Profiling the Urinary Microbiome in Men with Positive versus Negative Biopsies for Prostate Cancer

PURPOSE

Studies demonstrating bacterial DNA and cultivable bacteria in urine samples have challenged the clinical dogma that urine is sterile. Furthermore, studies now indicate that dysbiosis of the urinary microbiome is associated with pathological conditions. We propose that the urinary microbiome may influence chronic inflammation observed in the prostate, leading to prostate cancer development and progression. Therefore, we profiled the urinary microbiome in men with positive vs negative biopsies for prostate cancer.

MATERIALS AND METHODS

Urine was collected from men prior to biopsy for prostate cancer. DNA was extracted from urine pellet samples and subjected to bacterial 16S rDNA Illumina® sequencing and 16S rDNA quantitative polymerase chain reaction. We determined the association between bacterial species and the presence or absence of cancer, cancer grade, and type and degree of prostate inflammation.

RESULTS

Urine samples revealed diverse bacterial populations. There were no significant differences in α or β diversity and no clear hierarchical clustering of benign or cancer samples. We identified a cluster of pro-inflammatory bacteria previously implicated in urogenital infections in a subset of samples. Many species, including known uropathogens, were significantly and differentially abundant among cancer and benign samples, in low vs higher grade cancers and in relation to prostate inflammation type and degree.

CONCLUSIONS

To our knowledge we report the most comprehensive study to date of the male urinary microbiome and its relationship to prostate cancer. Our results suggest a prevalence of pro-inflammatory bacteria and uropathogens in the urinary tract of men with prostate cancer.

Clinical validation of an epigenetic assay to predict negative histopathological results in repeat prostate biopsies

PURPOSE

The DOCUMENT multicenter trial in the United States validated the performance of an epigenetic test as an independent predictor of prostate cancer risk to guide decision making for repeat biopsy. Confirming an increased negative predictive value could help avoid unnecessary repeat biopsies.

MATERIALS AND METHODS

We evaluated the archived, cancer negative prostate biopsy core tissue samples of 350 subjects from a total of 5 urological centers in the United States. All subjects underwent repeat biopsy within 24 months with a negative (controls) or positive (cases) histopathological result. Centralized blinded pathology evaluation of the 2 biopsy series was performed in all available subjects from each site. Biopsies were epigenetically profiled for GSTP1, APC and RASSF1 relative to the ACTB reference gene using quantitative methylation specific polymerase chain reaction. Predetermined analytical marker cutoffs were used to determine assay performance. Multivariate logistic regression was used to evaluate all risk factors.

RESULTS

The epigenetic assay resulted in a negative predictive value of 88% (95% CI 85-91). In multivariate models correcting for age, prostate specific antigen, digital rectal examination, first biopsy histopathological characteristics and race the test proved to be the most significant independent predictor of patient outcome (OR 2.69, 95% CI 1.60-4.51).

CONCLUSIONS

The DOCUMENT study validated that the epigenetic assay was a significant, independent predictor of prostate cancer detection in a repeat biopsy collected an average of 13 months after an initial negative result. Due to its 88% negative predictive value adding this epigenetic assay to other known risk factors may help decrease unnecessary repeat prostate biopsies.

AIM1 promoter hypermethylation as a predictor of decreased risk of recurrence following radical prostatectomy

PURPOSE

To evaluate the prognostic significance of six epigenetic biomarkers (AIM1, CDH1, KIF1A, MT1G, PAK3, and RBM6 promoter hypermethlation) in a homogeneous group of prostate cancer patients, following radical prostatectomy (RP).

PATIENTS AND METHODS

Biomarker analyses were performed retrospectively on tumors from 95 prostate cancer patients all with a Gleason score of 3 + 4 = 7 and a minimum follow-up period of 8 years. Using Quantitative Methylation Specific PCR (QMSP), we analyzed the promoter region of six genes in primary prostate tumor tissues. Time to any progression was the primary endpoint and development of metastatic disease and/or death from prostate cancer was a secondary endpoint. The association of clinicopathological and biomolecular risk factors to recurrence was performed using the Log-rank test and Cox proportional hazards model for multivariate analysis. To identify independent prognostic factors, a stepwise selection method was used.

RESULTS

At a median follow-up time of 10 years, 48 patients (50.5%) had evidence of recurrence: Biochemical/PSA relapse, metastases, or death from prostate cancer. In the final multivariate analysis for time to progression, the significant factors were: Older age, HR = 0.95 (95% CI: 0.91, 1.0) (P = 0.03), positive lymph nodes HR = 2.11 (95% CI: 1.05, 4.26) (P = 0.04), and decreased hypermethylation of AIM1 HR = 0.45 (95% CI: 0.2, 1.0) (P = 0.05).

CONCLUSIONS

Methylation status of AIM1 in the prostate cancer specimen may predict for time to recurrence in Gleason 3 + 4 = 7 patients undergoing prostatectomy. These results should be validated in a larger and unselected cohort.

Cyr61 is regulated by cAMP-dependent protein kinase with serum levels correlating with prostate cancer aggressiveness

BACKGROUND

Cysteine-rich angiogenic inducer 61 (Cyr61) is an extracellular matrix protein involved in the transduction of growth factor and hormone signaling. Previously, we demonstrated that Cyr61 was highly expressed in prostate cancer (PCa) but that the expression levels were associated with a lower risk of PCa recurrence. In the present study, we demonstrate that serum Cyr61 is a potential biomarker that correlates with PCa aggressiveness. Furthermore, we also explore the potential mechanism underlying the changes in Cyr61 expression during PCa progression.

METHODS

Cyr61 concentrations in the medium from PCa cell lines and in serum samples obtained from PCa patients were measured by sandwich ELISA. Serum Cyr61 levels were correlated with disease characteristics and the association between Cyr61 expression changes by several types of stimulation or stress and cAMP/cAMP-dependent protein kinase (PKA) pathway were examined.

RESULTS

There was a positive correlation between Cyr61 levels in cell supernatants and mRNA expression in these cell lines. Serum Cyr61 levels were significantly higher in non-organ-confined PCa patients (116.3 ± 140.2 ng/ml) than in organ-confined PCa patients (79.7 ± 56.1 ng/ml) (P = 0.031). Cyr61 expression was up-regulated in response to both lysophosphatidic acid and androgen treatments which promoted PCa cell invasion. Serum starvation and phosphoinositide-3-kinase inhibition also resulted in Cyr61 up-regulation; however, they suppressed cell proliferation. Cyr61 up-regulation was correlated with an increase in cAMP and suppressed by PKA inhibition.

CONCLUSIONS

These findings suggest that Cyr61 expression in PCa is regulated by the cAMP/PKA pathway and that circulating Cyr61 levels are a potential serum-based biomarker for characterizing PCa.

Evaluation of GSTP1 and APC methylation as indicators for repeat biopsy in a high-risk cohort of men with negative initial prostate biopsies

Study Type - Diagnostic (exploratory cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Hypermethylation of genes such as glutathione-S-transferase P1 (GSTP1) and adenomatous polyposis coli (APC) occurs with high frequency in prostate tumour tissue but is much less common in the benign prostate; however, the potential value of gene methylation biomarkers as an adjunct to biopsy histopathology has had little study. When measured in histologically benign prostate biopsy tissue, APC gene hypermethylation was found to have high negative predictive value and high sensitivity. GSTP1 hypermethylation was found to have lower performance than APC.

OBJECTIVE

To evaluate the performance of DNA methylation biomarkers in the setting of repeat biopsy in men with an initially negative prostate biopsy but a high index of suspicion for missed prostate cancer.

