This retrospective study concerning patients with a carcinomatous meningitis (CM) associated with solid tumour aimed at identifying risk markers of CM which could be used in the future in order to prevent from this neurological complication. From 1976 to 1996, the patients whose CSF sampling was positive cytologically, were registered recording baseline clinical data, tumour histology with grade, tumour dissemination, treatments and follow-up. Simultaneously to the recruitment of the patients the incidence of CM was derived at each 5-year period. The variables were analysed by uni- and multivariate statistics. Among the 41 cases, the first three sites of the primary were breast, lung, essentially small cell lung cancer, and urinary tumours. At their initial presentation, 22 patients revealed an M1 dissemination and 22 tumours were undifferentiated. Over the 20 years, the incidence of CM has significantly increased for urinary cancers, decreased for breast cancer while the administration of neoadjuvant chemotherapy was increasing, and remained unchanged for lung cancer. M1 and/or undifferentiated tumours shortened the time-to-CM whereas bone metastases, that were the most frequent site for secondary deposits, did not. Breast, lung and urinary cancers produced 80% of the CM in the series. Neoadjuvant chemotherapy possibly could save patients from the meningeal dissemination. M1 and undifferentiated tumours appeared to be independent risk factors, as well as osseous metastases. Other risk factors of CM should be identified in prospective trials.

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