John J. Bauer

Elevated levels of apoptosis regulator proteins p53 and BCL-2 are independent prognostic biomarkers in surgically treated clinically localized prostate cancer

PURPOSE The tumor suppressor gene (TSG) p53 and the proto-oncogene bcl-2 have been shown to be involved in the regulation of cell growth and apoptosis and have been implicated in hormone refractory prostate cancer (PC) and poor prognosis. The goal of this study was to determine the clinical utility of the presence of p53 and bcl-2 immunohistochemical (IHC) protein in the primary tumor as predictors of disease progression following radical prostatectomy (RP). MATERIALS AND METHODS The expression of p53 and bcl-2 was evaluated in archival paraffin-embedded RP specimens from 175 patients followed from 1 to 9 years (mean = 4.6 years) and correlated with stage, grade, race and serologic (PSA) recurrence following surgery. RESULTS Overexpression of bcl-2 was noted in 47 of 175 (26.9%) patients; these patients had a significantly higher 5-year failure rate than those who did not overexpress bcl-2 (67.0% versus 30.7%). Expression of p53 was noted in 114 of 175 (65.1%) patients with a 5-year failure rate of 51.1% compared with a 5-year failure rate of only 22% in p53 negative patients. When expression rates for p53 and bcl-2 were combined, the 5-year failure rate was 75.3%. Conversely, when both p53 and bcl-2 IHC staining were negative, the 5-year failure rate was 20.4%. Univariate Kaplan-Meier analysis showed a statistically significant difference between p53 and bcl-2 positive and negative patients (p < 0.001). Multivariate Cox Regression Analysis with backward elimination controlling for age, race, stage and grade showed both p53 (p = .0185) and bcl-2 (p = .004) to be independent predictors of disease-free survival. CONCLUSION p53 and bcl-2 appear to be important biomarkers that predict recurrence in clinically localized PC after RP.

CD34 IMMUNOHISTOCHEMICAL ASSESSMENT OF ANGIOGENESIS AS A PROGNOSTIC MARKER FOR PROSTATE CANCER RECURRENCE AFTER RADICAL PROSTATECTOMY

PURPOSE We assess the neovascularity of clinically localized prostate cancer by immunohistochemistry using the monoclonal antibody CD34 in an attempt to identify associations between angiogenesis and disease progression following radical prostatectomy. MATERIALS AND METHODS Microvascularity was evaluated using the CD34 monoclonal antibody in archival paraffin embedded radical prostatectomy specimens from 149 patients followed from 3 to 10 years (mean 6.6). Vessels were quantified by counting a minimum of 2 selected microscopic fields (200x, 0.754 mm.2) from each tumor, area of prostatic intraepithelial neoplasia and prostatic hyperplasia, and given a numerical value representing the microvessel density count. RESULTS Mean microvessel density count did not vary significantly with age or race. There was a significant association between the count and nuclear grade, Gleason sum and pathological stage. Cox survival analysis shows that microvessel density is significantly related to time to recurrence when considered as a continuous variable (p=0.03) as well as dichotomous variable (p=0.007) (microvessel density count less than 90 and 90 or greater). The 5-year recurrence-free survival was significantly higher for patients with a count less than 90 (71%) than for those with a count 90 or greater (51%) (p=0.006). The 5-year recurrence-free survival was also significantly different when microvessel density was used as a continuous variable (p=0.02). Controlling for stage, Gleason sum, race and nuclear grade, microvessel density remained significant in predicting recurrence (p=0.03) but when pretreatment prostate specific antigen was included in the model the count was no longer significant. The microvessel density count in the tumor area significantly increased with increasing Gleason sum and nuclear grade but it did not increase significantly in the adjacent benign prostate or areas of prostatic intraepithelial neoplasia in the same specimen. CONCLUSIONS Microvascularity or neovascularity as measured by the CD34 antigen may be a prognostic marker of recurrence for prostate cancer patients after radical prostatectomy but more study in prostate specific antigen era patients with sufficient followup is needed.

