trus biopsy prostate

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TRUS GUIDED

PROSTATE BIOPSY

Gaurav NaharDNB Urology(Std)MMHRC, Madurai


INTRODUCTION

• There is a significant decline in prostate cancer related mortality: d/t early prostate cancer detection programs.

• Role of PSA screening efforts, introduction & refinement of systematic transrectal ultrasonography (TRUS)– guided prostate biopsy techniques, and increased public awareness about prostate cancer.


• TRUS of the prostate- first described by Watanabe et al(1968).

• TRUS-guided systematic sextant biopsy protocol- introduced by Hodge et al(1989).

• TRUS: mainstay of many image-guided prostate interventions, including prostate biopsy, brachytherapy, cryotherapy, & high-intensity focused ultrasonography (HIFU), evaluation of appropriate patients for treatment of BPH.


ULTRASONOGRAPHICANATOMY OF PROSTATE

• The prostate lies between bladder neck and urogenital diaphragm, just anterior to rectum, an ideal position to be imaged by TRUS.


• On the basis of pathologic zonal architecture, prostate is divided into:

Anterior fibromuscular stroma (AFS) that is devoid of glandular tissue,

transition zone (TZ), central zone (CZ), periurethral zone, and peripheral zone (PZ).

• But these regions are not visible sonographically as distinct entities.


TRANSVERSE SAGITTAL


• Normal CZ and PZ(posterior): majority of adenocarcinomas; homogeneous echogenic appearance.

• TZ(anterior) is more heterogeneous.


GRAY-SCALE TRUS

• Most common imaging modality for prostate.

• Most commonly used for:prostate cancer detection,evaluation of other conditions such as

infertility,directing the biopsy of prostate cancer.


A, In the transverse plane with the hypoechoic urethra centrally located (star) and dotted line representing transverse measurement.

B, Midline sagittal view with the hypoechoic urethra running the length of the gland, D1 represents longitudinal and D2 anteroposterior measurement.


Seminal vesicles and vasadeferentia in the transverse plane


• Endorectal probes available in both side- and end-fire models; transmits frequencies of 6 to 10 MHz.

• Newer biplane probes provide simultaneous sagittal and transverse imaging modes.


• Increasing frequency yields increased resolution.

• The commonly used 7-MHz transducer produces a high-resolution image with a focal range from 1 to 4 cm from the transducer (best for PZ where most cancers arise).

• Lower frequency transducers (e.g.older 4-MHz) have a focal range from 2 to 8 cm but at lower resolution; they improve anterior delineation of large glands, increasing the accuracy of volume measurements, but provide poor internal architecture visualization.


• Medium-gray image of normal PZ serves as the "reference point" for judging lesions as hypoechoic (darker than the normal PZ), isoechoic (similar to the normal PZ), hyperechoic (lighter than the normal PZ), or anechoic (completely black).

• TRUS should be performed in both transverse and sagittal planes.


VOLUME CALCULATION:

• π/6 × transverse diameter × AP diameter × longitudinal diameter

• Mature average prostate-20-25 g and remains constant until age 50.

• For more accurate determination of prostate volume (Brachytherapy), Planimetry is required.


PROSTATE CANCER IMAGING ON TRUS

• All hypoechoic lesions within the PZ: consider biopsy.

• A hypoechoic lesion is malignant in 17-57% of cases, but they are not pathognomonic for cancer.

• Lack of a distinct hypoechoic focus doesn't preclude biopsy, as 39% of Ca prostate cases are isoechoic, & 1% hyperechoic on conventional gray scale TRUS.


• Granulomatous prostatitis, prostatic infarct & lymphoma- all may produce hypoechoic lesions.

• Extracapsular extension of prostate cancer, although not well visualized if present as a microfocus, is suggested by a focal loss of the typically bright white periprostatic fat.


Classic hypoechoic peripheral zone (PZ) lesion(dotted line) in the right midgland that transrectal

ultrasonography–guided biopsy proved to be aGleason 3 + 3 = 6 adenocarcinoma.


INDICATIONS FOR PROSTATE BIOPSY

TRUS without Biopsy

• Treatment planning volume measurements: brachytherapy, cryotherapy, BPH therapy (e.g.TUMT, RFA)

• Volume measurement during hormonal downsizing for EBRT or brachytherapy

• Placement of fiducial markers for EBRT

• Evaluation of azoospermia: ejaculatory duct cysts, seminal vesicle cysts, etc.

• Therapeutic aspiration or unroofing of prostatic cysts; drainage of prostatic abscess


TRUS-Directed Biopsy• Diagnosis of suspected symptomatic prostate cancer (i.e.,

bone metastasis, cord compression)

• Screening for prostate cancer in asymptomatic patient > age 50 with > a 10-year life expectancy (if strong family history or if African-American, consider screening at age 45)

Prostate nodule or significant prostate asymmetry regardless of PSA level

PSA > 4.0 ng/dL regardless of age In men < age 60 to 65 years, consider biopsy if PSA > 2.5

ng/dL If PSA > 0.6 ng/dL at age 40 Increased PSA velocity (>0.75 ng/dL/year) Free PSA in considering initial biopsy with PSA < 10

ng/mL: >25% no biopsy; >10% and <15%, consider biopsy; <10%, biopsy


• Prior to intervention in symptomatic BPH (e.g., surgical therapy or initiation of 5α-reductase inhibitors)

• Prior to cystoprostatectomy or orthotopic urinary diversion

• To diagnose failed radiation therapy before use of second-line therapy

• Follow-up biopsy (3-6 months) after diagnosis of high-grade PIN or ASAP.


