BioJet　
文献アーカイブ・
動画

Abstract: Accurate diagnosis of prostate cancer has eluded clinicians for decades. With
our current understanding of prostate cancer, urologists should devise and confidently
present the available treatment options – active surveillance/radical treatment/focal therapy
to these patients. The diagnostic modalities used for prostate cancer have the dual problem
of false negativity and overdiagnosis. Various modifications in the prostate biopsy techniques
have increased the accuracy of cancer detection, but we are still far from an ideal diagnostic
technique. Transperineal template-guided mapping biopsy of the prostate is an exhaustive
biopsy technique that has been improvised over the past decade, and has shown superior
results to other available modalities. We have carried out a PubMed search on the available
experiences on this diagnostic modality, and along with our own experiences, we present a
brief review on transperineal template-guided mapping biopsy of the prostate.

Prostate cancer (PCa) is the most common solid-organ malignancy among American men and the second most deadly. Current
guidelines recommend a 12-core systematic biopsy following the finding of an elevated serum prostate-specific antigen (PSA).
However, this strategy fails to detect an unacceptably high percentage of clinically significant cancers, leading researchers to develop
new, innovative methods to improve the effectiveness of prostate biopsies. Multiparametric-MRI (MP-MRI) has emerged as a
promising instrument in identifying suspicious regions within the prostate that require special attention on subsequent biopsy.
Fusion platforms, which incorporate the MP-MRI into the biopsy itself and provide active targets within real-time imaging, have
shown encouraging results in improving the detection rate of significant cancer. Broader applications of this technology, including
MRI-guided focal therapy for prostate cancer, are in early phase trials.

Introduction Multiparametric-MRI (mp-MRI) is an evolving noninvasive imaging modality that increases
the accurate localization of prostate cancer at the time of MRI targeted biopsy, thereby enhancing clinical risk assessment, and improving the ability to appropriately counsel patients regarding therapy.
Material and methods We used MEDLINE/PubMed to conduct a comprehensive search of the English medical literature. Articles were reviewed, data was extracted, analyzed, and summarized. In this review,
we discuss the mp-MRI prostate exam, its role in targeted prostate biopsy, along with clinical applications and outcomes of MRI targeted biopsies.
Results Mp-MRI, consisting of T2-weighted imaging, diffusion-weighted imaging, dynamic contrast-enhan-
ced imaging, and possibly MR spectroscopy, has demonstrated improved specificity in prostate cancer detection as compared to conventional T2-weighted images alone. An MRI suspicion score has been developed and is depicted using an institutional Likert or, more recently, a standardized reporting scale (PI-RADS). Techniques of MRI-targeted biopsy include in-gantry MRI guided biopsy, TRUS-guided visual estimation biopsy, and software co-registered MRI-US guided biopsy (MRI-US fusion). Among men with no previous biopsy, MRI-US fusion biopsy demonstrates up to a 20% increase in detection of clinically significant cancers compared to systematic biopsy while avoiding a significant portion of low risk disease. These data suggest
a potential role in reducing over-detection and, ultimately, over-treatment. Among men with previous negative biopsy, 72–87% of cancers detected by MRI targeted biopsy are clinically significant. Among men with known low risk cancer, repeat biopsy by MR-targeting improves risk stratification in selecting men appropriate for active surveillance secondarily reducing the need for repetitive biopsy during surveillance.
Conclusions Use of mp-MRI for targeting prostate biopsies has the potential to reduce the sampling error associated with conventional biopsy by providing better disease localization and sampling. MRI-ultrasound fusion-targeted prostate biopsy may improve the identification of clinically significant prostate cancer while limiting detection of indolent disease, ultimately facilitating more accurate risk stratification. Literature supports the clinical applications of MRI-targeted biopsy in men who have never been biopsied before, those with a prior negative biopsy, and those with low risk disease considering active surveillance.

