[Acute leukaemias after treatment using cytotoxic agents for rheumatological purpose. 19 cases among 2006 patients(author's transl)].

The authors undertook a retrospective study to determine the number of acute leukaemias developing amongst 2006 patients suffering from chronic inflammatory rheumatic conditions and connective tissue disorders, treated with cytotoxic agents. The follow-up period ranged from 1 to 13 years. Nineteen leukaemias were found, essentially granulocytic, with a latent period of 5.7 +/- 2, 8 years after the beginning of treatment. This incidence of almost 1% of leukaemias is probably less than the actual percentage since a number of patients were lost on follow up and since the period of observation is as yet too short. The majority of patients has been treated for more than one year. No cases were seen amongst patients treated for less than six months, or with less than 1g of chlorambucil or 50 g of cyclophosphamide. The risk would seem to be the same for both alkylating agents. No patients treated with azathioprine developed leukaemia, but few patients received this drug. Amongst 35 patients treated for severe psoriatic arthropathy with chlorambucil, 4 developed leukaemia. This particularly high percentage is such that all trials of alkylating agent in this condition should be stopped. The prevalence of leukaemia seen in the series as a whole is comparable to that found in mass studies carried out in various malignant diseases treated by cytotoxics. Awareness of this risk should, lead to even stricter limitations before the use of cytotoxic drugs in rheumatological conditions.