The impact of nerve sparing on incidence and location of positive surgical margins in radical prostatectomy.

OBJECTIVE: • To examine whether nerve-sparing surgery (NSS) is a risk factor for positive surgical margins (PSMs) in patients with either organ-confined prostate cancer or extracapsular extension (ECE). PATIENTS AND METHODS: • Clinicopathological outcome data on 945 consecutive patients treated with radical prostatectomy (RP) were prospectively collected. • All patients underwent RP (bilateral, unilateral or non-NSS) by one surgeon between 2002 and 2007. • Risk of PSMs and their locations with respect to NSS was determined by multivariate logistic regression analysis adjusting for preoperative risk factors for PSMs within pT2, pT3a and pT3b tumours. RESULTS: • Overall a PSM was identified in 19.6% of patients in an unscreened population with mean prostate-specific antigen (PSA) level of 8.1 ng/mL. • There was no significant difference in rates of PSMs between NSS groups on multivariate analysis (P= 0.147). • There was no significant difference in pT2 (P= 0.880), pT3a (P= 0.175) or pT3b (P= 0.354) tumours. • The only significant predictor of PSMs was preoperative PSA level (risk ratio 1.289, P= 0.006). • There was no significant difference in the location of PSMs except for the pT3a group, where the patients that had bilateral NSS were at higher risk of a posterolateral PSM (P= 0.028). CONCLUSIONS: • With appropriate selection of patients, NSS does not increase the risk of PSMs, whether the cancer is organ confined or ECE is present. • The adverse impact of the NSS procedure in the hands of an experienced surgeon is minimal and is a realistic compromise to obtain the increase in health-related quality of life offered by NSS.

High Gleason grade carcinoma at a positive surgical margin predicts biochemical failure after radical prostatectomy and may guide adjuvant radiotherapy.

UNLABELLED: Study Type - Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Only 30-35% of patients with positive surgical margins after radical prostatectomy develop recurrent disease. Adjuvant radiotherapy reduces the rate of biochemical relapse or metastasis and improves overall survival after radical prostatectomy. Various pathological factors, such as location and extent of positive margins, have been proposed as possible prognostic factors in men with margin-positive prostate cancer, however, the recent International Society of Urological Pathology consensus meeting in Boston noted that there is limited data on the significance of Gleason grade of the carcinoma at a positive margin. The present study shows that the presence of high grade prostate cancer, i.e. Gleason pattern 4 or 5, at a positive surgical margin is an independent predictor of biochemical recurrence after radical prostatectomy. Moreover, patients with lower grade carcinoma at the margin have a similar prognosis to men with negative margins. Hence, assessment of Gleason grade at the site of positive margin may aid optimal selection of patients for adjuvant radiotherapy. OBJECTIVE: • To establish predictors of biochemical recurrence by analysing the pathological characteristics of positive surgical margins (PSMs), including Gleason grade of the carcinoma at the involved margin. PATIENTS AND METHODS: • Clinicopathological and outcome data on 940 patients who underwent radical prostatectomy (RP) between 1997 and 2003 were collected. • Of these, 285 (30.3%) patients with PSMs were identified for pathological review, including assessment of location of margin, linear extent, number of PSMs, plane of margin and Gleason grade (3 vs 4 or 5) at the margin. RESULTS: • At a median follow-up of 82 months, the biochemical recurrence rate of the PSM cohort was 29%. • On univariate analysis, the presence of Gleason grade 4 or 5 at the margin (34.4% of cases) was significantly associated with biochemical recurrence (hazard ratio [HR] 2.80, 95% confidence interval [CI]= 1.82-4.32, P < 0.001) compared with the presence of Gleason grade 3. • Linear extent of margin involvement was also associated with recurrence (P= 0.009). • Single vs multiple margin involvement, location, and plane of the involved margin were not significant predictors of recurrence. • On multivariate analysis, Gleason grade 4 or 5 at the margin remained an independent predictor of recurrence (HR 2.14, 95% CI = 1.29-4.03, P= 0.003). CONCLUSION: • The Gleason grade at the site of a PSM identifies patients at increased risk of biochemical recurrence and should aid stratification of patients for adjuvant radiation therapy.

High-dose rate brachytherapy compared with open radical prostatectomy for the treatment of high-risk prostate cancer: 10 year biochemical freedom from relapse.

