Elsevier

European Urology

Volume 65, Issue 4, April 2014, Pages 809-815
European Urology

Prostate Cancer
Value of Targeted Prostate Biopsy Using Magnetic Resonance–Ultrasound Fusion in Men with Prior Negative Biopsy and Elevated Prostate-specific Antigen

https://doi.org/10.1016/j.eururo.2013.03.025Get rights and content

Abstract

Background

Conventional biopsy fails to detect the presence of some prostate cancers (PCas). Men with a prior negative biopsy but persistently elevated prostate-specific antigen (PSA) pose a diagnostic dilemma, as some harbor elusive cancer.

Objective

To determine whether use of magnetic resonance–ultrasound (MR-US) fusion biopsy results in improved detection of PCa compared to repeat conventional biopsy.

Design, setting, and participants

In a consecutive-case series, 105 subjects with prior negative biopsy and elevated PSA values underwent multiparametric magnetic resonance imaging (MRI) and fusion biopsy in an outpatient setting.

Intervention

Suspicious areas on multiparametric MRI were delineated and graded by a radiologist; MR–US fusion biopsy was performed by a urologist using the Artemis device; targeted and systematic biopsies were obtained regardless of MRI result.

Outcome measurements and statistical analysis

Detection rates of all PCa and clinically significant PCa (Gleason ≥3 + 4 or Gleason 6 with maximal cancer core length ≥4 mm) were determined. The yield of targeted biopsy was compared to systematic biopsy. The ability of an MRI grading system to predict clinically significant cancer was investigated. Stepwise multivariate logistic regression analysis was performed to determine predictors of significant cancer on biopsy.

Results and limitations

Fusion biopsy revealed PCa in 36 of 105 men (34%; 95% confidence interval [CI], 25–45). Seventy-two percent of men with PCa had clinically significant disease; 21 of 23 men (91%) with PCa on targeted biopsy had significant cancer compared to 15 of 28 (54%) with systematic biopsy. Degree of suspicion on MRI was the most powerful predictor of significant cancer on multivariate analysis. Twelve of 14 (86%) subjects with a highly suspicious MRI target were diagnosed with clinically significant cancer.

Conclusions

MR–US fusion biopsy provides improved detection of PCa in men with prior negative biopsies and elevated PSA values. Most cancers found were clinically significant.

Introduction

Prostate needle biopsy, when performed by the conventional method [1], may fail to detect the presence of cancer. The false-negative rate of ultrasound-guided systematic biopsy may be as high as 47% [2]. Men with prior negative biopsies and persistently elevated serum prostate-specific antigen (PSA) levels, a group numbering in the millions, constitute a diagnostic dilemma [3], [4]. Repeated biopsy sessions and PSA-related anxiety will follow in many of these men. In fact, 38% of Medicare patients undergo a repeat biopsy within 5 yr of an initial negative biopsy [5]. Attempts to reduce the false-negative rate by additional sampling, anterior sampling, and apical sampling have been only marginally successful [6], [7]. Transperineal template biopsy may detect additional prostate cancer (PCa) [1], [8], both serious and trivial, but it requires general anesthesia and risks increased morbidity [2], [9].

Targeted prostate biopsy, which uses findings from magnetic resonance imaging (MRI) to guide needle aiming, may help to establish a correct diagnosis for men in this group [10]. The technology involves either direct in-bore biopsy, performed by a radiologist [11], [12], [13], [14], or fusion biopsy, wherein the MRI features are combined with ultrasound guidance in a traditional urologic biopsy suite [15], [16], [17], [18], [19], [20]. Using one such fusion device (Artemis, Eigen, Grass Valley, CA, USA), we found that level of suspicion on MRI correlated with biopsy diagnosis of cancer; when MRI indicated a focus of greatest suspicion, cancer was diagnosed by fusion biopsy in 15 of 16 men [21].

In the present study, we sought to test the value of an office-based fusion device in the detection of PCa in men with prior negative biopsies and persistently elevated PSA levels. Conduct of the present study and preparation of this report were guided by conclusions from a recent international conference on this subject [22].

Section snippets

Study design

Subjects were culled from a prospective trial of magnetic resonance–ultrasound (MR–US) fusion biopsy at the University of California, Los Angeles (UCLA), which was approved in advance by the UCLA Institutional Review Board. Those included in the present study were all 105 men with one prior negative prostate biopsy or more and persistently elevated serum PSA levels who underwent multiparametric MRI (mpMRI) and MR–US fusion biopsy between March 2010 and August 2012. Prior biopsies were performed

Demographics and clinical characteristics

Table 2 displays demographics and clinical characteristics. The median interval from negative biopsy to MR–US fusion biopsy was 14 mo (interquartile range [IQR]: 9–26). At prior biopsies, a median of 13 cores was obtained (IQR: 12–16). At fusion biopsy, the median PSA level was 7.5 ng/ml (IQR: 5.0–11.2) and median prostate volume was 58 ml (IQR: 39–82). Targets were identified on mpMRI in 101 of the 105 patients (maximum image grade of 1, n = 4; grade 2, n = 11; grade 3, n = 42; grade 4, n = 34; and

Discussion

In the present study of men with a prior negative biopsy and persistently elevated PSA levels, a dilemma group, we found that MR–US fusion biopsy yielded a 34% cancer-detection rate. When highly suspicious MRI lesions were targeted, the great majority of cancers found were clinically significant, and few were insignificant. Because of these and other supporting data [15], [18], fusion biopsy can now be considered for men in the dilemma group. Although experience is limited, the fusion device

Conclusions

Office-based MR–US fusion biopsy improves detection of PCa in men with prior negative biopsies and elevated PSA levels. The majority of detected cancers are clinically significant.

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