BONE-MARROW SUPPRESSION AFTER SR-89 THERAPY AND LOCAL RADIATION-THERAPY IN PATIENTS WITH DIFFUSE MARROW INVOLVEMENT

Strontium-89 is routinely used for pain control in advanced skeletal m etastatic disease. A common side effect of Sr-89 therapy is a mild to moderate bone marrow suppression. To avoid complications from marrow s uppression, a pretreatment platelet count of >60,000/mm(3) and a WBC c ount of >2,400/mm(3) are suggested. The authors present two patients w ho, despite satisfying these criteria, developed profound and prolonge d bone marrow suppression after therapy. The severity of this response was most likely caused by pre-existing extensive bone marrow replacem ent with tumor. The contribution of local radiation therapy to bone ma rrow suppression is presumed to be minimal. The authors recommend that pretreatment criteria for determination of elgibility for Sr-89 thera py in selected patients be expanded to include steadily decreasing blo od counts, and evaluation of extent of marrow involvement by biopsy or MR imaging.