PATIENTS AND METHODS

We prospectively evaluated 86 men with an initial histologically negative prostate biopsy and high-risk features. All men underwent repeat 12-core ultrasonography-guided biopsy. DNA methylation of glutathione-S-transferase P1 (GSTP1) and adenomatous polyposis coli (APC) was determined using tissue from the initially negative biopsy and compared with histology of the repeat biopsy. The primary outcome was the relative negative predictive value (NPV) of APC compared with GSTP1, and its 95% confidence interval (CI).

RESULTS

On repeat biopsy, 21/86 (24%) men had prostate cancer. APC and GSTP1 methylation ratios below the threshold (predicting no cancer) produced a NPV of 0.96 and 0.80, respectively. The relative NPV was 1.2 (95% CI: 1.06-1.36), indicating APC has significantly higher NPV. Methylation ratios above the threshold yielded a sensitivity of 0.95 for APC and 0.43 for GSTP1. Combining both methylation markers produced a performance similar to that of APC alone. APC methylation patterns were consistent with a possible field effect or occurrence early in carcinogenesis.

CONCLUSIONS

APC methylation provided a very high NPV with a low percentage of false-negatives, in the first prospective study to evaluate performance of DNA methylation markers in a clinical cohort of men undergoing repeat biopsy. The potential of APC methylation to reduce unnecessary repeat biopsies warrants validation in a larger prospective cohort.

Small integrin-binding proteins as serum markers for prostate cancer detection

PURPOSE

The small integrin-binding ligand N-linked glycoprotein (SIBLING) gene family includes bone sialoprotein (BSP), dentin matrix protein 1 (DMP1), dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE), and osteopontin (OPN). Previous studies have separately reported elevated expression of BSP, OPN, or DSPP in prostate tumor paraffin sections. We hypothesized that SIBLINGs may be informative serum markers for subjects with prostate cancer.

METHODS

Expression levels of SIBLINGs in biopsies of normal tissue and tumors from prostate were determined by cDNA array and by immunohistochemical staining with monoclonal antibodies. Competitive ELISAs for measuring total BSP, DSPP, MEPE, and OPN were applied to a test group of 102 subjects with prostate cancer and 110 normal subjects and a validation group of 90 subjects.

RESULTS

BSP, DMP1, DSPP, and OPN exhibited elevated mRNA expression and protein levels in biopsies. BSP, DSPP, and OPN were elevated in serum from prostate cancer subjects, with serum DSPP exhibiting the greatest difference, yielding an area under the receiver operator characteristic curve value of 0.98. Serum BSP and OPN levels were significantly elevated only in late stages, whereas DSPP was significantly elevated at all stages. Optimal serum value cutoff points derived for BSP, OPN, and DSPP were applied as a validation test to a new group of 90 subjects and DSPP yielded a sensitivity of 90% and a specificity of 100%.

CONCLUSION

Of the SIBLING gene family members, DSPP appears to be a strong candidate for use in serum assays for prostate cancer detection.

DNA Ploidy as surrogate for biopsy gleason score for preoperative organ versus nonorgan-confined prostate cancer prediction

OBJECTIVES

Transformation of normal epithelium into cancer cells involves epigenetic and genetic changes and modifications in nuclear structure and tissue architecture. To evaluate nuclear morphometric alterations and clinicopathologic features for organ- vs nonorgan-confined prostate carcinoma (PCa) prediction.

METHODS

Of 557 prospectively enrolled patients, 370 had complete information and sufficient tumor area for all evaluated parameters (281 organ-confined and 89 nonorgan-confined PCa cases). Digital images of Feulgen DNA-stained nuclei were captured from biopsies using the AutoCyte imaging system, and the nuclear morphometric alterations were calculated. Logistic regression analysis with bootstrap resampling was used to determine the factors important for differentiation of the 2 groups and to generate models for organ- vs nonorgan-confined PCa prediction.

RESULTS

Several nuclear morphometric features were significantly altered and could differentiate organ- and nonorgan-confined disease. DNA ploidy was the most important factor among the significant nuclear morphometric features and was the second most important factor for organ- vs nonorgan-confined PCa prediction when considered with total prostate-specific antigen (PSA), complexed PSA, free/total PSA, biopsy Gleason score, and clinical stage. The combination of DNA ploidy with clinical stage, total PSA, and biopsy Gleason score showed an improvement of 1.5% in the area under the receiver operator characteristic curves compared with the combination of clinical stage, total PSA, and biopsy Gleason (73.97% vs 72.43%). The use of DNA ploidy in lieu of the biopsy Gleason score in each preoperative model evaluated resulted in equivalent or improved organ- vs nonorgan-confined PCa prediction.

CONCLUSIONS

The results of our study have shown that DNA ploidy can serve as a surrogate biomarker that has the potential to replace biopsy Gleason scores for organ- vs nonorgan-confined PCa prediction.

Endoglin (CD105) as a urinary and serum marker of prostate cancer

We have previously shown that endoglin (CD105) is upregulated in prostatic fluid of men with large volume prostate cancer. We chose to assess endoglin levels in urine and serum from men with prostate cancer or at increased risk for the disease: Urine samples were collected after digital rectal examination (DRE) from 99 men whose cancer status was confirmed by biopsy, and serum samples were collected from 20 men without prostate cancer at low risk for the disease and from 69 men diagnosed with prostate cancer that subsequently underwent radical prostatectomy (30 pT2, 39 pT3). Endoglin levels were assessed by ELISA. Urinary endoglin was elevated in men with biopsy-positive prostate cancer compared to biopsy-negative men (p=0.0014). Urinary endoglin levels in men with prostate cancer correlated with radical prostatectomy tumor volume. The area under the receiver operating characteristic (ROC) curve was 0.72 for urinary endoglin and 0.50 for serum prostate-specific antigen (PSA; sensitivity for cancer detection 73%, specificity 63%). There were no differences in serum endoglin between normal and cancer cases, but there were increases in serum endoglin in non-organ confined (NOC, pT3+) versus organ-confined (OC, pT2) cases (p=0.0004). The area under the ROC curve was 0.75 for serum endoglin and 0.63 for PSA for predicting NOC status, with a sensitivity of 67% and a specificity of 80%. In conclusion, elevations in post-DRE urinary endoglin suggest there may be value in further studying endoglin as a urinary biomarker of prostate cancer. Endoglin levels in both urine and serum may aid in prostate cancer detection and prognostication.

Long-term assessment of prostate cancer progression free survival: evaluation of pathological parameters, nuclear shape and molecular biomarkers of pathogenesis

BACKGROUND

Molecular pathways of proliferation, angiogenesis, neuroendocrine differentiation, apoptosis and alterations in nuclear structure of cancer epithelial cells are important in the pathogenesis of prostate cancer (PCa). Therefore, we evaluated the prognostic value of these parameters in 105 clinically localized PCa tumors with long-term follow-up after radical prostatectomy for progression-free survival (PFS).

METHOD

Nuclear roundness variance (NRV) was calculated for tumor nuclei using the graphic tracing DynaCELL system. Immunohistochemistry assessed expression of Ki67, PCNA (proliferation), Chromogranin A (neuroendocrine differentiation), CD31 (angiogenesis), BCL2 (apoptosis), and Her-2/neu (oncogene) in the tumors. Cox proportional hazards regression, Spearman's rank correlation, and Kaplan-Meier plots were employed to analyze the data.

