Prostate cancer detection rate in Indonesian men

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Asian Journal of Surgery (2017) xx, 1e7

Available online at www.sciencedirect.com

ScienceDirect journal homepage: www.e-asianjournalsurgery.com

ORIGINAL ARTICLE

Prostate cancer detection rate in Indonesian men Chaidir Arif Mochtar a, Widi Atmoko a, Rainy Umbas a, Agus Rizal Ardy Hariandy Hamid a,* a Department of Surgery, Division of Urology, Faculty of Medicine, University of Indonesia, Cipto Mangunkusumo Hospital, Jalan Diponegoro No. 71, Jakarta 10430, Indonesia

Received 23 August 2016; received in revised form 8 January 2017; accepted 11 January 2017

KEYWORDS detection rate; Indonesian men; prostate biopsy; prostate cancer; prostate-specific antigen

Summary Purposes of the study: To evaluate the overall detection rate of prostate cancer in biopsies according to serum prostate-specific antigen levels, determine the number of cores biopsied in Indonesian men, and provide a correlated staging of prostate cancer patients at varying intervals of prostate-specific antigen levels. Methods: We retrospectively analyzed the data from Indonesian men who had undergone prostate biopsy at two national referral medical centers in Jakarta from January 1995 to December 2014. Prostate biopsy was performed when levels of prostate-specific antigen were > 4.0 ng/ mL or malignancy was suspected upon digital rectal examination. Results: Of 2942 men who underwent biopsies, 844 (28.7%) were diagnosed with prostate cancer. When patients were stratified into five subgroups by serum prostate-specific antigen levels (< 4.0, 4.0e9.9, 10.0e19.9, 20.0e100.0, and > 100.0 ng/mL), the overall detection rate of prostate cancer was 21.0%, 9.3%, 13.1%, 35.4%, and 92.9%, respectively. The detection rate was significantly higher in patients who underwent 10-core biopsies than in patients who underwent 6-core biopsies (31.6% vs. 22.4%, p < 0.001). The receiver operating characteristic analysis to detect locally advanced/metastatic prostate cancer found that serum prostatespecific antigen levels of 42.7 ng/mL had a sensitivity of 74%, specificity of 73%, positive predictive value of 85.2%, and negative predictive value of 57.5%, with area under the curve of 0.81 (95% confidence interal 0.78 to 0.84). Conclusion: The overall detection rate of prostate cancer in Indonesian men was 28.7%. The prostate cancer detection rate appeared to be lower than that observed in white men. ª 2017 Asian Surgical Association and Taiwan Robotic Surgical Association. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

* Corresponding author. Division of Urology, Department of Surgery, Faculty of Medicine, University of Indonesia, Department of Urology, Cipto Mangunkusumo Hospital, Jalan Diponegoro Number 71, Jakarta 10430, Indonesia. E-mail address: [email protected] (A.R.A.H. Hamid). http://dx.doi.org/10.1016/j.asjsur.2017.01.001 1015-9584/ª 2017 Asian Surgical Association and Taiwan Robotic Surgical Association. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Mochtar CA, et al., Prostate cancer detection rate in Indonesian men, Asian Journal of Surgery (2017), http://dx.doi.org/10.1016/j.asjsur.2017.01.001

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1. Introduction According to the GLOBOCAN 2012 statistics, prostate cancer is the third most common urologic cancer in Indonesian men. The incidence of prostate cancer in Indonesia has been increasing rapidly, likely owing to a growing elderly population and better detection methods. The estimated age-standardized incidence rates for the Indonesian population increased from 10.6 (in 2008) to 14.8 (in 2012) per 100,000 men.1 Despite these facts, the incidence of prostate cancer is still much lower than in Singapore, Korea, Japan, or in white American men.1e3 Prostate cancer incidence varies based on ethnicity and region.4 The incidence of prostate cancer in North American men is 97.2 out of 100,000 men; however, in Malaysian men, who are of a comparably similar race to Indonesian men, the incidence has only been reported to be 10.8 of every 100,000 men.1 The serum prostate-specific antigen (PSA) test and digital rectal examination (DRE) are common methods used to screen for signs of prostate cancer. Catalona et al5 determined that PSA levels of 4 ng/mL is an appropriate cut-off point to indicate a prostate biopsy. Subranges of serum PSA levels have been used to help counsel men with regard to the detection rate of cancer on biopsy, and are commonly used by patients and clinicians to determine the necessity of prostate biopsy. Although transrectal ultrasound (TRUS)-guided systematic prostate biopsy has been well established as the standard diagnostic tool in prostate cancer, it is undeniable that the six-core biopsy is an inaccurate means of cancer detection (10e30% false negative rate).6,7 Recently, many investigators have indicated that extended prostate biopsy sampling with eight or more cores might improve the prostate cancer detection rate.8,9 Despite the increased likelihood of prostate cancer detection by performing extended biopsy, the appropriate number of cores is yet to be determined. It is expected that increasing the number of biopsy cores would lead to improved cancer detection. Developing a strategy for prostate cancer detection is of vital importance because the risk of detection of latent or insignificant prostate cancer may also be elevated because of false positive results. Additionally, there are no adequate data on the prostate cancer detection rate and PSA levels in an Indonesian population. Therefore, this study was conducted to evaluate the overall detection rate of prostate cancer based on core biopsy and serum PSA levels while evaluating the utility of 6-core and 10-core prostate biopsies in Indonesian men. As a secondary outcome, we also evaluated the detection rate of advanced prostate cancer based on serum PSA levels in order to determine the optimal PSA cut-off value to suggest prostate biopsy to diagnose early stage “curable” prostate cancer.