Background: When prostate cancer is suspected, the prostate gland is biopsied
with the aid of transrectal ultrasound (TRUS). The sensitivity of prostatic biopsyis about 50%. The fusion of magnetic resonance imaging (MRI) data with TRUS
enables the targeted biopsy of suspicious areas. We studied whether thisimproves the detection of prostate cancer.
Methods: 168 men with suspected prostate cancer underwent prostate MRIafter a previous negative biopsy. Suspicious lesions were assessed with the
classification of the Prostate Imaging Reporting and Data System and biopsiedin targeted fashion with the aid of fused MRI and TRUS. At the same sitting, a
systematic biopsy with at least 12 biopsy cores was performed.
Results: Prostate cancer was detected in 71 patients (42.3%; 95% CI,35.05–49.82). The detection rate of fusion-assisted targeted biopsy was 19%
(95% CI, 13.83–25.65), compared to 37.5% (95% CI, 30.54–45.02) withsystematic biopsy. Clinically significant cancer was more commonly revealed
by targeted biopsy (84.4%; 95% CI, 68.25–93.14) than by systematic biopsy(65.1%; 95% CI, 52.75–75.67). In 7 patients with normal MRI findings, cancer
was detected by systematic biopsy alone. Compared to systematic biopsy,targeted biopsy had a higher overall detection rate (16.5% vs. 6.3%), a higher
rate of infiltration per core (30% vs. 10%), and a higher rate of detection ofpoorly differentiated carcinoma (18.5% vs. 3%). Patients with negative biopsies
did not undergo any further observation.
Conclusion: MRI/TRUS fusion–assisted targeted biopsy improves the detectionrate of prostate cancer after a previous negative biopsy. Targeted biopsy is
more likely to reveal clinically significant cancer than systematic biopsy; nevertheless,systematic biopsy should still be performed, even if the MRI findings
are negative.

Purpose of review—Prostate cancer (CaP) may be detected on MRI. Fusion of MRI withultrasound allows urologists to progress from blind, systematic biopsies to biopsies, which aremapped, targeted and tracked. We herein review the current status of prostate biopsy via MRI/
ultrasound fusion.
Recent findings—Three methods of fusing MRI for targeted biopsy have been recentlydescribed: MRI–ultrasound fusion, MRI–MRI fusion (‘in-bore’ biopsy) and cognitive fusion.Supportive data are emerging for the fusion devices, two of which received US Food and DrugAdministration approval in the past 5 years: Artemis (Eigen, USA) and Urostation (Koelis,France). Working with the Artemis device in more than 600 individuals, we found that targeted
biopsies are two to three times more sensitive for detection of CaP than nontargeted systematicbiopsies; nearly 40% of men with Gleason score of at least 7 CaP are diagnosed only by targetedbiopsy; nearly 100% of men with highly suspicious MRI lesions are diagnosed with CaP; ability toreturn to a prior biopsy site is highly accurate (within 1.2 ± 1.1 mm); and targeted and systematicbiopsies are twice as accurate as systematic biopsies alone in predicting whole-organ disease.
Summary—In the future, MRI–ultrasound fusion for lesion targeting is likely to result in fewerand more accurate prostate biopsies than the present use of systematic biopsies with ultrasound　guidance alone.

Objective: Transperineal ultrasound-guided (TPUS) 12-core prostate biopsy was evaluated as an initial strategy for the
diagnosis of prostate cancer, The distribution of prostate cancer lesions was assessed with zone-specific biopsy.
Methods: From January 2010 to December 2012, 287 patients underwent TPUS-guided 12-core prostate biopsy. Multiple
cores were obtained from both the peripheral zone (PZ) and the transition zone (TZ) of the prostate. Participants’ clinical
data and the diagnostic yield of the cores were recorded and prospectively analyzed as a cross-sectional study.
Results: The diagnostic yield of the 12-core prostate biopsy was significantly higher compared to the 6-core scheme (42.16
vs. 21.6%). The diagnostic yield of the 10-core prostate biopsy was significantly higher compared to the 6-core scheme (37.6
vs. 21.6%). The 12-core scheme improved the diagnostic yield in prostates .50 ml (12-core scheme: 28.1% vs. 10-core
scheme: 20.4%; p = 0.034).
Conclusions: The 12-core biopsy scheme is a safe and effective approach for the diagnosis of prostate cancer. TZ biopsies in
patients with larger prostates should be included in the initial biopsy strategy.