RESULTS

Gleason score, focal vs. non-focal extra-prostatic extension, organ confined status, NRV, Her-2/neu, CD-31 and Ki67 were univariately significant predictors of PFS. NRV was the most significant prognostic indicator with the highest concordance index (0.7) for PFS. Gleason score, NRV and Her-2/neu were multivariately significant and yielded a concordance index of 0.77.

CONCLUSION

Her-2/neu oncogene and NRV were shown to be significant in the prediction of PFS. The assessment of alterations in nuclear structure using NRV proved to be the most significant factor in the prediction of PFS. Integration of image analysis-based NRV and molecular biomarkers with pathologic parameters should be considered for validation in the prediction of PFS.

Predicting the outcome of prostate biopsy: comparison of a novel logistic regression-based model, the prostate cancer risk calculator, and prostate-specific antigen level alone

OBJECTIVES

To develop a logistic regression-based model to predict prostate cancer biopsy at, and compare its performance to the risk calculator developed by the Prostate Cancer Prevention Trial (PCPT), which was based on age, race, prostate-specific antigen (PSA) level, a digital rectal examination (DRE), family history, and history of a previous negative biopsy, and to PSA level alone.

PATIENTS AND METHODS

We retrospectively analysed the data of 1280 men who had a biopsy while enrolled in a prospective, multicentre clinical trial. Of these, 1108 had all relevant clinical and pathological data available, and no previous diagnosis of prostate cancer. Using the PCPT risk calculator, we calculated the risks of prostate cancer and of high-grade disease (Gleason score > or =7) for each man. Receiver operating characteristic (ROC) curves for the risk calculator, PSA level and the novel regression-based model were compared.

RESULTS

Prostate cancer was detected in 394 (35.6%) men, and 155 (14.0%) had Gleason > or =7 disease. For cancer prediction, the area under the ROC curve (AUC) for the risk calculator was 66.7%, statistically greater than the AUC for PSA level of 61.9% (P < 0.001). For predicting high-grade disease, the AUCs were 74.1% and 70.7% for the risk calculator and PSA level, respectively (P = 0.024). The AUCs increased to 71.2% (P < 0.001) and 78.7% (P = 0.001) for detection and high-grade disease, respectively, with our novel regression-based models.

CONCLUSIONS

ROC analyses show that the PCPT risk calculator modestly improves the performance of PSA level alone in predicting an individual's risk of prostate cancer or high-grade disease on biopsy. This predictive tool might be enhanced by including percentage free PSA and the number of biopsy cores.

Prognostic value of Her-2/neu and DNA index for progression, metastasis and prostate cancer-specific death in men with long-term follow-up after radical prostatectomy

Abnormal DNA content in tumor cells represents large scale chromosomal alterations and reflects later changes of genetic instability. Her-2/neu oncogene is amplified in 20-30% of breast and ovarian cancer patients and is associated with poor prognosis. Therefore, we evaluated prognostic value of Her-2/neu expression and DNA content measurements in 252 clinically localized PCa patients with long-term follow-up after radical prostatectomy for progression, metastasis and PCa-specific death. Her-2/neu expression was determined by immunohistochemistry and DNA content measurements employed Feulgen-stained cancer nuclei captured using static image cytometry system. Cox proportional hazard regression and Kaplan-Meir plots were used to identify significant prognostic factors for progression, metastasis and PCa-specific death. The proportions of Her-2/neu positive and high %DNA index tumors significantly increased from nonprogressor to progressors without metastasis to progressors with metastasis (p < 0.0001; <0.0001). Further, the proportions of Her-2/neu positive and high %DNA index tumors significantly increased from patients who died from another cause without progression to those who died from another cause with progression to those died with PCa-specific death (p = 0.027; <0.0001). Her-2/neu expression and %DNA index were significant prognosticators for progression (p <or= 0.001), metastasis (p <or= 0.01) PCa-specific death (p <or= 0.04) in univariate analyses. Multivariately, Her-2/neu expression and %DNA index were also significant for progression (p = 0.001), metastasis (p = 0.001) and PCa-specific death (p = 0.02). When all other clinicopathologic information is available, the increment in concordance index by addition of either Her-2/neu or DNA index was approximately 2% and of both biomarkers was approximately 3% for progression, metastasis and PCa-specific death free survival models. Therefore, patients with Her-2/neu positive and high %DNA index are at a higher risk for disease progression, metastasis and PCa-specific death. Further, Her-2/neu expression and %DNA index may be used with clinicopathologic parameters for prediction of long-term prognosis in PCa.

External validation of University of California, San Francisco, Cancer of the Prostate Risk Assessment score

OBJECTIVES

In 2005, the University of California, San Francisco, proposed the Cancer of the Prostate Risk Assessment (UCSF-CAPRA) score to predict the risk of biochemical recurrence (BR) after radical prostatectomy. This study provides external validation and a modified version of the model using a large cohort of men treated with radical prostatectomy at a high-volume, tertiary referral center.

METHODS

From 1984 to 2006, 6737 men underwent radical prostatectomy at our institution for clinical Stage T1c-T3a prostate cancer with available follow-up information and no neoadjuvant or adjuvant therapy before BR. The BR-free survival was estimated using the Kaplan-Meier method and compared by UCSF-CAPRA score using the log-rank statistic. Performance of the UCSF-CAPRA was evaluated using Cox proportional hazards regression analysis and Harrell's concordance (c) index and compared with the Kattan nomogram. The UCSF-CAPRA score and final pathologic findings were assessed by odds ratios.

RESULTS

The 5-year BR-free survival rate was 83.1% overall and decreased from 94.4% for men with a UCSF-CAPRA score of 1 or less to 25.8% for those with a score of 7 or more (P <0.0001). The hazards ratio approximately doubled for each UCSF-CAPRA point until a score of 4, when the hazards ratio increased at a slower rate. The c-index of the UCSF-CAPRA and Kattan nomogram was 0.76 and 0.78, respectively. A greater UCSF-CAPRA score correlated with the final pathologic findings.

CONCLUSIONS

The UCSF-CAPRA performed well in this tertiary, referral-based cohort with a c-index similar to that of the Kattan nomogram. It remains an effective prognostic instrument for predicting the risk of biochemical recurrence after radical prostatectomy.

Effect of DNA methylation on identification of aggressive prostate cancer

OBJECTIVES

Biochemical (prostate-specific antigen) recurrence of prostate cancer after radical prostatectomy remains a major problem. Better biomarkers are needed to identify high-risk patients. DNA methylation of promoter regions leads to gene silencing in many cancers. In this study, we assessed the effect of DNA methylation on the identification of recurrent prostate cancer.

METHODS

We studied the methylation status of 15 pre-specified genes using methylation-specific polymerase chain reaction on tissue samples from 151 patients with localized prostate cancer and at least 5 years of follow-up after prostatectomy.

RESULTS

On multivariate logistic regression analysis, a high Gleason score and involvement of the capsule, lymph nodes, seminal vesicles, or surgical margin were associated with an increased risk of biochemical recurrence. Methylation of CDH13 by itself (odds ratio 5.50, 95% confidence interval [CI] 1.34 to 22.67; P = 0.02) or combined with methylation of ASC (odds ratio 5.64, 95% CI 1.47 to 21.7; P = 0.01) was also associated with an increased risk of biochemical recurrence. The presence of methylation of ASC and/or CDH13 yielded a sensitivity of 72.3% (95% CI 57% to 84.4%) and negative predictive value of 79% (95% CI 66.8% to 88.3%), similar to the weighted risk of recurrence (determined from the lymph node status, seminal vesicle status, surgical margin status, and postoperative Gleason score), a powerful clinicopathologic prognostic score. However, 34% (95% CI 21% to 49%) of the patients with recurrence were identified by the methylation profile of ASC and CDH13 rather than the weighted risk of recurrence.

