What constitutes a remission in CLL?

According to the National Cancer Institute-sponsored Working Group (NCI-WG) on Chronic Lymphocytic Leukemia, complete remission (CR) requires all of the following for a period of at least 2 months:

  1. absence of enlarged lymph nodes
  2. absence of enlarged spleen and liver
  3. absence of constitutional symptoms
  4. normal complete blood count (CBC) as exhibited by:
    1. neutrophils greater than or equal to 1,500 per microliter of blood
    2. platelets greater than 100,000 per microliter of blood
    3. hemoglobin greater than 11 grams per 100 milliliters of blood (untransfused)
  5. A bone marrow aspirate and biopsy should be performed 2 months after all of the above requirements have been met. The marrow sample must have less than 30% of nucleated cells that are lymphocytes, and lymphoid nodules should be absent. If the bone marrow is hypocellular, a repeat determination should be made in four weeks. Samples should be re-reviewed in conjunction with prior pathology.

A decrease in the absolute lymphocyte count is not considered in the response criteria for complete remission. Although this parameter may identify a therapy that has lymphocytotoxic activity, there is no evidence that it has long term clinical implications.

A partial remission (PR) requires that the patient exhibit the following features for a period of at least two months:

  1. a fifty percent or greater decrease in the peripheral lymphocyte count from the pretreatment baseline value
  2. a fifty percent or greater reduction in lymphadenopathy and/or
  3. a fifty percent or greater reduction in the size of the liver and/or spleen (if abnormal prior to therapy)

In addition to the factors outlined above, the patient must also exhibit one or more of the following:

  1. Neutrophils greater than or equal to 1,500 per microliter of blood or a fifty percent improvement over the pretreatment baseline
  2. Platelets greater than 100,000 per microliter of blood or a fifty percent improvement over baseline
  3. Hemoglobin greater than 11 grams per 100 milliliters of blood or a fifty percent improvement over baseline without transfusions.