Prostate biopsy

Prostate biopsy is a procedure in which small hollow needle-core samples are removed from a man's prostate gland to be examined for the presence of prostate cancer. It is typically performed when the result from a PSA blood test are high. It may also be considered advisable after a digital rectal exam (DRE) finds possible abnormality. PSA screening is controversial as PSA may become elevated due to non-cancerous conditions such as benign prostatic hyperplasia (BPH), by infection, or by manipulation of the prostate during surgery or catheterization. Additionally many prostate cancers detected by screening develop so slowly that they would not cause problems during a man's lifetime, making the complications due to treatment unnecessary. Prostate biopsy is a procedure in which small hollow needle-core samples are removed from a man's prostate gland to be examined for the presence of prostate cancer. It is typically performed when the result from a PSA blood test are high. It may also be considered advisable after a digital rectal exam (DRE) finds possible abnormality. PSA screening is controversial as PSA may become elevated due to non-cancerous conditions such as benign prostatic hyperplasia (BPH), by infection, or by manipulation of the prostate during surgery or catheterization. Additionally many prostate cancers detected by screening develop so slowly that they would not cause problems during a man's lifetime, making the complications due to treatment unnecessary. The most frequent side effect of the procedure is blood in the urine (31%). Other side effects may include infection (0.9%) and death (0.2%). The procedure may be performed transrectally, through the urethra or through the perineum. The most common approach is transrectally, and historically this was done with tactile finger guidance. The most common method of prostate biopsy as of 2014 was transrectal ultrasound-guided prostate (TRUS) biopsy. Extended biopsy schemes take 12-14 cores from the prostate gland through a thin needle in a systematic fashion from different regions of the prostate. A biopsy procedure with a higher rate of cancer detection is template prostate mapping (TPM) or transperineal template-guided mapping biopsy (TTMB), whereby typically 50 to 60 samples are taken of the prostate through the outer skin between the rectum and scrotum, to thoroughly sample and map the entire prostate, through a template with holes every 5mm, usually under a general or spinal anaesthetic. Antibiotics are usually prescribed to minimize the risk of infection. An enema may also be prescribed for the morning of the procedure. In the transrectal procedure, an ultrasound probe is inserted into the rectum to help guide the biopsy needles. A local anesthetic is then administered into the tissue around the prostate. A spring-loaded prostate tissue biopsy needle is then inserted into the prostate, making a clicking sound. If local anesthetic is satisfactory, discomfort is minimal. Since the mid-1980s, TRUS biopsy has been used to diagnose prostate cancer in essentially a blind fashion because prostate cancer cannot be seen on ultrasound due to poor soft tissue resolution. However, multi-parametric magnetic resonance imaging (mpMRI) has since about 2005 been used to better identify and characterize prostate cancer. A study correlating MRI and surgical pathology specimens demonstrated a sensitivity of 59% and specificity of 84% in identifying cancer when T2-weighted, dynamic contrast enhanced, and diffusion-weighted imaging were used together. Many prostate cancers missed by conventional biopsy are detectable by MRI-guided targeted biopsy. In fact, a side-by-side comparison of TRUS versus MRI-guided targeted biopsy that was conducted as a prospective, investigator-blinded study demonstrated that MRI-guided biopsy improved detection of significant prostate cancer by 17.7%, and decreased the diagnosis of insignificant or low-risk disease by 89.4%. Two methods of MRI-guided, or 'targeted' prostate biopsy, are available: (1) direct 'in-bore' biopsy within the MRI tube, and (2) fusion biopsy using a device that fuses stored MRI with real-time ultrasound (MRI-US). Visual or cognitive MRI-US fusion have been described. When MRI is used alone to guide prostate biopsy, it is done by an interventional radiologist. Correlation between biopsy and final pathology is improved between MRI-guided biopsy as compared to TRUS.