Biochemical failure and the temporal kinetics of prostate-specific antigen after radiation therapy with androgen deprivation
The accuracy of the American Society of Therapeutic Radiation Oncology consensus definition of biochemical failure (BF) after radiation therapy (RT) and androgen deprivation (AD) has been questioned, because posttreatment prostate-specific antigen (PSA) levels typically rise after release from AD, and misclassification of BF may be made. The temporal kinetics of posttreatment PSA levels was examined to define the error in the classification of BF.
Between December 1, 1991 and April 30, 1998, 688 men with T1c-T3 NX/0 M0 prostate cancer received three-dimensional conformal RT alone (n = 586) or in combination with either short-term (STAD: 3 to 12 months, n = 82) or long-term (LTAD: 12 to 36 months, n = 20) AD. Follow-up, calculated from the end of all treatment, was >/=48 months. The mean posttreatment PSA was calculated in 3-month intervals.
The median posttreatment clinical follow-up period was 76 months (range, 48-152 months). The posttreatment PSA values from the end of all treatment for the RT+STAD-BF group showed an initial period of rise followed by a period of decline at 30 months and then a continued rise again. The decline in the mean posttreatment PSA is explained in part by stabilization in PSA level after 3 consecutive rises. Nonbiochemical failures (NBF) after RT+STAD had a relatively constant mean PSA over time of approximately 0.5 ng/mL. Unlike the RT+STAD-NBF profile, the RT+LTAD-NBF profile rose continuously and steadily to a level approaching 1 ng/mL. The RT+LTAD-BF profile rose continuously but at a slower rate over time. Nine RT+STAD-NBF patients (22%) and 2 RT+LTAD-BF (29%) patients experienced 3 consecutive rises followed by a subsequent decline and stabilization of PSA compared to 10 RT-BF patients (5%). Redistributing these misclassified patients to their respective NBF groups changed the mean posttreatment PSA profiles as follows: The RT+LTAD-BF profile rose constantly and steadily with a doubling time of approximately 16 months, and the RT+LAD-NF initially rose to a value of approximately 0.5 ng/mL, then at 36 months began to decline.
The temporal kinetics of posttreatment PSA after RT+AD and RT alone are different. The American Society of Therapeutic Radiation Oncology definition for biochemical failure overestimates BF in 20-30% after RT+AD compared to 5% after RT alone.
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ABSTRACT: Recent advances on differently-expressed gene products and their functions during the progression from localized androgen-dependent states into androgen-independent and metastatic forms of prostate cancer are reported. The expression levels of numerous oncogenes and tumor suppressor genes in distinct prostatic cancer epithelial cell lines and tissues relative to normal prostate cells are described. This is carried out to identify the signaling elements that are altered during the initiation, progression and metastatic process of prostate cancer. Additional information on the interactions between certain deregulated signaling pathways such as androgen receptor (AR), estrogen receptors, epidermal growth factor receptor (EGFR), hedgehog and Wnt/beta-catenin cascades in controlling the proliferation, survival and invasion of tumor prostate epithelial cells during the disease progression is described. The emphasis is on the critical functions of the AR and EGF-EGFR systems at all stages during prostate carcinogenesis. Of therapeutic interest, new strategies for the diagnosis and treatment of localized and metastatic forms of prostate cancer by targeting multiple tumorigenic signaling elements are also reported.
Carcinogenesis 02/2006; 27(1):1-22. DOI:10.1093/carcin/bgi229 · 5.33 Impact Factor
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ABSTRACT: To assess the impact of a rising prostate-specific antigen (PSA) level in patients receiving neoadjuvant androgen deprivation therapy (N-ADT) before external beam radiotherapy for prostate cancer.
From prospectively collected data, we identified 182 patients who received between 3 and 12 months of N-ADT before definitive external beam radiotherapy and who had at least three PSA readings during the neoadjuvant period. One hundred fifty patients had PSA values that continued to fall (Non-Rise group), but 32 had a PSA value that started to rise (Rise group). The two groups were compared by Mann-Whitney U and Pearson chi-square tests. Kaplan-Meier and log-rank analyses were performed for time to treatment failure, cause-specific survival (CSS), and overall survival (OS).
The median follow-up was 62.5 months for the Non-Rise group and 53 months for the Rise group. Patients who sustained a PSA rise during the N-ADT period had a shorter time to PSA relapse (p = 0.013), poorer CSS (p = 0.027), and poorer OS (p = 0.03). Multivariate analysis confirms the significance of a PSA rise during the N-ADT period for CSS (p = 0.035) and OS (p = 0.038).
A subset of patients treated with N-ADT develop a rising PSA profile that likely represents early androgen resistance. They have significantly worse outcome.
International Journal of Radiation OncologyBiologyPhysics 06/2006; 65(1):59-64. DOI:10.1016/j.ijrobp.2005.09.048 · 4.26 Impact Factor
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ABSTRACT: In 1996 the American Society for Therapeutic Radiology and Oncology (ASTRO) sponsored a Consensus Conference to establish a definition of biochemical failure after external beam radiotherapy (EBRT). The ASTRO definition defined prostate specific antigen (PSA) failure as occurring after three consecutive PSA rises after a nadir with the date of failure as the point halfway between the nadir date and the first rise or any rise great enough to provoke initiation of therapy. This definition was not linked to clinical progression or survival; it performed poorly in patients undergoing hormonal therapy (HT), and backdating biased the Kaplan-Meier estimates of event-free survival. A second Consensus Conference was sponsored by ASTRO and the Radiation Therapy Oncology Group in Phoenix, Arizona, on January 21, 2005, to revise the ASTRO definition. The panel recommended: (1) a rise by 2 ng/mL or more above the nadir PSA be considered the standard definition for biochemical failure after EBRT with or without HT; (2) the date of failure be determined "at call" (not backdated). They recommended that investigators be allowed to use the ASTRO Consensus Definition after EBRT alone (no hormonal therapy) with strict adherence to guidelines as to "adequate follow-up." To avoid the artifacts resulting from short follow-up, the reported date of control should be listed as 2 years short of the median follow-up. For example, if the median follow-up is 5 years, control rates at 3 years should be cited. Retaining a strict version of the ASTRO definition would allow comparisons with a large existing body of literature.
International Journal of Radiation OncologyBiologyPhysics 08/2006; 65(4):965-74. DOI:10.1016/j.ijrobp.2006.04.029 · 4.26 Impact Factor
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