Needle tract seeding after percutaneous biopsies of pediatric renal masses: valid concern or unfounded fear? A systematic review, meta-analysis and call for change.
Mohit Butaney, MD, Patricio C. Gargollo, MD, Paul J. Thacker, MD, Candace F. Granberg, MD.
Mayo Clinic, Rochester, MN, USA.
Background: Percutaneous needle biopsies (PCNB) of suspicious kidney lesions in pediatric patients can provide histological confirmation and guide management. Recent SIOP analysis proved that PCNB of Wilms tumor did not independently increase risk of local recurrence or survival.  Although PCNB have a distinct advantage over open surgical biopsies, needle tract seeding with potential future tumor tract recurrence is an often quoted concern. However, the true incidence of needle tract recurrences with PCNB of renal masses in children is poorly defined. Our aim was to evaluate incidence of needle tract seeding, defined as a new neoplastic process outside the kidneys associated with the biopsy site or tract.
Methods: A systematic search was conducted in October 2018 according to the Preferred Reporting items for Systematic Reviews and Meta-analysis (PRISMA) statement guidelines. EMBASE and MEDLINE were used to search between 1990 and 2018 for studies reporting details on needle tract seeding following PCNB of suspicious renal masses. Only pediatric patients (age 0-18 years) who underwent PCNB of renal masses were included in our study. Data on patient demographics, diagnosis, needle size and biopsy technique, incidence of needle tract seeding, time to seeding, follow up, and oncologic outcome were extracted. The primary outcome was incidence of needle tract recurrences.
Results: Of 90 publications reviewed, 25 met inclusion criteria to obtain 808 patients for analysis. Overall incidence of PCNB tract recurrence was 0.003% (3/808). One case used an 18g Tru-Cut needle, one utilized multiple passes of a 16g core biopsy needle, and one (in 1995) did not detail needle size/technique. The median time to seeding was 4 months. All patients were alive at the time of the respective reports. Follow-up time was variable, from 5 months to 9 years.
Conclusions: This systematic review and meta-analysis documents incidence of needle tract tumor seeding following PCNB of pediatric renal masses at 0.003%. PCNB techniques have evolved to limit potential for seeding, and biopsy alone does not adversely affect local recurrence or survival. Thus, children should not be automatically upstaged after PCNB of renal masses. The role of PCNB in diagnosis of pediatric renal tumors should be revisited in cancer protocols.
Irtan, S., et al., Evaluation of needle biopsy as a potential risk factor for local recurrence of Wilms tumour in the SIOP WT 2001 trial. Eur J Cancer, 2019. 116: p. 13-20.
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