Ki-67 EXPRESSION IS A PROGNOSTIC MARKER OF PROSTATE CANCER RECURRENCE AFTER RADICAL PROSTATECTOMY

PURPOSE We assessed the cellular proliferation of clinically localized prostate cancer by immunohistochemistry using the monoclonal antibody MIB to Ki-67 antigen in an attempt to identify associations between proliferative indexes and disease progression following radical prostatectomy. MATERIALS AND METHODS Ki-67 proliferative antigen was evaluated using MIB 1 monoclonal antibody in archival paraffin embedded radical prostatectomy specimens from 180 patients followed for 1 to 9 years (mean 4.4). The percentage of tumor nuclei expressing Ki-67 antigen was measured and assigned and MIB 1 score (none or rare--negative, 1+--low score and 2 to 4+--high score) and analyzed for prostate specific antigen, stage, age, race, grade and serological recurrence postoperatively. RESULTS There was a significant association between MIB 1 score and nuclear grade (p < 0.001), Gleason score (p < 0.001) and pathological stage (p = 0.01). Patients with a high MIB 1 score had earlier progression and a lower 5-year recurrence-free survival rate (44%) than those with negative MIB 1 scores (71%, p < 0.001). In multivariate Cox regression analysis with backward elimination, pathological stage (p < 0.01), pretreatment prostate specific antigen (p = 0.04) and MIB 1 score (p = 0.05) were statistically significant predictors of disease-free survival, and patients with a high MIB 1 score were 3.1 times as likely to have recurrence as those with a negative score. Controlling for stage, patients with organ confined disease and a high MIB 1 score had a lower 5-year disease-free survival rate (68%) than those with a low MIB 1 score (95%, p < 0.01). CONCLUSIONS Proliferative activity as measured by the Ki-67 proliferative antigen, MIB 1, appears to be a prognostic marker of recurrent prostate cancer after radical prostatectomy.

PREDICTING RISK OF PROSTATE SPECIFIC ANTIGEN RECURRENCE AFTER RADICAL PROSTATECTOMY WITH THE CENTER FOR PROSTATE DISEASE RESEARCH AND CANCER OF THE PROSTATE STRATEGIC UROLOGIC RESEARCH ENDEAVOR DATABASES

PURPOSE Biostatistical models to predict stage or outcome in patients with clinically localized prostate cancer with pretreatment prostate specific antigen (PSA), Gleason sum on biopsy or prostatectomy specimen, clinical or pathological stage and other variables, including ethnicity, have been developed. However, to date models have relied on small subsets from academic centers or military populations that may not be representative. Our study validates and updates a model published previously with the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE, UCSF, Urology Outcomes Research Group and TAP Pharmaceutical Products, Inc.), a large multicenter, community based prostate cancer database and Center for Prostate Disease Research (CPDR), a large military database. MATERIALS AND METHODS We validated a biostatistical model that includes pretreatment PSA, highest Gleason sum on prostatectomy specimen, prostatectomy organ confinement status and ethnicity, including white and black patients. We then revised it with the Cox regression analysis of the combined 503 PSA era surgical cases from the CPDR prospective cancer database and 1,012 from the CaPSURE prostate cancer outcomes database. RESULTS The original equation with 3 risk groups stratified CaPSURE cases into distinct categories with 7-year disease-free survival rates of 72%, 42.1% and 27.6% for low, intermediate and high risk men, respectively. Parameter estimates obtained from a Cox regression analysis provided a revised model equation that calculated the relative risk of recurrence as: exponent (exp)[(0.54 x Race) + (0.05 x sigmoidal transformation of PSA [PSA(ST)]) + (0.23 x Postop Gleason) + (0.69 x Pathologic stage). The relative risk of recurrence, as calculated by the aforementioned equation, was used to stratify the cases into 4 risk groups. Very low-4.7 or less, low-4.7 to 7.1, high-7.1 to 16.7 and very high-greater than 16.7, and patients at risk had 7-year disease-free survival rates of 85.4%, 66.0%, 50.6% and 21.3%, respectively. CONCLUSIONS With a broad cohort of community based, academic and military cases, we developed an equation that stratifies men into 4 discrete risk groups of recurrence after radical prostatectomy and confirmed use of a prior 3 risk group model. Although the variables of ethnicity, pretreatment PSA, highest Gleason sum on prostatectomy specimen and organ confinement status on surgical pathology upon which the model is based are easily obtained, more refined modeling with additional variables are needed to improve prediction of intermediate risk in individuals.