2. Methods 2.1. Patients We retrospectively analyzed 2942 Indonesian men who had undergone prostate biopsy at two national referral medical

C.A. Mochtar et al. centers (Cipto Mangunkusumo Hospital, Jakarta and Dharmais Hospital National Cancer Center, Jakarta) from January 1995 to December 2014. When PSA levels exceeded 4.0 ng/mL, a TRUS-guided biopsy was performed. Patients with PSA < 4.0 ng/mL also underwent TRUS-guided biopsy if indicated by the DRE results (including induration, asymmetry, irregularity, or nodules suggesting cancer). Patients with a previous prostate biopsy were excluded from the study. The protocol of the study was approved by the local ethics committee (285/UN2.F1/ETIK/2016, The Ethics Committee of the Faculty of Medicine, University of Indonesia). Written informed consent was obtained from all of the patients.

2.2. Biopsy method Serum PSA levels were measured using the Abbott Architect i2000 (Abbott Laboratories, Abbott Park, IL, USA). Patients were placed in the lateral decubitus position, and TRUSguided needle biopsy was performed using the Ultrasound Scanner Class I Type B (B-K Medical, REF Type 8818 4e12 MHz, Mileparken, Herlev, Denmark). A spring-fired biopsy instrument (Bard Magnum, Ref MG1522, Bard Peripheral Vascular, Inc., Tempe, AZ, USA) attached to an 18gauge Bard Magnum Biopsy Needle (Ref MN1820, Bard Peripheral Vascular, Inc.) was used. Transverse and longitudinal section images were obtained. Prior to January 2004, our protocol for prostate biopsy was to perform a six-core biopsy. At that time, we tried to improve our detection rate by increasing the cores biopsied to 10. A proctoclysis enema was given one day prior to the biopsy. Patients taking anticoagulants and antiplatelets were advised to stop their medication 5 days prior to biopsy. Suppository ketoprofen was given 5 to 10 minutes before the TRUS biopsy procedure as a local anesthesia. Prostate biopsy specimens were analyzed by pathologists at the patient’s institution. Clinical parameters and pathological features were recorded on the prostate cancer database program developed for this study. Biopsy tissue was considered positive if adenocarcinoma was diagnosed, and the number of positive cores, Gleason score, and grade were reported. All other findings [e.g., high-grade prostatic intraepithelial neoplasia (PIN), atypia, and dysplasia] were considered as negative for prostate cancer.

2.3. Statistical analysis The detection rates of cancer upon biopsy were obtained and analyzing according to PSA levels and number of cores biopsied. We also compared PSA density between patients who underwent 6-core and 10-core biopsies in the subgroups with PSA < 20 ng/mL. Statistical analysis was performed by applying Chi-square test. A p value < 0.05 was considered statistically significant. For our secondary outcome, we conducted receiver operating characteristic (ROC) curve analysis. We divided prostate cancer staging into two categories as follow: (1) local, which included T1 and T2 prostate cancer without any existence of tumor spreading into the nodes or other organs, and (2) locally advanced and metastatic, which included T3, T4, N1, and M1. The statistics program International Business Machines

Please cite this article in press as: Mochtar CA, et al., Prostate cancer detection rate in Indonesian men, Asian Journal of Surgery (2017), http://dx.doi.org/10.1016/j.asjsur.2017.01.001

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Prostate cancer detection Indonesian men Table 1

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Patient characteristics.

