Prostate Biopsy

Prostate biopsy confirms prostate cancer when clinically significant disease is suspected and the result will change management. It is performed transrectally or transperineally under ultrasound guidance, and modern practice is increasingly MRI-first — a prior multiparametric MRI directs targeted sampling that is combined with systematic cores. The diagnostic pathway, staging, and biomarkers are covered in the Prostate Cancer topic; this page is the operative reference.

Indications

• Detection — a raised PSA (without UTI, retention, or acute prostatitis) or an abnormal DRE; restaging — rising PSA after non-surgical treatment; active-surveillance protocols; and suspicious-but-not-diagnostic prior histology.
• The PSA threshold is controversial (the PCPT found ~15% cancer even with PSA < 4); for BRCA carriers the referral threshold is 3 ng/mL. With PSA > 50 ng/mL and no benign explanation, biopsy may be omitted when it poses significant risk and treatment is urgent.
• Contraindications — significant coagulopathy, severe immunosuppression, and acute prostatitis.

The MRI-First Pathway

A multiparametric MRI before biopsy improves detection of clinically significant cancer and reduces over-detection of insignificant disease (PRECISION).

• PI-RADS scores each lesion 1–5; ≥ 4 → biopsy should be considered, while ≤ 3 depends on other factors (PSA density > 0.15, prior negative biopsy, DRE, family history).
• Combine targeted and systematic cores — do not omit systematic sampling (MRI-FIRST, Ahdoot). A negative MRI has an NPV of ~91% for grade-group ≥ 2 cancer, but ~10% (up to 20%) of negative MRIs still harbour significant cancer.
• Post-biopsy MRI should wait 6–8 weeks (haemorrhage mimics cancer).

Note: the Hinman atlas describes TRUS-guided biopsy as the "gold standard"; that framing predates the MRI-first paradigm, so this page leads with the topic's current pathway and uses the atlas for operative technique.

Choosing the Route

The transrectal and transperineal routes have similar cancer-detection rates but differ in infection risk and access to anterior/apical tumours.

	Transrectal	Transperineal
Trajectory	Through the rectum	Through perineal skin (avoids the rectum)
Advantages	Patient comfort/preference; familiarity	Fewer infections; better anterior/apical detection; feasible without a rectum
Drawbacks	Higher infection risk	May need more anaesthesia (but feasible under local)

Preparation

• Anticoagulation — low-dose aspirin can be continued; warfarin and clopidogrel are stopped 7–10 days before; NOACs (apixaban, dabigatran, rivaroxaban) 2–5 days before; biopsy when INR < 1.5, with heparin bridging for high thromboembolic risk.
• Antibiotic prophylaxis — for transrectal biopsy it is recommended for all patients (2019 AUA: a fluoroquinolone, or a cephalosporin + aminoglycoside; rectal-swab-targeted prophylaxis helps where fluoroquinolone resistance is a concern), continued for ≥ 24 hours. For transperineal biopsy the NORAPP trial (2022) found antibiotics do not significantly reduce infection. A cleansing enema improves the acoustic window.

Equipment

A transrectal probe generates 6–10 MHz for 180° transverse and sagittal views (biplane models show both at once) in a side-fire or end-fire configuration (equivalent detection), with the needle trajectory overlaid on the image. The spring-loaded core device has two needles: the inner notched needle fires forward 23 mm, followed a fraction of a second later by the outer hollow needle — anticipate the 23 mm throw to avoid the bladder. The tissue core measures 15–17 mm; the device is 18-gauge.

TRUS-Guided Systematic Biopsy

Positioning and Orientation

Place the patient in the left lateral decubitus position with the anal verge at the table edge and hips/knees flexed 90°; instil intrarectal lidocaine a few minutes beforehand and perform a pre-biopsy DRE (target any nodule). Insert the probe with constant pressure toward the spine and turn on the trajectory overlay. With a side-fire probe, clockwise rotation views the left prostate and counter-clockwise the right; using the anal sphincter as a fulcrum, angling toward the sacrum reaches the apex and toward the scrotum reaches the base.