Protein expression of p53, bcl-2, and KI-67 (MIB-1) as prognostic biomarkers in patients with surgically treated, clinically localized prostate cancer

BACKGROUND Protein expression in the primary tumor of the tumor suppressor gene p53 and the proto-oncogene bcl-2 have been shown to be prognostic biomarkers of cancer recurrence after radical prostatectomy in patients with clinically localized prostate cancer. Cancer cell proliferation as measured by immunohistochemical markers such as the MIB-1 antibody for Ki-67 has recently been suggested to be of prognostic value in prostate cancer. The goal of this study was to determine the clinical use of p53, Ki-67 (MIB-1), and bcl-2 immunohistochemical protein expression in the primary tumor as combined predictors of disease progression after radical prostatectomy (RP). METHODS Protein expressions of p53, Ki-67, and bcl-2 were evaluated in archival paraffin-embedded RP specimens from 162 patients monitored from 1 to 10 years (mean, 4.5 years) and correlated to stage, grade, race, and serologic (prostate-specific antigen) recurrence after operation. RESULTS Expression was detected in 112 (69.1%), 44 (27.2%), and 62 (38.3%) of 162 patients for p53 (1+ or greater), bcl-2 (1+ or greater), and Ki-67 (2+ or greater), respectively. Biomarker expressions were not correlated to age and race; however, all increased with increasing stage and grade. The degree of expression by percentage of malignant cells staining correlated to recurrence for p53 and Ki-67 but not for bcl-2. All three markers were correlated to raw and Kaplan-Meier recurrence by means of univariate analysis with recurrence estimates at 6 years of 60.7% versus 24.2%, 84.2% versus 38.6%, and 72.4% versus 30.6% comparing positive versus negative expression of p53, bcl-2, and Ki-67, respectively. p53 and bcl-2 remained as independent prognostic markers by Cox multivariate regression analysis. Although Ki-67 did not remain an independent marker, it added prognostic use in certain subsets of patients. CONCLUSIONS p53, bcl-2, and Ki-67 (MIB-1) appear to be important biomarkers to predict recurrence in patients with clinically localized prostate cancer after RP, and all three biomarkers deserve further study.

PROSTATE CANCER IN MEN AGE 50 YEARS OR YOUNGER:: A REVIEW OF THE DEPARTMENT OF DEFENSE CENTER FOR PROSTATE DISEASE RESEARCH MULTICENTER PROSTATE CANCER DATABASE

PURPOSE Prostate cancer in men age 50 years or younger traditionally has accounted for approximately 1% of those diagnosed with prostate cancer. Prior studies of prostate cancer in men of this age led many clinicians to believe that they have a less favorable outcome than older men. Most of these studies were conducted before the advent of prostate specific antigen (PSA) screening programs. We evaluated a surgically treated cohort of men age 50 years or younger to determine whether disease recurred more frequently among them than in those 51 to 69 years old in the PSA era. MATERIALS AND METHODS We reviewed the medical records of 477 men who underwent radical prostatectomy between 1988 and 1997. Age, ethnicity, preoperative PSA, clinical and pathological stage, margin and seminal vesicle involvement, and recurrence were compared between 79 men age 50 years or younger (study group) and 398, 51 to 69 years old (comparison group). Disease-free survival rates were compared using Kaplan-Meier and Cox regression techniques. RESULTS There were 6 (7.6%) recurrences in the study group (79) and 107 (26.9%) in the comparison group (398). The disease-free survival curves were significantly different (log-rank p = 0.010). Age remained a significant prognostic factor (Wald p = 0.033) in multivariate Cox regression analyses that controlled for race, clinical and pathological stage, and pretreatment PSA. Similar results were found when the comparison group was limited to 116 patients 51 to 59 years old (log-rank p = 0.034, Wald p = 0.069). CONCLUSIONS These data suggest that patients in the PSA era who underwent radical prostatectomy and were age 50 years or younger have a more favorable disease-free outcome compared to older men.

P53 AND BCL-2 IMMUNOHISTOCHEMISTRY IN PRETREATMENT PROSTATE NEEDLE BIOPSIES TO PREDICT RECURRENCE OF PROSTATE CANCER AFTER RADICAL PROSTATECTOMY

PURPOSE Immunohistochemical staining of radical prostatectomy specimens for p53 and bcl-2 proteins has been shown to correlate with prostate specific antigen (PSA) recurrence in a series of patients at our institution. We analyzed the relationship between staining of diagnostic prostate needle biopsies for p53 and bcl-2, and PSA recurrence. MATERIALS AND METHODS From 1986 to 1993, 335 radical prostatectomies were performed at our hospital. Of the prostatectomy specimens 199 had been evaluated for p53 and bcl-2 proteins in a prior series. Of 139 patients with biopsy material available for analysis 129 had enough for evaluation of 1 or both markers. Prospectively obtained clinical followup data were available, with a mean followup of 6 years. Commercially available antibodies were used for immunohistochemical staining. RESULTS The overall PSA recurrence rate was 37.6% for 199 radical prostatectomy cases and 37.9% for 129 with biopsy immunohistochemical staining. Staining of prostatectomies correlated well with PSA recurrence for p53 (p = 0.004) and bcl-2 (p = 0.001). However, biopsy staining did not correlate with prostatectomy staining or PSA recurrence for either marker. CONCLUSIONS The p53 and bcl-2 biomarkers appear to be important to predict recurrence of prostate cancer when prostatectomy specimens are analyzed but this usefulness is not apparent with immunohistochemical staining of prostate biopsies. This difference may reflect sampling error and/or the heterogeneous nature of prostate cancers, and deserves further study.

