Proceedings of the 38th Annual ASTRO Meeting 295

2034 HIGH DOSE CONFORMAL RADIOTHERAPY WITH ROTATIONAL MULTI-LEAF COLLIMATOR FOR GLIOBLASTOMA MULTIFORME TREATMENT RESULTS AND MULTIVARIATE ANALYSIS

K. Nakagawa K. Sakata. K. Katasawa Y. Onogi, A. Temhara, K. HasezawaY. Sasaki, and A. Akamuna(*)

Department of Radiology, University of Tokyo, Division of Radiation Health, National lnstttute of Radiological Sciences(*)

Purpose: Survival of patients with glioblastoma multiforme is extremely poor. Although this tumor is clearly radiation resistant, there is evidence of a dose response relationship. The purpose of the study is to evaluate the impact of higher dose dehvered with the rotational multi-leaf collimator (MLC) conformal radiation therapy.

Methods and Materials: From 1984 to 1995, 35 consecutive cases with histologically confirmed ghoblastoma multifonne in the brain were treated using the rotational multi-leaf collimator conformal therapy which is a combined continuous gantry rotation and MLC movement. There were 23 males and 12 females with a median age of 45.3 years (l? to 73 years). Mean Kamofsky Performance score was 78 (30-100). Mean tumor volume at the time of diagnosis was 104 cc (8-800 cc). All cases underwent surgical intervention prior to radiation therapy (biopsy only in one, partial resection m 13, and subtotal resection in 18, and gross total resection in three). Residual tumor volume ranged from 0 cc to 567 cc with

an average of 35 cc. Radiation dose was 60 to 80 Gy (mean 68.3 Gy) in 7-l cases before 1992 and 90 Gy in 14 cases after 1992, with an overall mean dose of 77 Gy. Before 1992, the rotational multi-leaf collimator conformal therapy was

combined with whole brain radiation of 30 Gy, whereas the latter was replaced by a generous field rotational conformal therapy after 1992. Dose fall-off proportional to the target volume was achieved using three-dimensional treatment planning in all cases. Biweekly intravenous administration of ACNU and Vincristm was combined.

Results: As for radiation toxicity, only one case developed and died of late brain edema four months after the completion of therapy with 90 Gy. The one-year, three-year, and five-year survival rates were 64 %, 36 %, and ?l % respectively, with a 50 9 survival time of 17 months. Two survived more than five years. Univariate analysm showed initial tumor volume, residual tumor volume, and Kamofsky performance score were statistically stgnificant factors for survival. Only residual tumor was statistically stgnificant by multtvariate analysis. Five-year survival rate of cases with tumors 2 cm or less in diameter was as good as 47 ‘70.

Conclustons: The rotattonal MLC conformal therapy in combmation wtth intenstve surgtcal resectton provided favorable treatment results as compared to those reported so far.

2035 DOSETIME CONSIDERATIONS IN THE TREATMENT OF ANAL CANCER.

Eugene C. Constantinou 1, William Daly 2, Claire Y. Fung 1,2, Christopher G. Willett2, and Thomas F. DeLaneyt.2

Departments of Radiation Oncology, tBoston University Medical Center/School of Medicine and 2Massachusetts General Hospital. Boston MA

Purpose: Concurrent chemoradiation has become the standard initial treatment of primary anal carcinomas. The objective of this study was to analyze the impact on treatment outcome of a variety of patient and treatment variables including radiation dose and overall treatment time in patients treated with concurrent chemoradiation for anal carcinomas.

Materiata and Methods: Retrospective chart review on 50 patients with MO anal cancer treated with concurrent chemoradiation during the years 19841993. Patients were identitied from the hospital tumor registries. l-4.29-33 and Mitomycin 10-15 mg/m2 days 1 f 29.

The majority of patients received treatment with 5-FU loo0 mg/m2 days

(median 54 Gy) usually by shrinking field technique. Radiation was given at 180-200 cGy daily starting at day 1 to total doses of 23.6-67.2 Gy Local control, disease-free survival, and overall survival of the group was determined and

then analyzed with respect to a variety of patient characteristics including T and N stage, histology, radiation dose, overall treatment time, hemoglobin at the start of treatment, age, HIV status, and sex. Local control, disease-free and overall survival were calculated using the Kaplan- Meier method. Tests for signifkance were done using the log-rank method.

Resuk Patient characteristics were: (1) histology-squamous 78 46, cloacogenic/basaioid 20%. and adenosquamous 2%; (2) age- range 30-82 years (median 58.5). (3) sex- female 58%. mate 42% (4) T stage- Tl 16 %, T2 46%. T3 24% T4 8%. TX 6%; (5) N stage- NO 69% N + 23 %, NX 8%; (6) HIV (+) 8%. HIV(-I?) 92%. Follow-up ranged from 2-132 months (median 43 months). Overall survival was 66% and 44% at 5 and 10 years. Disease-free survival was 67% at 5 years and 59% at 10 years. Local control was 70% at 5 and 10 years. Five year local control by T stage: T stage- Tl 87.5 W, ‘I2 63%. T3 83%. T4 67%. TX 50%. Doses of 2 54 Gy are associated with improved 5-year survival (84 % vs. 47%. p=O.OZ), disease-free survival (74% vs. 56%. p= 0.09). and local control (77% vs. 61%, p&.04). 5-year local control (86%

Them. is a suggestion of improvement in vs. 6646, pcO.47). disease-free (86% vs. 6396, p&24) and overall survival (86% vs. 60 96, p&14) when overall

treatment ttme is < 40 vs. 2 40 days. Females showed a trend towards improved overall 5-year survival ( 76 % vs. 58%. p&10) and local control (81% vs. 61%. e.32). Pm-treatment hemoglobin(Hgb) ranged from 7.9-16.4 (median 12.4, with 75% of the patients having a Hgb greater than 11.2). Only 4 patrents had pm-treatment Hgb < 10, but the outcome in this group was signiticantly worse than those with pte-treatment Hgb 2 10 with overall survival 50% vs. 68% (p=O.M). disease-free survival 70% vs. 67%(p=O.l I), and local control 74% vs. 67% (p~O.05). Age < 58 vs. 2 58 did not signitkantly affect treatment outcome. Wve year overall survival. dii-specific disease-free survival. and local control in the 4 HIV(+) pattents was 0%. 75 %, and 75 %. Five year overall survival, disease-specific relapse-free survival, and local control in the 46 HIV(R) patients was 71%. 67 46. and 71%.

Ccmclti In this retrospective survey of patients with MO anal carcinoma treated with concurrent chemoradiation, radiion doses of 2 54 Gy are associated with a statistically signiticant improvement in survival and local control. wrth a trend towards improved outcome but this was not statisticaLly sign&ant.

Overall treatment times of less than 40 days am associated

outcome. Pm-treatment Hgb ~10 is associated with worse tmatment

Survival of patients with anal carcinoma arising in association with HIV infection is poor, but the majority of such patients in this series died of intercurrent disease with theii anal carcinomas controlled by chemoradiation.