Prostate cancer in Korean men exhibits poor differentiation and is adversely related to prognosis after radical prostatectomy

Development and internal validation of a novel nomogram for predicting lymph node invasion for prostate cancer patients undergoing extended pelvic lymph node dissection

Background

Few studies have focused on the performance of Briganti 2012, Briganti 2017 and MSKCC nomograms in the Chinese population in assessing the risk of lymph node invasion(LNI) in prostate cancer(PCa) patients and identifying patients suitable for extended pelvic lymph node dissection(ePLND). We aimed to develop and validate a novel nomogram based on Chinese PCa patients treated with radical prostatectomy(RP) and ePLND for predicting LNI.

Methods

We retrospectively retrieved clinical data of 631 patients with localized PCa receiving RP and ePLND at a Chinese single tertiary referral center. All patients had detailed biopsy information from experienced uropathologist. Multivariate logistic-regression analyses were performed to identify independent factors associated with LNI. The discrimination accuracy and net-benefit of models were quantified using the area under curve(AUC) and Decision curve analysis(DCA).The nonparametric bootstrapping were used to internal validation.

Results

A total of 194(30.7%) patients had LNI. The median number of removed lymph nodes was 13(range, 11-18). In univariable analysis, preoperative prostate-specific antigen(PSA), clinical stage, biopsy Gleason grade group, maximum percentage of single core involvement with highest-grade PCa, percentage of positive cores, percentage of positive cores with highest-grade PCa and percentage of cores with clinically significant cancer on systematic biopsy differed significantly. The multivariable model that included preoperative PSA, clinical stage, biopsy Gleason grade group, maximum percentage of single core involvement with highest-grade PCa and percentage of cores with clinically significant cancer on systematic biopsy represented the basis for the novel nomogram. Based on a 12% cutoff, our results showed that 189(30%) patients could have avoided ePLND while only 9(4.8%) had LNI missing ePLND. Our proposed model achieved the highest AUC (proposed model vs Briganti 2012 vs Briganti 2017 vs MSKCC model: 0.83 vs 0.8 vs 0.8 vs 0.8, respectively) and highest net-benefit via DCA in the Chinese cohort compared with previous nomograms. In internal validation of proposed nomogram, all variables had a percent inclusion greater than 50%.

Conclusion

We developed and validated a nomogram predicting the risk of LNI based on Chinese PCa patients, which demonstrated superior performance compared with previous nomograms.

Validation of user-friendly models predicting extracapsular extension in prostate cancer patients

Objective

There are many models to predict extracapsular extension (ECE) in patients with prostate cancer. We aimed to externally validate several models in a Japanese cohort.

Methods

We included patients treated with robotic-assisted radical prostatectomy for prostate cancer. The risk of ECE was calculated for each patient in several models (prostate side-specific and non-side-specific). Model performance was assessed by calculating the receiver operating curve and the area under the curve (AUC), calibration plots, and decision curve analyses.

Results

We identified ECE in 117 (32.9%) of the 356 prostate lobes included. Patients with ECE had a statistically significant higher prostate-specific antigen level, percentage of positive digital rectal examination, percentage of hypoechoic nodes, percentage of magnetic resonance imaging nodes or ECE suggestion, percentage of biopsy positive cores, International Society of Urological Pathology grade group, and percentage of core involvement. Among the side-specific models, the Soeterik, Patel, Sayyid, Martini, and Steuber models presented AUC of 0.81, 0.78, 0.77, 0.75, and 0.73, respectively. Among the non-side-specific models, the memorial Sloan Kettering Cancer Center web calculator, the Roach formula, the Partin tables of 2016, 2013, and 2007 presented AUC of 0.74, 0.72, 0.64, 0.61, and 0.60, respectively. However, the 95% confidence interval for most of these models overlapped. The side-specific models presented adequate calibration. In the decision curve analyses, most models showed net benefit, but it overlapped among them.

Conclusion

Models predicting ECE were externally validated in Japanese men. The side-specific models predicted better than the non-side-specific models. The Soeterik and Patel models were the most accurate performing models.

Comparison of the clinicopathologic features of prostate cancer in US and Chinese populations

BACKGROUND

Prostate cancer (PCa) is the most common malignant tumor found among men in the United States. Incidence rates of PCa have recently grown in Asian countries, partially due to the comprehensive implementation of early detection systems. Interestingly, a prospective cohort study showed that adopting a westernized dietary pattern was associated with a higher risk of being diagnosed with PCa among Korean and Japanese men. However, a comparison of current clinicopathological features of PCa between American and Chinese men is lacking. In this study, we report the current clinicopathological features of PCa in Chinese men and compare them to those of patients in the USA.

MATERIALS AND METHODS

Case cohorts included, in total, 871 PCa cases with prostatectomy sequentially treated since 2017, including 299 cases from USA and 572 cases from two different academic hospitals in China. The parameters, including patient's age, preoperative Prostate-Specific Antigen (PSA) level, Gleason score, Grade Group, stage and tumor focality, were collected, analyzed and compared using two sample t-test, Wilcoxon rank sum test, Pearson's Chi-squared test and Fisher's exact test.

RESULTS

Significant differences were demonstrated in the mean age of patients, preoperative PSA levels, extra-prostatic extension, Gleason scores, and Grade Groups (p < 0.05). PCa patients in the Chinese group were older than patients in the USA group (67.81 vs. 63.53, p < 0.01). The preoperative PSA levels in the Chinese group were higher than those in the USA group (11.69 v.s 6.30, p < 0.01). A higher percentage of high Grade Groups (Groups 4 and 5) was observed in the Chinese group (25.7%) compared to the USA cohort (17.11%), while Grade Group 2 was more common in the USA group than in the Chinese group (51.68% vs. 32.52%, p < 0.01).

CONCLUSIONS

All these data suggest that the clinicopathologic features of PCa are different between the USA and Chinese populations, which may be influenced by treatment strategies (including surgical case selection criteria).

Validation of models predicting lymph node involvement probability in patients with prostate cancer

OBJECTIVES

There are many models to predict lymph node involvement in patients with prostate cancer. We aimed to externally validate several models in a Japanese cohort.

METHODS

We considered patients who were treated with robotic-assisted radical prostatectomy with extended pelvic lymph node dissection for prostate cancer. The risk of lymph node involvement was calculated for each patient in several models. Model performance was assessed by calculating the receiver operating characteristic curve and the area under the curve, calibration plots, and decision curve analyses.

RESULTS

We identified lymph node involvement in 61 (18.4%) of the 331 considered patients. Patients with lymph node involvement had a higher prostate-specific antigen level, percentage of positive biopsy cores, primary Gleason grade, Gleason group grade, and clinical T-stage category. The Memorial Sloan Kettering Cancer Center web calculator presented the highest area under the curve (0.78) followed by the Yale formula area under the curve (0.77), the updated version of Briganti nomogram of 2017 area under the curve (0.76), and the updated version of the Partin table by Tosoian et al. had an area under the curve of 0.75. However, the 95% confidence interval for these models overlapped. The calibration plot showed that the Memorial Sloan Kettering Cancer Center web calculator and the updated version of the Briganti nomogram calibrated better. In the decision curve analyses, all models showed net benefit; however, it overlapped among them. However, the Memorial Sloan Kettering Cancer Center web calculator and the updated Briganti nomogram presented the highest net benefit for lymph node involvement risks <35%.

CONCLUSION

Models predicting lymph node involvement were externally validated in Japanese men. The Memorial Sloan Kettering Cancer Center web calculator and the updated Briganti nomogram of 2017 were the most accurate performing models.

The national-wide incidence of prostate-specific antigen testing trend for a decade in Korea by age group

Purpose

To document nationwide serum prostate-specific antigen (PSA) testing trends over the past decade and to investigate the impact of testing on prostate cancer (PCa) detection.

Materials and Methods

Using annual National Health Insurance Service of Korea data for the period 2006 to 2016, PSA testing rates were investigated for men aged ≥40 years by decade, and associations between test rates and registered PCa cases were analyzed.

