The role of radiotherapy in the treatment of newly diagnosed supratentorial low-grade oligodendrogliomas: comparative analysis with immediate radiotherapy versus surgery alone.
OBJECTIVE
The purpose of this study was to evaluate the role of immediate postoperative radiotherapy (RT) in adult patients with a low-grade oligodendroglioma (LODG).


METHODS
A total of 74 patients, older than 15 years, were treated in our institution between April 1990 and March 2006 for newly diagnosed LODGs. After surgery, 43 patients were treated with immediate RT with a total dose of 54~55.8 Gy with 1.8 Gy fractions (RT group) and 31 patients were followed with no adjuvant RT (OP group). All patients were closely observed until tumor progression or death with frequent work-ups including neurological examinations and MRI. Primary endpoints were overall survival and progression-free survival. The median follow-up duration of survivors was 6.2 years in the RT group and 5.8 years in the OP group.


RESULTS
Median progression-free survival was 13.2 years in the RT group and 4.6 years in the OP group; multivariate analysis confirmed improved outcome with the use of immediate RT (hazard ratio, 0.22; 95% confidence interval-CI, 0.09~0.55; p<0.001). Median overall survival was 14.9 years in the RT group and 9.8 years in the OP group; the use of adjuvant RT was also associated with a trend toward better overall survival after immediate RT based on multivariate analysis (hazard ratio, 0.3; 95% CI, 0.08~1.17; p=0.082). No severe RT related complications were observed.


CONCLUSIONS
Immediate RT following surgery appears to be an effective treatment modality for supratentorial LODGs. However, the potential benefit of adjuvant RT for overall survival needs to be tested prospectively in the future.
Kang
Hyun-Cheol
HC
Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
Kim
Il Han
IH
Eom
Keun-Yong
KY
Kim
Jin Ho
JH
Jung
Hee-Won
HW