Tumor Percent Involvement Predicts Prostate Specific Antigen Recurrence After Radical Prostatectomy Only in Men With Smaller Prostate

Abstract

We determined the predictive power of tumor percent involvement on prostate specific antigen recurrence in patients when stratified by prostate weight. Data on 3,057 patients who underwent radical prostatectomy between 1988 and 2008 was retrieved from our institutional prostate cancer database. Patients with data on tumor percent involvement, prostate volume and prostate specific antigen recurrence were included in analysis. Patients were divided into 3 groups based on prostate volume less than 35, 35 to 45 and greater than 45 cc. The variables tumor percent involvement, age at surgery, race, prostate specific antigen, pathological Gleason score, positive surgical margins, extraprostatic extension, seminal vesicle invasion and surgery year were analyzed using the chi-square and Mann-Whitney tests to determine individual effects on prostate specific antigen recurrence. Tumor percent involvement and prostate specific antigen were evaluated as continuous variables. Significant variables on univariate analysis were included in multivariate Cox regression analysis to compare their effects on prostate specific antigen recurrence. Tumor percent involvement significantly predicted prostate specific antigen recurrence in men with a small prostate (p = 0.006) but not in those with a prostate of greater than 35 cc. Black race was a marginally significant predictor of prostate specific antigen recurrence in men with a medium prostate (p = 0.055). Age at surgery was a predictor of prostate specific antigen recurrence in men with a larger prostate (p = 0.003). Prostate specific antigen, positive surgical margins, seminal vesicle invasion and pathological Gleason score 7 or greater predicted prostate specific antigen recurrence in men with all prostate sizes. In men with a prostate of less than 35 cc tumor percent involvement is an important variable when assessing the risk of prostate specific antigen recurrence. Tumor percent involvement and prostate volume should be considered when counseling patients and determining who may benefit from heightened surveillance after radical prostatectomy.