Purpose: To determine the impact of whole pelvic irradiation on the risk of PSA failure in prostate cancer patients, at high predicted risk for lymph node involvement, receiving definitive radiotherapy.
Materials and Methods: Between October 1987 and December 1995, 506 patients with clinically localized prostate cancer were treated with definitive radiotherapy at UCSF and affiliated institutions. Treatment consisted of 4-field whole pelvic irradiation followed by a prostate-only boost, or prostate-only treatment (median follow-up was 35 months and 30 months, respectively). PSA failure was defined as: 1. a PSA value ≥ 1 ng/ml; or 2. a PSA value that rose ≥ 0.5 ng/ml in ≤ 1 year posttreatment on two consecutive measurements, with the first rise defined as the time of failure. The calculated risk of lymph node positivity (%rLN+) was defined as
(iPSA) + 10(GS-6), and high risk was defined as %rLN+ ≥ 15%. Univariate and multivariate analyses were performed.
Results: A total of 201 high-risk patients were identified. High-risk patients who received whole pelvic irradiation had significantly improved freedom from PSA failure compared to those who received prostate-only treatment (median PFS = 34.3 months vs. 21.0 months; p = 0.0001). Potential confounding variables, including initial PSA, Gleason score, T stage, radiation dose, year of treatment, use of three-dimensional (3D) conformal techniques, and use of hormone therapy, did not account for the observed difference in time to PSA failure. Multivariate analysis revealed type of radiation treatment to be the most significant independent predictor of outcome.
Conclusion: Whole pelvic radiotherapy significantly improves the PSA failure-free survival in patients with a high calculated risk of lymph node positivity. 相似文献
The purpose of our study was to evaluate the interdependency of spatial resolution, image reconstruction artifacts, and radiation
doses in virtual CT colonoscopy by comparing various CT scanning protocols. A pig's colon with several artificial polypoid
lesions was imaged after air insufflation with helical CT scanning using 1-, 3-, and 5-mm collimation, and pitch values varying
from 1.0 to 3.0. Virtual endoscopic images and “fly through” sequences were calculated on a Sun Sparc 20 workstation (Navigator
Software, GE Medical Systems, Milwaukee, Wis.). Several reconstruction artifacts as well as overall image quality were evaluated
by three independent reviewers. In addition, radiation doses for the different CT protocols were measured as multiple-scan
average dose using a 10-cm ion chamber and a standard Plexiglass body phantom. Generally, image quality and reconstruction
artifacts were less affected by pitch values than by beam collimation. Thus, narrow beam collimation at higher pitch values
(e. g. 3 mm/2.0) seems to be a reasonable compromise between quality of virtual endoscopic images and radiation dose load.
Received: 4 February 1999; Revised: 16 June 1999; Accepted: 17 June 1999 相似文献