Evidence for a clinically distinct new subtype of grade II astrocytomas in patients with long-term epilepsy.
OBJECTIVE
The authors tested the hypothesis that among Grade II astrocytomas with a particularly long seizure history, a subgroup is hidden with a different prognosis and possibly histological characteristics. To do so, clinical and histological characteristics of two groups of World Health Organization Grade II astrocytoma patients were analyzed: the long-term epilepsy-associated tumor (LEAT) astrocytoma group, with a mean duration of 12.5 years of seizures (n = 19), and the ordinary astrocytomas (n = 87), with a mean length of seizure history of 1.5 years (Non-LEAT).


METHODS
All astrocytomas operated on between 1988 and 1999 were collected and followed up for 2 to 13 years (median, 7.0 yr). The 19 LEAT astrocytomas belonged to a group of 207 long-term epilepsy-associated tumors from the epilepsy surgery program. The 87 Non-LEAT cases were 60 so-called ordinary or diffuse World Health Organization Grade II astrocytomas and 27 oligoastrocytomas without long-term epilepsy operated on during the same time period. All tumor cases have been reviewed and partly reclassified as a result of the use of modern immunohistochemical techniques. Statistical analyses for possible discriminating factors included chi(2) test, Fisher's exact test, Kaplan-Meier curves, and multifactorial analysis.


RESULTS
Histological subtyping revealed a possible new isomorphic astrocytoma subtype in seven patients. By use of Kaplan-Meier curves, this isomorphic subtype had 50% fewer recurrences at 7.5 years and an estimated long-term survival of 80%. LEAT astrocytomas differed from ordinary Non-LEAT astrocytomas in overall length of history, younger age at first seizure, and higher percentage of 10-year survivors (80%). Temporal location did not influence outcome, and the presence of epilepsy per se was also not a prognostic factor.


CONCLUSIONS
Differences between astrocytomas with a very long seizure history and those with a very short seizure history do exist. Significant factors for prognosis were age at surgery and presence of postoperative tumor residue but not the presence of epilepsy per se. A new subtype of astrocytomas, provisionally called isomorphic LEA astrocytoma, has putatively been identified with significantly better survival and lower recurrence rate. The negative prognostic factor of a gemistocytic differentiation pattern in diffuse astrocytomas was confirmed.
Schramm
Johannes
J
Department of Neurosurgery, University of Bonn Medical Center, Bonn, Germany. Johannes.Schramm@ukb.uni-bonn.de
Luyken
Cordelia
C
Urbach
Horst
H
Fimmers
Rudolf
R
Blümcke
Ingmar
I
D000293:Adolescent; D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis; D001254:Astrocytoma / Q000145:classification* / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D014408:Biomarkers, Tumor / Q000032:analysis; D002540:Cerebral Cortex / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D004730:Endothelium, Vascular / Q000473:pathology; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008869:Microtubule-Associated Proteins / Q000032:analysis; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000145:classification / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D015173:Supratentorial Neoplasms / Q000145:classification / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D017741:Survivors; D009626:Terminology as Topic; D014944:World Health Organization
D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D008869:Microtubule-Associated Proteins