• Int. J. Radiat. Oncol. Biol. Phys. · Nov 2006

    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.

    • Richard K Valicenti, Michelle DeSilvio, Gerald E Hanks, Arthur Porter, Harmar Brereton, Seth A Rosenthal, William U Shipley, Howard M Sandler, and Radiation Therapy Oncology Group Protocol 92-02.
    • Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA. Richard.Valicenti@mail.tju.edu
    • Int. J. Radiat. Oncol. Biol. Phys. 2006 Nov 15; 66 (4): 1064-71.

    PurposeWe evaluated whether posttreatment prostatic-specific antigen doubling time (PSADT) was predictive of prostate cancer mortality by testing the Prentice requirements for a surrogate endpoint.Methods And MaterialsWe analyzed posttreatment PSA measurements in a cohort of 1,514 men with localized prostate cancer (T2c-4 and PSA level <150 ng/mL), treated and monitored prospectively on Radiation Therapy Oncology Group Protocol 92-02. From June 1992 to April 1995, men were randomized to neoadjuvant androgen deprivation and 65-70 Gy of radiation therapy (n = 761), or in combination with 24 months of adjuvant androgen deprivation (n = 753). Using an adjusted Cox proportional hazards model, we tested if PSADT was prognostic and independent of randomized treatment in this cohort. The endpoints were time to PSADT (assuming first-order kinetics for a minimum of 3 rising PSA measurements) and cancer-specific survival (CSS).ResultsAfter a median follow-up time of 5.9 years, randomized treatment was a significant predictor for CSS (p(Cox) = 0.002), PSADT <6 months (p(Cox) < 0.001), PSADT <9 months (p(Cox) < 0.001), and PSADT <12 months (p(Cox) < 0.001) but not for PSADT <3 (p(Cox) = 0.4). The significant posttreatment PSADTs were also significant predictors of CSS (p(Cox)< 0.001). After adjusting for T stage, Gleason score and PSA, all of Prentice's requirements were not met, indicating that the effect of PSADT on CSS was not independent of the randomized treatment.ConclusionsProstatic specific antigen doubling time is significantly associated with CSS, but did not meet all of Prentice's requirements for a surrogate endpoint of CSS. Thus, the risk of dying of prostate cancer is not fully explained by PSADT.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…