
<b>Definition: Myelodysplasia is bone marrow failure, </b>"myelo" indicates bone marrow, and "dysplasia" means that the cells are not growing correctly.  Myelodysplasia can be lethal because it can cause low blood counts of one or more type of blood cells, or it can turn into cancer [often leukemia.]  It is caused by multiple chemotherapy or radiation treatments damaging the bone marrow cells.  Because of the very high doses of chemotherapy agents and radiation used to treat LMS, myelodysplasia is more likely to occur in LMS survivors.  Development of continuously low blood counts can also prevent further treatment with chemotherapy agents or radiation. 

In adults, the spine and the pelvic girdle usually contain the working bone marrow.  Adjuvant radiation for uterine LMS will often create problems with the bone marrow in the pelvic girdle.  Irradiation of the hip or spine likewise will cause damage to productive bone marrow.  