Three-dimensional computer-simulated prostate models: lateral prostate biopsies increase the detection rate of prostate cancer.

OBJECTIVES Urologists routinely use the systematic sextant needle biopsy technique to detect prostate cancer. However, recent evidence suggests that this technique has a significant sampling error. We developed a novel three-dimensional (3D) computer-assisted prostate biopsy simulator based on whole-mounted step-sectioned radical prostatectomy specimens to compare the diagnostic accuracy of various prostate needle biopsy protocols. METHODS We obtained digital images of 201 step-sectioned whole-mounted radical prostatectomy specimens. 3D computer simulation software was developed to accurately depict the anatomy of the prostate and all individual tumor foci. Additional peripheral devices were incorporated into the system to perform interactive prostate biopsies. We obtained 18 biopsies of each prostate model to determine the detection rates of various biopsy protocols. RESULTS The 10- and 12-pattern biopsy protocols had a 99.0% detection rate; the traditional sextant biopsy protocol rate was only 72.6%. The 5-region biopsy protocol had a 90.5% detection rate and the 14-pattern, which includes all the biopsies used in the patterns above, only added 1 additional positive case (99.5%). Transitional zone and seminal vesicle biopsies did not result in a significantly increased detection rate when added to the patterns above. Only one positive model was obtained when the transitional zone biopsies were added. The lateral sextant pattern had a detection rate of 95.5%, and the 4-pattern lateral biopsy protocol had a 93.5% detection rate. CONCLUSIONS Our results suggest that all the biopsy protocols that use laterally placed biopsies based on the 5-region anatomic model are superior to the routinely used sextant prostate biopsy pattern. Lateral biopsies in the mid and apical zones of the gland are the most important.

BIOSTATISTICAL MODELING USING TRADITIONAL PREOPERATIVE AND PATHOLOGICAL PROGNOSTIC VARIABLES IN THE SELECTION OF MEN AT HIGH RISK FOR DISEASE RECURRENCE AFTER RADICAL PROSTATECTOMY FOR PROSTATE CANCER

PURPOSE Biostatistical models predicting the risk of recurrence after radical prostatectomy for clinically localized prostate cancer are necessary. Identifying these high risk patients shortly after surgery, while tumor burden is minimal, makes them candidates for possible adjuvant therapy and/or investigational phase II clinical trials. This study builds on previously proposed models that predict the likelihood of early recurrence after radical prostatectomy. MATERIALS AND METHODS In our analysis we evaluate age, race, prostatic acid phosphatase and nuclear grade with the established prognostic variables of pretreatment prostate specific antigen, postoperative Gleason sum and pathological stage. RESULTS After multivariable Cox regression analysis using only statistically significant variables that predicted recurrence we developed an equation that calculates the relative risk of recurrence (Rr) as: Rr = exp[(0.51 x Race) + (0.12 x PSAST) + (0.25 x Postop Gleason sum) + (0.89 x Organ Conf.). These cases are then categorized into 3 distinct risk groups of relative risk of recurrence of low (< 10.0), intermediate (10.0 to 30.0) and high (> 30.0). Kaplan-Meier survival analysis of these 3 risk groups reveals that each category has significantly different risks of recurrence (p < 0.05). This model is validated with an independent cohort of radical prostatectomy patients treated at a different medical center by multiple primary surgeons. CONCLUSIONS This model suggests that race, preoperative prostate specific antigen, postoperative Gleason sum and pathological stage are important independent prognosticators of recurrence after radical prostatectomy for clinically localized prostate cancer. Race should be considered in future models that attempt to predict the likelihood of recurrence after surgery.

Biostatistical modeling using traditional variables and genetic biomarkers for predicting the risk of prostate carcinoma recurrence after radical prostatectomy

Approximately 50‐60% of patients treated with radical prostatectomy for clinically localized prostate carcinoma are found to have microscopic disease that is not organ‐confined, and a significant portion of these patients will relapse. Multiple studies have attempted to identify these high risk patients by evaluating many potential prognostic variables. These studies, however, have not included the more recent molecular biomarkers found to be independent predictors of disease recurrence.