OBJECTIVE: • To compare long-term biochemical control of high-risk prostate cancer in those men receiving high-dose rate brachytherapy (HDRB) and radical prostatectomy (RP). PATIENTS AND METHODS: • The 10-year biochemical freedom from relapse (BFR) was calculated for 243 patients who underwent either RP or combined therapy with HDRB + external beam radiotherapy + androgen deprivation between 1998 and 2000. • INCLUSION CRITERIA: clinical stage ≥ T2b, or Gleason sum ≥ 8, or PSA level of > 20 ng/mL. Groups were appraised using the Kattan nomogram for surgery to calculate progression-free probability (PFP). RESULTS: • For the RP group (153 patients) the median PSA level was 8.1 ng/mL and the median age was 62.2 years. The median 5- and 10-year predicted PFP for RP was 64% and 56 %, respectively. The 5- and 10-year BFR was 65.5% and 55.4%. There was no significant difference between the predicted and the actual PFP for the RP group (P= 0.525). • For HDRB group (90 patients). The median PSA level was 14.2 ng/mL and the median age was 67.6 years. The median 5- and 10-year predicted PFP for HDRB was 46% and 35%, respectively. The 5- and 10-year BFR was 79.6% and 53.6%. There was a significant improvement between the actual and the predicted PFP for the HDRB group (P= 0.002). CONCLUSIONS: • Amongst a high-risk cohort, patients undergoing RP performed as predicted by the pre-treatment surgical nomogram, whereas the patients undergoing HDRB performed significantly better than was predicted by the surgical nomogram at 10 years.

Low AZGP1 expression predicts for recurrence in margin-positive, localized prostate cancer.

BACKGROUND: Men with positive margins after radical prostatectomy (RP) for localized prostate cancer (PC) have a 40-50% biochemical relapse rate at 5 years. Adjuvant radiotherapy improves biochemical progression-free and overall survival in men with positive margins, but is associated with increased toxicity. There is an urgent need to identify new prognostic markers to define the group of patients who would benefit from multimodality therapy. METHODS: Nuclear ß-catenin, membranous secreted frizzled-related protein 4 (sFRP4), zinc-alpha 2-glycoprotein (AZGP1), and macrophage inhibitory cytokine-1 (MIC-1) have previously been identified as molecular markers of outcome in localized PC. From these published studies, we identified a subset of patients with positive margins. The aim of this study was to assess the association between these four molecular markers and outcome in men with margin-positive, localized PC. RESULTS: We identified 186 men with positive margins from 330 men with localized PC; 53% had preoperative PSA >10 ng/ml, 72% extraprostatic extension (EPE), 24% seminal vesicles involvement (SVI), and 57% RP Gleason score ≥ 7. AZGP1 (P = 0.009), membranous sFRP4 (P = 0.03) and MIC-1 (P = 0.04) expression predicted for biochemical relapse on univariate analysis. Only absent/low AZGP1 expression (P = 0.01) was an independent predictor of recurrence in margin-positive, localized PC when modeled with preoperative PSA (P = 0.2), EPE (P = 0.2), SVI (P = 0.4), Gleason score ≥ 7 (P = 0.5) and adjuvant treatment (P = 0.4). Furthermore, there was an association between absent/low AZGP1 expression and clinical recurrence (P = 0.007). CONCLUSIONS: AZGP1 is a potential molecular marker for biochemical relapse in men with margin-positive, localized PC. Routine assessment of this biomarker may lead to better selection of patients who will benefit from post-RP radiotherapy.

Stage migration in localized prostate cancer has no effect on the post-radical prostatectomy Kattan nomogram.

