不同前列腺穿刺活检方案检出前列腺癌的比较

目的探讨理想的前列腺穿刺活检方案。方法临床表现怀疑前列腺癌患者214例，其中前列腺特异抗原〉4．0ng／ml 203例。均行13针前列腺穿刺活检术。年龄50～90岁，平均70岁；PSA水平0．8～112．3ng／ml，平均18．7ng／ml；前列腺体积12．3～182．5ml，平均61．3ml；直肠指诊阴性173例，阳性者41例。依穿刺结果，对比分析13针中6、8、10和13针穿刺阳性率。结果13针穿刺阳性率为36．0％（77／214）。在各种穿刺点组合中包含前列腺尖部、中部、底部、外侧中部、外侧底部的10针法能发现全部前列腺癌阳性病例的97．4％，与13针穿刺结果的差异无统计学意义（P=0．5）。结论对于初次前列腺活检的病例，包含尖部、中部、底部、外侧中部、外侧底部的10针法是较为合理的选择。     

超声引导下经会阴定位模板的前列腺饱和穿刺活检

目的探讨超声引导下经会阴定位模板前列腺饱和穿刺活检的准确性、安全性。方法303例PSA〉4．0ng／ml和（或）DRE异常和（或）前列腺B超、CT或MRI异常者接受经会阴定位模板饱和穿刺活检。年龄35～90岁，平均69．7岁。PSA0．2～3000．0ng／ml，中位数13．7ng／ml。前列腺体积7～190ml，中位数47ml。结果每区活检1～4针，共11～44针，平均23．7针。前列腺癌活检阳性率37．6％（114／303）。PSA0～4．0、4．1～10．0、10．1～20．0、20．1～30．0、30．1～70．0及〉70．0ng／ml者阳性率分别为22．2％（4／18）、8．2％（6／73）、21．6％（22／102）、48．4％（15／31）、68．4％（26／38）及100．0％（41／41）。前列腺体积〈20、20～40、41～60及〉60ml者阳性率分别为68．0％（17／25）、51．4％（54／105）、27．5％（19／69）及23．1％（24／104）。无一例出现严重并发症。结论TRUS引导下经会阴定位模板饱和穿刺活检精确而安全，对于前列腺癌的准确分期有重要意义。     

维也纳表：一种有效的基于患者年龄和前列腺总体积而确定合理穿刺针数的穿刺新方法

为评价维也纳表（Vienna nomogram），即基于患者年龄和前列腺总体积而确定合理穿刺针数的前列腺癌检测新方法的有效性，作者对PSA2～10ng／ml的患者进行了前瞻性研究，共502例患者依据维也纳表所确定的穿刺针数进行前列腺穿刺活检，与既往采用传统方法的1051例患者进行比较，传统方法为标准的8针穿刺，若结果阴性则于6～8周后重复穿刺。结果发现采用维也纳表的前列腺癌总检出率为36．7％，而传统方法的首次检出率为22．0％，重复检出率为10．0％，即采用新方法后患者前列腺癌的检出率明显高于传统方法的首次检出率（P=0.002）．而与传统方法首次检出率加重复检出率相当。     

经直肠超声引导前列腺穿刺活检术（附136报告）

目的探讨经直肠超声引导前列腺穿刺活检方法及阴性患者随访策略。方法136例患者因血清tPSA〉4ng／ml或伴前列腺硬结接受穿刺活检术。根据前列腺体积或硬结情况分别选择6针、8针或10针穿刺。病理为阴性,但提示HGPIN、ASAP或PSA持续〉4ng／ml,建议3-6个月后重复穿刺活检。结果136例患者共接受1172针活检,平均8．6针。总阳性率为23．5％,其中6针、8针和10针穿刺阳性率分别为0、19．1％和34．5％（P〈0．01）。30例接受了2-3次重复活检,所有重复活检均为阴性。47例患者接受平均3．6年随访,仅1例后经TURP证实为前列腺癌,其余未发现可疑前列腺癌局部或远处转移表现。结论根据超声前列腺形态选择穿刺方案可使绝大部分前列腺癌患者初次穿刺即获得确诊。重复穿刺阳性率低,应注意选择适应症。     

