Serum triiodothyronine is increased in men with prostate cancer and benign prostatic hyperplasia

Triiodothyronine is the active thyroid hormone produced by de-iodination of the precursor thyroxine that is necessary for the growth of prostate cancer cells in vitro. For this reason we assessed serum triiodothyronine levels in men with localized prostate cancer, benign prostatic hyperplasia (BPH) and controls in the same age group.

Materials and Methods

We studied 161 men referred for treatment of localized prostate cancer, 20 with BPH and 27 controls. Serum triiodothyronine was determined by fluorometric immunoassay and a commercially available instrument.

Results

Men with BPH had the highest triiodothyronine levels, followed by those with prostate cancer. Controls had the lowest triiodothyronine. There was significant triiodothyronine variation among the 3 groups (1-way ANOVA p = 0.001). In men with BPH serum triiodothyronine was significantly different from that in men with prostate cancer (Tukey’s multiple range test p = 0.013). Men with prostate cancer had serum triiodothyronine that was significantly different than in controls (p = 0.048), as did those with BPH (p <0.001). Because serum triiodothyronine normally decreases with age, we performed multivariate analysis of variance controlling for age. There was a significant decrease in serum triiodothyronine with age (p = 0.020). There was also significant triiodothyronine variation among the 3 subject groups independent of age (p <0.001).

Conclusions

Urologists are actively seeking additional biomarkers of prostate cancer aggressiveness. Many prostate cancers are quite indolent and may never cause a problem but it is impossible to identify such tumors with certainty. With more and better biomarkers many older men with prostate cancer may be spared the rigors of radiation therapy and/or surgery as well as complications. Triiodothyronine may be such a biomarker. Also, new prostate cancer and BPH therapies may be directed toward inhibiting the mitogenic effects of triiodothyronine.     

Clinical usefulness of serum antip53 antibodies for prostate cancer detection: a comparative study with prostate specific antigen parameters

PURPOSE: Alterations in the p53 tumor suppressor gene located on human chromosome 17p13.1 are currently the most common genetic abnormalities associated with many different types of human malignancies. Recently serum p53 antibodies (p53-Abs) have been detected in the serum of patients with various cancers. To evaluate the clinical usefulness of serum p53-Abs we compared p53-Abs with prostate specific antigen (PSA) parameters in patients with benign prostatic disease (BPD) and prostate cancer. MATERIALS AND METHODS: Serum samples were obtained from 50 patients with BPD and 103 with histologically diagnosed prostate cancer, including T1c/2N0M0 in 50, T3N0M0 in 29 and TxNxM1 in 24. The serum p53-Abs titer was assessed by enzyme-linked immunoabsorbent assay using a MESCUP Kit II (Medical and Biological Laboratories Co., Ltd., Nagoya, Japan) antip53 test. Free and total PSA was measured using an Architect (Dinabott, Chicago, Illinois) PSA kit. The clinical values of p53-Abs were compared with total PSA, PSA density (PSAD), PSA density of the transition zone (PSATZD) and the free-to-total PSA ratio using ROC curves. RESULTS: All patients with prostate cancer had significantly higher total PSA, PSAD, PSATZD and p53-Abs than patients with BPD. While total PSA, PSAD, PSATZD and free-to-total PSA ratios were associated with stage progression, serum p53-Abs were not related to clinical stage. The Gleason sum 5 or less group had a higher level of p53-Abs than higher Gleason sum groups. Patients with T1c cancer had significantly higher p53-Abs than those with BPD. According to ROC curve analysis to distinguish prostate cancer from BPD the p53-Abs titer had the greatest AUC in the overall patient population and in patients without digital rectal examination findings. CONCLUSIONS: These results suggest that p53-Abs might be helpful in the clinical decision to perform prostate biopsy. In the current study the serum p53-Abs titer had the most useful validity in discriminating between prostate cancer and BPD in the overall patient population and in patients with normal digital rectal examination.     