Results

During the study period, the incidence of PCa increased about threefold (4,415 in 2006 to 15,046 in 2016). PCa incidences increased with age (p<0.001) and about 60% of cases were over 70 years old. Despite a fourfold increase in PSA testing (246,911 in 2006 to 937,548 in 2016), the average exposure rate among all men was only 7.27% in 2016, and the mean number of repeat tests for those that did not develop PCa during the study period was 2.9. PSA test rates increased with age and in 2016 were 1.65% for those in their 40s, 4.90% for those in their 50s, 12.0% for those in their 60s, 19.2% for those in their 70s, and 21.6% for those aged ≥80. Regardless of the age groups, a significant association was found between PSA test numbers and the detection of PCas.

Conclusions

In contrast to the soaring incidence of PCa especially in those aged over 70 years who have a more frequent chance for PSA testing triggered by concomitant voiding symptoms, low exposure in general and among relatively younger men favors a countrywide screening policy.

How Much Reliable Is the Current Belief on Grade Group 1 Prostate Cancer?

Objective: To evaluate the clinicopathological characteristics of grade group 1 (GG1) prostate cancer in Korean populations.

Methods: We retrospectively analyzed 492 consecutive radical prostatectomy specimens from our institution, which included those from 322 men with clinical GG1 and 170 with clinical GG2 tumors between years 2009 and 2018. The incidence of Gleason score (GS) upgrading, extraprostatic extension (EPE), and seminal vesicle invasion (SVI) were evaluated in patients with clinical GG1. In pathological GG1 cases, the distribution of adverse pathological features including EPE, lymphovascular invasion (LVI), perineural invasion (PNI), and biochemical recurrence (BCR) was analyzed.

Results: Altogether, 78 (24.2%) out of 322 men in the clinical GG1 group demonstrated upgrading of GS, including 19 men with pathological Gleason score 4 + 3 = 7 and 6 with ≥ pathological Gleason score 4 + 4 = 8 cases. EPE was found in 37 (11.5%) and 22 (8.9%) men in clinical GG1 and pathological GG1 group, respectively. The incidence of LVI and PNI in the pathological GG1 cases was 2.8% (n = 7) and 28.6% (n = 71), respectively. BCR was observed in 4 men in pathological GG1 T2 (n = 226) and 2 men in GG1 T3 (n = 22) group. When we compared the pathological features between pathological GG1 T3 vs. GG2 T2, there was no statistical differences in the incidence of LVI and PNI between the two groups.

Conclusions: Contrary to the current concept that GG1 is almost always clinically insignificant, it seems that GG1 still possess its respectable position as a group of cancer with aggressiveness. These findings should be kept in mind when deciding on treatment options for prostate cancer patients in the Asian populations.

Patients with Biopsy Gleason Score 3 + 4 Are Not Appropriate Candidates for Active Surveillance

OBJECTIVE

The aim of this study was to evaluate the feasibility of including patients with biopsy Gleason score (bGS) 3 + 4 prostate cancer in an active surveillance (AS) protocol.

METHODS

A total of 615 patients underwent a radical prostatectomy and satisfied the following requirements: prostate-specific antigen ≤10 ng/dL, clinical stage T1c or T2a, 2 or fewer positive biopsy cores, and bGS 6 or 3 + 4 prostate cancer. The patients were divided into two groups according to their bGS (bGS 6 group, n =534; bGS 3 + 4 group, n = 81).

RESULTS

The adverse pathological features were significantly higher in the bGS 3 + 4 group (16.7 vs. 49.4%, p< 0.001). Biochemical recurrence (BCR)-free survival was also significantly lower in this group (p < 0.001). In a multivariate analysis, clinical stage (odds ratio [OR] 2.026, p =0.007), maximum percentage of biopsy core involvement (OR 1.015, p = 0.014), and bGS (OR 1.913, p = 0.030) were independent risk factors for adverse pathological features. However, the bGS was the only variable to forecast BCR (hazard ratio 3.567, p < 0.001).

CONCLUSIONS

A bGS 3 + 4 was the leading risk factor for a worse postoperative prognosis. Therefore, patients with a bGS 3 + 4 are not appropriate candidates for AS.

Use of docetaxel plus androgen deprivation therapy for metastatic hormone-sensitive prostate cancer in Korean patients: A retrospective study

Purpose

We aimed to evaluate the efficacy and safety of the use of docetaxel plus androgen deprivation therapy (ADT) for metastatic hormone-sensitive prostate cancer (mHSPC) in Korean patients.

Materials and Methods

This study was conducted retrospectively. In total, 61 Korean patients with mHSPC who used docetaxel plus ADT were identified from medical records. Patients received docetaxel plus ADT at a dose of 75 mg/m2 every 3 weeks for 6 cycles. We evaluated prostate-specific antigen (PSA) response, PSA progression, progression to castration-resistant prostate cancer (CRPC), clinical progression, and adverse events.

Results

Most of the patients had high volume disease (98.3%) and 83.6% had a Gleason score of 8 or higher. The median PSA level at the start of ADT was 131.4 ng/mL. The percentage of patients whose PSA levels decreased to less than 0.2 ng/mL at 3, 6, and 12 months were 28.3%, 41.0%, and 45.0%, respectively. During a median of 12.0 months after treatment, PSA progression occurred in 13.3% of patients. Clinical progression and progression to CRPC were observed in 15.1% and 14.8%, respectively. Neutropenia grade ≥3 and febrile neutropenia occurred in 63.5% and 11.5%, respectively.

Conclusions

Comparing our findings with those of the prior chemohormonal therapy versus androgen ablation randomized trial for extensive disease in prostate cancer (CHAARTED) study, in Korean patients, the use of docetaxel plus ADT for mHSPC showed similar results for early oncologic outcomes including PSA response and time to clinical progression. However, we observed a higher rate of adverse events, which should be considered seriously.

Pathological Characteristics of Prostate Cancer in Men Aged < 50 Years Treated with Radical Prostatectomy: a Multi-Centre Study in Korea

BACKGROUND

Recently, younger prostate cancer (PCa) patients have been reported to harbour more favourable disease characteristics after radical prostatectomy (RP) than older men. We analysed young men (<50 years) with PCa among the Korean population, paying attention to pathological characteristics on RP specimen and biochemical recurrence (BCR).

METHODS

The multi-centre, Severance Urological Oncology Group registry was utilized to identify 622 patients with clinically localized or locally advanced PCa, who were treated with RP between 2001 and 2017. Patients were dichotomized into two groups according to age (< 50-year-old [n = 75] and ≥ 50-year-old [n = 547]), and clinicopathological characteristics were analysed. Propensity score matching was used when assessing BCR between the two groups.

RESULTS

Although biopsy Gleason score (GS) was lower in younger patients (P = 0.033), distribution of pathologic GS was similar between the two groups (13.3% vs. 13.9% for GS ≥ 8, P = 0.191). There was no significant difference in pathologic T stage between the < 50- and ≥ 50-year-old groups (69.3% vs. 68.0% in T2 and 30.7% vs. 32.0% in ≥ T3, P = 0.203). The positive surgical margin rates were similar between the two groups (20.0% vs. 27.6%, P = 0.178). BCR-free survival rates were also similar (P = 0.644) between the two groups, after propensity matching.

CONCLUSION

Contrary to prior reports, younger PCa patients did not have more favourable pathologic features on RP specimen and showed similar BCR rates compared to older men. These findings should be considered when making treatment decisions for young Korean patients with PCa.

A genetic variant in SLC28A3, rs56350726, is associated with progression to castration-resistant prostate cancer in a Korean population with metastatic prostate cancer

Background

Genetic variation which related with progression to castration-resistant prostate cancer (CRPC) during androgen-deprivation therapy (ADT) has not been elucidated in patients with metastatic prostate cancer (mPCa). Therefore, we assessed the association between genetic variats in mPCa and progession to CRPC.

Results

Analysis of exome genotypes revealed that 42 SNPs were significantly associated with mPCa. The top five polymorphisms were statistically significantly associated with metastatic disease. In addition, one of these SNPs, rs56350726, was significantly associated with time to CRPC in Kaplan-Meier analysis (Log-rank test, p = 0.011). In multivariable Cox regression, rs56350726 was strongly associated with progression to CRPC (HR = 4.172 95% CI = 1.223-14.239, p = 0.023).