CONCLUSIONS

The results of our study have shown that methylation of CDH13 alone or combined with methylation of ASC is independently associated with an increased risk of biochemical recurrence after radical prostatectomy even considering the weighted risk of recurrence score. These findings should be validated in an independent, larger cohort of patients with prostate cancer who have undergone radical prostatectomy.

Progression after radical prostatectomy for men in their thirties compared to older men

OBJECTIVE

To assess the biochemical outcome after radical prostatectomy (RP) specifically for men aged 30-39 years, as previous studies suggest that prostate cancer in young men might be more aggressive.

PATIENTS AND METHODS

From a large (15 899) database of RPs (1975-2007) we identified 42 men aged 30-39, 893 aged 40-49, 4085 aged 50-59, 3766 aged 60-69, and 182 men aged > or =70 years old. The clinical characteristics and treatment outcomes were compared between men aged 30-39 years and older men.

RESULTS

Among the men in their thirties, 81% had organ-confined disease in the RP specimen, vs 62% of men aged > or =40 years. At a mean follow-up of 5 years, there was biochemical progression in 4.8% of men in their thirties and 16.1% of men age > or =40 years (P = 0.055). The corresponding 5-year biochemical progression-free survival estimates were 95% for men in their thirties and 83% for men aged > or =40 years (P = 0.045). On multivariate analysis, increasing age was a significant independent predictor of biochemical progression.

CONCLUSION

Contrary to earlier reports, in the present study men in their thirties did not have more aggressive disease. Instead, they had more favourable pathological features and progression-free survival rates than their older counterparts. After controlling for other prognostic variables on multivariate analysis, being in the fourth decade was independently associated with a lower risk of biochemical progression. These results suggest that early aggressive treatment for these patients with a long life-expectancy is associated with favourable long-term biochemical outcomes.

CpG island hypermethylation profile in the serum of men with clinically localized and hormone refractory metastatic prostate cancer

PURPOSE

We have noted that hypermethylation at GSTP1 in the preoperative serum of men with localized prostate cancer predicts early prostate specific antigen failure following surgical treatment. In this study we investigated the hypermethylation profile of several genes in the serum of men with localized and hormone refractory prostate cancer.

MATERIALS AND METHODS

We assayed the serum of 192 men with clinically localized prostate cancer and 18 with hormone refractory metastatic disease. A total of 35 serum samples from patients with negative prostate biopsy served as a negative control. CpG Island hypermethylation status of certain genes was assessed, including MDR1, EDNRB, CD44, NEP, PTGS2, RASSF1A, RAR-beta and ESR1. The results of hypermethylation at GSTP1 were included from a previous study.

RESULTS

CpG island hypermethylation at MDR1 was positive in 38.2% of cases without PSA recurrence and in 16.1% of those with biochemical recurrence after radical prostatectomy. DNA hypermethylation at the remaining 7 gene loci was not detected in the serum of patients with localized prostate cancer. In serum from metastatic prostate cancer cases CpG island hypermethylation was detected at MDR1 in 15 (83.3%), EDNRB in 9 (50%), RAR-beta in 7 (38.9%), GTSP1 in 5 (27.8%) and NEP or RASSF1A in 3 (16.7%). CpG island hypermethylation at CD44, PTGS2 or ESR was not detected in any samples. All histologically normal cases were negative for CpG island hypermethylation.

CONCLUSIONS

DNA hypermethylation at MDR1 was detected in cases of localized prostate cancer. CpG island hypermethylation at several gene loci was detected in men with advanced disease. No single gene was consistently observed to be hypermethylated in men with hormone refractory disease. These results suggest that the CpG island hypermethylation status of a defined panel of genes may be a useful biomarker in men with hormone refractory prostate cancer.

The natural history of men treated with deferred androgen deprivation therapy in whom metastatic prostate cancer developed following radical prostatectomy

PURPOSE

We report on the natural history and factors influencing the prognosis of a cohort of hormone naïve, prostate specific antigen era patients in whom metastatic prostate cancer developed after radical prostatectomy who were followed closely and treated with deferred androgen deprivation therapy at the time of metastasis.

MATERIALS AND METHODS

A total of 3,096 men underwent radical prostatectomy performed by a single surgeon at Johns Hopkins Hospital between 1987 and 2005. Of these men 422 had prostate specific antigen failure. Distant metastasis developed in 123 patients, of whom 91 with complete data formed the study cohort initially treated during the prostate specific antigen era (1987 to 2005) and receiving androgen deprivation therapy after documented metastasis. A total of 41 men died of prostate cancer. Median survival times were estimated by Kaplan-Meier analysis. Prognostic impact was estimated as the hazard ratio derived from the Cox proportional hazards model.

RESULTS

Median followup from radical prostatectomy was 120 months (range 24 to 216). Kaplan-Meier median (range) times to failure were 24 months (12 to 144) from radical prostatectomy to prostate specific antigen failure, 36 months (0 to 132) from prostate specific antigen failure to metastasis, 84 months (12 to 180) from metastasis to death and 168 months (24 to 216) from radical prostatectomy to death. Statistically significant univariate risk factors for prostate cancer specific mortality at the time of metastasis were pain at diagnosis of metastases (p = 0.002), time from radical prostatectomy to metastasis (p = 0.024) and prostate specific antigen doubling time less than 3 months during the 24 months before metastasis (p = 0.016). Multivariable analysis demonstrated independent predictors of prostate cancer specific mortality at the time of metastasis, namely pain (HR 3.5, p = 0.003) and prostate specific antigen doubling time less than 3 months (HR 3.4, p = 0.017).

CONCLUSIONS

Men treated with deferred androgen deprivation therapy for the development of metastasis after radical prostatectomy may have a long life span, 169 months after radical prostatectomy (range 24 to 216). The presence of pain and short prostate specific antigen doubling time predicted an unfavorable outcome.

Prognostic value of preoperative serum cell-free circulating DNA in men with prostate cancer undergoing radical prostatectomy

PURPOSE

We evaluated the association of preoperative serum cell-free circulating DNA concentration in men with clinically localized prostate cancer who underwent radical prostatectomy with prostate-specific antigen (PSA) recurrence.

EXPERIMENTAL DESIGN

One hundred and ninety-two men with clinically localized prostate cancer, who underwent radical prostatectomy at the Johns Hopkins Hospital and had preoperative serum available for analyses constituted our study population. All serum samples were collected before prostate biopsy or at least 4 months after prostate biopsy. The total amount of serum cell-free circulating DNA from each sample was calculated using a standard curve generated via quantitative real-time PCR. PSA recurrence was defined as a single postoperative PSA level of > or =0.2. The natural logarithm (ln) of the DNA concentration was used for statistical analyses.

RESULTS

Of the 192 men in our study, 56 (29%) experienced PSA recurrence within the study period (median time to PSA recurrence 2 years). The median follow-up time for men free of disease at last follow-up was 3 years. The median serum cell-free DNA concentration of all men in the study was 5.3 ng/mL (mean 18.05 ng/mL; range 0.2-320 ng/mL). The mean serum DNA concentration for men who recurred and for those who did not was 3.8 +/- 34.1 and 13.7 +/- 33.6 ng/mL, respectively (P = 0.001). In a univariate analysis, ln DNA concentration was significantly associated with PSA recurrence (hazard ratio, 1.49; 95% confidence interval, 1.3-1.8; P < 0.001). In the multivariate model, ln DNA concentration was significantly associated with PSA recurrence (hazard ratio, 2.56; 95% confidence interval, 1.1-1.6; P = 0.003). Using bootstrap analyses, serum cell-free DNA concentrations > or =5.75 ng/mL were associated with an increased risk of PSA recurrence within 2 years of radical prostatectomy.

