Approximately one third of CLL patients will die from causes unrelated to their CLL. The majority, however, will die from CLL related causes. This question deals with some of the terminal aspects of CLL.

In many cases, patients live for several years without treatment and are able to carry on a normal lifestyle. In other cases, CLL may be much more aggressive. When symptoms of disease progression become apparent, treatment often alleviates symptoms through partial, and in some cases, complete remissions. As the disease progresses and becomes unresponsive to treatment (refractory), patients usually enter a terminal phase that can often last up to two years. During this terminal phase, there is considerable lack of wellness, both from the disease and from complications of therapy. Recurring hospitalization is not uncommon during this phase of CLL.

The most frequent causes of CLL-related death are, severe systemic infections such as, pneumonia and septicemia, bleeding, and severe wasting and weakness.

In a small number of cases, CLL will transform into diffuse large cell lymphoma (Richter's syndrome). In an equally small number of cases, CLL will transform into prolymphocytic leukemia. Both carry a poor prognosis, and there is no generally accepted, effective therapy for these terminal transformations. Physicians continue to study and evaluate treatment possibilities for this phase of CLL.