Materials and Methods

We assessed genetic variation among 1000 patients with PCa with or without metastasis, using 242,221 single nucleotide polymorphisms (SNPs) on the custom HumanExome BeadChip v1.0 (Illuminam Inc.). We analyzed the time to CRPC in 110 of the 1000 patients who were treated with ADT. Genetic data were analyzed using unconditional logistic regression and odds ratios calculated as estimates of relative risk of metastasis. We identified SNPs associated with metastasis and analyzed the relationship between these SNPs and time to CRPC in mPCa.

Conclusions

Based on a genetic variation, the five top SNPs were observed to associate with mPCa. And one (SLC28A3, rs56350726) of five SNP was found the association with the progression to CRPC in patients with mPCa.

Predictors of pathological upgrading in low-risk prostate cancer patients without hypointense lesions on an apparent diffusion coefficient map of multiparametric magnetic resonance imaging

PURPOSE

To examine the clinicopathological features and identify the predictors of pathological upgrading in low-risk prostate cancer (PCa) patients without hypointense lesions on the apparent diffusion coefficient (ADC) map calculated from multiparametric magnetic resonance imaging.

METHODS

We reviewed the medical records of 1905 PCa patients who underwent radical prostatectomy between 2007 and 2015. All ADC images were graded using the five-grade Likert scale; the positive hypointense lesions were graded 4-5. We analyzed 256 patients with low-risk classifications according to D'Amico criteria. Patients were classified into two groups according to the pathologic upgrading in the surgical specimens. The predictive factors for pathologic upgrading were evaluated using a multivariate logistic regression analysis.

RESULTS

In 256 patients with low-risk PCa, the percentage of positive cores [odds ratio (OR) 1.09; 95 % confidence interval (CI) 1.02-1.16], the percentage of cancer in the positive cores (OR 1.07, 95 % CI 1.03-1.12), and the presence of hypointensity on an ADC map (OR 2.28; 95 % CI 1.23-4.22) were independent predictors of pathologic upgrading. Notably, 138 of low-risk patients (53.9 %) had no hypointense lesions on an ADC map. Of these 138 patients, the percentage of positive cores (OR 1.09; 95 % CI 1.01-1.18) and the percentage of cancer in the positive cores (OR 1.06; 95 % CI 1.01-1.12) remained independent predictors of pathologic upgrading.

CONCLUSIONS

In low-risk PCa patients without hypointense lesions on an ADC map, biopsy-related parameters such as the percentage of positive cores and the percentage of cancer in the positive cores were independent predictors of pathological upgrading following radical prostatectomy.

Differences in the aggressiveness of prostate cancer among Korean, Caucasian, and African American men: A retrospective cohort study of radical prostatectomy

PURPOSE

We aimed to compare the pathologic aggressiveness of clinically localized prostate cancer (PCa) treated by radical prostatectomy in Korean and Western (Caucasian and African American [AA]) men by analyzing data from representative hospitals in the capitals of Korea (Seoul) and the United States (Washington, DC).

METHODS

We performed a retrospective cohort study of 1,939 patients who underwent radical prostatectomy for clinically localized PCa in the Asan Medical Center and Washington Hospital Center. After adjusting for confounding clinical variables, we used multivariate logistic regression analysis to assess differences in the aggressiveness of PCa.

RESULTS

We analyzed 1,152 Korean, 473 Caucasian, and 314 AA patients. There were significant differences between Korean and Western patients in terms of age at surgery, preoperative levels of prostate-specific antigen, and clinical stage (P<0.001). Overall, high-grade PCa (Gleason score≥8) was more common in Korean (19.4%) than in AA (6.1%) or Caucasian (5.5%) patients (P<0.001). The incidence of advanced-stage PCa (pT3 or higher) was higher in Korean (34.8%) than in AA (18.2%) or Caucasian (13.3%) patients (P<0.001). After adjusting for age, prostate-specific antigen, prostate volume, and clinical stage, multivariate logistic regression analysis showed that Korean men had a high risk of high-grade PCa (Korean vs. Caucasian, odds ratio [OR] = 3.48, P<0.001; Korean vs. AA, OR=3.14, P<0.001) or advanced-stage PCa (Korean vs. Caucasian, OR=2.40, P<0.001; Korean vs. AA, OR = 1.59, P = 0.009) than Western men.

CONCLUSIONS

There are differences in PCa aggressiveness between Korean and Western men. The incidence of high-grade or advanced-stage PCa is higher in Korean men.

Genome-wide detection of allelic genetic variation to predict advanced-stage prostate cancer after radical prostatectomy using an exome SNP chip

OBJECTIVES

Genetic variations among patients with prostate cancer (PCa) who underwent radical prostatectomies were evaluated to predict advanced stage above T3 using an exome single nucleotide polymorphism (SNP) chip array.

MATERIALS AND METHODS

We collected data of genetic SNP variants from 820 patients with PCa who underwent radical prostatectomy (RP) using a custom HumanExome BeadChip v1.0 (Illumina Inc.). We selected the SNPs that were most significantly associated with advanced-stage PCa (≥ T3) among the 242,186 SNPs that were genotyped, and we compared the accuracies of the associations using a multivariate logistic model that incorporated clinical factors and clinicogenetic factors.

RESULTS

Among the total cohort, 360 patients (43.9%) had advanced pathologic stage (≥ T3) after RP, of whom 262 (32.0%) had extracapsular extensions, 79 (9.6%) had seminal vesicle invasions, and 10 (1.3%) had bladder neck invasions. The exome array analysis indicated that 5 SNPs (rs6804162, rs8055236, rs56335308, rs6104, and rs12618769) were significant for predicting T3 stage after RP in patients with PCa. These genetic markers were significant factors after adjusting for other clinical parameters, and they increased the accuracy of a multivariate model for predicting advanced stage of PCa (83.9%-87.2%, P = 0.0001).

CONCLUSIONS

Based on a genetic array, the selected SNPs were found to be independent predictors for advanced stage after RP, and the addition of individualized genetic information effectively enhanced the accuracy of predicting advanced-stage disease. These results should be validated in another independent cohort.

Expression of Peroxisome Proliferator Activated Receptor gamma in Prostatic Adenocarcinoma

Peroxisome proliferator-activated receptor gamma (PPAR-γ), a ligand-activated transcription factor has been investigated as the target for cancer treatment as well as metabolic disorders. Recent studies have demonstrated that PPAR-γ ligands are anti-tumorigenic in prostate cancer due to anti-proliferative and pro-differentiation effects. The aim of this study was to validate PPAR-γ expression in malignant and benign prostate tissues by immunohistochemistry and quantitative real-time polymerase chain reaction (PCR). A total of 730 prostatic adenocarcinomas (PCAs) including 63 whole sections from radical prostatectomy specimens and tissue microarrays containing 667 PCAs were subject to immunostaining for two PPAR-γ antibodies. Twenty-five benign prostate tissues and PCAs were selected for investigating mRNA expression by quantitative real-time PCR. 10.7% of PCAs (78/730) showed cytoplasmic immunoreactivity of PPAR-γ and no nuclear immunoreactivity was noted in PCAs. Most benign prostatic glands showed negative immunoreactivity of PPAR-γ except for variable weak cytoplasmic staining in some glands. Nuclear immunoreactivity of PPAR-γ was noted some central zone and verumontanum mucosal epithelium. The constitutive PPAR-γ mRNA showed significantly lower level in PCAs compared to that in the benign tissues. There was no difference of PPAR-γ mRNA expression between low (≤7) and high (>7) Gleason score groups. There was no association of PPAR-γ mRNA level or cytoplasmic immunostaining with Gleason grade or pathologic stage. Our study supported the evidence of extra-nuclear localization and nongenomic actions of PPAR-γ. Further studies are needed to assess the functional role of PPAR-γ and to validate its therapeutic implication in prostate cancer.