Objectives—Prostate biopsy (Bx) has for three decades been performed in a systematic, butblind fashion using 2D ultrasound (US). Herein is described the initial clinical evaluation of a 3DBx tracking and targeting device (Artemis, Eigen, Grass Valley, CA). Our main objective was to
test accuracy of the new 3D method in men undergoing first and follow-up Bx to rule out prostate
cancer (CaP).
Methods & Materials—Patients in the study were men ages 35-87 (66.1 +/- 9.9 yrs), scheduledfor Bx to rule out CaP, who entered into an IRB-approved protocol. 218 subjects underwentconventional trans-rectal US (TRUS); the tracking system was then attached to the US probe; the
prostate was scanned and a 3D reconstruction was created. All Bx sites were visualized in 3D andtracked electronically. In 11 men, a pilot study was conducted to test ability of the device to returna Bx to an original site. In 47 men, multi-parametric 3 Tesla MRI – incorporating T2-weighted
images, dynamic contrast enhancement, and diffusion-weighted imaging – was performed in　advance of the TRUS, allowing the stored MRI images to be fused with real-time US during　biopsy. Lesions on MRI were delineated by a radiologist, assigned a grade of CaP suspicion, and
fused into TRUS for biopsy targeting.
Results—3D Bx tracking was completed successfully in 180/218 patients, with a success rate　approaching 95% among the last 50 men. Average time for Bx with the Artemis device was 15　minutes with an additional 5 minutes for MRI fusion and Bx targeting. In the tracking study, an
ability to return to prior Bx sites (n=32) within 1.2 +/- 1.1 mm S.D. was demonstrated and was　independent of prostate volume or location of Bx site. In the MRI fusion study, when suspicious　lesions were targeted, a 33% Bx-positivity rate was found compared to a 7% positivity rate for
systematic, non-targeted Bx (19/57 cores vs. 9/124 cores, p=0.03).
Conclusion—Use of 3D tracking and image fusion has the potential to transform MRI into a　clinical tool to aid biopsy and improve current methods for diagnosis and follow-up of CaP　The discovery that would have the greatest impact on our field would be the
development of accurate imaging of tumor within the prostate.

Purpose To evaluate a novel system for MRI/TRUS　fusion-guided biopsy for detection of prostate cancer
(PCa) in patients with previous negative prostate biopsyand determine diagnostic accuracy when using the Prostate
Imaging Reporting and Data System (PI-RADS) for multiparametricmagnetic resonance imaging (mpMRI) as proposed
by the European Society of Urogenital Radiology.
Methods Thirty-nine men with clinical suspicion of PCaand history of previous prostate biopsy underwent mpMRI
on a 3-T MRI. In total, 72 lesions were evaluated by theconsensus of two radiologists. PI-RADS scores for each
MRI sequence, the sum of the PI-RADS scores and theglobal PI-RADS were determined. MRI/TRUS fusionguided
targeted biopsy was performed using the BioJet™software combined with a transrectal ultrasound system.
Image fusion was based on rigid registration. PI-RADS scores of the dominant lesion were compared with histopathological
results. Diagnostic accuracy was determined using receiver operating characteristic curve analysis.
Results MRI/TRUS fusion-guided biopsy was reliable and successful for 71 out of 72 lesions. The global PIRADS
score of the dominant lesion was significantly higher in patients with PCa (4.0 ± 1.3) compared to patients with
negative histopathology (2.6 ± 0.8; p = 0.0006). Using a global PI-RADS score cut-off ≥4, a sensitivity of 85 %, a
specificity of 82 % and a negative predictive value of 92 %were achieved.
Conclusions The described fusion system is dependable and efficient for targeted MRI/TRUS fusion-guided biopsy.
mpMRI PI-RADS scores combined with a novel real-time MRI/TRUS fusion system facilitate sufficient diagnosis of
PCa with high sensitivity and specificity.