OBJECTIVE: To investigate the effect of prostate-specific antigen (PSA) testing on stage migration in an Australian population, and its consequences on the prognostic accuracy of the post-radical prostatectomy (RP) Kattan nomogram, as in North America widespread PSA testing has resulted in prostate cancer stage migration, questioning the utility of prognostic nomograms in this setting. PATIENTS AND METHODS: The study comprised 1008 men who had consecutive RP for localized prostate cancer between 1991 and 2001 at one institution. Two groups were assessed, i.e. those treated in 1991-96 (group 1, the early PSA era), and 1997-2001 (group 2, the contemporary PSA era). Differences in clinicopathological features between the groups were analysed by chi-squared testing and survival modelling. Individual patient data were entered into the post-RP Kattan nomogram and the efficacy assessed by receiver- operating characteristic curve analysis. RESULTS: Patients in group 2 had lower pathological stage disease (P = 0.01) and fewer cancers with Gleason score > or =8 (P < 0.001) than group 1. Multivariate analysis identified preoperative serum PSA level (P < 0.01) and Gleason score (P < 0.01) as strong predictors of biochemical relapse in both groups. In group 2 pathological stage was not significant, but margin involvement became highly significant (P = 0.004). There was no difference in the predictive accuracy of the Kattan nomogram between the groups (P = 0.253). CONCLUSIONS: These findings show a downward stage migration towards organ-confined disease after the introduction of widespread PSA testing in an Australian cohort. Despite this, the Kattan nomogram remains a robust prognostic tool in clinical practice.

HSD17B4 overexpression, an independent biomarker of poor patient outcome in prostate cancer.

Steroid hormones and their metabolising enzymes have been studied extensively for their potential role in prostate cancer, with more recent interest in the androgen/estrogen inactivating enzyme 17beta-hydroxysteroid dehydrogenase type 4 (HSD17B4). Gene expression profiling showed HSD17B4 to be significantly overexpressed in prostate cancer compared to matched-benign epithelium. We therefore hypothesized that altered HSD17B4 expression may contribute to prostate cancer progression via altered hormone balance. In this study, HSD17B4 mRNA and protein expression were assessed by in situ hybridisation (ISH) and immunohistochemistry (IHC), respectively, in tissue arrays of prostate tissue from 172 patients treated by radical prostatectomy. Overexpression of HSD17B4 mRNA and protein was associated with prostate cancer (P<0.0001) and multivariate Cox proportional hazards analysis, adjusted for known prognostic indicators, demonstrated HSD17B4 mRNA and high protein expression were significant independent predictors of poor patient outcome as measured by time until PSA relapse (mRNA: hazards ratio [HR]=1.90, 95% confidence interval [CI]=1.15-3.12; P<0.0001; and protein: HR=2.09, 95% CI=1.31-3.33; P=0.0026). Here we provide strong evidence that both mRNA and protein overexpression of HSD17B4 is not only associated with the presence of prostate cancer, but is also a significant independent predictor of poor patient outcome.

The propeptide mediates formation of stromal stores of PROMIC-1: role in determining prostate cancer outcome.

The extracellular matrix (ECM) is a reservoir of cellular binding proteins and growth factors that are critical for normal cell behavior, and aberrations in the ECM invariably accompany malignancies such as prostate cancer. Carcinomas commonly overexpress macrophage inhibitory cytokine 1 (MIC-1), a proapoptotic and antitumorigenic transforming growth factor-beta superfamily cytokine. Here we show that MIC-1 is often secreted in an unprocessed propeptide containing form. It is variably processed intracellularly, with unprocessed forms being secreted from several tumor lines, including prostate carcinoma lines, PC-3 and LNCaP. Once secreted, only unprocessed proMIC-1 binds ECM, demonstrating for the first time the occurrence of extracellular stores of MIC-1. The propeptide mediates this association via its COOH-terminal 89 amino acids. Xenograft models bearing tumors secreting various engineered forms of MIC-1 show that the propeptide regulates the balance between ECM stores and circulating serum levels of mature MIC-1 in vivo. The absence of propeptide results in approximately 20-fold increase in serum MIC-1 levels. The significance of stromal MIC-1 stores was evaluated in prostate cancer tissue cores, which show major variation in stromal levels of MIC-1. Stromal MIC-1 levels are linked to prostate cancer outcome following radical prostatectomy, with decreasing stromal levels providing an important independent predictor of disease relapse. In low-grade localized prostate cancer (Gleason sum score < or = 6), the level of MIC-1 stromal stores was the best predictor of future relapse when compared with all other clinicopathologic variables. The secretion and ECM association of unprocessed proMIC-1 is likely to play a central role in modulating local bioavailability of MIC-1 which can affect patient outcome in prostate cancer and other epithelial tumors.