Genome-wide detection of allelic genetic variation to predict biochemical recurrence after radical prostatectomy among prostate cancer patients using an exome SNP chip

PURPOSES

Genetic variations among prostate cancer patients who underwent radical prostatectomies were evaluated to predict biochemical recurrence, and used to develop a clinical-genetic model that combines data on clinicopathological factors of prostate cancer and individual genetic variations.

MATERIALS AND METHODS

We genotyped 242,186 SNPs on a custom HumanExome BeadChip v1.0 (Illuminam Inc.) from the blood DNA of 776 PCa patients who underwent radical prostatectomy. Genetic data were analyzed to calculate an odds ratio as an estimate of the relative risk of biochemical recurrence. And we compared accuracies from the multivariate model incorporating clinicopathological factors between included and excluded selected lead single nucleotide polymorphisms. Biochemical recurrence-free survival outcomes also analyzed using these genetic variations.

RESULTS

Genetic array analysis indicated that eight single nucleotide polymorphisms (rs77080351, rs200944490, rs2071292, rs117237810, rs191118242, rs4965121, rs61742396, and rs6573513) were significant to predict biochemical recurrence after radical prostatectomy. When a multivariate model incorporating clinicopathological factors was devised to predict biochemical recurrence, the predictive accuracy of model was 85.1 %. By adding in two individual variations of single nucleotide polymorphisms in the multivariate model, the predictive accuracy increased to 87.7 % (P = 0.045). With three variations of single nucleotide polymorphisms, the predictive accuracy further improved to 89.0 % (P = 0.025). These genetic variations had a significantly decreased biochemical recurrence-free survival rate.

CONCLUSIONS

Based on exome array, the selected single nucleotide polymorphisms were predictors for biochemical recurrence. The addition of individualized genetic information effectively enhanced the predictive accuracy of biochemical recurrence among prostate cancer patients who underwent radical prostatectomy.

Comparison of pathological and biochemical outcomes after radical prostatectomy in Korean patients with serum PSA ranges

The aim of this study was to assess surgical outcome at radical prostatectomy (RP) in Korean men with a serum prostate-specific antigen (PSA) level of 2.5 to 3.0 ng/mL and compared with those of patients who had a PSA level of 3.0-4.0 and 4.0-10.0 ng/mL. We retrospectively compared clinico-pathological characteristics and biochemical recurrence (BCR) risk in patients with PSA level of 2.5-3.0 (group 1, n = 92, 5.7%), 3.0-4.0 (group 2, n = 283, 17.5%), or 4.0-10.0 ng/mL (group 3, n = 1,242, 76.8%) who underwent RP between 1995 and 2013. The pathologic characteristics including Gleason score, pathologic stage, and percentage of significant cancer in group 1 were similar to those in group 2 and group 3. Furthermore, pathological upgrading and upstaging were found in 23 (30.7%) and 10 (14.7%) in group 1, 84 (33.9%) and 19 (8.8%) in group 2, and 321 (32.8%) and 113 (12.8%) in group 3, respectively, with no significant differences among the three groups (all P > 0.05). In multivariate analysis, PSA grouping was not an independent predictor of BCR. Within the population with PSA lower than 10 ng/mL, substratification of PSA is not a significant predictor for upgrading, upstaging, or adverse prognosis.

Efficacy and safety of degarelix in Korean patients with prostate cancer requiring androgen deprivation therapy: Open-label multicenter phase III study

Purpose

To assess the noninferiority, efficacy, and safety of degarelix in achieving and maintaining testosterone at castrate levels (≤0.5 ng/mL) in Korean patients (CS42) versus non-Asian patients with prostate cancer (PCa).

Methods

A Phase III, open-label, multicenter, single-arm trial was conducted in Korean patients with PCa. Degarelix was administered at a starting dose of 240 mg followed by monthly (28-day intervals) maintenance doses of 80 mg (240/80 mg dose regimen) for 7 months. The results were compared with non-Asian patients receiving degarelix 240/80 mg in the CS21 study.

Results

The estimated difference in the cumulative probabilities of testosterone ≤0.5 ng/mL from Day 28 to Day 196 between the trials was −2.3% (96.7% in CS42 vs. 99.0% in CS21). The lower limit of the 95% confidence interval was −5.5%, i.e., above the predefined noninferiority limit of −10% and thus noninferiority was established. Decreases in serum testosterone, prostate-specific antigen, and luteinizing hormone over time were similar in CS42 and CS21. There were no clinically significant differences in incidence of treatment-emergent adverse events (72% in CS42 vs. 70% in CS21) and changes in clinical chemistry and hematology parameters between the two trials. The most common adverse event was injection-site reaction.

Conclusions

Overall, degarelix was effective and well tolerated in Korean patients. Testosterone suppression was noninferior to that in non-Asian patients and safety findings were as would be expected for elderly men with PCa undergoing androgen deprivation therapy.

A clinicogenetic model to predict lymph node invasion by use of genome-based biomarkers from exome arrays in prostate cancer patients

Purpose

Genetic variations among prostate cancer (PCa) patients who underwent radical prostatectomy (RP) and pelvic lymph node dissection were evaluated to predict lymph node invasion (LNI). Exome arrays were used to develop a clinicogenetic model that combined clinical data related to PCa and individual genetic variations.

Materials and Methods

We genotyped 242,186 single-nucleotide polymorphisms (SNPs) by using a custom HumanExome BeadChip v1.0 (Illumina Inc.) from the blood DNA of 341 patients with PCa. The genetic data were analyzed to calculate an odds ratio as an estimate of the relative risk of LNI. We compared the accuracies of the multivariate logistic model incorporating clinical factors between the included and excluded selected SNPs. The Cox proportional hazard models with or without genetic factors for predicting biochemical recurrence (BCR) were analyzed.

Results

The genetic analysis indicated that five SNPs (rs75444444, rs8055236, rs2301277, rs9300039, and rs6908581) were significant for predicting LNI in patients with PCa. When a multivariate model incorporating clinical factors was devised to predict LNI, the predictive accuracy of the multivariate model was 80.7%. By adding genetic factors in the aforementioned multivariate model, the predictive accuracy increased to 93.2% (p=0.006). These genetic variations were significant factors for predicting BCR after adjustment for other variables and after adding the predictive gain to BCR.

Conclusions

Based on the results of the exome array, the selected SNPs were predictors for LNI. The addition of individualized genetic information effectively enhanced the predictive accuracy of LNI and BCR among patients with PCa who underwent RP.

The use of exome genotyping to predict pathological Gleason score upgrade after radical prostatectomy in low-risk prostate cancer patients

Background

Active surveillance (AS) is a promising option for patients with low-risk prostate cancer (PCa), however current criteria could not select the patients correctly, many patients who fulfilled recent AS criteria experienced pathological Gleason score upgrade (PGU) after radical prostatectomy (RP). In this study, we aimed to develop an accurate model for predicting PGU among low-risk PCa patients by using exome genotyping.

Methods

We genotyped 242,221 single nucleotide polymorphisms (SNP)s on a custom HumanExome BeadChip v1.0 (Illuminam Inc.) in blood DNA from 257 low risk PCa patients (PSA <10 ng/ml, biopsy Gleason score (GS) ≤6 and clinical stage ≤T2a) who underwent radical prostatectomy. Genetic data were analyzed using an unconditional logistic regression to calculate an odds ratio as an estimate of relative risk of PGU, which defined pathologic GS above 7. Among them, we selected persistent SNPs after multiple testing using FDR method, and we compared accuracies from the multivariate logistic model incorporating clinical factors between included and excluded selected SNP information.

Results

After analysis of exome genotyping, 15 SNPs were significant to predict PGU in low risk PCa patients. Among them, one SNP – rs33999879 remained significant after multiple testing. When a multivariate model incorporating factors in Epstein definition – PSA density, biopsy GS, positive core number, tumor per core ratio and age was devised for the prediction of PGU, the predictive accuracy of the multivariate model was 78.4% (95%CI: 0.726–0.834). By addition the factor of rs33999879 in aforementioned multivariate model, the predictive accuracy was 82.9%, which was significantly increased (p = 0.0196).