超声引导下经直肠系统性12＋1针前列腺穿刺活检术

目的探讨超声引导下经直肠系统性12＋1针前列腺穿刺活检术诊断前列腺癌的临床价值。方法回顾性分析816例经直肠前列腺系统性12＋1针穿刺活检的可疑前列腺癌患者。其中PSA＜4ng／ml、直肠指诊发现结节者66例;PSA介于4～10ng／ml、f／tPSA值异常、PSAD值异常者190例;PSA〉10ng／ml、任何f／tPSA、PSAD值者560例。结果816例患者中活检病理确诊为前列腺癌者358例,总阳性率为43．9％（358／816）。其中位于前列腺尖部阳性者235例,占确诊病例总数的65．6％（235／358）。术后发热9例（1．0％,9／816）,并发血尿49例（6．0％,49／816）。几乎所有患者皆有短时大便带血。无其他严重并发症发生。结论超声引导下经直肠系统性前列腺12＋1针穿刺活检术定位准确,创伤较小,并发症较少。可以随机增加穿刺点,利于提高前列腺癌检出率。     

直肠超声引导下经会阴前列腺穿刺活检615例并发症分析

目的探讨经直肠超声引导下经会阴部前列腺穿刺活检并发症发生的相关因素。方法回顾性分析经直肠超声引导下经会阴前列腺穿刺活检患者615例,分析并发症发生率和相关因素。结果本组615例中,213例（213／615,34．63％）出现并发症,其中肉眼血尿117例（117／213,54．93％）,尿路刺激征40例（40／213,18．78％）,尿潴留27例（27／213,12．68％）,血管迷走神经反射11例（11／213,5．16％）,血尿合并血精8例（8／213,3．76％）,发热6例（6／213,2．82％）,会阴部肿胀伴出血4例（4／213,1．88％）。穿刺针数与并发症发生存在相关性（P=0．007）。结论经直肠超声引导下经会阴前列腺穿刺活检是早期前列腺癌诊断的安全有效的方法。使用16G或18G穿刺针合理穿刺可以有效降低并发症发生率。     

游离前列腺特异抗原百分比/前列腺特异抗原密度在前列腺癌诊断中的应用

目的探讨游离前列腺特异抗原百分比（FPSA／TPSA值）／前列腺特异抗原密度[（F／T）／PSAD值]在前列腺癌诊断中的意义。方法回顾分析204例行经直肠超声引导前列腺穿刺活检患者的诊断资料,其中前列腺癌90例、良性前列腺增生114例,分析总PSA（TPSA）、FPSA／TPSA值、PSAD、（F／T）／PSAD值等指标在判断前列腺癌的敏感性为90％时的截点及相应的特异性。结果不同血清PSA水平（〈4．0,4．0～,10．1～和〉20．0μg／L）的前列腺癌患者的（F／T）／PSAD值与良性前列腺增生患者比较,差异有统计学意义（P〈0．05）;前列腺癌患者的（F／T）／PSAD值低于良性前列腺增生患者;（F／T）／PSAD值比FPSA／TPSA值和PSAD更有助于提高诊断特异性,在敏感性为90％左右的前提下,FPSA／TPSA值的特异性为31．6％,PSAD的特异性为45．6％,（F／T）／PSAD值的特异性为64．0％;PSA水平不同,取的（F／T）／PSAD值截点也不同：PSA〈4．0μg/L时截点为2．5,PSA为4．0～20．0μg／L时截点为0．8;PSA〉20．0μg／L时截点为0．5。结论应用（F／T）／PSAD值能够在保持较高敏感性的前提下,显著提高前列腺癌诊断的特异性。     

不同穿刺针数经直肠前列腺穿刺活检诊断前列腺癌的研究

目的探讨针对国人的不同体积前列腺理想的前列腺活检穿刺针数。方法临床表现怀疑前列腺癌患者879例,按照前列腺体积分为10～30ml组、30.1～40ml组,40.1～50ml组,以及50.1ml组,记录患者一般临床资料以及活检结果。依穿刺结果,按照不同体积对比分析不同穿刺针数的穿刺结果。结果总的肿瘤检测率为27.3%,随着前列腺体积的增大,肿瘤检测率降低(P0.05)。6、8、10和12针的肿瘤检测率分别为18.0%、28.0%、32.0%和29.0%。与8、10和12针比较,传统的6针穿刺有较低的穿刺阳性率(P0.05)。在不同的前列腺体积之间,8、10和12针穿刺阳性率之间比较,差异无统计学意义(P0.05)。在经直肠超声和经直肠指诊有可疑的患者中,穿刺阳性率分别为71.0%和65.0%。结论 6针穿刺具有较低的穿刺阳性率,按照不同的前列腺体积,8、10和12针有相似的穿刺阳性率,可疑部位活检能够提高穿刺的阳性率。     