CONCLUSION

Our study suggests that preoperative serum cell-free DNA concentration may be a useful prognostic biomarker for men with clinically localized prostate cancer treated with radical prostatectomy.

Association between two unlinked loci at 8q24 and prostate cancer risk among European Americans

BACKGROUND

Recent studies have provided evidence of associations between genetic markers at human chromosome 8q24 and an increased risk of prostate cancer. We examined whether multiple independent risk variants exist in this region and whether the strength of observed associations differs as a function of disease aggressiveness.

METHODS

We evaluated associations between 18 single-nucleotide polymorphisms (SNPs) in a 1-Mb interval at 8q24 and the risk of prostate cancer among 1563 case patients (1017 of whom had high-grade [Gleason score > or = 7] and/or non-organ-confined disease) and 576 control subjects of European American ancestry. Differences in genotype frequencies between case and control subjects were compared using logistic regression analysis, with adjustment for age, and the Wald chi-square test. All statistical tests were two-sided.

RESULTS

We identified multiple SNPs in a 50-kb region (referred to as locus 1) that are in linkage disequilibrium with a previously reported risk-associated SNP at 8q24, rs1447295, but were more strongly associated with prostate cancer risk in our study population. We also identified a novel susceptibility SNP, rs6983267, at a second locus (locus 2) that is approximately 70 kb centromeric of rs1447295 and in linkage equilibrium with, and independent of, locus 1. Risk alleles at locus 2 were common in our study population (minor allele frequency approximately 50%, 25% homozygous for risk-associated allele). Analysis of the National Cancer Institute's Cancer Genetic Markers of Susceptibility (CGEMS) prostate cancer association study database alone and in combination with our data provided further evidence for this second prostate cancer risk locus; in the combined analysis, the allele frequencies for rs6983267 differed statistically significantly between case patients and control subjects (P = 1.61 x 10(-9)). We also identified a third locus at 8q24, approximately 400 kb centromeric to locus 2, that was statistically significantly associated with prostate cancer risk in a combined analysis of our data and CGEMS study data (P = 6.8 x 10(-4)). A joint analysis of loci 1 and 2 indicated that 35% of the control subjects carried risk genotypes at one or both these loci; compared with men with the non-risk genotype at both loci, men with risk genotypes at both loci had an odds ratio of prostate cancer of 2.68 (95% confidence interval [CI] = 1.62 to 4.43) and men with risk genotypes at either locus had an odds ratio of prostate cancer of 1.70 (95% CI = 1.39 to 2.07).

CONCLUSIONS

Three loci at 8q24 are independent genetic risk factors for prostate cancer.

Do racial differences in prostate size explain higher serum prostate-specific antigen concentrations among black men?

OBJECTIVES

To determine whether elevated serum prostate-specific antigen (PSA) values in black men are due, at least partially, to larger prostate size among black men.

METHODS

The study population consisted of two cohorts: (1) 1410 men undergoing radical prostatectomy between 1988 and 2005 at five equal-access medical centers comprising the Shared Equal Access Regional Cancer Hospital (SEARCH) Database; and (2) 9601 men undergoing radical prostatectomy between 1988 and 2004 at the Johns Hopkins Hospital. We evaluated the association between race and serum PSA value and prostate weight using multivariable linear regression while adjusting for demographic and clinicopathologic cancer characteristics.

RESULTS

In both cohorts, black men had higher serum PSA values (P < or = 0.001). After adjusting for either demographic characteristics or demographic and cancer-specific characteristics, there were no significant associations between race and prostate size in either cohort. After adjusting for multiple demographic, clinical, and pathologic cancer-specific characteristics, black men had 15% higher serum PSA values relative to white men in both the SEARCH (P = 0.001) and Hopkins cohorts (P < 0.001).

CONCLUSIONS

In this study of patients undergoing radical prostatectomy in two very different practice settings, black men in both cohorts had higher serum PSA values relative to white men, despite adjustment for demographic and cancer-specific characteristics, including prostate weight. The lack of significant association between race and prostate size suggests that alternative reasons are needed to explain higher serum PSA values in black men.

Updated nomogram to predict pathologic stage of prostate cancer given prostate-specific antigen level, clinical stage, and biopsy Gleason score (Partin tables) based on cases from 2000 to 2005

OBJECTIVES

To update the 2001 "Partin tables" with a contemporary patient cohort and revised variable categorization, correcting for the effects of stage migration.

METHODS

We analyzed 5730 men treated with prostatectomy (without neoadjuvant therapy) between 2000 and 2005 at the Johns Hopkins Hospital. Average age was 57 years. Multivariable logistic regression was used to estimate the probability of organ-confined disease, extraprostatic extension, seminal vesicle involvement, or lymph node involvement. Predictor variables included preoperative prostate-specific antigen (PSA) level (0 to 2.5, 2.6 to 4.0, 4.1 to 6.0, 6.1 to 10.0, and greater than 10.0 ng/mL), clinical stage (T1c, T2a, and T2b/T2c), and biopsy Gleason score (5 to 6, 3 + 4 = 7, 4 + 3 = 7, or 8 to 10). Bootstrap resampling was used to generate 95% confidence intervals for predicted probabilities.

RESULTS

Seventy-seven percent of patients had T1c, 76% had Gleason score 5 to 6, 80% had a PSA level between 2.5 and 10.0 ng/mL, and 73% had organ-confined disease. Nomograms were developed for the predicted probability of pathologically organ-confined disease, extraprostatic extension, seminal vesicle invasion, or lymph node involvement. The risk of non-organ-confined disease increased with increases in any individual prognostic factor. The dramatic decrease in clinical stage T2c compared with the patient series used in the previous models resulted in T2b and T2c being combined as a single predictor in the nomogram.

CONCLUSIONS

These updated "Partin tables" were generated to reflect trends in presentation and pathologic stage for men diagnosed with clinically localized prostate cancer at our institution. Clinicians and patients can use these nomograms to help make important decisions regarding management of prostate cancer.

Death in patients with recurrent prostate cancer after radical prostatectomy: prostate-specific antigen doubling time subgroups and their associated contributions to all-cause mortality

PURPOSE

Among patients with biochemical recurrence after radical prostatectomy, we found previously that postoperative prostate-specific antigen doubling time (PSADT) was associated with risk of prostate cancer death. However, given the small number of patients in the highest risk PSADT subgroup, it is unclear which PSADT subgroups contribute the greatest to prostate cancer-specific death and how this influences all-cause mortality.

PATIENTS AND METHODS

This study was a retrospective analysis of 379 patients treated with radical prostatectomy between 1982 and 2000 who had a biochemical recurrence and PSADT data available. Mean and median follow-up after surgery was 11.4 (standard deviation, 5.4) and 11.0 years, respectively (range, 1.6 to 23.0 years).

RESULTS

Shorter PSADT was significantly associated with prostate cancer-specific and all-cause mortality (P < .001). Although patients with a PSADT less than 3 months were at the greatest risk of death, because of the limited number of patients in this group, they accounted for only 13% of prostate cancer deaths at 15 years after biochemical recurrence, whereas patients with an intermediate PSADT (3.0 to 8.9 months) accounted for 58% of all prostate cancer deaths. Among patients with a PSADT less than 15 months, prostate cancer accounted for 90% of all deaths. Only patients in the slowest PSADT subgroup (> or = 15 months) had a greater risk of competing-causes mortality compared with that from prostate cancer.

