Purpose: We compared pathological findings with prostate specific antigen (PSA) failure rates following radical prostatectomy for large volume cancers (6 cc or greater).
Materials and methods: A total of 191 men whose radical prostatectomy specimen had a cancer volume of 6 cc or greater were followed for a mean of 3.6 years (range 0.3 to 11.1) and 112 (58.6%) had PSA failure (PSA 0.07 ng./ml. or greater and increasing). Percent Gleason grade 4/5 (the Stanford modified Gleason scale), cancer volume, seminal vesicle invasion, regional lymph nodes, capsular penetration, positive surgical margin, location of the largest cancer in the peripheral or transition zone, prostate weight, patient age, preoperative PSA and clinical stage were analyzed using univariate and multivariate Cox proportional hazards analyses.
Results: In univariate regression analysis percent Gleason grade 4/5, lymph node involvement, cancer volume, cancer location in the peripheral zone, capsular penetration and positive surgical margins were significant predictors of biochemical failure. Seminal vesicle invasion, preoperative serum PSA, patient age, prostate weight and clinical stage were not statistically significant. Forward stepwise, multivariate analysis showed that percent Gleason grade 4/5 (p <0.0001, relative risk ratio 2.498), cancer location in the peripheral zone (p = 0.0097, 1.887), cancer volume (p = 0.0157, 1.691) and lymph node involvement (p = 0.0317, 1. 666) were the only independent predictors of biochemical failure. When 52 men with organ confined, large volume prostate cancer were analyzed separately, univariate and multivariate analyses showed that only cancer location in the peripheral zone (p = 0.0021, relative risk ratio 13.473) and percent Gleason grade 4/5 (p = 0. 0449, 4.111) were independent predictors of failure.
Conclusions: Percent Gleason grade 4/5, cancer location in the peripheral zone, cancer volume and lymph node involvement have prognostic value in large volume prostate cancer. Cancer location in the peripheral zone and percent Gleason grade 4/5 are the most powerful predictors of biochemical failure in men whose cancer is 6 cc or greater and contained in the prostatic capsule. Preoperative serum PSA is not helpful in distinguishing biochemical failure rates in these large volume cancers whether they are organ confined or not.