超声引导下经不同针数直肠前列腺穿刺活检对前列腺癌的早期诊断效果对比

目的探讨超声引导下经直肠前列腺穿刺活检在诊断前列腺癌的价值。方法选取2013年1月至2016年12月在本院就诊的疑似前列腺癌患者62例，均超声引导下经直肠前列腺穿刺活检，分析不同穿刺法的阳性检出情况。结果本组研究62例患者，穿刺活检病理结果为前列腺癌患者25例（40.32%），其中34例接受10针法穿刺，28例接受12+1针法穿刺，两种穿刺的阳性率分别为35.29%（12/34）和46.43%（13/28），差异无统计学意义（P＞0.05）；前列腺体积≥90 mL患者10针法阳性检出率为33.33%（5/15），明显低于12+1针法的87.50%（7/8），差异比较有统计学意义（P＜0.05）；10针法和12+1针法在不同年龄、前列腺特异性抗原（PSA）及指诊情况下阳性检测率比较差异无统计学意义（P＞0.05）；10针法和12+1针法穿刺后血尿、血便、疼痛、尿潴留及感染发生比例差异比较无统计学意义（P＞0.05）。结论 应根据患者具体情况选取穿刺方法，当患者前列腺体积超过90 mL时，应采取12+1针法穿刺，有助于前列腺癌的检出，而当＜90 mL时，选取10针法穿刺较适宜。     

经直肠超声引导下经会阴前列腺穿刺315例分析

目的 探讨经直肠超声（TRUS）引导下经会阴前列腺穿刺的临床意义。方法 对315例PSA〉4ng／ml、直肠指检异常或B超发现异常回声的患者行经会阴的6点系统加异常回声处活检。年龄43～91岁，平均72岁。PSA〈4ng／ml者66例，4～10ng／ml者96例，10～20ng／ml者90例，〉20ng／ml者63例。结果 穿刺活检证实为前列腺癌111例，阳性率35．2％。PSA〉4ng／ml、指检异常、B超发现异常回声及PSAD〉0．15者穿刺阳性率分别为43．4％（108／249）、42．9％（75／175）、32．8％（63／192）及52．1％（75／144）。以PSAD〉0．15时的阳性率为最高，与其余3种标准相比差异有统计学意义。结论 TRUS引导下经会阴前列腺穿刺准确率高，并发症少而轻，是诊断前列腺癌的重要方法。     

8点及12点前列腺穿刺活检诊断前列腺癌的价值比较研究

目的比较8点及12点前列腺穿刺活检诊断前列腺癌的价值,分析前列腺特异性抗原(PSA)、前列腺特异性抗原密度(PSAD)及前列腺体积(PV)对前列腺癌检出率(PCDR)的影响。方法回顾性分析260例因PSA异常增高而接受首次直肠超声引导下前列腺穿刺活检的患者相关资料,其中132例患者接受8点穿刺,128例患者接受12点穿刺。结果依据PSA、PV、PSA与PV及PSAD,患者被进一步分组。8点及12点的总的PCDR没有显著的差异,在PV≥45mL、PSA≥10ng/mL且PV≥45mL及0.15ng/(mL·cm3)≤PSAD≤0.25ng/(mL·cm3)组中,12点的PCDR明显高于8点。结论 8点及12点前列腺穿刺总的PCDR没有显著区别(P0.05),但在PV较大同时PSA较高或者PSAD处于中等大小时(0.15~0.25)ng/(mL·cm3),12点的PCDR明显高于8点(P均0.05)。     

