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Isabelle Salmon, Olivier Dewitte, Jean-Lambert Pasteels, Jacqueline Flament-Durand, Jacques Brotchi, Pierre Vereerstraeten, and Robert Kiss

✓ High-grade astrocytic tumors constitute the most serious as well as the most common group of primary brain tumors. Although several prognostic factors have been proposed, little is known about the prognostic value of deoxyribonucleic acid (DNA) ploidy in adult astrocytic tumors. In a series of 146 adult patients, aged 16 to 82 years, the individual prognostic values of six variables were studied, namely: tumor histopathological grade, treatment, patient age, extent of tumor, ploidy level, and DNA histogram type. Cox's proportional hazard model was then applied to the data to ascertain which factors might independently determine patient survival. Univariate analyses revealed that histopathological grade, age, and DNA histogram type were very powerful prognostic factors. The statistical significance of the influence of adjuvant radiotherapy and chemotherapy was at a borderline level, and the two remaining variables (tumor extent and ploidy level) had no prognostic relevance. Multivariate analyses showed that age, histopathological grade, and DNA histogram type were independent, statistically significant prognostic factors.

A prognostic score was calculated from Cox's polynomial function in which those factors were introduced. The best score corresponded to a patient aged 16 years with a hypertriploid low-grade astrocytoma, while the worst score corresponded to a patient aged 82 years with a diploid high-grade astrocytoma. The worst score:best score ratio revealed a risk 71 times higher for a bad prognosis. It is concluded that patient age, histopathological grade, and DNA histogram type are very powerful prognostic factors for adult astrocytic tumors. A prognostic score including those factors could be used to characterize astrocytic tumor aggressiveness presurgically on fine-needle aspirates, and to monitor the patient's postsurgical evolution to define the appropriate therapy.

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Christine Decaestecker, Isabelle Salmon, Olivier Dewitte, Isabelle Camby, Philippe Van Ham, Jean-Lambert Pasteels, Jacques Brotchi, and Robert Kiss

✓ The authors investigated whether cytometry-related variables generated by means of computer-assisted microscopic analysis of Feulgen-stained nuclei can contribute significant information toward the characterization of low-grade astrocytic tumor aggressiveness. This investigation was conducted using the nearest-neighbor rule (a traditional classification method used in pattern recognition) to analyze a series of 250 supratentorial astrocytic tumors from adult patients. This series included 39 low-grade astrocytomas and 211 high-grade astrocytic tumors (including 47 anaplastic astrocytomas and 164 glioblastomas multiforme [GBMs]). The results show that the 3-nearest-neighbors rule enabled a subgroup of “atypical” astrocytomas to be distinguished from the “typical” tumors. The atypical astrocytoma species exhibited a DNA content (DNA ploidy level) and morphonuclear characteristics that were statistically more similar to the characteristics of GBMs than to those exhibited by the typical astrocytomas. An analysis of survival data revealed that patients with atypical astrocytomas survived for a significantly shorter period (p < 0.001) than patients with typical lesions of this kind. In fact, patients with atypical astrocytomas had a survival period similar to that of patients with anaplastic astrocytomas, whereas patients with typical astrocytomas had a survival period significantly longer (p < 0.0001) than those associated with anaplastic astrocytomas and GBMs.