Characteristic

Nonprostate cancer

Prostate cancer

Patients (n) Mean age (y) Mean prostate mass (g) Mean PSA (ng/mL)* Number of biopsy cores** 6-core, n (%) 10-core, n (%)

2098 67.4  9.4 57.3  29.1 21.9  1.6

844 72.1  10.8 68.7  33.5 371.3  43.1

712 (77.6) 1386 (68.4)

205 (22.4) 639 (31.6)

* p < 0.001 by independent t test. ** p < 0.001 by Chi-square test. PSA Z prostate-specific antigen.

Statistical Package for Social Sciences, version 21.0, for Windows (Armonk, New York, United States) was used.

3. Results The mean age of the study population was 69.8  7.4 years (range 31e95). Of the 2942 men who underwent prostate biopsy, 844 (28.7%) were diagnosed with prostate cancer. The mean serum PSA levels were 21.9  1.6 ng/mL in the nonprostate cancer group and 371.3  43.1 ng/mL in the prostate cancer group (p < 0.001). Both groups were comparable in terms of patient age and prostate size (Table 1). Of the 844 patients with prostate cancer, there were 641 (75.9%) with PSA > 20 ng/mL. When patients were stratified by serum PSA levels into five different subgroups (< 4.0, 4.0e9.9, 10.0e19.9, 20.0e100.0, and > 100.0 ng/mL), the number of patients diagnosed with prostate cancer in each subgroup was found to be 143 (21.0%), 67 (9.3%), 106 (13.1%), 329 (35.4%), and 312 (92.9%), respectively. The number of patients who underwent 6- and 10-core biopsy was 917 (31.1%) and 2025 (68.8%), respectively. The detection rate was significantly higher in the 10-core group than in the 6-core group (31.6% vs. 22.4%, p < 0.001) (Table 1). An overall 9.3% increase in Gleason grade  7 was observed in the 10-core group (p Z 0.34). The detection rate was significantly higher in the 10core group when compared to the 6-core group in patients with PSA < 4.0 ng/mL and 10.0e19.9 ng/mL (10-core vs. 6-

Table 2

core: 41.9% vs. 12%, p < 0.001 and 15.1% vs. 7.8%, p Z 0.005, respectively) (Table 2). In patients with PSA < 20 ng/mL and PSA density < 0.15 ng/mL/g, the prostate cancer detection rate was significantly higher in the 10-core biopsy group than in the 6-core biopsy group (11.2% vs. 4.8%, p Z 0.02). However, there was no significant difference between the 6and 10-core biopsy groups in patients with PSA < 20 ng/mL and PSA density > 0.15 ng/mL/g. Based on PSA levels and DRE findings, the prostate cancer detection rate was significantly higher in the group with abnormal DRE compared to normal DRE in patients with PSA 4e9.9 ng/mL and 10e19.9 ng/mL (p < 0.001, Table 3). The detection rate in patients with abnormal DRE findings was 35.3% (233 of 660) and 35.6% (520 of 1457) when undergoing 6-core and 10-core biopsy, respectively (p Z 0.77). The detection rates of advanced prostate cancer for patients in each PSA interval can be seen in Table 4. The ROC analysis to detect locally advanced/metastatic prostate cancer showed that serum PSA levels of 42.7 ng/mL had a sensitivity of 74%, specificity of 73%, positive predictive value of 85.2%, and negative predictive value of 57.5%, with area under the curve (AUC) of 0.81 (95% confidence interval 0.78 to 0.84) (Figure 1).

4. Discussion The incidence of prostate cancer is increasing in Indonesia, although it is still lower than in Western and other Asian countries.1 The detection rate of prostate cancer by serum PSA levels has been shown to be different in Indonesian men as compared to other populations. In this study, 844 men (28.7%) were diagnosed with prostate cancer, and 641 (75.9%) had PSA > 20 ng/mL. In their study, Yuri et al10 observed a prostate cancer diagnosis rate of 40.1%. This value was much higher than we observed. However, they included all patients who underwent prostate biopsy and prostatectomy. Shahab et al11 estimated that PSA levels of around 6.95 ng/mL was an appropriate cutoff point in their study for prostate cancer detection in Indonesia (97.8% sensitivity and 19.6% specificity). Literature reviews from a number of Asian countries found that the detection rate of prostate cancer in patients with raised PSA levels lay within the range of 14.6% to 26.5%.2,12e15