Conclusion

The rs33999879 SNP is a predictor for PGU. The addition of genetic information from the exome sequencing effectively enhanced the predictive accuracy of the multivariate model to establish suitable active surveillance criteria.

Predictive factors of unfavorable prostate cancer in patients who underwent prostatectomy but eligible for active surveillance

PURPOSE

To investigate the predictive factors of unfavorable prostate cancer in Korean men who underwent radical prostatectomy but eligible for active surveillance according to Epstein criteria.

METHODS

We retrospectively reviewed the medical records of 2,036 patients who underwent radical prostatectomy for prostate cancer between 1994 and 2011. Among these, 233 patients were eligible for active surveillance based on Epstein criteria. Unfavorable prostate cancer was defined as pathologic Gleason sum ≥7 or non-organ-confined disease. We investigated pathologic outcomes and predictive factors for unfavorable prostate cancer.

RESULTS

Of 233 cases, 91 patients (39.1%) were pathologic Gleason sum ≥7, 11 (4.7%) had extracapsular extension, and three (1.3%) had seminal vesicle invasion. Ninety-eight patients (42.1%) had unfavorable prostate cancer. When comparing clinically insignificant and significant prostate cancer, there were significant differences in mean age (P=0.007), prostate volume (P=0.021), prostate-specific antigen (PSA) density (P=0.03), maximum tumor volume in biopsy core (P<0.001), and rate of two positive cores (P=0.001). On multivariate analysis, age (P=0.015), PSA density (P=0.017) and two positive cores (P=0.001) were independent predictive factors for unfavorable prostate cancer.

CONCLUSIONS

A significant proportion of patients who were candidates for active surveillance had unfavorable prostate cancer. Age, PSA density, and two positive cores were independent significant predictive factors for unfavorable prostate cancer. These factors should be considered when performing active surveillance.

Pre- and post-operative nomograms to predict recurrence-free probability in korean men with clinically localized prostate cancer

Objectives

Although the incidence of prostate cancer (PCa) is rapidly increasing in Korea, there are few suitable prediction models for disease recurrence after radical prostatectomy (RP). We established pre- and post-operative nomograms estimating biochemical recurrence (BCR)-free probability after RP in Korean men with clinically localized PCa.

Patients and Methods

Our sampling frame included 3,034 consecutive men with clinically localized PCa who underwent RP at our tertiary centers from June 2004 through July 2011. After inappropriate data exclusion, we evaluated 2,867 patients for the development of nomograms. The Cox proportional hazards regression model was used to develop pre- and post-operative nomograms that predict BCR-free probability. Finally, we resampled from our study cohort 200 times to determine the accuracy of our nomograms on internal validation, which were designated with concordance index (c-index) and further represented by calibration plots.

Results

Over a median of 47 months of follow-up, the estimated BCR-free rate was 87.8% (1 year), 83.8% (2 year), and 72.5% (5 year). In the pre-operative model, Prostate-Specific Antigen (PSA), the proportion of positive biopsy cores, clinical T3a and biopsy Gleason score (GS) were independent predictive factors for BCR, while all relevant predictive factors (PSA, extra-prostatic extension, seminal vesicle invasion, lymph node metastasis, surgical margin, and pathologic GS) were associated with BCR in the post-operative model. The c-index representing predictive accuracy was 0.792 (pre-) and 0.821 (post-operative), showing good fit in the calibration plots.

Conclusions

In summary, we developed pre- and post-operative nomograms predicting BCR-free probability after RP in a large Korean cohort with clinically localized PCa. These nomograms will be provided as the mobile application-based SNUH Prostate Cancer Calculator. Our nomograms can determine patients at high risk of disease recurrence after RP who will benefit from adjuvant therapy.

Can microfocal prostate cancer be regarded as low-risk prostate cancer?

PURPOSE

Prostate specific antigen (PSA) screening for prostate cancer has become widespread, the prostate biopsy technique has evolved, and the occurrence of low-risk prostate cancer has been increasing. Even low-risk patients may demonstrate disease upgrading or upstaging. We aimed to evaluate the clinical importance of a single microfocal prostate cancer at biopsy in patients subsequently treated with radical prostatectomy.

METHODS

A total of 337 cases of patients who underwent radical prostatectomy after prostate biopsies were retrospectively reviewed. Microfocal prostate cancer was defined as Gleason score 6 and a single positive core with ≤5% cancer involvement after the standard 12-core extended biopsy.

RESULTS

Of the 337 prostatectomy specimens, 22 (6.5%) were microfocal prostate cancer based on prostate biopsy. On final pathology, microfocal patients were found to have significant 45% Gleason score upgrading (P=0.02) and 27% positive surgical margins (P=0.04) despite low PSA, compared with the nonmicrofocal prostate cancer group. Gleason upgrading was significantly higher in the microfocal prostate cancer group (P=0.02), whereas Gleason downgrading was significantly higher in the nonmicrofocal prostate cancer group (P<0.01). Furthermore, biochemical recurrence rate was no different between microfocal and nonmicrofocal prostate cancer at mean 31 months (P=0.18). Overall, 13 of 22 cases (53.1%) in the microfocal prostate cancer group showed Gleason upgrading or stage upgrading.

CONCLUSIONS

Based on higher rates of Gleason score upgrading or stage upgrading cases in microfocal prostate cancer group, compared with nonmicrofocal prostate cancer group, active surveillance should be cautiously applied to these patients.

Quantification of median lobe protrusion and its impact on the base surgical margin status during robot-assisted laparoscopic prostatectomy

PURPOSE

Protrusion of the median lobe (PML) is thought to add technical difficulty during robot-assisted laparoscopic prostatectomy (RALP). Thus, we quantified PML using preoperative magnetic resonance imaging (MRI) and evaluated its impact on base surgical margin (BSM) status during RALP.

METHODS

The clinical data of consecutive patients who underwent RALP were retrieved from a prospectively registered database. Of the 655 eligible men, 9 patients were excluded because they did not undergo MRI. PML was measured in a T2-weighted mid-sagittal scan. We performed univariate and multiple logistic regression analyses.

RESULTS

The mean PML was 8.3 ± 3.6 mm. The rate of positive surgical margins was 17.3 % (73/423) in pathologic stage T2 and 34.6 % (226/646) in all cases. The BSMs were positive in 10.1 % (66/646) of cases. A logistic regression analysis revealed that PML was significantly correlated with BSM positivity in all cases (odds ratio [OR] 1.080, p = 0.026). In particular, they had a stronger correlation with pathologic stage T3 or higher (OR 1.1143, p = 0.004). PML was an independent predictor of BSM positivity (OR 1.113, p = 0.046) in pathologic stage T3 or higher, as were preoperative prostate-specific antigen, prostate size, and pathologic stage. Cases with 10 mm or higher PML had significantly more BSM positivity than cases with <10 mm PML (35.9 vs. 20.1 %, p = 0.012).

CONCLUSIONS

Protrusion of the median lobe measured using preoperative MRI was significantly correlated with positive BSMs during RALP. Surgeons should pay more attention to patients with 10 mm or higher PML and advanced stages.

Is small prostate volume a predictor of Gleason score upgrading after radical prostatectomy?

PURPOSE

We aimed to analyze the relationship between prostate volume and Gleason score (GS) upgrading [higher GS category in the radical prostatectomy (RP) specimen than in the prostate biopsy] in Korean men.

MATERIALS AND METHODS

We retrospectively analyzed the medical records of 247 men who underwent RP between May 2006 and April 2011 at our institution. Transrectal ultrasound (TRUS) volume was categorized as 25 cm³ or less (n=61), 25 to 40 cm³ (n=121) and greater than 40 cm³ (n=65). GS was examined as a categorical variable of 6 or less, 3+4 and 4+3 or greater. The relationship between TRUS volume and upgrading of GS was analyzed using multivariate logistic regression.

RESULTS

Overall, 87 patients (35.2%) were upgraded, 20 (8.1%) were downgraded, and 140 (56.7%) had identical biopsy and pathological Gleason sum groups. Smaller TRUS volume was significantly associated with increased likelihood of upgrading (p trend=0.022). Men with prostates 25 cm³ or less had more than 2.7 times the risk of disease being upgraded relative to men with TRUS volumes more than 40 cm³ (OR 2.718, 95% CI 1.403-8.126).