Quantitative GSTP1 methylation clearly distinguishes benign prostatic tissue and limited prostate adenocarcinoma

PURPOSE: Hypermethylation of the glutathione S-transferase gene (GSTP1) is the most common (greater than 90%) reported epigenetic alteration in prostate cancer. It occurs early in cancer progression and it is a promising marker for detecting organ confined disease. To evaluate its use as a diagnostic tool for cancer we used quantitative GSTP1 methylation to test for the presence of cancer in 45 prostate needle biopsy samples. MATERIALS AND METHODS: Paraffin tissue samples from 45 patients with minute foci of intermediate grade prostatic adenocarcinoma or benign disease on needle biopsy were tested for GSTP1 hypermethylation using quantitative fluorogenic real-time methylation specific polymerase chain reaction. This assay was performed in blinded fashion without previous knowledge of the histopathological diagnosis. RESULTS: DNA from 29 of the 45 paraffin samples was amenable to polymerase chain reaction amplification. In these 29 samples GSTP1 methylation was detected in 11 of 15 cases of limited cancer and in 0 of 14 of benign disease (2-sided Fisher's exact test, p <0.0001). Thus, this assay had 73% sensitivity, 100% specificity, 100% positive and 78% negative predictive values. CONCLUSIONS: Quantitation of GSTP1 hypermethylation accurately detects the presence of cancer even in small, limited tissue samples. It represents a promising diagnostic marker that could be used as an adjunct to tissue biopsy as part of prostate cancer screening.     

Her-2/neu expression in prostate cancer: high level of expression associated with exposure to hormone therapy and androgen independent disease

PURPOSE: HER-2/neu is a proto-oncogene that encodes a transmembrane receptor belonging to the family of epidermal growth factor receptors. Increasing evidences indicates that HER-2/neu may contribute to hormone resistance in prostate cancer. We investigated HER-2/neu expression in primary, androgen dependent and advanced androgen independent prostate cancer, and its potential value as a marker of disease progression. MATERIALS AND METHODS: Immunohistochemical testing was performed to investigate HER-2/neu expression in 81 patients with prostate cancer, including 31 with pathological stage C disease treated with radical prostatectomy without preoperative androgen ablation therapy (untreated group), 30 with pathological stage C disease treated before surgery with androgen ablation therapy (treated group) and 20 with advanced androgen independent prostate cancer (androgen independent group). Tumors were classified based on the percent of tumor cells showing HER-2/neu membrane immunoreactivity as low (50% or less) and high (50% or greater) expression. RESULTS: Of the 31 prostate tumors in the untreated group 9 (29%) showed high HER-2/neu expression versus 15 of 30 (50%) in the treated and 17 of 20 (85%) in the androgen independent groups. The difference in HER-2/neu expression was significant in the untreated and androgen independent (p <0.001) and in the treated and androgen independent (p = 0.016) groups. There was a significant association of Gleason score with HER-2/neu expression in the untreated group (p = 0.038) but not in the treated group. No association was found of tumor substage with HER-2/neu expression. In the untreated group patients with tumors showing high HER-2/neu expression had a decreased survival rate (p = 0.044). CONCLUSIONS: High HER-2/neu expression is highly associated with exposure to hormone therapy and androgen independence. It may contribute to androgen independence in prostate cancer and identify patients with prostate cancer more likely to have disease progression, particularly those not exposed to previous hormone therapy.     

Strategies combining total and percent free prostate specific antigen for detecting prostate cancer: a prospective evaluation