Cancer detection in PSA intervals in patients with 6-core or 10-core biopsies. 6 cores (n Z 917)

PSA levels (ng/mL)

< 4.0 4.0e9.9 10.0e19.9 20.0e100.0 > 100.0

10 cores (n Z 2025)

No. of patients

No. of cancers detected, n (%)

No. of patients

No. of cancers detected, n (%)

100 235 230 282 70

12 18 18 92 65

43 488 581 647 266

18 (41.9) 49 (10) 88 (15.1) 237 (36.6) 247 (92.9)

(12) (7.7) (7.8) (32.6) (92.9)

p*

< 0.001 0.30 0.005 0.24 1.00

*By Chi-square test. PSA Z prostate-specific antigen.

Please cite this article in press as: Mochtar CA, et al., Prostate cancer detection rate in Indonesian men, Asian Journal of Surgery (2017), http://dx.doi.org/10.1016/j.asjsur.2017.01.001

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C.A. Mochtar et al. Table 3

Detection rate of prostate cancer on biopsy according to serum PSA levels and DRE.

PSA (ng/mL)

Normal DRE

< 4.0 4.0e9.9* 10.0e19.9* 20.0e100.0 > 100.0 Total

Abnormal DRE

No. of patients, n (%)

No. of cancers detected, n (%)

No. of patients, n (%)

No. of cancers detected, n (%)

e 466 (64.5) 245 (30.2) 100 (10.8) 14 (4.2) 825 (28.0)

e 27 15 36 13 91

143 (100) 257 (35.5) 566 (69.8) 829 (89.2) 322 (95.8) 2117 (72.0)

30 (21) 40 (15.6) 91 (16.1) 293 (35.3) 299 (92.8) 753 (35.6)

(5.8) (6.1) (36.0) (92.8) (11.0)

* p < 0.001, Chi-square test. DRE Z digital rectal examination; PSA Z prostate-specific antigen.

Data from other countries in Asia uniformly reported a low cancer detection rate in connection with PSA levels ranging from 4 ng/mL to 10 ng/mL. However, in Western countries, the detection rate of prostate cancer at similar PSA levels is approximately 25%.16 In this study, regardless of DRE findings, the detection rate of prostate cancer in patients with PSA 4e10 ng/mL was still lower than that in Korean men (15.9%) as reported by Yang et al2 and in American men (25%) as reported by Gretzer and Partin.16 The same pattern was also observed in men with PSA > 10 ng/mL. The detection rate of prostate cancer in Indonesian men was found to be 36%, which is lower than the rates observed in Japanese,12 Singaporean,17 and American16 men (59.5%, 50%, and 67%, respectively). Interestingly, in this study, of 143 men with PSA < 4 ng/ mL and abnormal DRE findings, 30 (21.0%) were diagnosed with prostate cancer. Thus, we observed a much higher cancer detection rate in patients with PSA < 4 ng/mL (21%) than in patients with PSA 4e9.9 ng/mL (9.3%) and 10e19.9 ng/mL (13.1%). This detection rate in patients with PSA < 4 ng/mL was rather high. Egawa et al12 observed a prostate cancer detection rate around 14.7%, whereas other studies conducted in a Western male population reported the rate of detection to range from 10% to 21%.18e20 The most effective method to increase the detection rate of prostate biopsy is to consider both the DRE findings and serum PSA levels.18,21 However, DRE is a subjective test, as it is examiner-dependent. There was a larger interobserver variation in this study, as it was performed by 70 different clinicians, including faculty, staff, or residents majoring in

urology during the 5-year study period. Nonetheless, in the patients with PSA 4e9.9 ng/mL and 10e19.9 ng/mL, DRE findings significantly contributed to the detection rate (p < 0.001, Table 2). The prostate cancer detection rate was significantly higher in patients with an abnormal DRE compared to patients with a normal DRE when PSA was 4e9.9 ng/mL and 10e19.9 ng/mL (15.6% vs. 5.8% and 16.1% vs. 6.1%, respectively). We believed that a study to elucidate the correlation between the detection rate of cancer and DRE findings in patients with serum PSA < 4 ng/mL was important for establishing the criteria for prostate biopsy. Many studies from Western countries have reviewed improvements in the detection rate by extended biopsies.22 The 10-core biopsy was implemented in January 2004. In this study, 917 out of 2942 men underwent 6-core biopsy and 2025 underwent 10-core biopsy. The detection rate was significantly higher in the 10-core group than in the 6-core group (31.6% vs. 22.4%, p < 0.001) in this study. On further

Table 4 Proportion of cancer stage in patients with prostate cancer according to serum PSA levels. PSA (ng/mL)

< 4.0 4.0e9.9 10.0e19.9 20.0e100.0 > 100.0

No. of patients

30 67 106 328 311

Cancer stage Local, n (%)

Locally advanced/ Metastasis, n (%)

22 (73.3) 52 (77.6) 62 (58.5) 112 (34.1) 25 (8.0)

8 (26.7) 15 (22.4) 44 (41.5) 216 (65.9) 286 (92.0)

PSA Z prostate-specific antigen.