Ultrasound-guided transrectal extended prostate biopsy： a prospective study

AIM: To evaluate the diagnostic value of the 10 systematic transrectal ultrasound-guided (TRUS) prostate biopsy compared with the sextant biopsy technique for patients with suspected prostate cancer. Methods: One hundred and fifty-two patients with suspected prostate cancer were included in the study. Patients were entered in the study because they presented with high levels of prostate specific antigen (PSA) (over 4 ng/mL) and/or had undergone an abnormal digital rectal examination (DRE). In addition to sextant prostate biopsy cores, four more biopsies were obtained from the lateral peripheral zone with additional cores from each suspicious area revealed by transrectal ultrasound. Sextant, lateral peripheral zone and suspicious area biopsy cores were submitted separately to the pathological department. Results: Cancer detection rates were 27.6% (42/152) and 19.7% (30/152) for the 10-core and sextant core biopsy protocols, respectively. Adding the lateral peripheral zone (PZ) to the sextant prostate biopsy showed a 28.6% (12/42) increase in the cancer detection rate in patients with positive prostate cancer (P < 0.01). The cancer detection rate in patients who presented with elevated PSA was 29.3% (34/116). When serum PSA was 4-10 ng/mL TRUS-guided biopsy detected cancer in 20.6%, while the detection rate was 32.4% and 47.0% when serum PSA was 10-20 ng/mL and above 20 ng/mL, respectively. Conclusion: The 10 systematic TRUS-guided prostate biopsy improves the detection rate of prostate cancer by 28.6% when compared with the sextant biopsy technique alone, without increase in the morbidity. We therefore recommend the 10-core biopsy protocol to be the preferred method for early detection of prostate cancer.     

The incidence of prostate cancer in men with prostate specific antigen greater than 4.0 ng/ml: a randomized study of 6 versus 12 core transperineal prostate biopsy

PURPOSE: The prostate cancer detection rate in patients with elevated prostate specific antigen (PSA) increases with extended needle biopsy protocols. Transperineal biopsy under transrectal ultrasound guidance is rarely reported, although notable cancer diagnoses are obtained with this technique. We describe the results of 6 and 12 core transperineal biopsy. MATERIALS AND METHODS: A total of 214 patients with PSA greater than 4.0 ng/ml were prospectively randomized to undergo 6 or 12 core transperineal biopsy. Each group of 107 patients was comparable in terms of clinical characteristics. The procedure was performed on an outpatient basis using local anesthesia. Specimens were obtained with a fan technique with 2 puncture sites slightly above the rectum (1 per lobe) under transrectal ultrasound guidance. Cores were taken from all peripheral areas, including the far lateral aspect of the prostate. RESULTS: The overall cancer detection rate was 38% and 51% for 6 and 12 core biopsy, respectively. In patients with PSA between 4.1 and 10 ng/ml the cancer detection rate was 30% and 49% for 6 and 12 core biopsy, respectively. CONCLUSIONS: The 12 core transperineal prostate biopsy is superior to 6 core biopsy. The technique provides optimal prostate cancer diagnosis. About half of the patients with PSA greater than 4.0 ng/ml and a slightly lower percent with PSA between 4.1 and 10 ng/ml have prostate cancer.     

Detection rate and factors predictive the presence of prostate cancer in patients undergoing ultrasonography‐guided transperineal saturation biopsies of the prostate

Study Type – Diagnostic (case series)
Level of Evidence 4

OBJECTIVES

To assess the prostate cancer detection rate and predictive factors for prostate cancer after transrectal ultrasonography (TRUS)‐guided transperineal saturation re‐biopsies of the prostate, using a 24‐core scheme.

PATIENTS AND METHODS

We evaluated 143 consecutive patients undergoing TRUS‐guided transperineal saturation re‐biopsy of the prostate using a 24‐core scheme. The inclusion criteria were a previous negative biopsy and a prostate‐specific antigen (PSA) level of ≥10.0 ng/mL, or of 4.0–10.0 ng/mL with a free/total ratio of <20% or an abnormal digital rectal examination or previous high‐grade prostatic intraepithelial neoplasia (HGPIN) or atypical small acinar proliferation (ASAP).

RESULTS

The mean (sd ) age of the patients was 66.5 (6.1) years and the median (interquartile range) PSA level was 9.0 (6.1–12.8) ng/mL. The number of previous biopsies was one in 59% of patients, two in 26% and three or more in 15%. We detected prostate cancer in 26%, ASAP in 5.6% and HGPIN in 2.1%. The cancer detection rate was 47%, 25.5% and 14% for prostate volumes of <40, 40–60 and ≥60 mL, respectively (P = 0.002). On a multivariate analysis the total prostate volume (40–60 vs <40 mL, hazard ratio 5.683; >60 vs <40 mL, hazard ratio 6.965; P = 0.01) was the only significant predictor of prostate cancer at saturation biopsy.

