Why Are Pretreatment Prostate-specific Antigen Levels And Biochemical Recurrence Poor Predictors Of Prostate Cancer Survival?

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Cancer / Oncology
Article Date: 26 Oct 2009 - 4:00 PDT

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UroToday.com - In the online edition of Cancer, Dr. James Denham and colleagues evaluated the initial, pretreatment PSA (iPSA) level as a prognostic predictor of prostate cancer (CaP) survival. A cohort of 802 patients from Australia and New Zealand received radiotherapy (XRT) with either 0, 3, or 6 months of neoadjuvant androgen deprivation therapy (ADT). Trial endpoints were biochemical recurrence free survival (BRFS) and prostate cancer specific survival (PCSS). A modified version of the Phoenix definition of biochemical recurrence was applied. Secondary therapeutic intervention (STI) was any anticancer therapy initiated at or after BR. PSA doubling time (PSADT) was also computed.

Of the 802 men, 454 (57%) failed primary treatment, 342 (43%) received STI, and 241 (30%) died (125 [16%] from CaP). In multivariable modeling with iPSA as the categorical variable and adjusting for pretreatment age, Gleason score, stage, and treatment arm, increasing iPSA category was an independent predictor of BRFS, but not for PCSS.

All other pretreatment variables were independent predictors of BPFS with increasing Gleason score and T stage strongly associated with decreasing survival expectations. The arm receiving ADT for 6 months predicted for better PCSS compared with the arm receiving XRT alone. Among the 436 patients experiencing BR, greater clinical stages, Gleason score, and iPSA was found when compared with those who did not experience BR. Assessing PCSS from the time of BR indicated that increasing PSA category was a predictor of increasing survival probability.

Interestingly, the category of men with PSA <10ng/ml had significantly inferior PCSS after BR relative to men in all iPSA categories. A second model was performed to assess whether time to BR (TTBR) might explain this. Increasing TTBR produced a superior model and survival 5 years after BR was 44% for men with TTBR <1 year, compared with 93% for men with TTBR >4 years. Additional modeling demonstrated that TTBR was of greater prognostic value than the occurrence of BR itself. In a model of PCSS from BR, decreasing PSADT was the strongest predictor of early CaP death. Survival probability 5 years after BR was 32% for men with a PSADT <3 months, compared with 95% in patients with a PSADT >24 months.

Denham JW, Steigler A, Wilcox C, Lamb DS, Joseph D, Atkinson C, Tai KH, Spry NA, Gleeson PS, D'Este C
Cancer. 2009 Aug 18;115(19):4477-4487.
doi:10.1002/cncr.24484

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