Periprostatic Nerve Block

The neurovascular bundle lies at the 5 and 7 o'clock positions. In the sagittal view at the seminal-vesicle–prostate junction, inject a periprostatic block bilaterally (1% lidocaine, max 3 mg/kg — or 7 mg/kg with epinephrine — ~5 mL per side; the atlas uses 10 mL of a 50:50 mix of 1% lidocaine and 0.25% bupivacaine via a 22-gauge spinal needle), optionally adding up to 5 mL at the lateral apex.

Prostate Volume

Measure in axial and sagittal planes; the ellipsoid estimate is π/6 × transverse × AP × longitudinal diameter, and 1 cc ≈ 1 g of prostate tissue.

12-Core Template

Sample the peripheral zone at apex, mid, and base. At the lateralmost aspect (rotate until the prostate disappears, then back slightly), take three cores (apex/mid/base) by angling on the anal fulcrum — do not rotate the probe during apex/mid/base sampling (it causes medial-lateral deviation). Rotate medially for three more, then repeat on the contralateral side for 12 cores total (apical and far-lateral cores are key). Submit the sextant cores in separate containers; the transition zone and seminal vesicles are not routinely sampled (isolated TZ tumours occur < 5%), and seminal-vesicle biopsy is reserved for suspected SV invasion or planned salvage cryotherapy. Saturation biopsy (18–21 cores) is reserved for repeat biopsy.

Apical Biopsy and the Dentate Line

Above the dentate line innervation is visceral (responds to stretch); below it is somatic (sensitive to pain). To minimise pain on apical biopsy, stay above the dentate line by advancing the probe further into the anal canal and angling toward the sacrum.

Transperineal Template Biopsy

A grid-guided route that passes the needle through the perineal skin, avoiding rectal flora entirely — favoured for patients concerned about infection (or with risk factors for it) and for a prior negative TRUS biopsy with persisting suspicion of a missed anterior cancer, since the template samples the whole gland including the anterior and apical zones that TRUS reaches poorly. The reported learning curve is ~50 cases (fewer for clinicians experienced in brachytherapy).

Setup and Equipment

• Typically performed under general anaesthesia as a day case (the atlas's practice), though it is increasingly feasible under local/pudendal block (the pudendal nerve lies ~2 cm lateral to the anal verge and ~3 cm deep). Ensure a sterile preoperative urine culture and an empty rectum (laxative/enema).
• (Antibiotics: the atlas uses a 3-day oral fluoroquinolone — norfloxacin 400 mg twice daily from the day before — plus perioperative IV ceftriaxone; note this institutional regimen predates the NORAPP finding above that antibiotics do not significantly reduce transperineal infection.)
• A stepper fixed to the table holds a biplanar TRUS probe (7.5 MHz) and a brachytherapy grid against the perineum. The standard grid is 6 × 6 cm with 5-mm spacing — 13 points per axis, 169 openings. Cores are taken with an 18-gauge Tru-Cut needle.

Technique

1. Position and prep — dorsal lithotomy; routine DRE; elevate the scrotum and prep the perineum with povidone-iodine; fix the stepper and introduce the probe with light constant pressure.
2. Survey and measure — sweep the probe rostro-caudally to image the whole gland; identify the urethra, apex, any middle lobe, and the seminal vesicles, and note hypoechoic areas correlating with the MRI/DRE. Measure volume by the prolate-ellipsoid formula (width × length × height × π/6).
3. Stratify the gland by size — around 30 mL / 4–5 cm length: smaller glands into two regions, larger glands into three (adding a midsection and larger transition zone). The Barzell-adapted scheme takes up to ~22 cores from 14 or 18 locations — a compromise between morbid 5-mm saturation mapping and peripheral-only sampling — deliberately sparing the paraurethral transition zone and bladder neck while sampling the cancer-prone zones.
4. Sample posterior-first, apex-to-base so a forming hematoma does not distort the next level: begin at the posterior apex (4 cores, 2/side), then the posterior base (8 cores — 2 posterolateral + 2 posterior per side); return for the anterior apex (1/side), then the anterior base (per side: 1 anterior fibromuscular, 2–3 transition zone, 1 lateral horn-tip), with larger glands adding 8 mid-gland cores. Transition-zone cores scale with TZ size (small 2, medium 3, large 4).
5. Needle handling — the gun fires forward 2 cm, so place the needle tip 2 cm proximal to the target; rapid passage minimises deflection (the bevel steers it). Never biopsy the neurovascular bundle or the midline/paraurethral transition zone (retention risk); if using MRI or cognitive fusion, take the target cores first before any hematoma forms; if the needle strikes the pubic arch, reposition rather than persist (theoretical osteitis pubis).

