Introduction: Renal biopsy is recommended if its outcome might alter therapeutic decisions in unclear renal masses or to include patients into active surveillance protocols. Little is known about long term results and follow up.
Methods: Retrospective analysis of an institutional database at a tertiary referral center including patients between 2003 and 2005 with a follow-up of at least 15 years. Renal biopsies were taken percutaneously with a coaxial technique according to guideline recommendations with an off-line guided ultrasound approach.
Results: We identified n=106 patients who underwent renal biopsy with an unclear renal mass. Median age of 58.7 years (43.7-66.2). Patients had a median of 4.2 (3-6) biopsies taken at the initial time of diagnosis. In 6 patients tumor seeding leading to local growth of lesions was identified after a median time of 8.2 years. Four lesions were resected and had the same histology as the biopsy result without further recurrence. In 45 pts the result of the biopsy revealed a histology that led to a different therapy but surgery (n=28 lymphoma, n=6 metastasis from other malignancies, n=11 oncocytoma). 61 patients were treated for their renal cell carcinoma with either surgery or ablation. No patient developed metastatic spread related to seeding.
Conclusions: In a large proportion of patients, the result of the biopsy changed the therapy.
Indication for renal biopsy should be discussed carefully as seeding does not seem to be anecdotal in long-term follow-up.
Source of Funding: This work was submitted and accepted for AUA 2020 but could not have been presented due to the pandemic.
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