Wednesday

Prostatic Acid Phosphatase Adversely Affects Cause-Specific Survival in Patients with Intermediate to High-Risk Prostate Cancer Treated with Brachythe

Objectives
To perform a retrospective analysis to assess the utility of pretreatment serum prostatic acid phosphatase (PAP) as a predictor of cause-specific survival (CSS) in patients with higher risk prostate cancer treated with palladium-103 (103Pd) brachytherapy and supplemental external beam radiotherapy (EBRT).

Methods
From 1992 to 1996, 193 patients with clinically localized prostate adenocarcinoma, a pretreatment PAP level, and Gleason score 7 or more, and/or a prostate-specific antigen (PSA) level of 10 ng/mL or more were treated with 103Pd brachytherapy and supplemental EBRT. The patients underwent EBRT of 41.4 Gy to a limited pelvic field and 103Pd brachytherapy with a prescribed minimum 103Pd dose of 80 Gy. Multivariate analysis was performed to analyze the predictive value of PAP, PSA, and Gleason score on CSS.

Results
The 10-year CSS rate for patients with a PAP level of less than 1.5, 1.5 to 2.4, and 2.5 U/L or more was 93%, 87%, and 75%, respectively (P = 0.013). The 10-year CSS rate for patients with a PSA level of less than 10, 10 to 20, and greater than 20 ng/mL was 92%, 76%, and 83%, respectively (P = 0.393). The 10-year CSS rate for patients with a Gleason score of 6, 7, 8, and 9 was 90%, 89%, 70%, and 68%, respectively (P = 0.002). On Cox multivariate regression analysis, PAP (hazard ratio 1.31, P <0.0001) and Gleason score (hazard ratio 2.37, P = 0.0007) were associated with CSS. PSA was not predictive of CSS (P = 0.393).

Conclusions
The results of this study demonstrated that PAP is a stronger predictor of CSS than PSA or Gleason score in men with higher risk prostate cancer treated with 103Pd brachytherapy and EBRT. Given the findings of this analysis, the use of PAP should be reconsidered in these patients.

Body Mass Index and Prostate-Specific Antigen Failure Following Brachytherapy for Localized Prostate Cancer.

PURPOSE:
Increasing body mass index (BMI) is associated with prostate-specific antigen (PSA) failure after radical prostatectomy and external beam radiation therapy (EBRT). We investigated whether BMI is associated with PSA failure in men treated with brachytherapy for clinically localized prostate cancer.

PATIENTS AND METHODS:
Retrospective analyses were conducted on 374 patients undergoing brachytherapy for stage T1c-T2cNXM0 prostate cancer from 1996-2001. Forty-nine patients (13%) received supplemental EBRT and 131 (35%) received androgen deprivation therapy (ADT). Height and weight data were available for 353 (94%). Cox regression analyses were performed to evaluate the relationship between body mass index (BMI) and PSA failure (nadir + 2 ng/ml definition). Covariates included age, race, preimplantation prostate-specific antigen (PSA), Gleason score, T category, percent of prescription dose to 90% of the prostate, use of supplemental EBRT, and ADT.

RESULTS:
Median age, PSA, and BMI were 66 years (range, 42-80 years), 5.7 ng/ml (range, 0.4-22.6 ng/ml), and 27.1 kg/m(2) (range, 18.2-53.6 kg/m(2)), respectively. After a median follow-up of 6.0 years (range, 3.0-10.2 years), there were 76 PSA recurrences. The BMI was not associated with PSA failure. Six-year PSA failure rates were 30.2% for men with BMI less than 25 kg/m(2), 19.5% for BMI of 25 or greater to less than 30 kg/m(2), and 14.4% for BMI of 30 kg/m(2) or greater (p = 0.19). Results were similar when BMI was analyzed as a continuous variable, using alternative definitions of PSA failure, and excluding patients treated with EBRT and/or ADT. In multivariate analyses, only baseline PSA was significantly associated with shorter time to PSA failure (adjusted hazard ratio, 1.12; 95% confidence interval, 1.05-1.20; p = 0.0006).

CONCLUSIONS:
Unlike after surgery or EBRT, body mass index (BMI) is not associated with prostate-specific antigen (PSA) failure in men treated with brachytherapy for prostate cancer. This raises the possibility that brachytherapy may be a preferred treatment strategy in obese patients.

Tuesday

Prostate specific antigen versus prostate specific antigen density as a prognosticator of pathological characteristics and biochemical recurrence foll

PURPOSE: The usefulness of prostate specific antigen (PSA) density for predicting pathological stage and biochemical recurrence after radical prostatectomy has not been well defined. We investigated whether prostate specific antigen density yielded an advantage over total prostate specific antigen for predicting adverse pathological characteristics and disease recurrence following radical prostatectomy.

MATERIALS AND METHODS: A total of 13,434 men who underwent radical prostatectomy for clinically localized prostate cancer between 1984 and 2006 were included in this study. The study population was stratified by Gleason score (6 or less, 7, and 8 or greater), and the clinical and pathological characteristics of each group were compared. We constructed ROC curves and determined the ROC AUC and concordance index to specifically investigate the accuracy of prostate specific antigen (PSA) and prostate specific antigen density for predicting pathological stage and biochemical recurrence.

RESULTS: Prostate specific antigen density was better than prostate specific antigen (PSA)for predicting extraprostatic extension and biochemical-free recurrence in patients with a biopsy Gleason score of 6 or less (each p <0.001). In patients with a biopsy Gleason score of 7 prostate specific antigen was more predictive than prostate specific antigen density for seminal vesicle involvement (p <0.001), lymph node involvement (p = 0.017) and biochemical-free recurrence (p <0.001). In men with a biopsy Gleason score of 8 or greater there was no statistical difference between prostate specific antigen and prostate specific antigen density in terms of prognostic value for pathological or clinical outcomes.

CONCLUSIONS: Prostate specific antigen density is highly associated with pathological stage and biochemical-free survival following radical prostatectomy. In lower grade prostate cancers prostate specific antigen density is significantly more accurate for predicting extraprostatic extension and biochemical-free recurrence compared to total prostate specific antigen. It should be considered when counseling patients on outcomes following radical prostatectomy.