Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is the most common cancer occurring in children. ALL is a cancer of the bone marrow and lymph system, characterized by the presence of too many immature lymphocytes, or white blood cells, which are produced by the bone marrow. These immature lymphocytes never mature enough to perform their specific function of fighting infection. In addition, these are rapidly dividing cells that crowd out and suppress the formation of other important blood cells such as red blood cells, which carry oxygen to tissues, and platelets, which aid the blood in clotting.

With the use of modern chemotherapy treatment, over 80% of children with ALL are cured. However, 5-10% of children with ALL have a return of the cancer to their brain. Unfortunately, those who experience a recurrence in the brain usually have a poor outcome because the relapse ultimately leads to a return of the cancer in the bone marrow and blood. Since ALL relapse often occurs in the central nervous system (the brain and spine), standard initial treatment includes not only systemic chemotherapy, but also preventative administration of combination chemotherapy delivered specifically to the brain and spine. This is done because it is easier to prevent the cancer cells from returning than it is to destroy them once they are present.

Many chemotherapy drugs do not easily reach the central nervous system, so administration of these drugs directly into the spinal fluid promotes the desired delivery to these areas. A lumbar puncture is the process through which drugs are administered into the spinal fluid. During this procedure, chemotherapy drugs are administered through a large needle inserted near the spine. Patients with ALL undergo several lumbar punctures as part of their treatment.

Results from a clinical study published in the Journal of the American Medical Association indicate that lumbar puncture, a procedure through which chemotherapy is administered directly into spinal fluid appears to be safe for children with acute lymphoblastic leukemia (ALL) who also have low platelet levels (thrombocytopenia).

Since low platelet levels may be associated with severe bleeding, there has been concern regarding the effects of thrombocytopenia on the safety of repeated lumbar punctures in patients with ALL. Patients with ALL may experience thrombocytopenia from the leukemia itself, or from treatments they receive for their disease.

Physicians from St. Jude’s Children’s Research Hospital recently evaluated the records of almost 1,000 children with ALL who also had thrombocytopenia. They attempted to determine if an association existed between thrombocytopenia and complications with a lumbar puncture. Over 5,000 lumbar punctures were performed on patients who had platelet levels as low as 10,000 (normal levels are over 100,000). There were no reports of any serious complications due to the procedure.

These physicians concluded that lumbar punctures were safe for children with ALL and thrombocytopenia. Children with platelet counts under 10,000 were not adequately evaluated in this study and may benefit from platelet transfusions prior to lumbar punctures. The importance of this study is to alleviate fears of parents concerning the risks of severe bleeding due to performing a lumbar puncture in children with thrombocytopenia. The risks of withholding appropriate treatment far outweigh the risks of the procedure.

Parents who have children with ALL may wish to speak with their doctor about the risks and benefits of a lumbar puncture or the participation in a clinical trial further evaluating this procedure or other promising treatments. Two sources of information that can be discussed with a doctor include comprehensive, easy-to-use services provided by the National Cancer Institute ( cancer.gov) and eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients. ( Journal of the American Medical Association, Vol 284, No 17, pp 2222-2224, 2000)