Figure 1 ROC curve analysis to detect locally advanced / metastasis prostate cancer based on serum PSA levels. PSA Z prostate-specific antigen; ROC Z receiver operating characteristic.

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Prostate cancer detection Indonesian men evaluation in patients having PSA < 4.0 ng/mL and 10.0e19.9 ng/mL, the detection rate was significantly higher in the 10-core group than in the 6-core group (41.9% vs. 12%, p < 0.001 and 15.1% vs. 7.8%, p Z 0.005, respectively). Among the patients with PSA density < 0.15 ng/mL/g and diagnosed with prostate cancer, 9 (4.8%) were detected by 6-core biopsy and 41 (11.2%) by 10-core biopsy. Among the patients with PSA density < 0.15 ng/mL/g, the prostate cancer detection rate was significantly higher in the 10core biopsy group than in the 6-core biopsy group (p Z 0.02). Our results indicate that 6-core prostate biopsy might be inadequate in patients with low PSA density. In patients with PSA density < 0.15 ng/mL/g, 10-core biopsy improved the prostate cancer detection rate when compared to 6-core biopsy. An overall 9.3% increase in Gleason grade  7 was found in the 10-core group compared to the 6-core group (p Z 0.34). This result is similar to a study conducted by Nomikos et al.23 They found an overall 9.8% increase in Gleason 7 detection rate. This was detected when comparing a 24-core to a 10-core biopsy group (p Z 0.24). In their study, men with PSA < 10 ng/mL who received an initial 24-core biopsy did not have a statistically significant increase in Gleason 7 detection rate when compared to patients with the same PSA levels undergoing 10-core biopsy . Furthermore, there was no difference in Gleason 8 and 9 detection rates between the two biopsy protocols. Scattoni et al24 have also shown that, although not statistically significant, using the 18-core technique as an initial strategy demonstrated a higher cancer detection rate when compared to a 12-core protocol in men with PSA < 10 ng/mL. However, they did not find any differences in Gleason score. We found that the detection rate in patients with abnormal DRE findings was 35.3% (233 of 660) and 35.6% (520 of 1457) using the 6-core and 10-core biopsies, respectively. Six-core biopsy provided a similar cancer detection rate when compared with 10core biopsy in patients with abnormal DRE findings. One of the weaknesses of this study is the number of cores biopsied. We took 6- and 10-core biopsies instead of 12- or 21-core biopsies. Optimizing prostate cancer detection rates in clinical practice includes defining the ideal number and location of biopsy cores to maximize clinically significant cancer detection while minimizing insignificant cancer detection, and reducing the necessity for repetitive rebiopsy.25 Historically, comparison of cancer detection rate between six-core biopsy protocols and extended-core biopsy protocols (involving 10e12 cores) have demonstrated an increased rate of cancer detection with more cores biopsied.26 Although increasing the cores from 6 to 12 results in a significant increase in cancer detection rate, increasing the number of cores to 18 or 21 (saturation biopsy) as an initial biopsy strategy does not appear to provide a similar increase.8 De La Taille et al,27 in a study of 303 men, found that the cancer detection rate using sextant, extended 12-core, 18-core, and 21-core biopsy schemes were 22.7%, 28.3%, 30.7%, and 31.3%, respectively. Diagnostic yield improved by 24.7% when the number of cores increased from 6 to 12, but only by 10.6% when the number of cores increased from 12 to 21. In their review of the diagnostic value of systematic prostate biopsies, Eichler et al28 noted that taking more than 12 cores did not