CONCLUSIONS

TRUS‐guided transperineal saturation re‐biopsy of the prostate using a 24‐core scheme resulted in a high cancer detection rate also in patients who had had two or more previous biopsies. The total prostate volume was the only predictor of prostate cancer.     

Cancer detection rates of different prostate biopsy regimens in patients with renal failure

We aimed to evaluate the cancer detection rates of 6-, 10-, 12-core biopsy regimens and the optimal biopsy protocol for prostate cancer diagnosis in patients with renal failure. A total of 122 consecutive patients with renal failure underwent biopsy with age-specific prostate-specific antigen (PSA) levels up to 20?ng/mL. The 12-core biopsy technique (sextant biopsy?+?lateral base, lateral mid-zone, lateral apex, bilaterally) performed to all patients. Pathology results were examined separately for each sextant, 10-core that exclude parasagittal mid-zones from 12-cores (10a), 10-core that exclude apex zones from 12-cores (10b) and 12-core biopsy regimens. Of 122 patients, 37 (30.3%) were positive for prostate cancer. The cancer detection rates for sextant, 10a, 10b and 12 cores were 17.2%, 29%, 23.7% and 30.7%, respectively. Biopsy techniques of 10a, 10b and 12 cores increased the cancer detection rates by 40%, 27.5% and 43.2% among the sextant technique, respectively. Biopsy techniques of 10a and 12 cores increased the cancer detection rates by 17.1% and 21.6% among 10b biopsy technique, respectively. There were no statistical differences between 12 core and 10a core about cancer detection rate. Adding lateral cores to sextant biopsy improves the cancer detection rates. In our study, 12-core biopsy technique increases the cancer detection rate by 5.4% among 10a core but that was not statistically different. On the other hand, 12-core biopsy technique includes all biopsy regimens. We therefore suggest 12-core biopsy or minimum 10-core strategy incorporating six peripheral biopsies with elevated age- specific PSA levels up to 20?ng/mL in patients with renal failure.     

超声引导下前列腺12针系统穿刺活检增加前列腺癌检出率的研究

目的:探讨不同年龄及前列腺特异性抗原(PSA)分组对12针穿刺活检前列腺癌检出率及肿瘤特征的影响。方法:临床表现怀疑前列腺癌患者210例,按照患者的年龄分为≤59岁组、60～69岁组、70～79岁组、≥80岁组,按照PSA水平分为0～4μg/L组、4.1～10μg/L组、10.1～20μg/L组、20.1～50μg/L组、>50μg/L组,记录患者临床资料及活检结果。提出不同的穿刺方案并计算其检出率。结果:210例怀疑为前列腺癌患者,检出前列腺癌91例,总的前列腺癌检出率为43.3%,随着年龄的增长,PSA水平的提高,检出率逐渐提高。年龄的增长、PSA水平的提高与体积较大、分级较高的肿瘤密切相关。外周带穿刺与旁正中矢状尖部穿刺有较高的前列腺癌检出率。当患者年龄<60岁,PSA水平<20μg/L时,12针穿刺活检为较佳方案。结论:12针穿刺活检可以弥补6针穿刺活检的缺陷,随着患者年龄的增长,PSA水平的提高,肿瘤的体积增大、病理分级较差。传统6针穿刺法与12针相比,受患者年龄、PSA水平的影响较大。     

The morbidity of transperineal template-guided prostate mapping biopsy

OBJECTIVE

To evaluate the effect of transperineal template‐guided prostate mapping biopsy (TTMB) on urinary, bowel and erectile function.

PATIENTS AND METHODS

In all, 129 men had TTMB; a median of 56 biopsy cores were obtained per patient. Tamsulosin (0.8 mg daily) was initiated 2 days before TTMB and continued for 2 weeks. The International Prostate Symptom Score (IPSS), Rectal Function Assessment Score (R‐FAS), International Index of Erectile Function (IIEF)‐6 and the postvoid residual volume (PVR) were assessed at baseline and after 30 days, except for the IPSS, which was also assessed at 7 days. Several variables were evaluated as predictors of TTMB‐induced morbidity.