• Data from the Prostate Cancer Prevention Trial have shown that no safe PSA threshold can rule out prostate cancer in any age range.

• For a serum PSA value between 4.0 and 10.0 ng/mL, using a % free PSA threshold of <25% allowed detection of 95% of cancers while eliminating 20% unnecessary biopsies.


• Volume-based PSA parameters evaluated to reduce confounding from BPH.

• These include:PSA density (PSAD; PSA divided by

prostate volume),complexed PSA density (complexed

PSA divided by prostate volume), andPSA transition zone density (PSA

divided by transition zone volume).


• PSA levels between 4 and 10 ng/mL and a normal DRE:

PSAD ≥ 0.15- prostate biopsy recommended.

PSA transition zone volume was the parameter with highest overall sensitivity & specificity.


PSA Dynamics/PSA Velocity(PSAV):• Rate of change in PSA.• With PSA levels between 4-10 ng/mL, PSAV

≥ 0.75 ng/mL/year: a specific marker for the presence of prostate cancer.

• In PSA <4, PSAV > 0.5ng/mL/yr is significant.

• PSAV may play a role in the prediction of life-threatening prostate cancer .

• A PSAV > 0.35 ng/mL/year 10-15 years prior to diagnosis- fivefold increased risk of life-threatening prostate cancer more than a decade later.


CONTRAINDICATIONS TO PROSTATE BIOPSY

• Significant coagulopathy

• Painful anorectal conditions

• Severe immunosuppression, and

• Acute prostatitis.


PATIENT PREPARATION

• Written, informed consent.

• All anticoagulant therapy (warfarin, clopidogrel, aspirin/NSAIDs, herbal supplements) should be stopped 7-10 days before prostate biopsy.

• For coagulopathic pts., INR correction below 1.5.


ANTIBIOTIC PROPHYLAXIS

• Oral FQ one dose 30-60 min.before biopsy - continue for 3 days.

• Single dose oral FQ=3day regimen.

• High risk pts.(endocarditis, prosthetic joints, pacemakers, automated implanted cardiac defibrillators)- i.v. Ampicillin/Vancomycin + Gentamicin preop f/b 3days oal FQ.


Cleansing enema:

• decreases the amount of feces in the rectum, thereby producing a superior acoustic window for prostate imaging.

• may reduce bacterial seeding of the prostate.


Analgesia:

• Topical lidocaine jelly.

• Infiltration anesthesia around nerve bundles.

• Direct infiltration(Intraprostatic injection).

• Skin & subcut.infiltration for transperineal biopsy.


• Left lateral decubitus position with knees and hips flexed 90 degrees.

• Lithotomy position preferred for transperineal biopsies, brachytherapy treatment planning, or placement of fiducial gold markers for external-beam therapy.

• Lithotomy position is preferred when color Doppler imaging is used to identify areas of hyperemia for targeted biopsy of the prostate(distribution of color Doppler flow within the prostate is dependent on patient position)


TRUS PROSTATE BIOPSY TECHNIQUES

• Assess prostate volume.

• Prostate imaging in transverse & sagittal planes(from base to apex).

• Note location and characteristics of any lesions (i.e., hypoechoic, hyperechoic, calcifications, contour abnormalities, cystic structures).


• A spring-driven, 18-gauge, needle core biopsy device or biopsy gun, passed through the needle guide attached to the ultrasound probe.

• Biopsy gun advances the needle 0.5 cm and samples subsequent 1.5 cm of tissue with the tip extending 0.5 cm beyond the area sampled.


BIOPSY GUN


18-gauge prostate needle biopsy core specimen


SEXTANT BIOPSY:• one core, bilaterally,

each from base, mid, and apex.

• samples both PZ & TZ.

• Vast majority of AdenoCa- posterolateral PZ.

TRUS BIOPSY SCHEMES


EXTENDED CORE BIOPSY SCHEMES

• Improved cancer detection rates by incorporating additional laterally directed cores into the standard systematic sextant technique.

• At present, 6 cores are considered inadequate for routine prostate biopsy for cancer detection.


• TZ and SVs are not routinely sampled(low yields for cancer detection at initial biopsy).

• TZ and anteriorly directed biopsies may occasionally prove necessary to diagnose prostate cancer in patients with persistently elevated PSA levels and prior negative biopsies.

• A role for TZ biopsies in men with gland size > 50 mL, with an additional yield of 15% cancer detection.


• Seminal vesicle biopsy is not routinely performed unless there is a palpable abnormality, when PSA value > 30, or if brachytherapy is being considered.


Various reported systematic biopsy schemes.

