Leukemia Effects On Organs.

Cancer cells invading the tissues surrounding the brain can cause severe headache, nausea, and vomiting. Moreover, cancer cells in the brain and spinal cord are effectively protected from the action of most chemo-therapeutic drugs by a thin membrane called the "blood-brain barrier," which prevents the drugs from diffusing into the spinal fluid. The testicles in men are another "sanctuary" organ.

Since all malignant cells in these sanctuaries must be destroyed to prevent a relapse, radiation is used in place of chemotherapy. Although not all leukemia patients show definite evidence of malignant cells in sanctuary areas, most adults and almost all children with acute leukemia now receive about 2,400 rads of radiation to the brain, as well as repeated doses of methotrexate given by direct injection through the blood-brain barrier to the spinal fluid. Except for occasional acute seizures, the additional early side effects of this therapy are small mostly drowsiness and nausea. Longer-term, some children who undergo this treatment suffer mild impairment of intellect. As is often the case in serious medical problems, risks and benefits must be weighed. On balance, the benefit from treatment of potential sanctuary areas greatly outweighs the loss.

Controversies exist about how best to treat the testicles when they are a potential sanctuary for leukemia cells. Whatever method is used, it is probably wise to consider banking specimens of sperm before administering the therapy. Diminished fertility is a recognized side effect of many of the treatments used in leukemia, although this is not universal. There have been several studies involving boys and young men who were cured of leukemia and later became fathers.