Clinical and laboratory assessment and therapeutic problems in longstanding polycythaemia vera.

With the very long life expectancy of Polycythaemia Vera late complications are often observed: progressive resistance to treatment, bad tolerance to maintenance by phlebotomy, progression towards myelofibrosis. Resistance to phosphorus 32 is reflected by a progressive reduction in the duration of remission and by a gradually decreasing remission rate. A complete resistance appears after a mean duration of disease of 7 years. In the maintenance treatment by hydroxyurea, there is a secondary resistance in one third of cases with a poor control of the excess platelets. Resistance to Pipobroman is less frequent (10%). The phosphorus resistance could be delayed by addition of maintenance treatment by Hydroxyurea. In the presence of resistance to 32 P, Hydroxyurea and Pipobroman often remain effective. In the case of resistance to Hydroxyurea or Pipobroman, we have several possibilities: inversion of chemotherapy, other chemotherapy as Busulfan, 32 phosphorus. Intolerance of phlebotomy as baseline treatment is almost constant. Three complications lead to discontinuation of phlebotomy: development of cardiovascular complications, raised platelet count to above 800,000 and often more than 1 million, progressive increase in the size of the spleen with appearance of signs of myeloid splenomegaly. Exclusive phlebotomies are not indicated as baseline treatment of Polycythaemia Vera. The progression towards myelofibrosis (spent phase, post polycythaemia myeloid splenomegaly) increases with the duration of the disease and the frequency of transformation differs according to the type of treatment. The time to transformation is much shorter in the patients treated by phlebotomy. The transformation towards myelofibrosis is demonstrated by bone marrow biopsy and isotope investigations (bone marrow scintigraphy and kinetic by iron 59 and chromium 51).(ABSTRACT TRUNCATED AT 250 WORDS)