Interstitial 125I radiosurgery of supratentorial de novo WHO Grade 2 astrocytoma and oligoastrocytoma in adults: long-term results and prognostic factors.
BACKGROUND
Detailed long-term outcome data are not available for adult patients with World Health Organization (WHO) Grade 2 astrocytoma or oligoastrocytoma.


METHODS
A previously published short-term data set of 239 adult patients with circumscribed de novo supratentorial astrocytoma (187 patients) and oligoastrocytoma (52 patients) treated with interstitial iodine-125 ((125)I) radiosurgery as primary treatment (1979-1992) was revisited. Survival, progression-free survival, functionally independent survival, postrecurrence survival, and time to malignant transformation were estimated with the Kaplan-Meier method. Prognostic factors were obtained from the Cox multivariate proportional hazards model.


RESULTS
Five-, 10-, and 15-year survival was 56%, 37%, and 26%, respectively (median follow-up, 10.3 yrs). Progression-free survival was 45%, 21%, and 14%, respectively. The corresponding malignant transformation rates were 33%, 54%, and 67%. No leveling off of the Kaplan-Meier curves could be observed for any of the chosen endpoints. Age > 50 years, a tumor volume > 20 mL, and/or a Karnofsky score < or = 80 were associated with decreased survival or progression-free survival. Age > 35 years and/or a tumor volume > 20 mL increased risk of malignant transformation. Prognostic factors determined subsets of patients with 10-year survival ranging from as low as 6% to as high as 55% and progression-free survival ranging 1-31%.


CONCLUSIONS
Long-term tumor stabilization is rare. As outcome is mainly determined by treatment-independent factors, minimization of any treatment-related risk must be considered essential.
Department of Neurosurgery, Grosshadern Clinic, Ludwig-Maximilians-University, Marchioninistrasse 15, 81377 Munich, Germany. fkreth@med.uni-muenchen.de
Friedrich W
FW
Kreth
Michael
M
Faist
Stefan
S
Grau
Christoph B
CB
Ostertag
D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000145:classification / Q000401:mortality / Q000601:surgery*; D002471:Cell Transformation, Neoplastic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016634:Radiosurgery; D012189:Retrospective Studies; D015173:Supratentorial Neoplasms / Q000145:classification / Q000401:mortality / Q000601:surgery*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014944:World Health Organization
D007457:Iodine Radioisotopes