CSF cytology has limited value in the evaluation of patients with ependymoma who have MRI evidence of metastasis

Abstract

Purpose To investigate the usefulness of cerebrospinal fluid (CSF) cytology in pediatric patients with ependymoma who relapsed after focal irradiation. Methods Eighty‐eight patients with ependymoma received conformal radiotherapy (CRT) from July 1997 through January 2003 on an IRB approved prospective treatment protocol. CSF cytology results from evaluations performed prior to CRT and at the time of failure were reviewed for patients who progressed after CRT as documented by magnetic resonance imaging (MRI). Results Twenty‐two patients had MRI documented evidence of progression after CRT. Ten patients developed distant failure without local failure, four had combined local and distant failure and eight had local failure without distant failure. The median time from the start of CRT to progression was 19 months (range: 6–73). CSF cytology at diagnosis was negative for the presence of malignant cells in all patients. At the time of progression, CSF cytology was performed in 16 of 22 patients including all 10 patients with distant failure without local recurrence. Malignant cells were not found in any of the evaluated CSF specimens including those with distant failure documented by MRI. Conclusions CSF cytology does not add valuable information when evaluating patients with ependymoma who have evidence of distant failure documented by MRI. The usefulness of CSF cytology in the general follow‐up evaluation of pediatric patients with ependymoma remains uncertain.