ABSTRACT
PURPOSE: A report of biochemical outcomes for patients treated with palladium-103 (Pd-103) brachytherapy over a fixed time interval. METHODS AND MATERIALS: Two hundred thirty patients with clinical stage T1-T2 prostate cancer were treated with Pd-103 brachytherapy and followed with prostate-specific antigen (PSA) determinations. Kaplan-Meier estimates of biochemical failure on the basis of two consecutive elevations of PSA were utilized. Multivariate risk groups were constructed. Aggregate PSA response by time interval was assessed. RESULTS: The overall biochemical control rate achieved at 9 years was 83.5%. Failures were local 3.0%; distant 6.1%; PSA progression only 4.3%. Significant risk factors contributing to failure were serum PSA greater than 10 ng/ml and Gleason sum of 7 or greater. Five-year biochemical control for those exhibiting neither risk factor was 94%; one risk factor, 82%; both risk factors, 65%. When all 1354 PSA determinations obtained for this cohort were considered, the patients with a proportion of PSAs < or = 0.5 ng/ml continued to increase until at least 48 months post-therapy. These data conformed to a median PSA half-life of 96.2 days. CONCLUSIONS: Prostate brachytherapy with Pd-103 achieves a high rate of biochemical and clinical control in patients with clinically organ-confined disease. PSA response following brachytherapy with low-dose-rate isotopes is protracted.
Subject(s)
Brachytherapy/methods , Palladium/therapeutic use , Prostate-Specific Antigen/blood , Prostatic Neoplasms/blood , Prostatic Neoplasms/radiotherapy , Radioisotopes/therapeutic use , Radiopharmaceuticals/therapeutic use , Aged , Analysis of Variance , Cohort Studies , Disease-Free Survival , Follow-Up Studies , Half-Life , Humans , Male , Neoplasm Staging , Prospective Studies , Prostatic Neoplasms/pathology , Treatment Failure , Ultrasonography, InterventionalABSTRACT
PURPOSE: To compare the prostate volumes defined by transrectal ultrasound (TRUS) versus computed tomographic (CT) scans used for brachytherapy planning. METHODS AND MATERIALS: Ten unselected patients underwent evaluation for prostate brachytherapy with TRUS and CT imaging. Axial prostate contours were obtained at 5-mm intervals in both studies. The CT images were photographed, scanned into a commercial software program, and reprinted from a laser printer at 600 dots per inch to provide individual images that were interpreted independently by the three physician authors (BK, KW, and JB). An effort was made to exclude pelvic floor muscles from the defined prostate contour. Volumes were calculated in cubic centimeters. The prostate volume and maximum dimension in each plane were compared for each imaging modality. RESULTS: The CT-based prostate volumes ranged from 31.1 cc to 48.1 cc. The TRUS-based volumes ranged from 26.6 cc to 46.4 cc. There was close agreement between imaging modalities (r = 0.9). The anterior-posterior, lateral, and craniocaudal prostatic dimensions were similar between modalities. To test for consistency between observers, the CT volumes were drawn independently by KB, KW, and JB. The prostatic measurements were consistent in all dimensions between observers. CONCLUSION: CT scan volumes and measurements correlate well with those obtained by TRUS, and are appropriate for pre- or postimplant dosimetry.
Subject(s)
Prostatic Neoplasms/diagnostic imaging , Tomography, X-Ray Computed , Brachytherapy , Humans , Male , Prostatic Neoplasms/pathology , Prostatic Neoplasms/radiotherapy , Radiotherapy, Conformal , UltrasonographyABSTRACT
The purpose of the study was to determine which clinical parameters might predict individual prostate volume changes from prostate brachytherapy. Fifty consecutive, unselected patients treated at the University of Washington by I-125 or Pd-103 implantation for prostatic carcinoma in 1998 were analyzed. The prostate contours on preimplant transrectal ultrasound (TRUS) images were digitized and the prostate volumes calculated. Postimplant axial CT images of the prostate was obtained at 0.5 cm intervals with patients in the supine position the morning after the implant. The postimplant prostate volume increased by an average factor of 1.7 (+/-0.34) compared with the preimplant volume, the size increase being primarily in the anterior-posterior dimension. The absolute volume change was similar in patients with small vs. large preimplant prostate volume (r = -0.39), but the proportional change was less in patients with a larger prostate volume (r = -0.71). Because patients with a small preimplant prostate had proportionately greater volume increase, their postimplant target coverage was generally less. No single parameter, including preimplant prostate volume, preimplant hormonal deprivation, or supplemental external beam radiation therapy (EBRT) can accurately predict the degree of swelling. The precise significance of and practical solution to implant-related prostate volume changes remains to be determined.