Objectives: To evaluate the efficacy of targeted therapy after complete resection of metastatic
lesions in patients with metastatic renal cell carcinoma.
Methods: We retrospectively reviewed the medical records of 53 patients with metastatic renal cell carcinoma who underwent complete surgical resection of metastatic lesions between January 2006 and December 2012. Immediate postoperative targeted therapy was given to a subgroup of patients. Progression-free survival and cancer-specific survival were assessed.
Results: All patients underwent curative surgery for a primary tumor. A total of 13 patients (24.5%) had metastatic disease at initial diagnosis, and 49 (92.5%) had single-organ involvement at the time of first metastasis. None of the patients met the poor-risk criteria. Of the 19 patients who received immediate postoperative targeted therapy, five (26.3%) experienced relapse. Of the 34 patients who did not receive immediate postoperative targeted therapy, 27
(79.4%) experienced disease recurrence. Targeted therapy was restarted in 30 patients (93.8%) after relapse with excellent disease control rates (complete response: 3.3%, partial response: 36.7%, stable disease: 46.7%). Immediate postoperative targeted therapywas associated
with better median progression-free survival (not reached vs 20.0 months; P = 0.017), but not better cancer-specific survival.
Conclusions: Postoperative targeted therapy after complete metastasectomy seems to be associated with better progression-free survival in patients with metastatic renal cell carcinoma, but not with cancer-specific survival.

Abstract: Accurate diagnosis of prostate cancer has eluded clinicians for decades. With our current understanding of prostate cancer, urologists should devise and confidently present the available treatment options – active surveillance/radical treatment/focal therapy to these patients.
The diagnostic modalities used for prostate cancer have the dual problem of false negativity and overdiagnosis. Various modifications in the prostate biopsy techniques have increased the accuracy of cancer detection, but we are still far from an ideal diagnostic technique. Transperineal template-guided mapping biopsy of the prostate is an exhaustive biopsy technique that has been improvised over the past decade, and has shown superior results to other available modalities.
We have carried out a PubMed search on the available experiences on this diagnostic modality, and along with our own experiences, we present a
brief review on transperineal template-guided mapping biopsy of the prostate.

Objectives: To evaluate the correlation between multiparametric prostate MRI (MP-MRI) suspicion for seminal
vesicle invasion (SVI) by prostate cancer (PCa) and pathology on MRI/ultrasound (US) fusion-guided biopsy.
Patients and Methods: From March 2007 to June 2013, 822 patients underwent MP-MRI at 3 Tesla and MRI/US fusion-guided biopsy. Of these, 25 patients underwent targeted biopsy of the seminal vesicles (SVs). In six patients, bilateral SVI was suspected, resulting in 31 samples. MP-MRI findings that triggered these SV biopsies were scored as low, moderate, or high suspicion for SVI based on the degree of involvement on MRI. Correlative prostate biopsy and radical prostatectomy (RP) pathology were reviewed by a single genitourinary pathologist.
Results: At the time of MP-MRI, the median age was 64 years with a median prostate-specific antigen of 10.74 ng/mL. Of the 31 SV lesions identified, MP-MRI suspicion scores of low, moderate, and high were assigned to 3, 19, and 9 lesions, respectively. MRI/US fusion-guided biopsy detected SVI in 20/31 (65%) of cases. For the four patients who underwent RP after a preoperative assessment of SVI, biopsy pathology and RP pathology were
concordant in all cases.
Conclusions: As this technology becomes more available, MP-MRI and MRI/US fusion-guided biopsy may play a role in the preoperative staging for PCa. Future work will determine if improved preoperative staging leads to better surgical outcomes.

Purpose: To compare prostate cancer detection rates between 12 cores transrectal ultrasound-guided prostate biopsy (TRUS-Bx)
and visually estimated multiparametric magnetic resonance imaging (mp-MRI)-targeted prostate biopsy (MRI-visual-Bx) for patients with prostate specific antigen (PSA) level less than 10 ng/mL. Materials and Methods: In total, 76 patients with PSA levels below 10 ng/mL underwent 3.0 Tesla mp-MRI and TRUS-Bx prospectively in 2014. In patients with abnormal lesions on mp-MRI, we performed additional MRI-visual-Bx. We compared pathologic results,
including the rate of clinically significant prostate cancer cores (cancer length greater than 5 mm and/or any Gleason grade
greater than 3 in the biopsy core).
Results: The mean PSA was 6.43 ng/mL. In total, 48 of 76 (63.2%) patients had abnormal lesions on mp-MRI, and 116 targeted biopsy
cores, an average of 2.42 per patient, were taken. The overall detection rates of prostate cancer using TRUS-Bx and MRI-visual-
Bx were 26/76 (34.2%) and 23/48 (47.9%), respectively. In comparing the pathologic results of TRUS-Bx and MRI-visual-Bx cores,
the positive rates were 8.4% (77 of 912 cores) and 46.6% (54 of 116 cores), respectively (p<0.001). Mean cancer core lengths and mean
cancer core percentages were 3.2 mm and 24.5%, respectively, in TRUS-Bx and 6.3 mm and 45.4% in MRI-visual-Bx (p<0.001). In addition,
Gleason score ≥7 was noted more frequently using MRI-visual-Bx (p=0.028). The detection rate of clinically significant
prostate cancer was 27/77 (35.1%) and 40/54 (74.1%) for TRUS-Bx and MRI-visual-Bx, respectively (p<0.001).
Conclusion: MRI-visual-Bx showed better performance in the detection of clinically significant prostate cancer, compared to
TRUS-Bx among patients with a PSA level less than 10 ng/mL.

