Multiple myeloma on polycythemia vera following radioactive phosphorus therapy

A 74-year-old white man with established polycythemia vera was treated with radioactive phosphorus after phlebotomies alone failed to control his disease. About 2 3/4 years later he died of multiple myeloma. The mutagenic effect of radioactive phosphorus may have caused or possibly accelerated preexisting myeloma. Basic nonmalignant disease deserves careful consideration before radiation or radiomimetic agents are used. One might consider a probably less mutagenic drug such as hydroxyurea in patients with polycythemia vera when phlebotomy alone does not give good control of red cell mass and thrombocytosis.