Incidence of needle-tract seeding following prostate biopsy for suspected cancer: a review of the literature. 
With the widespread clinical use of prostate-specific antigen (PSA), biopsy of the prostate has become one of the most commonly performed urological procedures.  In general it is well tolerated, although there is some morbidity and risk of infection.  In recent years, there have been increasing concerns that prostate biopsy may lead to tumour seeding along the needle tract.  The aim of the present paper was to review the evidence on the prevalence of tumour seeding after prostate biopsy and to define the risk of this event in the context of current clinical practice.  A PubMed literature search was conducted in January 2014 according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement.  Literature was examined with emphasis on the incidence of seeding, clinical presentation and on risk factors including type of needle used, transrectal vs transperineal approach, as well as tumour grade and stage.  In all, 26 publications were identified reporting needle-tract seeding after prostate biopsy.  In all, 42 patients with needle-tract seeding were identified.  In most cases, seeding was reported after transperineal biopsy of the prostate, while nine cases occurred after transrectal biopsy.  Based on the reviewed series the incidence of seeding appears to be <1%.  The increase in the number of biopsies and cores taken at each biopsy over the years has not resulted in an increase in the reported cases of seeding.  In conclusion, seeding along the needle track is a rare complication after prostate biopsy.  Its actual incidence is presently difficult to quantify.  It is reasonable to advise appropriate counselling and take measures to reduce this event where possible; however, we do not advocate avoidance of biopsies as the benefits of appropriate cancer diagnosis and management outweigh any potential risks from seeding.