PURPOSE: Determining total prostate specific antigen (PSA) in plasma can often identify men who are subsequently diagnosed with prostate cancer. However, excess false-positives create large financial and psychological burdens in prostate cancer screening. The percent free PSA is lower when prostate cancer is present, although to our knowledge no large prospective analyses to date have evaluated whether adding testing for free PSA may decrease false-positives, while maintaining or perhaps improving the detection of potentially curable tumors. MATERIALS AND METHODS: We measured total and percent free PSA in banked plasma samples from the Physicians' Health Study in 430 men who were later diagnosed with prostate cancer and 1,642 age matched controls who were not diagnosed with prostate cancer during a 12-year observation period. We calculated the number of cancers detected and the number of false-positives for various strategies of combined free and total PSA levels, and compared them to the use of total PSA alone. RESULTS: Total PSA with a cutoff of 4 ng./ml. detected 149 cases but also yielded 144 false-positives. A strategy that applied percent free PSA to men with total PSA 4 to 10 ng./ml. detected 133 to 140 cancers and decreased false-positives to 83 of 117 depending on the percent free PSA cutoff used. As the percent free PSA cutoff was lowered from 25% to 20%, additional undetected cancers did not occur until year 9 of followup and the 20% cutoff decreased false-positives and, thus, potential negative biopsies, by 42%. Percent free PSA was superior to total PSA for discriminating cases from controls within the total PSA range of 4 to 10 or 3 to 10 ng./ml. (p <0.0001). A percent free PSA cutoff of 20% in men with total PSA 3 to 10 ng./ml. detected 10% more cancers with 12.5% fewer false-positives than the conventional strategy of total PSA greater than 4 ng./ml. Cancers missed by combined total and free PSA testing had longer intervals between blood sampling and diagnosis, and a greater likelihood of later diagnosis at an organ confined stage. CONCLUSIONS: These results demonstrate that in a prospective setting with long-term followup free PSA strategies can be identified that decrease unnecessary biopsies, while preserving or even improving cancer detection. Thus, total and free PSA can be combined without the need to weigh subjectively the trade-offs and relative costs of false-negative and false-positive results.     

Neuroendocrine expression in node positive prostate cancer: correlation with systemic progression and patient survival

PURPOSE: Neuroendocrine cells are ubiquitous but uncommon in benign and neoplastic prostate epithelium, and they are considered important for regulating cell growth and differentiation. The predictive value of neuroendocrine immunoreactivity for patient outcome after radical prostatectomy is uncertain. In this study we determined the expression of 2 important neuroendocrine markers, chromogranin and serotonin, in benign epithelium, primary prostate cancer and lymph node metastases, and correlated cellular expression with patient outcome. MATERIALS AND METHODS: We studied 196 patients with node positive prostate adenocarcinoma who underwent bilateral pelvic lymphadenectomy and radical prostatectomy at Mayo Clinic between 1987 and 1992. Mean followup was 6.8 years (range 0.3 to 11). The cellular expression of chromogranin and serotonin in matched samples of benign tissue, primary prostate cancer and lymph node metastases from the same patients was evaluated by immunohistochemical staining using commercially available monoclonal antibodies. Results were correlated with patient age, pathological findings (Gleason score, DNA ploidy and cancer volume) and patient outcome, including clinical progression, cancer specific and all cause survival. RESULTS: Chromogranin immunoreactivity was greater in benign prostatic epithelium and primary cancer cases (99% each) than in those of lymph node metastases (37.5%) (pairwise comparisons with metastases p <0.001). The mean incidence of immunoreactive cells in benign epithelium, primary cancer and metastases was 6% (median 5%), 6% (median 3%) and 2.2% (median 0%), respectively. Serotonin immunoreactivity was greatest in benign prostate epithelium cases (98.5%) with less in primary cancer (95%) and lymph node metastases (21.5%) (pairwise comparisons p <0.001). The mean incidence of immunoreactive cells in benign epithelium, primary cancer and metastases was 2.2% (median 3%), 2.4% (median 2%) and 0.4% (median 0%), respectively. Chromogranin expression was invariably greater than that of serotonin for all 3 diagnostic categories (p <0.0001). There was a marginally significant positive trend in the level of chromogranin expression in benign prostatic epithelium and systemic progression (p = 0.05) but no significant association with cancer specific or all cause survival (p >0.1). No significant association was observed of chromogranin expression in primary cancer or lymph node metastases with any patient outcomes (p >0.1). There was a significant association of the level of serotonin expression in benign prostatic epithelium with cancer specific survival (p = 0.03) but no significant association with systemic progression or all cause survival (p > 0.1). There were positive trends in the association of serotonin immunoreactivity in primary cancer with systemic progression (p = 0.09) and cancer specific survival (p = 0.05) but not with all cause survival (p >0.1). No significant association was observed of serotonin expression in lymph node metastases with any patient outcomes (p >0.1). CONCLUSIONS: Benign prostatic epithelium and primary prostate cancer express a significantly greater number of chromogranin and serotonin immunoreactive cells than lymph node metastases, suggesting that decreased expression of neuroendocrine markers is involved in cancer progression. However, neuroendocrine expression was marginally useful for predicting the outcome in patients with node positive prostate cancer treated with radical prostatectomy.     

