2073 Outcome of oligodendroglioma treatment in the era of modern neuroimaging

Proceedings

of the 39th Annual

ASTRO

277

Meeting

2073 OUTCOME

OF OLIGODENDROGLIOMA

Lawrence

R. Kleinberg,

TREATMENT

Edward

Silverman,

IN THE ERA

Henry

Brem,

OF MODERN

Moody

NEUROIMAGING

D. Wharam

Jr.

Purpose/Objective: The benefit of routine postoperative ramotherapy for low grade oligodendroglioma remains controversml. Most published serlea include many patients treated before the availability of CT or MRI scans which allow early diagnosis, guide surgery, detect residual disease, improve radiotherapy, and detect asymptomatic recurrences. The purpose of this analysis is to determine whether observation rather than radiation continues to be an appropriate option for selected patients with the availability of modern neuroimaging. Materials & Methods: 58 patients (age 2-67 years , 6 pts. < 18 years old) with low grade oligodendroglioma (mixed and anaplastic/malignant histology as well as recurrent disease were excluded) underwent resection (1981-1995) and were followed at Johns Hopkins with mean follow up 4.7 years. (median 3.9). 58% got immediate post-op RT (median dose 54 Gy ). The following previously identified adverse prognostic factors were assessed: presentation with focal deficits and/or mass effect vs. seizures only, partial resection/biopsy instead of gross total resection, older age, and presence of symptoms for less than a year prior to diagnosis. No GTR Mean M Sx=2 poor prognostic Results: Two and five year actuarial freedom from local progression was 93 +//- 4% and 75% +/- 8% whereas 2 and 5 year overall survival was 94% +I- 3% and 80% +I/- 7%. Despite the imbalance of prognostic factors, there was no significant difference whether or not postoperative RT was given. With RT, 2 and 4 year actuarial freedom from progression was 94% +/- 4% and 78% +/- 8%. whereas without RT it was 94% +I- 6% at 2 and 4 years. Similarly, 2 and 4 year actuarial survival was 94% +I- 4% and 78% +I- 8% with RT and was 91% +/- 8% without RT. 5110 recurrences were detected radiologically without new or progressive clinical symptoms. Conclusion: These data support the hypothesis that, in the era of modern neuroimaging, the imtial observation of good risk patients and immediate irradiation of poor risk patients is an appropriate treatment approach which results in good medium term control and survival for law grade oligodendroglioma patients. A pohcy of treatment vs. observation based on selected prognostic factors wdl be tested prospectively in an Intergroup trial for low grade glioma hlstologies.

2074 RADIATION

THERAPY

Pham, Huong Larson, David Departments

T.. M.D.*, A., M.D., of Radiation

FOR Sneed, Ph.D.*# Oncology

INTRACRANIAL Penny

K., M.D.*,

* and Neurological

EPENDYMOMAS: Wara,

William

Surgery

IMPACT

M., M.D.*,

#, University

Edwards,

of California,

OF AGE Michael

ON

OUTCOME

S., M.D.#,

San Francisco,

Wilson,

Charles

B., M.D.#,

CA

Purpose: The records of Kamofsky

of patients with intracranial ependymoma who received radiation therapy performance statlls (KPS), age, histology, and treatment on outcome.

Materials

& Methods:

at UCSF

were reviewed

retrospectively

to evaluate

the impact

Between 1978 and 1996,45 patients with intracranial ependymoma received postoperative radiation therapy. Overall survival (OS) and progression free survival (PFS) were calculated from the date of diagnosis. Median follow up for surviving patients was 72 months. Ages ranged from 4 months to 56 years, with a median of 8 years. The tumor was infratentorial in 35 and supratentorial in 10. All patients had either biopsy (3), subtotal resection (30), or gross total resection (12). There were 29 low grade and 16 anaplastic ependymomas. Thirty-seven patients received standard fractionation to a median dose of 54 Gy. Eight patients received byperfractionation at 1 .O Gy BID to a median dose of 72 Gy. Thirty-eight patients had partial brain irradiation and seven had cranrospinal irradiation. Twenty-three patients received adjuvant chemotherapy. For the infants 3 years old (n=l2), all but one had a subtotal resection and most received chemotherapy prior to radiation therapy. Seven infants received radiation therapy at the time of disease progression and five had radiation therapy prior to progression. Most of the patients > 3 years old were irradiated prior to progression.

<

Results: The five-year actuarial OS and PFS were 65% and 46% for the whole group. Histology and treatment factors such as extent of resection, hyperfractionation, and adjuvant chemotherapy did not significantly affect outcome. Overall, 25/45 patients had disease progression. Only two patients failed in the brain outside the primary site. Six patients developed leptomeningeal spread (four concurrent with local failure and two subsequent to local failure). Five-year OS for patients s 3 years old was 21% versus 80% for patients > 3 years old (p~O.001) and five-year PFS was 17% versus 54% (p=O.O02). For the 3 1 patients > 3 years old who were irradiated prior to progression, the 5 year OS and PFS were 8 1% and 61%. KPS > 60 and age 718 years were favorable prognostic factors for OS and PFS in these patients, respectively. For patients < 3 years old, the median OS for patients irradiated prior to progression (n=5) was not significantly different from those irradiated at the time of progression (n=7), 26 months versus 30 months. However, patients who did not receive radiation therapy initially failed sooner (median PFS of 7 months versus 17 months).

Conclusions: The majority of failures are local. Because leptomeningeal spread occurs craniospinal irradiation is not necessary. Young patients generally have 60 and age > 18 years are favorable prognostic factors. Patients < 3 years initially or at the time of progression. More effective treatment is needed

only in the presence of local failure, prophylactic whole brain or a worse prognosis than older patients. For patients > 3 years old, KPS > old have a poor prognosis, regardless of whether radiation therapy is used for these children.