Objectives: To report our early experience with manually controlled targeted biopsy with
real-time multiparametric magnetic resonance imaging and transrectal ultrasound fusion
images for the diagnosis of prostate cancer.
Methods: A total of 20 consecutive patients suspicious of prostate cancer at the multiparametric magnetic resonance imaging scan were recruited prospectively. Targeted biopsies were carried out for each cancer-suspicious lesion, and 12 systematic biopsies using the BioJet system. Pathological findings of targeted and systematic biopsies were analyzed.
Results: The median age of the patients was 70 years (range 52–83 years). The median preoperative prostate-specific antigen value was 7.4 ng/mL (range 3.54–19.9 ng/mL). Median preoperative prostate volume was 38 mL (range 24–68 mL). The number of cancer-detectedcases was 14 (70%).
The median Gleason score was 6.5 (range 6–8). Cancer-detected rates ofthe systematic and targeted biopsy cores were 6.7 and 31.8%, respectively (P < 0.0001). In six patients who underwent radical prostatectomy, the geographic locations and pathological grades of clinically significant cancers and index lesions corresponded to the pathological results of the targeted biopsies.
Conclusion: Prostate cancers detected by targeted biopsies with manually controlled targeted biopsy using real-time multiparametric magnetic resonance imaging and transrectal ultrasound fusion imaging have significantly higher grades and longer length compared with those detected by systematic biopsies. Further studies and comparison with the pathological findings of whole-gland specimens have the potential to determine the role of this biopsy
methodology in patients selected for focal therapy and those under active surveillance.

Objectives
To compare targeted, transperineal magnetic resonance imaging (MRI)/ultrasound (US)-fusion biopsy to systematic transrectal biopsy in patients with previous negative or first prostate biopsy and to evaluate the gain in diagnostic information with systematic biopsies in addition to targeted MRI/US-fusion biopsies.
Patients and Methods In all, 263 consecutive patients with suspicion of prostate cancer were investigated. All patients were evaluated by 3-T
multiparametric MRI (mpMRI) applying the European Society of Urogenital Radiology criteria. All patients underwent MRI/US-fusion biopsy transperineally (mean nine cores) and additionally a systematic transrectal biopsy (mean12 cores).
Results
In all, 195 patients underwent repeat biopsy and 68 patients underwent first biopsy. The median age was 66 years, median PSA level was 8.3 ng/mL and median prostate volume was 50 mL. Overall, the prostate cancer detection rate was 52% (137/263). MRI/US-fusion biopsy detected significantly more