5 significantly improve cancer yield. The lower detection rate in our study could be caused by the lower number of cores biopsied. The main reason for not performing extended-core biopsy (12 or more cores) is associated with the anesthesia technique used. Performing biopsies on more than six cores may provide an advantage in cancer detection. This has encouraged more practitioners to explore various methods of achieving analgesia/anesthesia during biopsy. Both rectal and prostatic anesthesia may limit pain during the procedure. Intrarectal local anesthesia has been used as lubrication in order to reduce friction and protect the mucosa during instrumentation as well as to ease the discomfort that comes along with the introduction of the ultrasound probe. A variety of anesthetic agents have been employed, including lidocaine, prilocaine, nifidipine, and dimethyl sulfoxide, in various combinations with different results.25 Periprostatic nerve block is associated with significantly less pain during biopsy than lidocaine gel or placebo, and is superior to intrarectal instillation of anesthetic cream.29,30 Extensive biopsy protocols may be comfortably performed in an office setting using local anesthesia with 22 mL 1% lidocaine injection.31 Despite the lack of a standardized dose, periprostatic anesthetic infiltration should be considered the gold standard.32 The introduction of periprostatic nerve block has allowed extended prostate biopsy to be performed easily in the office while increasing the number of biopsies taken without increasing patient discomfort or pain.25 However, the standard anesthesia protocol at our institution employs rectal ketoprofen. This is the main reason why extended prostate biopsy is not routinely performed at our institution. One possible bias of this study is in selection, as the patients who underwent biopsy were not drawn from a population PSA screening, but from “for-cause” PSA tests and suspicion from prostate digital examination. No official PSA screening guideline is available for prostate cancer screening in Indonesia. Yuri et al9 have developed an Indonesian Prostate Cancer Risk Calculator to predict prostate cancer based on an Indonesian population. This calculator includes age, PSA levels, DRE findings, and prostate volume as variables. However, this calculator was not used as a screening tool for prostate biopsy in our study. The participants in our study were patients who presented to the urologic outpatient clinic with voiding symptoms, hematuria, or some other concern, and we examined the PSA levels based on the clinical condition and age of the patient. Our study demonstrated that of 844 patients with prostate cancer, there were 641 patients (75.9%) with PSA > 20 ng/mL. Proper detection and early diagnosis of prostate cancer is a public health concern. As a result, the proportion of advanced disease seemed very high compared with Western countries. This may also have contributed to the lower prostate cancer detection rate upon biopsy compared to other Asian countries, such as Singapore, where the official guidelines on health screening state that men older than 50 years and having risk factors for prostate cancer should be screened. In Japan, the Japanese Urological Association has issued a PSA screening guideline. Japanese urologists think that population-based PSA screening is useful and a screening system should be maintained. On the other hand, Korea has no national PSA

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6 screening program. The Korean Urological Oncology Society conducted a population-based screening study to obtain the data for prostate cancer diagnosis.33 One possible explanation for the decreased incidence of prostate cancer in Asian countries is the high soy consumption. The large intake of isoflavones may prevent prostate cancer in Asian countries, although more evidence is needed. In the future, a large multinational study in Asia is needed to clarify whether or not isoflavone consumption has efficacy in preventing prostate cancer.34 Although atypical small acinar proliferation and PIN may be diagnosed as prostate cancer by repeat biopsy, we classified these in the noncancer group because our study used only the findings from the first biopsy. In Western countries, the average incidence of high-grade PIN on prostate biopsy specimens has been reported as 6% (range 1.5e16.5%).34 In our study, the rate was very low (0.002%). We do not know the exact reason for this discrepancy. However, we postulate that the incidence of high-grade PIN would be much lower in Indonesia, owing to the lower incidence of prostate cancer. The other possible factor is that uropathologists in Indonesia cannot detect high-grade PIN as well as Western pathologists. Other shortcomings of this study were that the number of cores biopsied was not standardized, and the biopsies were performed by multiple investigators. This is a problem of retrospective multicenter studies, such as ours, and a future prospective study must be performed to address this. In spite of this caveat, our data would represent the detection rate of prostate cancer on biopsies according to serum PSA levels in an actual practical setting for Indonesian men. In conclusion, the overall prostate cancer detection rate was 28.7% (844 of 2942 patients). The cancer detection rate with 10-core TRUS-guided biopsy was significantly higher than that with 6-core biopsy. The prostate cancer detection rate appeared to be lower than detection rates observed in white men. This data represents a potential ethnic difference in prostate cancer.

Acknowledgments

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There were no financial grants or other funding for this work. 16.

Conflict of interest

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The authors declare no potential conflict interest. 18.

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Prostate cancer detection Indonesian men

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Please cite this article in press as: Mochtar CA, et al., Prostate cancer detection rate in Indonesian men, Asian Journal of Surgery (2017), http://dx.doi.org/10.1016/j.asjsur.2017.01.001