CONCLUSION

In our study, smaller prostate volumes were at increased risk for GS upgrading after RP. This finding should be kept in mind when making treatment decisions for men with prostate cancer that appears to be of a low grade on biopsy, especially in Asian urologic fields.

Tumor volume adds prognostic value in patients with organ-confined prostate cancer

PURPOSE

This study was designed to assess the independent prognostic value of tumor volume (TV) and whether adding TV provides additional prognostic information for predicting biochemical recurrence (BCR) after radical prostatectomy.

METHODS

We reviewed the medical records of 1,129 patients who underwent radical prostatectomy between July 2005 and July 2011. TV was categorized as minimal (≤1.0 ml), moderate (1.1-5.0 ml), or extensive (>5.0 ml). Cox regression analysis was performed to identify independent predictors of BCR. The predictive accuracies of Cox's proportional hazard regression models with and without TV were quantified and compared using time-dependent receiver operating characteristic curve analysis.

RESULTS

Increasing TV was associated with higher prostate specific antigen, pathological Gleason score, and pathologic tumor stage. TV was an independent predictor of BCR in multivariate analysis (p<0.001). When patients were stratified by organ-confined and nonorgan-confined tumor groups, TV remained an independent predictor of BCR in organ-confined tumors (p<0.001). In the nonorgan-confined tumor group, a significant difference was found only between extensive versus minimal TV (p=0.023). The predictive accuracy of the Cox regression model increased significantly by adding TV in organ-confined tumor group (0.748 vs. 0.704, p<0.05) but not in nonorgan-confined group (0.742 vs. 0.734, p>0.05).

CONCLUSIONS

TV was an independent prognostic predictor of BCR in organ-confined prostate cancers and provided additional prognostic information with increased predictive accuracy. In contrast, TV did not increase the predictive accuracy in nonorgan-confined tumor. TV should be considered as a prognosticator in organ-confined tumors.

Biochemical outcomes after robot-assisted radical prostatectomy in patients with follow-up more than 5-years

In this study, we assessed biochemical outcomes after robot-assisted radical prostatectomy (RARP). Between July 2005 and November 2007, one hundred and seventy-six consecutive patients treated by RARP without neoadjuvant treatment were included in this study. All procedures were performed by a single surgeon and the median follow-up period was 60 months (interquartile range (IQR): 59-69). The median prostate specific antigen was 7.50 ng ml(-1) (IQR: 5.14-11.45) and 39.2% of the patients were classified as intermediate risk and 15.3% were classified as high risk; on final pathological examination, 35.2% of the patients had non-organ confined disease and 37.5% and 14.2% had Gleason scores of 7 and 8-10, respectively. The biochemical recurrence (BCR)-free survival rates at 3 and 5 years were 85.6% and 81.2%, respectively. The 5-year BCR-free survival rates stratified by pathologic Gleason scores were 93.1% in Gleason scores of 6 or less, 74.5% in a Gleason score of 7, and 58.1% in Gleason scores of 8 or greater, respectively (P<0.001). When stratified by pathologic stage, the BCR-free survival rates were 89.8% in pT2 patients, 66.2% in pT3a patients, and 39.3% in pT3b patients at 5 years following RARP, respectively (P<0.001). Preoperative prostate-specific antigen (PSA), pathologic stage, postoperative Gleason score and surgical margin status were independently associated with BCR in multivariate analysis. In this study, we report biochemical outcomes after RARP with the longest follow-up periods to date in Asian men. We found that robotic surgery provided satisfactory biochemical outcomes, and that RARP is a safe and effective procedure in terms of oncologic outcomes.

Biochemical recurrence in Gleason score 7 prostate cancer in korean men: significance of the primary Gleason grade

Purpose

To evaluate the impact of primary Gleason grade in Gleason score (GS) 7 prostate cancer on biochemical recurrence (BCR) after radical prostatectomy in Korean men.

Materials and Methods

We retrospectively reviewed records of 1,026 patients who underwent radical prostatectomy at Seoul National University Bundang Hospital between November 2003 and June 2009. We excluded patients who had received neoadjuvant therapy and had positive resection margins. Finally, 295 and 113 patients with GS 3+4 and GS 4+3, respectively, were included in this study. All patients were followed for at least 2 years.

Results

Of the 408 GS 7 patients, 295 (72.3%) were 3+4 and 113 (27.7%) were 4+3. Mean serum prostate specific antigen level in primary Gleason 3 was 8.99 ng/ml and primary Gleason 4 was 11.11 ng/ml. Patients with GS 4+3 were more likely to have extracapsular extension (30.1% vs. 17.6%, p<0.010) and lymphatic invasion (16.8% vs. 7.1%, p<0.005). After 2 years follow up BCR was detected in a total of 40 patients. In GS 7 with primary Gleason 3, BCR occurred in 15 (5.08%) patients while 20 (17.70%) showed BCR in GS 7 with primary Gleason 4.

Conclusions

In this study of a large, single center cohort of Korean men with GS 7 prostate cancer a noticeable difference in BCR was seen. Primary Gleason grade 4 have a higher risk of BCR compared to primary Gleason grade 3. This information may be useful when counseling patients on their prognosis and further management options.

Clinical experience with limited lymph node dissection for prostate cancer in Korea: single center comparison of 247 open and 354 robot-assisted laparoscopic radical prostatectomy series

PURPOSE

There are limited data on the role of limited pelvic lymph node dissection (PLND) in patients with prostate cancer in Korea. The objective of this study was to demonstrate our clinical experience with limited PLND and the difference in its yield between open retropubic radical prostatectomy (RRP) and robot-assisted laparoscopic radical prostatectomy (RALP) for prostate cancer patients in Korea.

MATERIALS AND METHODS

We retrospectively analyzed 601 consecutive patients undergoing radical prostatectomy and bilateral limited PLND by either RRP (n=247) or RALP (n=354) in Asan Medical Center. All patients were divided into three groups according to the D'Amico's risk stratification method. Clinicopathologic data, including the yield of lymph nodes, were thoroughly reviewed and compared among the three risk groups or between the RRP and RALP subjects.

RESULTS

The mean patient age was 64.9 years and the mean preoperative prostate-specific antigen was 9.8 ng/ml. The median number of removed lymph nodes per patient was 5 (range, 0 to 20). The numbers of patients of each risk group were 167, 199, and 238, and the numbers of patients with tumor-positive lymph nodes were 1 (0.6%), 4 (2.0%), and 17 (7.1%) in the low-, intermediate-, and high-risk groups, respectively. In the high-risk group, the lymph node-positive ratio was higher in RRP (14.9%) than in RALP subjects (2.4%).

CONCLUSIONS

We speculate that limited PLND may help in prostate cancer staging in intermediate- and high-risk prostate cancer groups. RRP is a more effective surgical modality for PLND than is RALP, especially in high-risk prostate cancer groups.

Practice patterns of Korean urologists for screening and managing prostate cancer according to PSA level

PURPOSE

There are still debates on the benefit of mass screening for prostate cancer (PCA) by prostate specific antigen (PSA) testing, and on systemized surveillance protocols according to PSA level. Furthermore, there is a paucity of literature on current practice patterns according to PSA level in the Korean urologic field. Here, we report the results of a nationwide, multicenter, retrospective chart-review study.

MATERIALS AND METHODS

Overall 2122 Korean men (>40 years old, PSA >2.5 ng/mL) were included in our study (from 122 centers, in 2008). The primary endpoint was to analyze the rate of prostate biopsy according to PSA level. Secondary aims were to analyze the detection rate of PCA, the clinical features of patients, and the status of surveillance for PCA according to PSA level.