CONCLUSION

Among a select cohort of young, healthy patients with PSA recurrence after radical prostatectomy and a PSADT less than 15 months, prostate cancer accounted for an estimated 90% of all deaths by 15 years after recurrence. The majority of prostate cancer deaths occurred among patients with an intermediate PSADT (3.0 to 8.9 months).

Radical prostatectomy for clinical stage T3a disease

BACKGROUND

Men with clinical stage T3a disease are at high risk and are often encouraged to undergo radiation therapy with concomitant hormonal therapy. The long-term outcomes among men treated with radical prostatectomy for clinical stage T3a disease were examined.

METHODS

Among 3397 men treated by radical prostatectomy by 1 surgeon between 1987 and 2003, 62 (1.8%) men were identified who had clinical stage T3a disease. Among the 56 men not treated with neoadjuvant or adjuvant therapies before prostate-specific antigen (PSA) recurrence, the long-term outcomes of PSA-free survival, metastasis-free survival, and prostate cancer specific survival were examined. Median and mean follow-up after surgery were 10.3 and 13 years, respectively (range, 1-17).

RESULTS

Ninety-one percent of men in this group had pathological T3 disease. PSA-free survival at 15 years after surgery was 49%. Metastasis-free survival and cause-specific survival at 15 years after surgery were 73% and 84%, respectively. Among men with a PSA recurrence, 46% received secondary therapy before metastasis. The only preoperative or pathological feature that predicted risk of prostate cancer death was lymph node metastasis (hazard ratio [HR]: 9.22, 95% confidence interval [CI]: 1.06-80.02, P = .044). Among the 28 men with a PSA recurrence, PSA doubling time (PSADT) data were available for 23, of which 11 (48%) has a PSADT >/=9 months. No patient with a PSADT >/=9 months died of prostate cancer. A PSADT <9 months was significantly associated with increased risk of prostate cancer death (log-rank, P = .004).

CONCLUSIONS

In a select cohort of men with clinical stage T3a disease, radical prostatectomy alone provides long-term cancer control in about half of the men and results in a prostate cancer-specific survival of 84%. Among men with a PSA recurrence, PSADT at the time of recurrence is a useful determinant of risk of prostate cancer death.

Time to Prostate Specific Antigen Recurrence After Radical Prostatectomy and Risk of Prostate Cancer Specific Mortality

PURPOSE

In patients treated with radical prostatectomy who have biochemical recurrence we have previously reported that time from surgery to biochemical recurrence and postoperative prostate specific antigen doubling time are significantly related to the risk of prostate cancer death. We performed a more thorough examination of the association of time from surgery to biochemical recurrence and the risk of prostate cancer death.

MATERIALS AND METHODS

We retrospectively studied the records of 379 patients treated with radical prostatectomy between 1982 and 2000 who had had biochemical recurrence. We examined the association of time from surgery to prostate specific antigen recurrence and prostate specific antigen doubling time, and the risk of prostate cancer death using the Spearman correlation and Cox proportional hazards regression, respectively.

RESULTS

Longer time from surgery to prostate specific antigen recurrence was associated with a slower prostate specific antigen doubling time (Spearman r = 0.36, p < 0.001) and a decreased risk of prostate cancer death (RR 0.76, 95% CI 0.66 to 0.88, p < 0.001). The 15-year actuarial prostate cancer specific survival rate after biochemical recurrence in patients with recurrence at 3 years or less was 41% (95% CI 29 to 53) compared to 87% (95% CI 75 to 93) in patients with recurrence more than 3 years after radical prostatectomy. On multivariate analysis a shorter time from surgery to prostate specific antigen recurrence was associated with an increased risk of prostate cancer death (3 or less vs more than 3 years, RR 2.70, 95% CI 1.37 to 5.31, p = 0.004).

CONCLUSIONS

Earlier prostate specific antigen recurrence is associated with an increased risk of prostate cancer death. These data suggest that perhaps time to prostate specific antigen recurrence may be a reasonable intermediate end point in patients treated with radical prostatectomy, although this must be validated in other studies.

Pathological outcomes and biochemical progression in men with T1c prostate cancer undergoing radical prostatectomy with prostate specific antigen 2.6 to 4.0 vs 4.1 to 6.0 ng/ml

PURPOSE

Recent studies have suggested that the cut point for recommending prostate biopsy among men with a normal digital rectal examination should be greater than 2.5 ng/ml as opposed to the more traditional greater than 4.0 ng/ml. We compared outcomes between men with clinical stage T1c disease undergoing radical prostatectomy who had a low vs slightly increased prostate specific antigen.

MATERIALS AND METHODS

The study population consisted of 2,896 men treated with radical prostatectomy between 1985 and 2004 at a tertiary care referral center with clinical stage T1c disease and a pre-biopsy prostate specific antigen between 2.6 and 6.0 ng/ml. Using multivariate analysis we evaluated the association between pre-biopsy prostate specific antigen 2.6 to 4.0 ng/ml (784) vs 4.1 to 6.0 ng/ml (2,112), and pathological outcomes and biochemical progression.

RESULTS

After adjusting for multiple clinical and pathological characteristics, lower preoperative serum prostate specific antigen values were associated with decreased odds of Gleason score 7 or greater in the surgical specimen (p = 0.004), positive surgical margins (p = 0.02) and extraprostatic extension (p = 0.001). There was no significant association between these preoperative prostate specific antigen groups and odds of seminal vesicle invasion (p = 0.47) or lymph node metastasis (p = 0.90). Among the 1,534 men with followup information available there was a trend for increased risk of biochemical progression associated with a higher preoperative prostate specific antigen, although this trend did not reach statistical significance (relative risk 1.48, 95% CI 0.69-3.19, p = 0.31).

CONCLUSIONS

In the current study of men with clinical stage T1c treated with radical prostatectomy a lower preoperative prostate specific antigen was associated with significantly more favorable pathological findings. Whether this degree of improved outcomes justifies the limitations associated with decreasing the prostate specific antigen cut point (eg increased biopsies performed and diagnosis of insignificant cancers) remains to be determined.

Relationship between primary Gleason pattern on needle biopsy and clinicopathologic outcomes among men with Gleason score 7 adenocarcinoma of the prostate

OBJECTIVES

To examine the relationship among needle biopsy primary grade, prostatectomy grade, and postprostatectomy biochemical recurrence among men with Gleason score 7 disease.

METHODS

We identified 320 men with Gleason score 7 tumors on prostate biopsy treated with radical prostatectomy between 1991 and 2001 by a single surgeon. None of these patients had received neoadjuvant or adjuvant hormonal therapy or radiotherapy. The chi-square test and Kaplan-Meier method were used to evaluate the correlation among biopsy Gleason score, prostatectomy Gleason score, and biochemical recurrence.

RESULTS

A total of 252 (79%) and 68 (21%) men had primary Gleason pattern 3 and 4 identified on needle biopsy, respectively. Of the patients with Gleason pattern 3 + 4 tumors on biopsy, 24% were upgraded to primary pattern 4 or more on final pathologic analysis. Of the patients with Gleason pattern 4 + 3 tumors on biopsy, 47% were downgraded to primary pattern 3 or less on final pathologic analysis. The actuarial risk of biochemical prostate-specific antigen recurrence was significantly lower among patients with Gleason pattern 4 + 3 on biopsy, if the prostatectomy Gleason score was downgraded to 3 + 4 or less (P = 0.03).

