CORRELATION BETWEEN POLYSIALIC-NEURAL CELL-ADHESION MOLECULE LEVELS IN CSF AND MEDULLOBLASTOMA OUTCOMES

Purpose: To quantify CSF levels of polysialic-neural cell adhesion mol ecule (PSA-NCAM) in patients with medulloblastoma (MB) metastasis, to assess the correlation with other diagnostic techniques (imaging and c ytology) and clinical features, and to determine whether it is a suita ble marker to monitor response to treatment and subsequent follow-up d ata. Patients and Methods: PSA-NCAM levels were measured using a doubl e-site enzyme-linked immunoadsorbant assay (ELISA) in 145 samples from 14 controls and 29 patients with MB. Clinical status of patients, ima ging, and cytologic data were available at the time of each lumbar pun cture. Medians and ranges for the 131 pooled PSA-NCAM concentrations w ere calculated far the MB versus the control groups, and for MB patien ts for normal versus abnormal groups at cytology or imaging, and for f our clinical subgroups, respectively. For patients with MB, three PSA- NCAM measurements that corresponded to punctures performed during thre e rime periods following surgery were selected. The kappa measure of a greement was calculated between normal and abnormal groups of. cytolog y or imaging, and between groups of patients in remission and refracto ry, respectively. For the same phases, sensitivity and specificity of PSA-NCAM and cytology tests and their 95% confidence intervals (95% Cl s) were computed, Results: PSA-NCAM was never detected in control CSF. PSA-NCAM concentration medians were higher in C5F with metastatic cel ls or that corresponded to abnormal imaging than in the corresponding normal groups (P < .05). The PSA-NCAM concentration median was signifi cantly higher (P < .05) in CSF from patients refractory to treatment o r who relapsed than from patients in remission. Agreements between PSA -NCAM and clinical status and between PSA-NCAM and cytology were excel lent during and after treatment The sensitivity of PSA-NCAM test was a lways better than that of cytology, whereas its specificity was lower for phases that corresponded to more than 1 month following surgery. H owever, specificity was 100% for patients refractory to treatment or w ith relapse. Conclusion: PSA-NCAM measurement appears to be a new biol ogic marker of possible use in the management of patients with MB. (C) 1996 by American Society of Clinical Oncology.