Is It Possible To Compare PSA Recurrence-Free Survival After Surgery And Radiotherapy Using Revised ASTRO Criterion-"Nadir + 2"?

Main Category: Prostate / Prostate Cancer
Also Included In: Radiology / Nuclear Medicine;  Clinical Trials / Drug Trials
Article Date: 19 Apr 2008 - 0:00 PDT

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UroToday.com - A lack of randomized trials for radiotherapy (XRT) and radical prostatectomy (RP) make it difficult for patients to compare outcomes. Biochemical recurrence (BR) after RP is defined as an initial level of 0.2ng/ml or greater, with a second confirmatory PSA level of 0.2ng/ml or greater. In 2005 The American Society for Therapeutic Radiology and Oncology (ASTRO) revised the definition for failure after XRT and concluded that a PSA value of 2ng/ml greater than the absolute nadir with failure defined at the point of call was best. In the online edition of Urology, Dr. Nielsen and the group from Johns Hopkins applied this definition to their RP series to determine its accuracy.

A final cohort of 2,570 men treated with RP between 1986 and 2004 were evaluated. They all had stage T1c disease, were operated on by one surgeon and had a mean follow-up of 6.2 years. No patient was treated with androgen deprivation therapy or XRT unless they had disease recurrence. The authors applied the PSA nadir + 2 definition to their series by defining N+2 BR as a postoperative serum PSA level of 2ng/ml or greater. The biochemical recurrence-free survival (BRFS) probabilities for the group were determined by the 0.2ng/ml or more and N+2 definitions of failure.

The N+2 definition of failure significantly overestimated the BRFS in this study relative to the 0.2ng/ml or more definition. Using actuarial analysis and defining failure as 0.2ng/ml or greater, the BRFS estimate at 5, 10, 15 years was 88.6%, 81.2%, and 78.1%, respectively. The corresponding percentages for the N+2 definition were 94.6%, 89.4%, and 84.3%. For 322 patients with a postoperative PSA level of 0.2ng/ml or greater, the median time to BR was 2.8 years for the 0.2ng/ml or more definition vs. 7.9 years for the N+2 definition. The N+2 definition resulted in a highly significant delay in the determination of failure, relative to the 0.2ng/ml definition.

Correlating biochemical failure to clinical failure, the N+2 definition significantly overestimated the BRFS for both local and distant recurrence. At 5 years, the N+2 definition overestimated the BRFS by 52% among patients with a clinical local recurrence and by 17% among those with a metastatic recurrence. The actuarial 10-year risk of developing metastases was significantly greater among men meeting the N+2 criterion (48%) compared with all men with a PSA level of 0.2ng/ml or more (31%).

Nielsen ME, Makarov DV, Humphreys E, Mangold L, Partin AW, Walsh PC

Reported by UroToday.com Contributing Editor Christopher P. Evans, MD, FACS

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