CONCLUSIONS

Approximately 47% of men with a diagnosis of Gleason pattern 4 + 3 on needle biopsy are downgraded at radical prostatectomy and will have biochemical prostate-specific antigen recurrence-free outcomes similar to patients originally diagnosed with Gleason pattern 3 + 4 adenocarcinoma. This group of patients may benefit from definitive treatment such as radical prostatectomy for management of their disease.

Clinical and pathologic outcome after radical prostatectomy for prostate cancer patients with a preoperative Gleason sum of 8 to 10

BACKGROUND

Men with a biopsy Gleason sum of 8 to 10 are considered high-risk. The current study sought to identify whether there was a subset of men with high biopsy Gleason sums who would have a good pathologic and biochemical outcome with surgical monotherapy. To increase the generalizability of the findings, data were used from patients treated at 2 very different practice settings: a tertiary care referral center (Johns Hopkins Hospital) and multiple equal-access medical centers (Shared Equal Access Regional Cancer Hospital [SEARCH] Database).

METHODS

The data were retrospectively reviewed from men with biopsy Gleason sums 8 to 10 treated by radical prostatectomy at the Johns Hopkins Hospital (n = 220, 3.8% of total cohort) and within the SEARCH Database (n = 149, 7.7% of total cohort). The preoperative clinical characteristics predicting unfavorable pathologic disease (nonorgan-confined and/or positive surgical margins) and time to biochemical recurrence were determined using logistic regression and Cox proportional hazards analysis, respectively.

RESULTS

Favorable pathologic outcome (organ-confined and negative surgical margins) was observed in 21% of the men in the Johns Hopkins cohort and 41% from the SEARCH cohort. On multivariate analysis, higher serum prostate-specific antigen (PSA) was the only variable that significantly predicted an unfavorable pathologic outcome from both the Johns Hopkins (P = .047) and SEARCH cohorts (P = .002). The 5-year and 10-year estimated biochemical-free survival rates in the Johns Hopkins cohort were 40% (95% confidence interval [CI], 33-48%) and 27% (95% CI, 18-36%), respectively, and 32% (95% CI, 22-42%) and 28% (95% CI, 18-38%) in the SEARCH cohort, respectively. Among men with favorable pathologic findings, the 5- and 10-year estimated biochemical-free survival rates in the Johns Hopkins cohort were 79% (95% CI, 62-89%) and 50% (95% CI, 25-71%), respectively, and 49% (95% CI, 32-65%) and 49% (95% CI, 32-65%) in the SEARCH cohort, respectively. No single preoperative variable significantly predicted the risk of biochemical progression in both the SEARCH or Johns Hopkins cohorts.

CONCLUSIONS

The majority of men with a biopsy Gleason sum of >or=8, regardless of where the patient is treated, had unfavorable pathologic disease and experienced a biochemical progression after radical prostatectomy. Even among men with organ-confined disease and negative surgical margins or pathologic Gleason sum <8, at least half of the men experienced a PSA recurrence. Patients with biopsy Gleason sum 8 to 10 cancers are good candidates for multimodal therapy. Whereas multimodal therapy has often meant radiation plus hormonal therapy, newer possibilities for multimodal therapy exist such as surgery with neoadjuvant or adjuvant chemohormonal therapy or surgery with adjuvant radiation.

OBESITY AND CAPSULAR INCISION AT THE TIME OF OPEN RETROPUBIC RADICAL PROSTATECTOMY

PURPOSE

The goal of radical prostatectomy (RP) is complete removal of the intact prostate. Obese men can represent a technical challenge. However, to our knowledge objective data linking obesity with technically inferior surgery are lacking. Therefore, we examined the association between body mass index (BMI) and capsular incision at RP as a surrogate of a poor technical operation in men treated for prostate cancer by several high volume surgeons at a center of excellence.

MATERIALS AND METHODS

The study population consisted of 7,027 men treated with anatomical retropubic RP between 1996 and 2004 by 7 high volume surgeons. We evaluated the association between BMI and capsular incision using logistic regression, adjusting for clinical and pathological variables, and for the surgeon.

RESULTS

Overall capsular incision was noted in 4.6% of all RP specimens. After adjustment for preoperative prostate specific antigen, patient race, height, year of surgery, clinical stage, pathological Gleason sum, prostate weight, extraprostatic extension and seminal vesicle invasion increased BMI was associated with increased odds of capsular incision (p trend = 0.005). After further adjustment for surgeon mild obesity was associated with 30% increased odds of capsular incision (OR 1.30, 95% CI 0.92 to 1.83), while moderate and severe obesity was associated with 57% increased odds of capsular incision (OR 1.57, 95% CI 0.82 to 3.00) relative to normal weight men (p trend = 0.06).

CONCLUSIONS

In a study of more than 7,000 men treated by 7 experienced surgeons BMI was positively related to capsular incision. This suggests that open retropubic RP is technically more difficult in obese men, which results in a greater likelihood of a less than technically ideal operation. Although this may be predicted to have a negative impact on disease-free survival outcomes in obese men, it is unlikely to alone explain the worse outcomes in obese men noted in previous RP series.

Association between serum adiponectin, and pathological stage and grade in men undergoing radical prostatectomy

PURPOSE

Adiponectin is a polypeptide hormone produced by adipocytes that has anti-angiogenic properties. Circulating adiponectin is lower in obese men. Obesity has been associated with advanced stage and a higher risk of biochemical progression following radical prostatectomy (RP) in several series. We examined whether serum adiponectin is associated with advanced disease stage at RP.

MATERIALS AND METHODS

Adiponectin was measured by enzyme-linked immunosorbent assay in the preoperative serum of 236 men treated with RP between 1998 and 1999. The odds ratio (OR) of advanced stage (pT3a or greater) and high grade disease (pathological Gleason sum 7 or greater) associated with quartiles of adiponectin were estimated using multivariate logistic regression models.

RESULTS

Serum adiponectin weakly correlated inversely with body mass index (Spearman r = -0.22, p = 0.01). Serum adiponectin was not associated with cancer stage or grade. However, in normal weight men adiponectin was positively associated with high stage disease (OR 1.14, 95% CI 1.02 to 1.29, p = 0.03), although there was no statistically significant association with high grade disease (OR 1.05, 95% CI 0.94 to 1.18, p = 0.38). In overweight and obese men adiponectin was inversely associated with high grade disease (OR 0.94, 95% CI 0.87 to 1.01, p = 0.09), although there was no statistically significant association with high stage disease (OR 0.97, 95% CI 0.91 to 1.04, p = 0.43). Further adjustments for body mass index had little impact on any ORs.

CONCLUSIONS

These data provide evidence to suggest that adiponectin may be related to prostate cancer aggressiveness, although the direction of the associations may depend on the extent of adiposity and on cancer grade.

THE PROSTATIC SPECIFIC ANTIGEN ERA IS ALIVE AND WELL: PROSTATIC SPECIFIC ANTIGEN AND BIOCHEMICAL PROGRESSION FOLLOWING RADICAL PROSTATECTOMY

PURPOSE

Prostate specific antigen (PSA) has been shown to predict the presence of prostate cancer on biopsy, pathological stage, and biochemical progression following primary therapy. A recent study found only a weak association between PSA and tumor volume in the radical prostatectomy (RP) specimen and concluded that the PSA era is over. We examined the association between PSA and clinical progression in men undergoing RP.

MATERIALS AND METHODS

The study population consisted of 2,312 men treated with RP between 1992 and 2004 by a single surgeon. We evaluated the association between preoperative PSA and biochemical progression on multivariate analysis.