Aberrant neuropeptide Y and macrophage inhibitory cytokine-1 expression are early events in prostate cancer development and are associated with poor prognosis.

Studies to elucidate dysregulated gene expression patterns in premalignant prostate lesions have identified several candidate genes with the potential to be targeted to prevent the development and progression of prostate cancer and act as biomarkers of early disease. Herein, we explored the importance of two proteins, neuropeptide Y (NPY) and macrophage inhibitory cytokine-1 (MIC-1), as biomarkers of preinvasive prostate disease and investigated the relationship of expression to biochemical recurrence following treatment for localized prostate cancer. NPY and MIC-1 protein expression was determined by immunohistochemistry on tissue microarrays containing 1,626 cores of benign, low-grade prostatic intraepithelial neoplasia (PIN), high-grade PIN (HGPIN), and prostate cancer tissue from 243 radical prostatectomy patients. Both NPY and MIC-1 showed higher proportional immunostaining in HGPIN and prostate cancer compared with benign epithelium (P < 0.0001). NPY and MIC-1 immunostaining was higher in low-grade PIN compared with other benign tissues (both P < 0.0001) and was equivalent to immunostaining in HGPIN. NPY immunostaining of prostate cancer was independently associated with relapse, after adjusting for traditional prognostic factors, as a categorical variable in 20% intervals (P = 0.0449-0.0103) and as a continuous variable (P = 0.0017). Low MIC-1 immunostaining (20% categories) was associated with pathologic stage >2C after adjusting for predictors of pathologic stage (P = 0.3894-0.0176). This is the first study to show that altered NPY and MIC-1 expression are significantly associated with prostate cancer progression and suggests that these molecules be developed further as biomarkers in the management of prostate disease.

Survival analysis of genome-wide gene expression profiles of prostate cancers identifies new prognostic targets of disease relapse.

Current models of prostate cancer classification are poor at distinguishing between tumors that have similar histopathological features but vary in clinical course and outcome. Here, we applied classical survival analysis to genome-wide gene expression profiles of prostate cancers and preoperative prostate-specific antigen (PSA) levels from each patient, to identify prognostic markers of disease relapse that provide additional predictive value relative to PSA concentration. Three of approximately 200 probesets showing strongest correlation with relapse were identified as the gene for the putative calcium channel protein, trp-p8, with loss of trp-p8 mRNA expression associated with a significantly shorter time to PSA relapse-free survival. We observed subsequently that trp-p8 is lost in the transition to androgen independence in a prostate cancer xenograft model and in prostate cancer tissue from patients treated preoperatively with antiandrogen therapy, suggesting that trp-p8 is androgen regulated, and its loss may be associated with more advanced disease. The identification of trp-p8 and other proteins implicated in the phosphatidylinositol signal transduction pathway that are associated with prostate cancer outcome, both here and in other published work, suggests an integral role for this pathway in prostate carcinogenesis. Thus, our findings demonstrate that multivariable survival analysis can be applied to gene expression profiles of prostate cancers with censored follow-up data and used to identify molecular markers of prostate cancer relapse with strong predictive power and relevance to the etiology of this disease.

Expression of the zinc transporter ZnT4 is decreased in the progression from early prostate disease to invasive prostate cancer.

We have utilized oligonucleotide microarrays to identify novel genes of potential clinical and biological importance in prostate cancer. RNA from 74 prostate cancers and 164 normal body samples representing 40 different tissues were analysed using a customized Affymetrix GeneChip oligonucleotide microarray representative of over 90% of the expressed human genome. The gene for the zinc transporter ZnT4 was one of several genes that displayed significantly higher expression in prostate cancer compared to normal tissues from other organs. A polyclonal antipeptide antibody was used to demonstrate ZnT4 expression in the epithelium of all 165 elements of benign and 326 elements of localized prostate cancers examined and in nine of 10 advanced prostate cancer specimens by immunohistochemistry. Interestingly, decreased intensity of ZnT4 immunoreactivity occurred in the progression from benign to invasive localized prostate cancer and to metastatic disease. Immunofluorescence analysis and surface biotinylation studies of cells expressing ZnT4 localised the protein to intracellular vesicles and to the plasma membrane. These findings are consistent with a role for ZnT4 in vesicular transport of zinc to the cell membrane and potentially in efflux of zinc in the prostate.