Treatment of leptomeningeal metastases evaluated by interphase cytogenetics

Purpose: Although cytologic examination of CSF is the primary method for th e evaluation of response to therapy for leptomeningeal metastases (LMMs), t he procedure's sensitivity decreases throughout the course of protracted th erapy. We studied whether this response could be monitored more accurately through the detection of numerical chromosomal aberrations by interphase cy togenetics, using fluorescence in situ hybridization (FISH), Patients and Methods: Seven patients treated for LMMs and with a known nume rical aberration for chromosome; 1 in their pretreatment CSF were included in this study, Up to 16 consecutive CSF samples were analyzed by means of t he fluorescence in situ hybridization (FISH) technique for cells with aberr ant chromosome 1 content, The results of routine cytology and FISH analyses were compared and were correlated with each patient's neurologic status. Results: Routine cytology detected malignancies in only 24 of the 76 sample s, all of which were classified as chromosomally abnormal by FISH (except f or two samples that could not be evaluated). Moreover, FISH demonstrated an eusomic cells in 32 additional samples, which could therefore be classified as malignant, The FISH results correlated better with patient neurologic s tatus in that more malignant cells were detected in the CSF of neurological ly deteriorating patients. Conclusion: Using FISH in addition to performing routine cytologic examinat ion of CSF leer to a more accurate evaluation of response to treatment in p atients treated for LMMs. J Clin Oncol 18:2053-2058. (C) 2000 by American S ociety of Clinical Oncology.