RESULTS

The rate of prostate biopsy was 7.1%, 26.3%, 54.2%, and 64.3% according to PSA levels of 2.5-3.0, 3.0-4.0, 4.0-10.0, and >10.0 ng/mL, respectively, and the PCA detection rate was 16.0%, 22.2%, 20.2%, and 59.6%, respectively. At a PSA level >4.0 ng/mL, we found a lower incidence of prostate biopsy in local clinics than in general hospitals (21.6% vs. 66.2%, respectively). A significant proportion (16.6%) of patients exhibited high Gleason scores (≥8) even in the group with low PSA values (2.5-4.0 ng/mL).

CONCLUSION

We believe that the results from this nationwide study might provide an important database for the establishment of practical guidelines for the screening and management of PCA in Korean populations.

Changes in Prostate Cancer Aggressiveness over a 12-Year Period in Korea

Purpose

To investigate whether tumor aggressiveness in patients with prostate cancer has changed in Korea since the introduction of prostate-specific antigen (PSA) testing.

Materials and Methods

The data from 2,508 patients with pathologically confirmed prostate cancer who underwent radical prostatectomy at Asan Medical Center between 2000 and 2011 were reviewed. The patients were divided into four 3-year time series, and the changes between the groups in terms of serum PSA levels, pathological Gleason score (GS), and pathological stage were assessed. The change in GS over time in organ-confined disease and in patients whose PSA was below 10 ng/ml was also analyzed.

Results

The mean PSA levels dropped significantly over the 12-year period (p<0.001). The frequency of organ-confined disease increased (55.7% vs. 64.7% vs. 62.9% vs. 63.5%, p=0.043). The frequency of patients with a GS of 8 or more decreased (38.9% vs. 25.7% vs. 18.2% vs. 19.7%) and the frequency of patients with a GS of 6 or less increased (15.0% vs. 18.9% vs. 26.7% vs. 18.2%, p=0.003). However, the vast majority (more than 70%) of all cases had a high GS (7 or greater) at all time points. The GS distribution did not change over time in patients whose PSA levels were below 10 ng/ml or in those who had organ-confined disease.

Conclusions

In 2000 to 2011, the preoperative PSA, pathological stage, and pathological GS dropped. However, the majority of the prostate cancers in Korean men were poorly differentiated, even when the patients had organ-confined disease or their PSA levels were less than 10 ng/ml.

Prostate cancer and sexual function

Prostate cancer is now ranked fifth in incidence among cancers in Korean adult males. This is attributable to the more Westernized dietary style which increases the morbidity of prostate cancer and the development of cancer diagnostic technologies, such as prostate-specific antigen and advanced medical systems, increasing the rate of prostate cancer diagnosis. Prostate cancer effects include not only erectile dysfunction caused by the disease itself, but also by psychiatric disorders caused by prostate cancer or its treatments. Prostate cancer by itself reduces sexual desire and the frequency of sexual intercourse. Additionally, surgery or hormonal therapy to block testosterone further increases the frequency of erectile dysfunction. Erectile dysfunction following radical prostatectomy is primarily attributable to nerve injury caused by intraoperative nerve traction, thermal injury, ischemic injury, and local inflammatory reactions. Additionally, the absence of nocturnal penile tumescence causes persistent hypoxia of the corpus cavernosum, which, secondarily, causes anatomical and functional changes in the corpus cavernosum. Preservation of erectile function is one of the most significant issues for patients with local prostate cancer. Erectile dysfunction following radical prostatectomy is known to have various prognoses, depending on preservation of the neurovascular bundle, patient age, and preoperative erectile status. Intracavernosal injections, PDE5 inhibitors, and penile rehabilitation therapy using a vacuum constriction device after radical prostatectomy are known to improve the recovery of erectile function. Recently, testosterone replacement therapy has also drawn attention as a treatment method.

Can the prostate risk calculator based on Western population be applied to Asian population?

BACKGROUND

We developed a korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy using clinical and laboratory data from a Korean male population (http://pcrc.korea.ac.kr). We compared its performance to prostate-specific antigen (PSA) testing and the Prostate Risk Calculator 3 (PRC 3) based on data from the Dutch part of European Randomized Study of Screening for Prostate Cancer (ERSPC), which predicts biopsy results for previously unscreened men.

METHODS

Data were collected from 602 Korean men who were previously unscreened and underwent initial ten-core prostate biopsies. Multiple logistic regression analysis was performed to determine the significant predictors. Area under the receiver operating characteristic curve (AUC) and calibration plots of both calculators were evaluated.

RESULTS

Prostate cancer (PCa) was detected in 172 (28.6%) men. Independent predictors of a positive biopsy included advanced age, elevated PSA levels, reduced volume of the transition zone, and abnormal digital rectal examination findings. The AUC of the KPCRC was higher than the PRC 3 and PSA alone on internal and external validation. Calibration plots of the KPCRC showed better performance than the other models on internal and external validation. Applying a cut-off of 10% of KPCRC implied that 251 of the 602 men (42%) would not have been biopsied and that 12 of the 172 PCa cases (7%) would not have been diagnosed.

CONCLUSIONS

The KPCRC improves the performance of the PRC 3 and PSA testing in predicting Korean population's risk of PCa. It implies that Asian populations need their own risk calculators for PCa.

Recent changes in the clinicopathologic features of Korean men with prostate cancer: a comparison with Western populations

PURPOSE

The aim of this study was to evaluate the recent changes in the clinicopathologic features of prostate cancer in Korea and to compare these features with those of Western populations.

MATERIALS AND METHODS

We retrospectively reviewed the data of 1582 men undergoing radical prostatectomy for clinically localized prostate cancer between 1995 and 2007 at 10 institutions in Korea for comparison with Western studies. The patients were divided into two groups in order to evaluate the recent clinicopathological changes in prostate cancer: Group 1 had surgery between 1995 and 2003 (n=280) and Group 2 had surgery between 2004 and 2007 (n=1302). The mean follow-up period was 24 months.

RESULTS

Group 1 had a higher prostate-specific antigen level than Group 2 (10.0 ng/mL vs. 7.5 ng/mL, respectively; p<0.001) and a lower proportion of biopsy Gleason scores ≤6 (35.0% vs. 48.1%, respectively; p<0.001). The proportion of patients with clinical T1 stage was higher in Group 2 than in Group 1. Group 1 had a lower proportion of organ-confined disease (59.6% vs. 68.6%; p<0.001) and a lower proportion of Gleason scores ≤6 (21.3% vs. 33.0%; p<0.001), compared to Group 2. However, the relatively higher proportion of pathologic Gleason scores ≤6 in Group 2 was still lower than those of Western men, even though the proportion of organ-confined disease reached to that of Western series.

CONCLUSION

Korean men with prostate cancer currently present better clinicopathologic parameters. However, in comparison, Korean men still show relatively worse pathologic Gleason scores than Western men.

Are clinically insignificant prostate cancers really insignificant among Korean men?

PURPOSE

We aimed to determine whether 12 core-extended biopsies of the prostate could predict insignificant prostate cancer (IPCa) in Koreans reliably enough to recommend active surveillance.

MATERIALS AND METHODS

Two hundred and ninety-seven patients who underwent radical prostatectomy after 12 core-extended prostate biopsies were retrospectively reviewed. 38 cases (12.8%) were shown to be IPCa.

RESULTS

The average age was 65.2 years, serum PSA was 5.49 ng/dL, and the PSA density was 0.11. The Gleason scores (GS) were 6 (3+3) in 31, 5 (3+2) in 4, and 4 (2+2) in 3. After radical prostatectomy, higher GS was given in 16 (42.1%), whereas lower GS was given in 1 case (2.6%), as compared with the GS obtained from biopsy. 11 (28.9%) had GS of 7 (3+4) and 5 (13.2%) had GS of 7 (4+3). 6 in GS 7 (4+3) and 1 in GS 7 (3+4) showed prostate capsule invasion and 1 in GS 7 (4+3) had seminal vesicle invasion. Prostate capsule invasion was observed in 1 with GS 6 (3+3). The rate of inaccuracy of the contemporary Epstein criteria was 42.1%. Only PSA density was a reliable indicator of clinically IPCa (odds ratio=1.384, 95% CI, 1.103 to 2.091).

CONCLUSION

Diagnosis of IPCa from a prostate biopsy underestimated the true nature of prostate cancer in as many as 42.1% of Koreans.

