Determinants of Change in Prostate-Specific Antigen Over Time and Its Association With Recurrence After External Beam Radiation Therapy for Prostate Cancer in Five Large Cohorts
- Department of Biostatistics, University of Michigan, Ann Arbor, MI (United States)
- Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia)
- Departments of Urology, Epidemiology, and Biostatistics, University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)
- William Beaumont Hospital, Royal Oak, MI (United States)
- Department of Statistics, Radiation Therapy Oncology Group, American College of Radiology, Philadelphia, PA (United States)
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States)
Purpose: To assess the relationship between prognostic factors, postradiation prostate-specific antigen (PSA) dynamics, and clinical failure after prostate cancer radiation therapy using contemporary statistical models. Methods and Materials: Data from 4,247 patients with 40,324 PSA measurements treated with external beam radiation monotherapy in five cohorts were analyzed. Temporal change of PSA after treatment completion was described by a specially developed linear mixed model that included standard prognostic factors. These factors, along with predicted PSA evolution, were incorporated into a Cox model to establish their predictive value for the risk of clinical recurrence over time. Results: Consistent relationships were found across cohorts. The initial PSA decline after radiation therapy was associated with baseline PSA and T-stage (p < 0.001). The long-term PSA rise was associated with baseline PSA, T-stage, and Gleason score (p < 0.001). The risk of clinical recurrence increased with current level (p < 0.001) and current slope of PSA (p < 0.001). In a pooled analysis, higher doses of radiation were associated with a lower long-term PSA rise (p < 0.001) but not with the risk of recurrence after adjusting for PSA trajectory (p = 0.63). Conversely, after adjusting for other factors, increased age at diagnosis was not associated with long-term PSA rise (p = 0.85) but was directly associated with decreased risk of recurrence (p < 0.001). Conclusions: We conclude that a linear mixed model can be reliably used to construct typical patient PSA profiles after prostate cancer radiation therapy. Pretreatment factors along with PSA evolution and the associated risk of recurrence provide an efficient and quantitative way to assess the impact of risk factors on disease progression.
- OSTI ID:
- 21128210
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 72, Issue 3; Other Information: DOI: 10.1016/j.ijrobp.2008.01.056; PII: S0360-3016(08)00290-3; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
Similar Records
Maximum vs. Mono Androgen Blockade and the Risk of Recurrence in Men With Localized Prostate Cancer Undergoing Brachytherapy
Posttreatment prostatic-specific antigen doubling time as a surrogate endpoint for prostate cancer-specific survival: An analysis of Radiation Therapy Oncology Group Protocol 92-02