Chronic lymphocytic leukemia
Leukemia is a group of cancers, originating in the bone marrow, that cause high numbers of (immature) white blood cells.
First, we need to remember, what are myeloid and lymphoid cells, and more specifically, what are myeloblasts and lymphoblasts?
Right, types of leukemia
- We can divide based on the lineage affected:
- Myeloid
- Lymphoid
- And based on onset
- Chronic
- Acute
First, let’s take an overall look at the four main types of leukemia.
Today, we’re talking about Chronic Lymphocytic leukemia, aka CLL!
CLL is a malignant disorder of the bone marrow causing clonal expansion of B-cell lymphocytes and it is the most common leukaemia in the west accounting for almost ⅓ of cases. Males are twice as likely to be affected and the general age of onset is about 70 y.o.
The exact cause of CLL is unknown, although hep C has been associated with splenic lymphoma and villous lymphocytes. Familial clustering is more common in CLL than in other leukemias, so there is a clear genetic component. The genes most commonly implicated are TP53 and SF3B1.
Leukemia cells in CLL are homogenous and appear to be normal mature lymphocytes, however there is uncontrolled proliferation of monoclonal B-cells that then accumulate in the bone marrow, lymph nodes, liver, spleen and sometimes other organs.
Image: “Chronic lymphocytic leukemia” by Mary Ann Thompson ( VashiDonsk at en.wikipedia ), CC BY-SA 3.0, via Wikimedia Commons.
Most patients with CLL are asymptomatic, and diagnosis is made when lymphocytosis is nodded in peripheral blood incidentally. Symptoms such as fatigue, lethargy, loss of appetite, weight loss and reduced exercise tolerance are non-specific and non-diagnostic. Many patients will develop enlarged lymph nodes as the disease progresses (and more B-cells become deposited). Nodes are commonly soft, mobile and discrete before later becoming large and matted. Organ failure from infiltration of B-cells is rare.
On diagnosis look out for high lymphocyte counts (5000-6000,0000 x 10*9/uL) in peripheral blood, with 20% of patients having anemia as well.
Treatment should be considered if the patient is symptomatic, if Ig genes are unmutated and/or 17p deletions. Treatment is Fludarabine + cyclophosphamide + rituximab first line. Radiotherapy helps treat lymphadenopathy and splenomegaly.
⅓ never progress, ⅓ slowly progress and ⅓ progress actively.