Prostate stem cell antigen expression is associated with gleason score, seminal vesicle invasion and capsular invasion in prostate cancer

PURPOSE: Few successful therapeutic options exist for men who present with metastatic prostate cancer (CaP) or for the 30% with recurrence. The development and characterization of molecular markers are vital to the development of prognostic and therapeutic modalities in CaP. We investigated the expression and potential clinical usefulness of prostate stem cell antigen (PSCA) in CaP using tissue microarrays. MATERIALS AND METHODS: Immunohistochemical analysis using a PSCA monoclonal antibody was performed on tissue microarrays constructed from paraffin embedded specimens from 246 patients who underwent radical retropubic prostatectomy. PSCA staining was correlated with established prognostic factors, such as Gleason score, prostate specific antigen (PSA), and seminal vesicle invasion. In addition, recurrence-free survival was analyzed. RESULTS: A high PSCA intensity of 3 was associated with adverse prognostic features, such as Gleason score 7 and above (p = 0.001), seminal vesicle invasion (p = 0.005) and capsular involvement (p = 0.033). On univariate analysis tumors with a PSCA intensity of 3 carried an increased risk of PSA recurrence (p = 0.031, HR 1.77, 95% CI 1.05 to 2.96). However, after adjusting for these variables a PSCA intensity of 3 was no longer an independent predictor of PSA recurrence. CONCLUSIONS: We found that high PSCA intensity is significantly associated with adverse prognostic features such as high Gleason score and extra-organ disease. The results of this study suggest that PSCA is a promising tumor marker for the selection of patients at high risk but additional studies are necessary to assess the usefulness of PSCA in patient biopsies.     

Pan-cadherin as a high level phenotypic biomarker for prostate cancer

PURPOSE: High level phenotypic biomarkers such as cadherins are needed to identify individuals at risk for biologically active prostate cancer and determine which individuals with elevated prostate specific antigen or a prostate nodule are candidates for re-biopsy. Cadherins are a high level phenotypic biomarker associated with decreased cell adhesion, which is a cardinal event in carcinogenesis. Recently we reported that G-actin and tissue transglutaminase type II are potential biomarkers for prostate cancer. In this study we present cadherins as a potential third component of the biomarker profile. MATERIALS AND METHODS: Prostate tissues from 38 patients with cancer and 33 controls with a 10-year prostate cancer-free followup were labeled for pan-cadherin by immunohistochemical testing. Immunoreactivity was quantified using a Pathology Workstation (Autocyte Inc., Elon College, North Carolina). RESULTS: Visually benign glands from controls generally expressed cadherins, whereas regions of adenocarcinoma were generally negative. On quantitative immunohistochemistry 36 of 38 prostate cancer cases expressed a lower mean percent area positive for cadherin than the 19 benign prostatic hyperplasia and 14 prostatitis cases (odds ratio 978, 95% confidence interval 45 to 21,140, relative risk 18, 95% confidence interval 5 to 67, p <0.0001). Receiver operating characteristics analysis of immunohistochemical testing data showed that an optimal threshold of 7 produced 95% sensitivity and 100% specificity. CONCLUSIONS: Quantitative down-regulation of cadherin expression in prostate cancer tissue sections is a strong biomarker for prostate cancer. Analysis of cadherin and other high level phenotypic biomarker expression in the premalignant field may provide additional diagnostic information to decide which patients need re-biopsy, more intensive monitoring or chemoprevention.     