The prognostic significance of percentage of tumour involvement according to disease risk group in men treated with radical prostatectomy

We investigated the prognostic significance of percentage of tumour involvement (PTI) according to the clinicopathological features of prostate cancer among patients who underwent radical prostatectomy (RP). A retrospective study of 534 patients who underwent RP between September 2003 and March 2008 without any neoadjuvant or adjuvant therapy was performed. The associations of PTI with various clinicopathological features and biochemical recurrence-free survival were examined via uni- and multivariate analyses. The predictive accuracy of the multivariate model was assessed with a receiver operating characteristics-derived area under the curve. PTI was demonstrated to be significantly associated with preoperative prostate-specific antigen (PSA) level (P=0.001), pathological Gleason score (P<0.001), extraprostatic tumour extension (P<0.001), seminal vesicle invasion (P<0.001) and positive surgical margin (P<0.001) in univariate analyses. When patients were stratified into disease risk groups, PTI was an independent predictor of biochemical recurrence-free survival in multivariate analysis only among the low-risk group (P=0.033) but not the intermediate- (P=0.287) or the high-risk groups (P=0.828). The addition of the PTI did not significantly increase the accuracy of the multivariate model devised for the prediction of biochemical recurrence-free survival among both total patients (P=0.459) and the low-risk group (P=0.268), respectively. In conclusion, although PTI appeared to be a more significant prognostic factor among patients with low-risk disease than among those with higher risk diseases, overall, the PTI may not provide additional prognostic information beyond what can already be obtained via established prognostic factors.

Is it suitable to eliminate bone scan for prostate cancer patients with PSA ≤ 20 ng/mL?

PURPOSE

We evaluated the relationship between bone metastasis (BM) and clinical or pathological variables, including the serum prostate-specific antigen (PSA) concentration.

METHODS

This retrospective study included 579 consecutive patients with newly diagnosed prostate cancer (Pca) who underwent a bone scan study at our institution between 2002 and 2010. We used receiver operating characteristics curves to evaluate accuracy of bone metastasis between serum PSA 10 and 20 ng/mL.

RESULTS

A positive bone scan result was found in 83 men (14.3%) with PCa. However, 27 men (4.6%) with serum PSA between 10 and 20 ng/mL, 29/579 men (5.0%) with GS ≤ 7, and 21/83 (25.3%) with serum PSA ≤ 20 ng/mL and Gleason score (GS) ≤ 7 had positive bone scans. In the logistic regression analyses, clinical T stage (odds ratio [OR] = 3.26; 95% CI, 2.29-4.33; P = 0.021), GS (OR = 3.41; 95% CI, 2.91-4.63; P = 0.019), and serum PSA (OR = 8.37; 95% CI, 3.91-19.21; P < 0.001) were predictive factors of detecting the BM. When the serum PSA concentration ≤20 ng/mL and GS ≤ 7, AUC value of bone scans for the detection of BM was 0.640 (P = 0.020; 95% CI, 0.563-0.717). With serum PSA at 10 ng/mL and GS ≤ 7, the AUC values of bone scans were 0.828 (P < 0.001; 95% CI, 0.773-0.883).

CONCLUSIONS

Bone scans might be necessary in men with serum PSA between 10 and 20 ng/mL. New guidelines for eliminating bone scans in patients with newly diagnosed Pca are needed, especially in Asians.

Biochemical recurrence after radical prostatectomy with or without pelvic lymphadenectomy in Korean men with high-risk prostate cancer

OBJECTIVE

To identify predictors of biochemical recurrence (BCR) after radical prostatectomy with or without standard pelvic lymphadenectomy in Korean men with high-risk prostate cancer.

METHODS

The clinical and pathologic data of 199 patients with high-risk features were reviewed retrospectively. High-risk features were prostate-specific antigen level >20 ng/ml, biopsy Gleason score ≥8 or clinical tumor category ≥2c. All patients were followed up by measuring their prostate-specific antigen levels every 3 months. The median follow-up period was 37.0 months (range: 1.0-143.0).

RESULTS

During the follow-up period, biochemical recurrence was observed in 68 patients (34.2%). The 1-, 3- and 5-year biochemical recurrence-free survival rates were 79.6, 61.9 and 49.2%, respectively. Surgical Gleason score ≥8, positive surgical margin, extracapsular extension, and seminal vesicle invasion correlated significantly with biochemical recurrence-free survival (all P < 0.05), but pelvic lymphadenectomy did not. Multivariate Cox's proportional hazard analysis revealed that the only significant independent prognostic factor of biochemical recurrence-free survival was seminal vesicle invasion (P = 0.035, relative risk = 1.81).

CONCLUSIONS

Men with seminal vesicle invasion appear to have a significantly higher biochemical recurrence risk in patients with high-risk prostate cancer. However, since the natural history of prostate cancer is variable and accurate means of identifying those who will progress are currently available, it will be necessary to conduct further studies to find prognostic parameters that will allow the early identification of high-risk patients who could benefit from early salvage or adjuvant therapy.

Initial biopsy outcome prediction in Korean patients-comparison of a noble web-based Korean prostate cancer risk calculator versus prostate-specific antigen testing

We developed and validated a novel Korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy in a Korean population. Data were collected from 602 Koreans who underwent initial prostate biopsies due to an increased level of prostate-specific antigen (PSA), a palpable nodule upon digital rectal examination (DRE), or a hypoechoic lesion upon transrectal ultrasound (TRUS). The clinical and laboratory variables were analyzed by simple and multiple logistic regression analysis. The area under the receiver operating characteristic curve (AUC) was computed to compare its performance to PSA testing alone. Prostate cancer was detected in 172 (28.6%) men. Independent predictors included age, DRE findings, PSA level, and prostate transitional zone volume. We developed the KPCRC using these variables. The AUC for the selected model was 0.91, and that of PSA testing alone was 0.83 (P < 0.001). The AUC for the selected model with an additional dataset was 0.79, and that of PSA testing alone was 0.73 (P = 0.004). The calculator is available on the website: http://pcrc.korea.ac.kr. The KPCRC improved the performance of PSA testing alone in predicting the risk of prostate cancer in a Korean population. This calculator would be a practical tool for physicians and patients.

Biochemical recurrence-free and cancer-specific survival after radical prostatectomy at a single institution

Purpose

To analyze the biochemical recurrence-free and cancer-specific survival after radical prostatectomy in a consecutive series of patients with prostate cancer.

Materials and Methods

We retrospectively reviewed data for 1,822 patients who underwent radical prostatectomy with pelvic lymph node dissection at our institution between 1990 and 2009. After excluding 498 patients who were treated with neoadjuvant androgen deprivation therapy or who were followed up for ≤6 months, we included 1324 patients (mean age, 64.4 years; mean prostate-specific antigen [PSA] level, 12.3 ng/ml). We assessed patient age at the time of surgery, preoperative PSA concentration, biopsy and pathologic Gleason scores, pathologic stage, surgical margin status, disease progression, and survival.

Results

The mean follow-up time was 40 months (range, 6-193 months). The 5- and 10-year biochemical recurrence-free survival rates were 73.2% and 66.2%, respectively, and the 10-year cancer-specific survival rate was 92.4%. The mean time from surgery to biochemical recurrence was 18 months. In the multivariate analysis, Gleason score (4+3 vs. 2-6, p=0.004; 8-10 vs. 2-6, p<0.001), pathologic stage (pT3a vs. pT2, p=0.001; pT3b-4 vs. pT2, p<0.001; pN1 vs. pT2, p<0.001), and resection margin status (p<0.001) were statistically significant predictors of biochemical recurrence, with only pathologic stage (pT3b-4 vs. pT2, p=0.006; pN1 vs. pT2, p=0.010) being a statistically significant predictor of cancer-specific survival.

Conclusions

Radical prostatectomy resulted in favorable cancer control in more than 70% of patients after 5 years and a low (<10%) cancer-specific mortality rate after 10 years. The factors predictive of biochemical recurrence were Gleason score, pathologic stage, and resection margin status.