RESULTS

The mean patient age was 64.7 years with a mean prostate volume of 74.3 mL; 60 men (46.5%) were diagnosed with prostate cancer. After TTMB, 39.4%, 7.1% and 1.6% of patients remained catheter‐dependent at 0, 3 and 6 days. The median catheter‐dependency was 0, 1, 2 and 3 days for prostate volumes of <60, 60–90, 90–120 and >120 mL, respectively. No patient remained catheter‐ dependent for >12 days or required a transurethral resection secondary to TTMB. The mean IPSS before TTMB was 10.4, and was 4.6 and 3.8 at 7 and 30 days. At baseline and 30 days the mean PVR was 35 and 40 mL, and the median R‐FAS and IIEF scores for patients potent before TTMB were 2.0 and 2.2, and 27.0 and 26.0, respectively.

CONCLUSIONS

TTMB is a promising procedure for diagnosing prostate cancer. TTMB‐related morbidity differs from that of standard TRUS biopsy primarily in the incidence of temporary urinary retention, and is comparable in terms of urinary, bowel and erectile function.     

Prostate-specific antigen cut-off point of 2.5 ng/mL and increasing the number of prostate biopsies results in the detection of curable prostate cancer even in Japanese population

AIM: There is a trend for the cut-off point of Prostate-specific antigen (PSA) to be lower and the number of biopsies to be increased for detecting prostate cancer. I divided patients who visited my institution for prostate biopsy into 3 groups based on the time of examination. The results were evaluated retrospectively. METHODS: The three groups were: group A, PSA cut-off point of 4.0 ng/mL and sextant biopsy; group B, 2.5 ng/mL and 12 core biopsies; and group C, 2.5 ng/mL and saturation biopsy. I evaluated the rates of cancer detection, localized cancer, T1c, high grade cancer, major complications, insignificant cancer and the pain scores, and compared biopsy number and cancer detection rates with PSA range. Only the patients with T1c and PSA 2.6-10.0 ng/mL were evaluated about high grade cancer and insignificant cancer rates. RESULTS: Cancer detection rates, localized cancer rates and T1c rates were significantly high in group C. There were no significant differences in the high grade cancer rates, major complication rates and the insignificant cancer rates. A comparison between biopsy number and cancer detection rates was significantly high in the saturation biopsy group with PSA 4.1-10.0 ng/mL. CONCLUSION: A PSA cut-off point of 2.5 ng/mL and increasing the number of biopsies results in the increased detection of localized prostate cancer. The insignificant cancer rate, the high grade cancer rate and the complication rate were not significantly different among the groups. I recommend a PSA cut-off point of 2.5 ng/mL and an increased number of biopsies, saturation biopsy particularly in cases with PSA 4.1- 10.0 mg/mL.     

Computer simulated additional deep apical biopsy enhances cancer detection in palpably benign prostate gland

OBJECTIVES: The objective of this study was to use computer simulation to investigate the optimal biopsy scheme for enhancing the detection of cancer in palpably benign prostate glands. METHODS: The predominant distribution of palpably benign prostate cancer is anterior apex to mid-prostate. We used computer simulation to optimize apical samplings and to simulate the biopsy procedure, including angle and length. A total of 254 consecutive patients with palpably benign prostate glands underwent sextant biopsy plus two additional deep apical biopsies. RESULTS: Based on the computer simulation, lateral sextant and two additional medially located deep apical cores with a sagittal penetration angle of 80 degrees had the maximum cancer detection. Of the 254 patients, 58 (22.8%) had prostate cancer: 28 (48.3%) were positive only at the standard sextant sites, 12 (20.7%) were positive exclusively at the deep apical sites, and the remaining 18 (31.0%) were positive at both sites. Patients with gray-zone prostate-specific antigen (PSA) ranges of 4.1-10.0 ng/mL had increased cancer detection rates of 24% compared to sextant biopsy. Enhanced cancer detection by the deep apical biopsy was also evident in patients with a prostatic volume >40 cm3 (by 36.4%) and PSA 2.1-4.0 ng/mL (by 13.3%). CONCLUSIONS: Using a computer simulation-based biopsy scheme with deep apical sampling cores enhanced the detection of prostate cancer in palpably benign glands, especially in men with PSA ranges of 4.1-10.0 ng/mL or a gland volume of >40 cm3. Our approach with fewer sampling cores may have been more cost-effective than other extensive biopsy schemes, but further studies with larger samples are warranted.