[Therapeutic effectiveness of ranimustine chemotherapy for essential thrombocythemia in the elderly].

We studied the therapeutic effectiveness of chemotherapy by ranimustine (MCNU) for essential thrombocythemia (ET) in 14 ET patients over 60 years of age. The median age was 73 years (range: 61-88 years), and the male/female ratio was 6:8. The mean platelet counts before chemotherapy was 1,157 +/- 28.4 x 10(3)/microliter. Five of them had been referred because of thrombotic episodes before admission to our hospital, while one was referred because of nasal bleeding. The platelet counts were maintained at a level below 500 x 10(3)/microliter by intravenous administration of MCNU in 12 patients and below 700 x 10(3)/microliter in two patients. One of the patients suffered cerebral infarction during MCNU therapy. No other patient suffered thrombotic episodes during MCNU therapy. The patient who was referred because of nasal bleeding had no hemorrhagic episode during control of platelet counts by chemotherapy. MCNU chemotherapy appears effective for the prevention of thrombosis and bleeding in ET.