【目的】今回，われわれは，MRI-TRUS融合画像リアルタイムガイド下経会陰式前立腺標的狙撃生検による前立腺癌診断の有用性について検討した．
【方法】対象は，2014年1月から11月までに，PSA値20ng/ml以下で，mpMRIにおいて，前立腺癌が存在する可能性が示唆された（PI-RADS classification 2-5）症例．
各症例に対して，BioJet®（D&K Technologies GmbH，Barum，Germany）を用いた標的狙撃生検，および系統的12カ所生検を初回生検として行った．
【結果】対象は，90症例．対象症例の年齢中央値は68歳，PSA中央値は6.7 ng/ml，前立腺体積中央値は37mlで，症例毎の生検穿刺数中央値は14カ所であった．51症例（57%）で癌が検出され，系統的生検コアおよび標的狙撃生検コアにおける癌検出率は，それぞれ6.0%および38%で有意差が認められた（p＜0.0001）．MRIにおいて癌が強く疑われた，いわゆるPI-RADS classification 4および5の病変における癌陽性率は，52%および82%であった．系統的生検コアおよび標的狙撃生検コアにおける癌組織長の中央値は，2mmおよび8mm（p＜0.0001），癌組織の割合は，16%および58%（p<0.0001）であった．Gleason score中央値は，6および6.5（p=0.001）と有意差が認められた．標的狙撃生検により診断されたsignificant cancerの局在診断は，摘出標本におけるsignificant cancerの局在およびGleasonscoreと，全症例（n=16）で一致が認められた．

Rapid technical advances have enabled multiparametric
magnetic resonance imaging (mpMRI) combined with
magnetic resonance (MR)–targeted biopsy to become
valuable tools for early detection of clinically significant
prostate cancer (PCa) while reducing overdiagnosis of
indolent PCa [1–6]. There has been concern, however, that
the widespread implementation and acceptance of mpMRI
could be impaired by a lack of standardisation of image
acquisition, interpretation and reporting guidance, and
inter- and intraobserver variability that could result in poor
clinical test performance in daily practise [7].

Abstract
Objective: To evaluate the accuracy of real-time elastic fusion image-guided transperineal prostate biopsy with needle tracking involving a mechanical position-encoded stepper in detecting clinically significant prostate cancer for biopsy-naïve men.
Methods: We prospectively recruited patients with serum prostate-specific antigen levels of 4.0-20 ng/mL and suspicious of prostate cancer on multiparametric magnetic resonance imaging. They underwent targeted biopsies for cancer-suspicious lesions and 12-core systematic biopsies. Pathological findings from biopsy cores and whole-mount specimens (for those who underwent radical prostatectomy) were analyzed.
Results: A total of 250 patients were included, in whom targeted and systematic biopsies detected significant cancers in 55% and 25%, respectively (P < 0.001). The targeted biopsy cores (n = 527) showed significantly greater biopsy-proven significant cancer detection rates (P < 0.001), cancer core length (P < 0.0001), cancer core percentage (P < 0.001) and Gleason scores (P < 0.001) than did the systematic biopsies. The significant cancer detection rate for targeted lesions (those with Prostate Imaging and Reporting and Data System classification scores of 5) was 80%. Biopsy-proven significant cancer detection rates for targeted lesions ≤10 mm and >10 mm were similar for Prostate Imaging and Reporting and Data System scores of 4 (P = 0.707) and 5 (P = 0.386). In whole-mount specimens (n = 30), locations for 95% of significant cancers were diagnosed preoperatively. Targeted biopsies alone diagnosed 79% of significant cancers.
Conclusions: Although targeted biopsies are superior to systematic biopsies in detecting significant cancers, systematic biopsies maintain an important role in the diagnosis of prostate cancer in biopsy-naïve men.
Keywords: cancer detection; fusion image-guided biopsy; magnetic resonance imaging; prostate cancer; significant cancer.

要旨：
（目的）MRI-TRUS 融合画像ガイド下生検により診断された限局性前立腺癌に対する HIFU をもちいた Fo-
cal Therapy について，1 年間の臨床成績を報告すること．
（対象と方法）対象は，血清 PSA 値が 20ng/ml 以下で，MRI-TRUS 融合画像ガイド下標的生検により signifi-
cant cancer が検出された低，中リスク前立腺癌症例．Significant cancer 局在区域に対して，HIFU を用いた
focal therapy を施行した．
（結果）対象症例は 10 例．年齢中央値は 68 歳，血清 PSA 中央値は 7.07ng/ml，治療時間中央値は 29.5 分間
であった．治療後全例が 24 時間以内に尿道カテーテルを抜去し，退院した．治療後の造影 MRI では，全例に
おいて significant cancer を含む治療領域の血流消失し，治療後 3 カ月目の血清 PSA 値中央値は 1.35ng/ml
まで有意に低下した．治療 6 カ月目の生検では，治療領域外から significant cancer が 1 例で検出された．
IPSS，OABSS，最大尿流量，IIEF-5，EPIC および SF-36 では，治療前後で有意な増悪は認められなかった．
合併症として尿路感染症が 1 例，1 カ月以内に自然消失した切迫性尿失禁が 1 例で認められた．
（考察）本治療の 1 年間の臨床成績は，治療の安全性と有効性を示唆させる結果であった．
（日泌尿会誌 109（4）：194～203，2018）
キーワード：限局性前立腺癌，Focal Therapy，高密度焦点式超音波療法

