Proceedings of the 36th Annual ASTRO Meeting 165

Table 1. Median survivvb(;,o) 2-year survival (%) Class # pts. Present Present RTOG’

I 15 ?? 58.6 87 58.6 1 n/a 37.4 n/a 37.4

24 38.8 17.9 74 17.9 IV 35 20.0 11.1 34 11.1 V 37 15.5 8.9 23 8.9 VI 3 8.7 4.6 0 4.6 * median survival not reached: n/a - not applicable

1 Curran, WJ, et. al. Recursive partitioning analysis of prognostic factors in three Radiation Therapy Oncology Group malignant glioma trials. JNCI. 85: 704-710; 1993.

22 COMPARISON OF STEREOTACTIC RADIOSURGERY AND BRACHYTHERAPY IN THE TREATMENT OF RECURRENT GLIOBLASTOMA MULTIFORME.

Dennis C. Shrievel*3, Eben Alexander, 1112, Patrick Y. Wen4, Howard A. Fine5, Hanne M. Kooy l, Peter McL. Black2 and Jay S. Loeffler1,3

1Joint Center for Radiation Therapy, Departments of 2Neurological Surgery, 3Radiation Oncology and 4Neurology, Brigham and Women’s Hospital, 5Department of Medicine, Dana Farber Cancer Institute, Harvard Medical School, Boston MA

Purpose: To compare the outcome of patients with recurrent glioblastoma multiforme treated with stereotactic radiosurgery with those treated with interstitial high activity 1251 brachytherapy.

Materials and Methods: Between 1211185 and 7/l/93, 118 patients were treated for recurrent glioblastoma multiforme (GBM). Patients had either progressive GBM or pathologically proven GBM as recurrence following previous treatment for a lower grade astrocytoma. Thirty-two patients were seated with interstitial brachytherapy and 86 received treatment with stereotactic radiosurgery (SRS). Patient characteristics were similar in the two groups. Patients treated with SRS (age 9-77, median 41 y) had a median tumor volume of 10.1 cm3 (range 2.2-83 cm3). Interval from initial diagnosis was from 2.3 to 115 mo (median 10.3 mo). Median SRS dose (usuallv mescribed to the 80% isodosel was 13 Gv (range 6-20 Gv) delivered with a dedicated 6 MV linear accelerator. Seven&-seven patients (90%) were &eated using 1 (47) or 2 (30) i&centers. h&i& collimat& size was 37.5 mm (17.5-50 mm). Patients treated with brachytherapy ranged in age from 9 to 70 y (median, 45 y) and had a median tumor volume of 41 cm3 (range, 5- 200 cm3). Interval from initial diagnosis to recurrence ranged from 1.5 mo to 54 mo (median 7.3 mo). Minimum tumor doses were 38.7-63.6 Gy (median 50 Gy), delivered at dose rates of 34-100 cGy/h (median 43 cGy/h) over 2.1 to 5.7 days.

Results: Twenty-one patients (24%) treated with SRS were alive with median follow-up of 17.5 mo (6.8-45.1 mo). Median actuarial survival, measured from the time of treatment, for all patients treated with SRS was 10.2 mo, with 12 mo and 24 mo survivals being 45% and 19%. respectivel) Younger age (~46 Y) was medictive of better outcome: median survival 15.5 vs. 8.2 mo, ~=0.005. Patients with smaller tumors (<lo.1 cm3) also survived long& fofi&wing‘SRS: median survival 15.1 mo vs. 8.1 mo, p=O.O07. Tumor d&e, interval from initial diagnosis and need for re&eration were not predictive of outcome following SRS. Five patients (16%) treated with brachvtherauv were alive with median follow-uu of 43.3 mo (8.3-64.4 mo). Me&an actuarial survival for all p&ents treated-with br&hytherapy was 10.9 moi surv&ls at 12 and 24 mo were 38% and’l4%, respe&ely. Patient age, tumor volume, interval from initial diagnosis and tumor dose did not predict for outcome in these patients. Comparison of results between patients treated with SRS and brachytherapy indicated similar median, l-year and 2-year survivals, p=O.953. Twenty-one patients required reoperation following SRS (24%) compared to 14 (44%) in the brachytherapy group. Actuarial risk for reoperation was 33% at 12 mo and 48% at 24 mo following SRS compared to 54% and 65%, respectively, following brachytherapy (p=O. 195). Patients undergoing reoperation following brachytherapy survived longer than similar patients not undergoing reoperation (p=O.O09). Outcome following SRS was independent of need for reoperation, p=O.226.

Conclusions: Treatment of recurrent glioblastoma multiforme with SRS resulted in survival similar to that obtained with interstitial high activity 1251 implantation. This outpatient procedure is currently the treatment of choice for recurrent glioblastoma multiforme at our institution in patients whose disease is amenable to SRS. Younger patients with smaller recurrent tumor volumes made up a group of patients with significantly longer survival following SRS (median survival 26 mo). Larger tumor volumes were included in the group treated with brachytherapy. However, our results do not indicate a significant advantage of brachytherapy over SRS for larger recurrent tumors (>30 cm3). groups with greater than 50% risk for patients surviving longer than 2 years.

Reoperation rates were similar in the two treatment