Early identification of individuals with prostate cancer in negative biopsies

PURPOSE: The use of prostate specific antigen (PSA) to screen individuals for prostate cancer has changed the management of the disease, permitting early detection in men. Repeat biopsies for persistently increased PSA are not uncommon with prostate cancer never being detected in many of the men. The novel prostate cancer marker, EPCA, is expressed throughout the prostate of individuals with prostate cancer but not in those without the disease. MATERIALS AND METHODS: The expression of ECPA was studied to identify those men with initially negative biopsies who were ultimately found to have prostate cancer. Negative biopsies, subsequent biopsies and prostatectomy specimens were evaluated by quantitative immunohistochemistry. RESULTS: The EPCA staining intensity in the samples analyzed from the patient cohort with prostate carcinoma were significantly different compared to controls (p <0.001) with almost no overlap in staining results. Sensitivity of the EPCA immunohistochemistry is 84% and specificity is 85%. CONCLUSIONS: An immunohistochemical test for EPCA could serve as an adjunct to the current diagnostic approach to a patient who undergoes prostate needle biopsy, and could identify individuals with prostate cancer as much as 5 or more years earlier than the current diagnostic approach and algorithms. In addition, this test might also help limit the numbers of biopsies performed as part of subsequent routine evaluation for increased PSA.     

Tissue microarray analysis of hMSH2 expression predicts outcome in men with prostate cancer

PURPOSE: Mismatch repair genes are responsible for the coordinated correction of misincorporated nucleotides formed during DNA replication. Mismatch repair expression is altered in a subset of prostate cancers (PCs) and a recent study suggested that time to biochemical recurrence following prostatectomy correlated with the degree of hMSH2 immunohistochemical staining. We compared hMSH2 expression and survival in clinically organ confined PC. MATERIALS AND METHODS: A prostate tissue microarray was constructed using 243 specimens from patients who underwent radical prostatectomy with extended lymph node dissection for clinically organ confined PC with up to 12 years of followup. Immunohistochemistry was performed with anti-human MSH2 monoclonal antibody. Three independent observers evaluated hMSH2 expression on a scale of 0 to 4. Low expression was defined as a score of less than 2 and high expression was defined as a score of 2 or higher. Statistical analysis used the Fisher exact test, and Goodman and Kruskal gamma coefficient. RESULTS: Higher Gleason score significantly correlated with higher hMSH2 expression (p < 0.0002). Low hMSH2 expression correlated with increased overall, disease-free and biochemical disease-free survival (all p < 0.01). Analysis comparing low vs high hMSH2 expression was significant with respect to overall (p = 0.0004), disease-free (p = 0.005) and biochemical disease-free (p = 0.0177) survival. CONCLUSIONS: hMSH2 is differentially expressed in malignant prostate tissue and hMSH2 immunohistochemical staining intensity correlates with Gleason score, overall and disease-free survival. Taken together our results suggest that hMSH2 expression may be a useful prognostic biomarker for outcome in men with clinically organ confined PC.     

Determination of prognosis in patients with prostate cancer treated with radical prostatectomy: prognostic value of CD44v6 score

PURPOSE: A third of the patients treated with radical prostatectomy experience progression even when tumors are confined pathologically to the prostate. CD44 may be a promising prognostic marker for determining malignant potential. However, there has not been a standard scoring system because of its heterogeneous staining pattern. Thus, we developed an objective scoring system to evaluate reliably CD44v6 (Bender Medsystems, Vienna, Austria) as a prognostic marker for prostate cancer. MATERIALS AND METHODS: A total of 22 patients with metastatic stage pT3bN0M0 or any pTN1M0 disease and 18 with nonmetastatic disease less than stage pT3bN0M0 were selected from a well examined group of 114 who underwent radical retropubic prostatectomy. Mean followup was 33 months (range 4 to 78). A combined CD44v6 score was determined by adding the scores of the primary and secondary areas. CD44v6 expression in terms of the CD44v6 score in primary and metastatic tissues was examined. The relationships of CD44v6 expression with pathological stage, progression and PSA-free survival were also evaluated. The prognostic value of the CD44v6 score for progression was analyzed by multivariate analysis. RESULTS: Progression in the metastatic group was significantly higher than in the nonmetastatic group (p <0.0001). CD44v6 expression of the primary tumors differed significantly in the 2 groups (p = 0.014). The CD44v6 score in primary tumor tissues inversely correlated with pathological stage (p = 0.004) and progression (p = 0.035), and positively correlated with PSA-free survival (p = 0.041). Furthermore, patients in the nonmetastatic group with a CD44v6 score of greater than 75 (cutoff value) had a significantly better prognosis (log rank test p = 0.0022), while those with a CD44v6 score of less than 75 had a prognosis similar to those in the metastatic group. On multivariate analysis pathological stage and surgical margin positivity were independent factors for progression but the CD44v6 score was not. CONCLUSIONS: According to our results the suggested CD44v6 score system is useful. A CD44v6 score of less than 75 may be a predictor of poor prognosis in the nonmetastatic group and this property may have potential application for planning adjuvant therapy.     

