Prognostic value of cerebrospinal fluid cytology in pediatric medulloblastoma

Background. Although the demonstration of leptomeningeal dissemination is t he most important predictor of poor outcome in children with medulloblastom a, there is lack of consensus on the prognostic value of a positive cerebro spinal fluid (CSF) cytology (i.e., stage M1). Patients and methods. Eighty-six pediatric medulloblastoma patients treated in Switzerland between 1972-1991 were retrospectively studied regarding th e influence of M-stage on prognosis. 39 were M0, 13 M1, 15 Mx, 17 M2, and 2 M3. Results: Five- and 10-year overall survival rates were 76% and 54% for MO, 68% and 50% for Mr, 36% and 25% for M1, and 22% and 22% for M2-3 (P < 0.001 ), respectively. No significant survival differences were observed between M1 and M2-3 patients. Among 26 patients with only postoperative CSF cytolog ies, seven were positive. Their outcome was similar to that of six preopera tively staged M1 and significantly different from that of MO patients (P = 0.001). In 14 patients both pre and postoperative CSF cytology was performe d. Total agreement was observed between the pre- and postoperative results (six positive and eight negative). Among the 19 M2-3 patients CSF cytology was positive in eight, negative in five, and unknown in six. Conclusions: A positive CSF cytology either pre- or postoperatively predict s for a poor outcome, similar to that observed in stage M2-3 patients. A po stoperative cytology is likely to be concordant with cytologic results obta ined preoperatively, and seems to have the same prognostic significance. A negative cytology however, does not exclude a more advanced stage.