[1003] Towards a New Definition of Clinically Insignificant Prostate Cancer Using Clinico-Pathologic Data of the ERSPC-Rotterdam

TH Van der Kwast, T Wolters, PJ Van Leeuwen, RF Hoedemaeker, GL Van Leenders, M Roobol, FH Schroeder. Erasmus MC, Rotterdam, Netherlands; Sint Franciscus Gasthuis, Rotterdam, Netherlands

Background: Currently, the criteria for insignificant prostate cancer (PC) include a tumour volume (TV) threshold of <0.5 ml, irrespective of patient's age. This threshold is based on a study published in 1993 of incidentally detected prostate cancers in a cystoprostatectomy series (1). However, TV as an independent prognosticator is now controversial (2). Using data of the European Randomized Screening study of Prostate Cancer (ERSPC)-Rotterdam, we tried to redefine the criteria for clinically insignificant prostate cancer.
Design: Modeling of population based screening data of the screening and control arm of the ERSPC pointed at a 27% rate of clinically insignificant PC in men aged 55 after a single screen and a 47% rate in screened men aged 65. Using these rates we determined TV and pretreatment PSA thresholds for clinically insignificant PC in 325 screened men who were treated with radical prostatectomy (RP). Their predictive value for biochemical progression as a indication for relevant disease was analyzed using Cox proportional hazards analyses.
Results: The TV and PSA thresholds were 0.46 ml and 4.8 ng /ml for the whole cohort, 0.23 ml and 3.6 ng /ml for the age group 55-65 and 2.56 ml and 9.7 ng/ml for the age group 65-75. None of the TV thresholds differentiated between patients showing biochemical recurrence or not, in the cohort of 174 patients with organ-confined PC without Gleason pattern 4/5, but a trend towards differentiation between patients with and without biochemical progression was seen using a PSA threshold. This study was limited by the fact that all patients were treated and true significance of the PC thus cannot be established.
Conclusions: TV was not a useful criterion for the identification of clinically insignificant PC in patients with organ-confined PC without Gleason pattern 4/5. Age-adjusted PSA values may be a better criterion than TV to define clinically insignificant PC, but further investigations are needed before recommendations can be made. 1. Stamey TA, Freiha FS, McNeal JE, et al. Localized prostate cancer. Relationship of tumor volume to clinical significance for treatmetn of prostate cancer. Cancer 1993; 71: 933-938. 2. Wolters T, Roobol MJ, Van Leeuwen P, et al. Should prostate tumor volume routinely be reported by the pathologist? Eur Urol, 2010, Epub ahead of print.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 126, Monday Afternoon


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