P r o c e e d i n g s o f the 40 th A n n u a l A S T R O Meet ing

2127 DOES EVERY PATIENT WITH NEWLY DIAGNOSED PROSTATE CANCER NEED AN ABDOMINAL AND PELVIC COMPUTED TOMOGRAPHY SCAN AS WELL AS A RADIONUCLIDE BONE SCAN?

Nancy Lee, M.D.*, Jeffrey Newhouse, M.D.**, Peter B. Schiff, M.D., Ph.D.*, Rashid Fawwaz, M.D.** Emilia Bagiella, Ph.D.***, Arun Singh*, Ronald D. Ennis, M.D.*

*Department of Radiation Oncology, **Department of Radiology, ***Department of Biostatistics, Columbia-Presbyterian Medical Center, New York, NY 10032

Purpose: Although computed tomography (CT) scan of the abdomen and pelvis as well as radionuclide bone scan (BS) are frequently recommended as part of the staging evaluation for newly diagnosed prostate cancer, most scans are negative for metastases. We hypothesized that Gleason score, PSA, and clinical stage could predict for a positive CT or BS and that a low risk group of patients could be identified ~.~ whom CT and/or BS might be omitted.

Methods: All patients who had both pathologic review of their prostate cancer biopsies and abdominopelvic CT scan or radionuclide BS at our institution between 1/90 and 5/96 were studied. Cdeason score, PSA, and clinical stage (AJCC, 4th ed) were evaluated by univariate and multivariate analyses for their ability to predict a positive CT scan of the abdomen and pelvis (lymph node, bone, and liver metastases) or BS. Groups analyzed were Gleason 2-6 vs 7 vs 8-10; PSA 0-15 vs >15-50 vs >50; and clinical stage Tla-T2b vs T2c-T4. Univariate analysis using Chi-Square and multivariate analysis using Logistic Regression were performed,

Results: Of 588 consecutive patients, 41 (7%) had a positive CT scan. Majority of the CT scans (90%) was positive for lymph node metastases. Multivariate analysis (44 excluded due to missing PSA and/or clinical stage) showed Gleason score, PSA, and clinical stage to be significant independent predictors for positive CT scan, all with p<0.001. The odds ratios were 6.17 (95% C1=1.58-24) for Gleason 8-10 vs 2- 6; 2.25 (CI=1.24-4) for PSA >50 vs 0-15; 2.08 (CI=1.70-3.21) for clinical stage T2c-T4 vs < T2b. Similarly, among the 630 consecutive patients, 88 (14%) had positive BS, Multivariate analysis (64 excluded due to missing PSA and/or clinical stage) showed Gleason sore, PSA, and clinical stage to be significant independent predictors for positive BS, p<0.002, p<0.001, p<0.001 respectively. The odds ratios were 2.25 (CI = 1.43-3.54) for Gleason 8-10 vs 2-6; 5.25 (CI=3.43-8.04) for PSA > 50 vs 0-15; 2.15 (CI = 1.54-2.99) for clinical stage T2c-T4 vs < T2b.

Two out of 311 (0.6%) had a positive CT scan and a 3/308(1%) had a positive BS in patients with Gleason 2-7, PSA -< 50, and clinical stage < T2b. In the subset of the same risk group with PSA <15, all 237 patients and all 244 patients had negative BS and CT scans respectively. In the high risk Gleason 8-10 patients, 28/126 (22%) had positive CT scan. In patients with PSA > 50, 49/99 (49.5%) had positive BS.

Conclusion: Gleason score, PSA, and clinical stage were independent predictors for a positive abdominopelvic CT scan and a radionuclide BS in newly diagnosed prostate cancer patients. Gleason score seems to be the driving force for nodal metastases vs PSA for skeletal metastases. About half of the patients are at low risk for metastases (Gleason 2-7, PSA < 50, clinical stage < T2b) and elimination of CT scan and BS in these patients would result in considerable economic savings.

291

2128 PHASE lI EVALUATION OF PRE-IRRADIATION DOWNSIZING OF T H E PROSTATE USING FLUTAMIDE

Sharon Prokop RN, BSN, OCN, Amy Strowbridge MD, Renu Sharma MS, Sam Tekyi-Mensah, Ph.D, and Jeffrey D. Forman MD

Gershenson Radiation Oncology Center, Barbara Ann Karmanos Cancer Institute, and Wayne State University, Detroit, MI

Purpose: To prospectively evaluate the efficacy and toxicity of the anti-androgen fiutamide in downsizing prostate gland size.

Materials & Methods: Eighteen patients with stage T1-T2 prostate carcinoma were prospectively registered on an IRB approved Phase II study. Patients were scheduled to receive 4 months of flutamide (250mg.TlD) prior to definitive radiotherapy. The prostate gland volume, both pre hormone and post horlllone, were compared. Volumes wcre estimated from both transrectal ultrasound and CT images. Patients received medication calendars to quaatify compliance and had monthly visits to monitor toxicities. Laboratory monitoring included liver function studies, complete blood connts, PSA, and testosterone. Gynecomastia, nipple tenderness, potency, and GI complaints were evaluated through history and physical.

Results: Of the eighteen eligible patients, twelve (67%) completed the 4 months of flutamide. Six patients could not complete the scheduled treatment due to toxicities. These included: 2 patients with elevated LFT's and one with cholestatic jaundice, 2 patients with a decline in hemoglobin of more lhan 2 gin., 2 with dian'hea not alneliorated by dose adjustment. Of the remaining 12 evaluable patients, 4 experienced significant diarrhea. Nine patients (50%) complained of nipple tenderness. One patiezlt developed gynecomastia treated with radiation therapy. Nine patients (50%) reported a change in libido and/or erectile dysfunction. In total 57% of patients had a significant drug induced toxicity excluding the impact on libido. There was a 27% reduction in the mean volume of the prostate. Analysis of response data pre hormone and post hormone therapy was as follows:

Mean Prostate Volume

Average PSA

Average Testosterone

* Wilcoxon Sign Rank Test

Pre

96.2 cc.

12.5 ng/ml

6.07 ng/ml

Post P- Value*

70.1 cc. 0.0005

2.66 ng/ml 0.0005

6.65 ng/ml 0.3

Conclusion: The use of anti-androgen monotherapy resulted in a significant downsizing of the prostate gland. However, the frequency and severity of toxicities may limit the widespread applicability of this approach.