Prostate Size and Risk of High-Grade, Advanced Prostate Cancer and Biochemical Progression After Radical Prostatectomy: A Search Database Study

Abstract

Prostate growth and differentiation are under androgenic control, and prior studies suggested that tumors that develop in hypogonadal men are more aggressive. We examined whether prostate weight was associated with tumor grade, advanced disease, or risk of biochemical progression after radical prostatectomy (RP). We evaluated the association of prostate weight with pathologic tumor grade, positive surgical margins, extracapsular disease, and seminal vesicle invasion using logistic regression and with biochemical progression using Cox proportional hazards regression among 1,602 men treated with RP between 1988 and 2003 at five equal-access medical centers, which composed the Shared Equal Access Regional Cancer Hospital (SEARCH) Database. In outcome prediction models including multiple predictor variables, it was found that the predictor variable of prostate weight was significantly inversely associated with the outcomes of high-grade disease, positive surgical margins, extracapsular extension (all P < or = .004), and biochemical progression (comparing prostate weight < 20 v > or = 100 g: relative risk = 8.43; 95% CI, 2.9 to 24.0; P < .001). Similar associations were seen between preoperative transrectal ultrasound-measured prostate volume and high-grade disease, positive surgical margins, extracapsular extension (all P < or = .005), seminal vesicle invasion (P = .07), and biochemical progression (P = .06). Men with smaller prostates had more high-grade cancers and more advanced disease and were at greater risk of progression after RP. These results suggest that prostate size may be an important prognostic variable that should be evaluated for use pre- and postoperatively to predict biochemical progression.