概要
臨床的に意義のある前立腺癌（csPC）の診断において、解剖学的及び機能的データを組み
合わせた有用性が故に、マルチパラメトリック MRI（mpMRI）を使用するケースが増えて
きている。MRI-経直腸超音波（TRUS）融合画像ガイド下前立腺生検等の MRI 標的生検は、
csPC の検出及び局所診断（位置特定）の精度が高い。この新しい診断技術は、排尿機能や
性機能に関連する解剖学的構造を維持しながら csPC を治療する、局所療法としてのオーダ
ーメイド医療の開発に一役買っている。初期の局所療法は、TRUS ガイド下系統生検で患
者を選別し、低リスク PC 患者を対象に治療を実施していた。mpMRI やマッピング生検が
導入された今、治療範囲は個々の癌の局在診断に基づいて決定される。最近報告されたプ
ロスペクティブ研究によると、治療を受けた患者の 87.4%が、中リスク及び高リスク PC で
あった。しかしながら、局所療法には 2 つの限界がある。第 1 に、局所療法と根治療法を
受ける患者間の病理学的特徴に差があるため、ランダム化比較試験の設計が困難であると
いうことだ。従って、局所療法と根治療法の比較に、ペアマッチ研究（pair-matched
studies）及び/又は歴史的対照研究が実施されている。第2 に、長期（≥10年）のフォローア
ップ研究が行われていないことが挙げられる。ただ、最近のプロスペクティブ研究では、
尿禁制や勃起機能の良好な維持に寄与するという理由から、限局性PCにおける治療戦略と
して、局所療法が奨励されている。
キーワード：Prostate cancer ・ Multi-parametric magnetic resonance imaging ・ Magnetic
resonance imaging–transrectal ultrasound fusion image-guided prostate biopsy ・
Focal therapy

要旨　【目的】今回，われわれは，MRI-TRUS融合画像リ
アルタイムガイド下経会陰式前立腺標的狙撃生検による前
立腺癌診断の有用性について検討した．
　【 方 法 】 対 象 は，2014年1月 か ら11月 ま で に，PSA値20ng/ml以下で，mpMRIにおいて，前立腺癌が存在する可能性が示唆された（PI-RADS classification 2-5）症例．
各 症 例 に 対 し て，BioJet ® （D&K Technologies GmbH，Barum，Germany）を用いた標的狙撃生検，および系統的12カ所生検を初回生検として行った．
　【結果】対象は，90症例．対象症例の年齢中央値は68歳，PSA中央値は6.7 ng/ml，前立腺体積中央値は37mlで，症例毎の生検穿刺数中央値は14カ所であった．51症例（57%）で癌が検出され，系統的生検コアおよび標的狙撃生検コアにおける癌検出率は，それぞれ6.0%および38%で有意差が認められた（p＜0.0001）．MRIにおいて癌が強く疑われた，いわゆるPI-RADS classification 4および5の病変における
癌陽性率は，52%および82%であった．系統的生検コアおよび標的狙撃生検コアにおける癌組織長の中央値は，
2mmおよび8mm（p＜0.0001），癌組織の割合は，16%および58%（p<0.0001）であった．Gleason score中央値は，6および6.5（p=0.001）と有意差が認められた．標的狙撃生検により診断されたsignificant cancerの局在診断は，摘出標本におけるsignificant cancerの局在およびGleason scoreと，全症例（n=16）で一致が認められた．
　【考察】本検討における標的狙撃生検は，significant cancerの検出およびその局在診断において，有用である可
能性が示唆された．
Transperineal targeted biopsy with real-time fusion image of multiparametric magnetic resonance image and transrectal ul-trasound image for the diagnosis of prostate cancer