Insulin-like growth factor-1 and insulin-like growth factor binding protein-3 for prostate cancer detection in patients undergoing prostate biopsy

PURPOSE: Laboratory and epidemiological studies suggest that high circulating insulin-like growth factor (IGF)-1 and low IGF binding protein-3 are associated with increased prostate cancer risk. However, the usefulness of serum IGF-1 or IGF binding protein-3 for predicting pathology results in men undergoing prostate biopsy is unclear. We examined the relationships of serum IGF-1, IGF binding protein-3 and the results of prostate biopsy. MATERIALS AND METHODS: A total of 652 consecutive patients with elevated serum prostate specific antigen (PSA) or abnormal digital rectal examination who were referred for transrectal ultrasound sextant prostate needle biopsy underwent blood sampling before biopsy. PSA, free PSA, IGF-1 and IGF binding protein-3 were measured. There were 244 men (37.4%) with cancer and 408 controls with benign conditions. RESULTS: Mean IGF-1 plus or minus SD in the cancer and control groups was 176.1 +/- 58.3 and 178.7 +/- 54.7 ng./ml., respectively (p = 0.57). Mean IGF binding protein-3 in the cancer and control groups was 2,724 +/- 647 and 2,673 +/- 589 ng./ml., respectively (p = 0.3). Adjustment for age and PSA showed significantly lower IGF-1 in cancer cases, while IGF binding protein-3 was not significant. ROC values were significantly higher for free-to-total PSA and PSA than for crude and age adjusted IGF-1 and IGF binding protein-3. CONCLUSIONS: Our data indicate that serum IGF-1 or IGF binding protein-3 does not predict the results of prostate biopsy in men with elevated PSA or abnormal digital rectal examination. This finding implies that while there is evidence that the IGF-1 level is a risk factor for prostate cancer, neither IGF-1 nor IGF binding protein-3 can be used as a tumor marker for this disease.     

Detection of prostate cancer using serum proteomics pattern in a histologically confirmed population

PURPOSE: We retrospectively identified a panel of serum proteins that can discriminate between men with prostate cancer (clinically organ confined) and men with benign prostate disease. MATERIALS AND METHODS: A contemporary set of 345 men who had an archival serum sample available were included in this study. The cancer group consisted of 246 men who underwent radical prostatectomy at the Johns Hopkins Hospital between March 1999 and April 2001. The noncancer group included 99 men with no histological evidence of prostate cancer on biopsy between April 1997 and April 2001 at the same institution. Serum proteomics mass spectra of these patients were generated using ProteinChip arrays and a ProteinChip Biomarker System II surface enhanced laser desorption/ionization time of flight mass spectrometer (Ciphergen Biosystems, Inc., Fremont, California). The cases and controls were randomly split into training and testing groups by a stratified sampling procedure. A combination of bioinformatics tools including ProPeak (3Z Informatics, Charleston, South Carolina) was used to reveal the optimal panel of biomarkers for maximum separation of the prostate cancer and the benign prostate disease cohorts. RESULTS: A panel of 3 proteins (PC-1, PC-2 and PC-3) was selected using the training data. Performance of each of the protein markers and a linear regression derived composite index (PC-com3) were evaluated on the testing data. The area under the curve for prostate specific antigen (PSA), PC-1, PC-2, PC-3 and PC-com3 was 0.542, 0.585, 0.600, 0.636 and 0.643, respectively. Improvement of PC-com3 compared to PSA is observed at specificity range 30% to 80%. At a selected specificity of 45% the sensitivity of PC-com3 is 76%, significantly better than the PSA sensitivity of 57% (p <0.0001). CONCLUSIONS: Serum proteomics patterns may potentially aid in the early detection of prostate cancer.     

