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Journal articles
Confirmation of a low α/β ratio for prostate cancer treated by external beam radiation therapy alone using a post-treatment repeated-measures model for PSA dynamics.: Estimation of ratio of prostate cancer using repeated post-treatment PSA measures
Abstract : PURPOSE: To estimate the α/β ratio of prostate cancer treated with external beam radiation only by use of a model of long-term prostate-specific antigen (PSA) dynamics. METHODS AND MATERIALS: Repeated measures of PSA from 5,093 patients from 6 institutions treated for localized prostate cancer by external beam radiation therapy (EBRT) without planned androgen deprivation were analyzed. A biphasic linear mixed model described the post-treatment evolution of PSA, rather than a conventional model of time to biochemical recurrence. The model was adjusted for standard prognostic factors (T stage, initial PSA level, and Gleason score) and cohort-specific effects. The radiation dose fractionation effect was estimated from the long-term rate of rise of PSA level. RESULTS: Adjusted for other factors, total dose of EBRT and sum of squared doses per fraction were associated with long-term rate of change of PSA level (p = 0.0017 and p = 0.0003, respectively), an increase of each being associated with a lower rate of rise. The α/β ratio was estimated at 1.55 Gy (95% confidence band, 0.46-4.52 Gy). This estimate was robust to adjustment of the linear mixed model. CONCLUSIONS: By analysis of a large EBRT-only cohort along with a method that uses all the repeated measures of PSA after the end of treatment, a low and precise α/β was estimated. These data support the use of hypofractionation at fractional doses up to 2.8 Gy but cannot presently be assumed to accurately represent higher doses per fraction.
Cited literature [25 references]
https://www.hal.inserm.fr/inserm-00621004
Contributor : Cecile Proust-Lima <>
Submitted on : Friday, September 9, 2011 - 11:22:56 AM
Last modification on : Wednesday, August 7, 2019 - 2:34:15 PM
Long-term archiving on: : Saturday, December 10, 2011 - 2:21:49 AM
Contributor : Cecile Proust-Lima <>
Submitted on : Friday, September 9, 2011 - 11:22:56 AM
Last modification on : Wednesday, August 7, 2019 - 2:34:15 PM
Long-term archiving on: : Saturday, December 10, 2011 - 2:21:49 AM
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