A, Sextant biopsy scheme originally proposed by Hodge and associates (Hodge et al, 1989b)

B, The 10-core biopsy of Presti and coworkers (2000).

C, The 12-core, or double sextant, biopsy.

D, The 13-core “5-region biopsy” of Eskew and colleagues


Cross-sectional view of commonlybiopsied zones.


REPEAT PROSTATE BIOPSY

• Use of a 2nd prostate biopsy in all cases of a negative finding on initial biopsy is justified.

• But 3rd and 4th repeat biopsies should only be obtained in selected patients with high suspicion of cancer and/or poor prognostic factors on the 1st or 2nd biopsy.


• Overall cancer detection rates for repeat prostate needle biopsy with various biopsy templates ranges from 10% - 38%.

• Indications for a repeat prostate biopsy include the following:

1) A highly suspicious DRE (digital rectal examination)

2) A persistently rising serum PSA (> 0.4 – 0.75 ng/ml/yr.)

3) A low free PSA (certainly < 10%, maybe < 22% - 25%)

4) Presence of PIN or atypia on prior biopsy


RISKS & COMPLICATIONS OF PROSTATE BIOPSY

Immediate:• Hematuria• Vasovagal episode• Rectal bleeding

Delayed:• Persistent hematuria• Vague pelvic discomfort• Dysuria• Hematochezia• Hematospermia• Postbiopsy infections(low grade febrile illness,

UTI,acute prostatitis, epididymitis, fatal septicemia)


ADVANCED USG TECHNIQUES FOR PROSTATE IMAGING

COLOR & POWER DOPPLER TRUS:• Color Doppler imaging is based on

the frequency shift in the reflected sound waves from the frequency of insonation.

• depicts the velocity of blood flow in a directionally dependent manner.


• Color assignment is based on the direction of blood flow related to the orientation of the transducer receiving the signal; flow toward the transducer- red and flow away in shades of blue; color is not specific for arterial or venous flow.


Transrectal ultrasonography.

• Top image, solid white arrow depicts hypoechoic lesion within the peripheral zone concerning for prostate cancer.

• Lower image depicts hypervascular area seen with color Doppler imaging, yellow and red area corresponds to the hypoechoic area seen on the grayscale ultrasonography above.


POWER DOPPLER IMAGING (enhanced color Doppler, color amplitude imaging [CAI], or color angiography)

• uses amplitude shift to detect flow in a velocity and directionally independent manner.

• Advantages: ability to detect slower flow and to have less reliance on the Doppler angle, making it more suitable for detection of prostate cancer neovascularity.


A. Color Doppler transrectal ultrasonography (TRUS) andB. Power Doppler TRUS identify a Gleason 4 + 4 = 8

adenocarcinoma in the left midgland


• Patients with detectable color Doppler flow within their dominant tumor at the time of TRUS-guided biopsy are at a 10-fold increased risk for PSA recurrence after radical retropubic prostatectomy.


CONTRAST ENHANCED TRUS(CE-TRUS):

• Intravenous microbubble ultrasound contrast agents, infused systemically during gray-scale and TRUS Doppler imaging amplify flow signals within the microvasculature of prostate tumors, allowing selective visualization of malignant foci.

• These agents increase the echogenicity of the intravascular space on grey-scale imaging and provide a dramatic visible increase in the Doppler signal.

• These are constructed with air or higher-molecular-weight gas agents encapsulated (albumin or polymer hard shell, lipid- or surfactant-coated) for longevity.


• CE-TRUS + 3D IMAGE RECONSTRUCTION of enhanced power doppler.

• GREY-SCALE HARMONIC imaging: better spatial & temporal resolution.

• FLASH REPLENISHMENT IMAGING: improved visualisation of vessels.


Unenhanced color (A) transrectal ultrasonography (TRUS) and power Doppler (B) TRUS fail to detect evidence of an underlying malignancy. After infusion of a

microbubble contrast agent, color (C) TRUS and power Doppler (D) TRUS demonstrate an area of increased flow in the left midgland that proved to be a Gleason

3 + 4 = 7 adenocarcinoma on targeted biopsy


OTHER TECHNIQUESARTIFICIAL NEURAL NETWORKS

ELASTOGRAPHY: • New sonography technique.• employs real-time sonographic imaging of

the prostate at baseline and under varying degrees of compression.

• Through computerized calculations, differences in displacement between ultrasonic images from baseline and during compression may be visualized, and regions with decreased tissue elasticity may be tagged as suggestive of malignancy.


Elastography demonstrates an area of decreased compliance in the right base consistent with an underlying malignancy (blue near arrow). Note color scale in upper right corner indicating relative tissue “firmness.” Targeted biopsy of

this region revealed a Gleason 4 + 4 = 8 adenocarcinoma


ENDORECTAL MRI & MR SPECTROSCOPIC IMAGING(MRSI):

• MRSI identifies biochemical changes within the tissue that may predate the appearance of histological changes.

• MRSI suggestive of malignancy may not have biopsy detectable PCa at the time of MRSI but may develop histological cancer at a later date.


ThankYou!!

trus biopsy prostate

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