Conference report and review: current status of biomarkers potentially associated with prostate cancer outcomes

PURPOSE: The use of prostate specific antigen screening to diagnose and monitor prostate cancer is associated with well-known shortcomings. A 2-day Prostate Cancer Biomarker Conference was convened to identify promising areas of research and focus efforts on the most critical needs. MATERIALS AND METHODS: The conference provided a forum for the presentation and discussion of ongoing prostate cancer biomarker research. This meeting also sought to identify a range of critical issues in the development and validation of biomarkers, foster research collaboration between groups representing government, academic and industry initiatives, and coordinate efforts with planned and ongoing clinical trials. RESULTS: Taken collectively the conference presentations offered various new technologies for biomarker discovery and pathological assessment of clinical disease as well as the promise of biomarkers for improving prostate cancer diagnosis and treatment decisions. However, research efforts focused on biomarker validation and implementation clearly lag behind those directed toward initial biomarker discovery. It is apparent that guidelines are desperately needed to ensure the consistency of sample collection across institutions. CONCLUSIONS: Several ongoing and planned adjuvant prostate cancer trials will provide a tremendous opportunity for biological sample collection along with the potential to validate many biomarkers. Practicing urologists have an opportunity to have a critical role in the successful accrual of patients into these trials.     

Comparison of preoperative prostate specific antigen density and prostate specific antigen for predicting recurrence after radical prostatectomy: results from the search data base

PURPOSE: Prostate specific antigen (PSA) density based on the surgical weight of the radical prostatectomy specimen has previously been shown to be an independent predictor of biochemical recurrence after radical prostatectomy. We determined whether preoperative PSA density calculated using transrectal ultrasound prostate volume was a better predictor of advanced pathological findings or biochemical recurrence after radical prostatectomy relative to PSA. MATERIALS AND METHODS: We examined 552 men from the newly established Shared Equal Access Regional Cancer Hospital data base of men treated with radical prostatectomy at equal access medical centers to determine whether preoperative PSA density was a significant predictor of an adverse pathological condition or PSA recurrence after radical prostatectomy. Models using PSA density were compared with models using PSA to determine whether PSA density improved risk stratification relative to PSA. PSA density was examined as a continuous and a categorical variable using cutoffs to separate patients into groups at different risks for PSA failure. RESULTS: PSA density and PSA were significant predictors of adverse pathological findings on univariate analysis. Using PSA density in the multivariate model resulted in slightly better but statistically insignificant improvement in prediction of positive surgical margins (p = 0.134) and extracapsular extension (p = 0.771) relative to using PSA in the model. Neither PSA nor PSA density were significant independent predictors of seminal vesicle invasion. Area under the ROC curves for predicting biochemical recurrence for PSA and PSA density were not significantly different (0.589 and 0.58, respectively, p = 0.691). On separate multivariate analyses PSA density and PSA were significant independent predictors of biochemical failure. The multivariate model using PSA density provided only slight improvement in risk assessment relative to the model using PSA (index C = 0.589 and 0.581, respectively). To determine whether using PSA density as a categorical variable would result in improved prognostication we evaluated PSA density to determine the cutoff points that would provide the greatest risk stratification. PSA density cutoffs of less than 0.4, 0.4 to 1 and greater than 1 ng./ml./cc separated patients into 3 distinct groups at increasing risk for biochemical failure (p <0.001). While these cutoffs provided better risk stratification than when PSA density was examined as a continuous variable (index C = 0.684 versus 0.58), they provided only marginal improvement relative to the standard PSA cutoffs of less than 10, 10 to 20 and greater than 20 ng./ml. (index C = 0.676). CONCLUSIONS: The use of preoperative PSA density relative to PSA provided only slight improvement for predicting adverse pathological findings and biochemical recurrence after radical prostatectomy. The minimal and statistically insignificant improvement in preoperative risk assessment provided by PSA density does not justify the time and effort necessary to calculate this value.