Complications

Generally well tolerated (stay usually < 3 hours) and — unlike transrectal biopsy — septicaemia and major rectal bleeding are very rare. Transient urinary retention ~2% (rising to ~8% with saturation core counts; minimised by avoiding paraurethral cores), self-limiting hematuria in ~half, near-universal hematospermia (a month or more), low-grade UTI ~3% (fever < 38.5 °C, oral antibiotics suffice), and mild perineal pain (paracetamol adequate for ~85%; ~15% need opioids).

MRI-Fusion Targeted Biopsy

When to Use

Because of cost, fusion biopsy is not routine for every patient — it is reserved for a prior negative TRUS biopsy with persisting suspicion (rising PSA or a DRE change) and for active-surveillance follow-up (targeting and tracking abnormal areas). If the MRI is normal there is nothing to target — do not perform fusion biopsy.

MRI and Region-of-Interest Preparation

Obtain a 3-T multiparametric MRI (phased-array body coil; endorectal coil not routine, enema before, no antibiotics for the scan) with T1/T2, diffusion-weighted, and dynamic contrast-enhanced sequences — T2 best shows cancer as low signal within the high-signal peripheral zone. The radiologist contours and segments the gland into a 3-D model, marks each region of interest, assigns a PI-RADS suspicion score, and transfers the study to the fusion platform.

Platforms

• UroNav — an external electromagnetic field generator tracks a sensor on the probe; the operator scans free-hand.
• Artemis — a semirobotic mechanical arm with joint sensors holds and tracks the probe and needle.

Procedure

Give an enema and the same antibiotic protocol, position the patient per the platform, and introduce the end-fire probe. Because fusion takes longer, inject a larger anaesthetic volume (5–10 mL per side at the seminal-vesicle–base junction, avoiding the prostate and intravascular injection). Capture a sweep (a ~200° rotation on the Artemis arm) for segmentation, outline the prostate borders in transverse and sagittal planes, globally align the MR and ultrasound by matching landmarks, and fuse them into a model. Target each region of interest (≥ 2 cores per target) with the needle shown in real time, re-aligning (motion compensation) if the borders drift, and add systematic extended-sextant cores — especially when there is no known cancer diagnosis.

Postprocedural Care

Tamponade the anal canal with gentle pressure (leaving the probe in, or with rolled 4×4 gauze) for 2–3 minutes; watch for vasovagal episodes and have the patient rise slowly; continue antibiotics for ≥ 24 hours.

Complications

• Bleeding — hematuria ~50% (the atlas cites up to 70%; intervention < 1%), hematospermia ~50% (persists > 4 weeks in ~30%), and rectal bleeding ~30% (intervention ~2.5%; avoided by the transperineal route).
• Infection — transrectal ~5–7% (higher than transperineal), with hospitalisation for infection in ~1–3%; severe infection (acute prostatitis, bacteraemia, urosepsis) is the feared complication.
• Other — transient LUTS 6–25%, urinary retention < 1%, transient erectile dysfunction < 1%, and false negatives (about ~75% of TRUS biopsies are negative, false-negative rate ~20–30%).