RESULTS

Men with higher preoperative PSA concentrations had higher grade cancers in the biopsy and RP specimen, and more adverse pathological features. After adjusting for the clinical covariates of age, race, grade, stage, and year of surgery, preoperative PSA was significantly associated with the risk of biochemical progression. When only men with PSA less than 10 ng/ml were examined, PSA remained a significant predictor of biochemical progression on multivariate analysis (RR 1.30, 95% CI 1.18 to 1.44, p <0.001). For each 2-point increase in PSA, the risk of biochemical progression increased approximately 2-fold.

CONCLUSIONS

Preoperative PSA was significantly associated with high grade disease and adverse pathological findings. After adjusting for clinical covariates, PSA was significantly associated with the risk of biochemical progression, even in men with PSA less than 10 ng/ml. Despite multiple limitations, PSA remains the best prostate cancer tumor marker available.

Obesity and risk of biochemical progression following radical prostatectomy at a tertiary care referral center

PURPOSE

We have previously reported that obesity is an independent predictor of biochemical progression after radical prostatectomy (RP) in men treated by a single surgeon at our institution. We sought to validate or refute these findings using data on men treated by multiple other surgeons at our institution.

MATERIALS AND METHODS

The study population consisted of 2,796 men treated with anatomical radical RP between 1988 and 2004 by 1 of 17 surgeons at our institution, a tertiary care referral center. We evaluated the association between body mass index (BMI), and adverse pathological features and biochemical progression.

RESULTS

On multivariate analysis increased BMI was associated with high grade disease in the RP specimen (p = 0.03), positive surgical margins (p <0.001), extraprostatic extension (p <0.001) and lymph node metastasis (p = 0.01) but not with seminal vesicle invasion (p = 0.59). After multivariate adjustment for preoperative clinical characteristics increased BMI was significantly associated with an increased risk of biochemical progression (p <0.001), which was somewhat but not completely attenuated by further adjusting for RP specimen pathological features (p = 0.03). Adjustment for surgeon did not affect these results.

CONCLUSIONS

In men undergoing RP increased BMI was associated with adverse pathological features and a greater risk of biochemical progression. These findings together with the results of several recently published series collectively provide strong evidence that obese men undergoing RP are more likely to have aggressive prostate cancer.

Preoperative serum DNA GSTP1 CpG island hypermethylation and the risk of early prostate-specific antigen recurrence following radical prostatectomy

PURPOSE

Hypermethylation of the CpG island at the promoter region of the pi-class glutathione S-transferase gene (GSTP1) is the most common somatic genome abnormality in human prostate cancer. We evaluated circulating cell-free DNA GSTP1 CpG island hypermethylation as a prognostic biomarker in the serum of men with prostate cancer.

EXPERIMENTAL DESIGN

Prostate cancer DNA GSTP1 CpG island hypermethylation was detected using a restriction endonuclease quantitative PCR technique. We analyzed preoperative serum from 85 men with clinically localized prostate cancer treated with radical prostatectomy and from 35 men with a negative prostate biopsy. We then assayed preoperative serum from a data set of 55 pairs of men with clinically localized prostate cancer treated with radical prostatectomy, matched for Gleason score, comprising 55 men suffering prostate-specific antigen (PSA) recurrence (median, 2 years) and 55 men who were free of disease at last follow-up (median, 3 years). The association of serum GSTP1 CpG island hypermethylation and PSA recurrence was determined.

RESULTS

Circulating cell-free DNA with GSTP1 CpG island hypermethylation was not detected in the serum of men with a negative prostate biopsy but was detected in 12% of men with clinically localized disease and 28% of men with metastatic cancer (P = 0.003). In the matched data set, eight men (15%) who developed PSA recurrence were positive for DNA with GSTP1 CpG hypermethylation, whereas no patient who was free of disease was positive for GSTP1 CpG island hypermethylation (McNemar test, chi(2) = 6.1, P = 0.01). In a multivariable analysis that accounted for recognized prognostic factors, the presence of serum DNA with GTSP1 CpG island hypermethylation was the most significant predictor of PSA recurrence (hazard ratio, 4.4; 95% confidence interval, 2.2, 8.8; P < 0.001).

CONCLUSION

Our study suggests that GSTP1 CpG island hypermethylation may be an important DNA-based prognostic serum biomarker for prostate cancer.

Risk of prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy

CONTEXT

The natural history of biochemical recurrence after radical prostatectomy can be long but variable. Better risk assessment models are needed to identify men who are at high risk for prostate cancer death early and who may benefit from aggressive salvage treatment and to identify men who are at low risk for prostate cancer death and can be safely observed.

OBJECTIVES

To define risk factors for prostate cancer death following radical prostatectomy and to develop tables to risk stratify for prostate cancer-specific survival.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort study of 379 men who had undergone radical prostatectomy at an urban tertiary care hospital between 1982 and 2000 and who had a biochemical recurrence and after biochemical failure had at least 2 prostate-specific antigen (PSA) values at least 3 months apart in order to calculate PSA doubling time (PSADT). The mean (SD) follow-up after surgery was 10.3 (4.7) years and median follow-up was 10 years (range, 1-20 years).

MAIN OUTCOME MEASURE

Prostate cancer-specific mortality.

RESULTS

Median survival had not been reached after 16 years of follow-up after biochemical recurrence. Prostate-specific doubling time (<3.0 vs 3.0-8.9 vs 9.0-14.9 vs > or =15.0 months), pathological Gleason score (< or =7 vs 8-10), and time from surgery to biochemical recurrence (< or =3 vs >3 years) were all significant risk factors for time to prostate-specific mortality. Using these 3 variables, tables were constructed to estimate the risk of prostate cancer-specific survival at year 15 after biochemical recurrence.

CONCLUSION

Clinical parameters (PSADT, pathological Gleason score, and time from surgery to biochemical recurrence) can help risk stratify patients for prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy. These preliminary findings may serve as useful guides to patients and their physicians to identify patients at high risk for prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy to enroll them in early aggressive treatment trials. In addition, these preliminary findings highlight that survival in low-risk patients can be quite prolonged.

Stronger Association between Obesity and Biochemical Progression after Radical Prostatectomy among Men Treated in the Last 10 Years

BACKGROUND

Prior prospective cohort studies found that obesity was associated with increased risk of prostate cancer death. However, in the last 20 years dramatic changes in both the extent of obesity and prostate cancer screening and treatment have occurred. Whether the association between obesity and aggressive disease has changed as a result of these temporal changes is unclear.

METHODS

The study population consisted of 2,832 men treated by anatomic radical retropubic prostatectomy between 1985 and 2004 by a single surgeon. We evaluated the associations of obesity (body mass index > or =30 kg/m(2))with tumor stage and grade using logistic regression and with biochemical progression using Cox proportional hazards regression. We examined whether these associations have changed over the last 20 years.

RESULTS

On multivariable analysis, the strength of the positive association between obesity and high-grade disease increased over time whereas the strength of the positive association between obesity and positive surgical margins decreased over time. The strength of the positive association between obesity and extraprostatic extension fluctuated over time, although the strongest and only statistically significant association was among men treated since 2000. The association between obesity and biochemical progression was strongest among men treated since 1995 (relative risk, 1.90; 95% confidence interval, 1.09-3.30; P = 0.02).

CONCLUSIONS

In the current study, with the exception of positive surgical margins, the positive association between obesity and high-grade disease, advanced stage, and biochemical progression after radical retropubic prostatectomy was in general strongest among men treated in the last 10 years. The reasons for these findings are not clear, although factors possibly related to prostate-specific antigen-based screening and/or other temporal changes in prostate cancer diagnosis and treatment may play a role.