenously every 2 to 3 weeks for up to 6 months until remission is achieved. Kidney function test along with creatinine levels is monitored as this drug is excreted through kidneys.
Cladribine can be given either as a 7 day continuous IV infusion, daily/weekly IV infusions of 6 doses or as subcutaneous injections for 5 consecutive days. Along with pentostatin and cladribine, since they suppress immune system, thus increasing chances of infection, antibiotics/antivirals are prescribed in low doses to reduce the risk of infection.
Other treatment options include interferon-A and rituximab. Rituximab is used in combination with pentostatin or cladribine in cases of relapse. Interferon-A is preferred in patients with a diagnosis of infection, either alone or in combination therapy with cladribine or pentostatin.
Splenectomy is rarely performed with the advent and success rate of current drugs. However, it is still performed in cases of excessive splenomegaly and blood burden.
Monitoring of Patients with Hairy Cell Leukemia
Regular monitoring of patients is required in hairy cell leukemia and blood counts begin to reach normal levels within few weeks of treatment. The response of treatment is assessed by blood tests and bone marrow tests. Bone marrow test is an unpleasant experience, but is of great value in assessing the treatment rationale, progression and remission. About 40% of patients relapse, which is noted by decreased blood count and confirmed by bone marrow examination. Retreatment is also successful in hairy cell leukemia cases, but with shorter periods of remission. About 30% of patients have a chance of developing secondary cancers after being treated for hairy cell leukemia, so long term follow up of patients is quite necessary.