A Retrospective Review of Patients Evaluated for Small Solid Renal Masses During a Two Year Period
Brian Kowal, MD, William Bihrle, III, MD, Andrew Forauer, MD, John D. Seigne, MB.
Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
BACKGROUND: There is considerable controversy about the management of small solid renal masses. Over the last 2 years, we have subscribed to a policy of referring patients with a renal mass < 4cm for percutaneous biopsy prior to definitive treatment. We have performed a retrospective review of patient’s records to evaluate #1: how often biopsy was performed prior to definitive management, #2: predominate reasons biopsy was omitted, #3: the impact of our biopsy program on patient care.
The medical records of all patients evaluated in our clinic by two of the co-authors between November 2006 and October 2008 were reviewed (N=560). New patients evaluated for a solid renal mass < 4cm in diameter were included in the study group. All biopsy, intervention, pathology, and follow-up data were recorded.
RESULTS: A total of 118 patients met inclusion criteria. Sixty-nine (69) patients underwent percutaneous biopsy of their renal mass. Overall, 18 (26%) were benign, 42 (61%) were malignant, and 9 (13%) were indeterminate. There were 13 minor complications associated with biopsy (19%), and no major complications.
Forty-nine (49) patients did not undergo renal biopsy. Twenty-four (24) patients elected surveillance, 20 of those patients had documented reasons for not undergoing biopsy including: advanced age (4), benign appearance radiographically/no growth (8), history of previous benign renal mass (2), intervening medical issues (4), not recommended by provider (1) and patient declined (1). One patient previously on surveillance has been scheduled for biopsy due to interval growth. Eighteen (18) patients elected to proceed directly to surgery. Documented reasons included: patient declined (6), surgery already scheduled at another institution (3), technical concerns with biopsy (1), CRF/poorly functioning kidney (2), provider recommendation (4), 2cm interval growth between studies (1), and multiple lesions in the setting of VHL (1). Four patients that underwent surgery had benign pathology (24%). Two of these patients declined biopsy, one patient could not have a biopsy due to technical difficulty, and the last was not recommended biopsy. Seven patients were lost to follow-up (6%).
CONCLUSIONS: Over the last 2 years, renal biopsy was performed in the majority of patients evaluated in our clinic for renal masses < 4cm. For those patients electing surveillance or surgery without prior biopsy, 90% had a documented, compelling reason for skipping the biopsy. In four patients to date the decision to forego initial biopsy was in error. Three patients had surgery for benign lesions when biopsy was technically feasible. The fourth is scheduled for biopsy after interval growth of her mass.
Biopsy has proven to be a valuable option in this patient population. 63 patients (91% of biopsy group) were able to get a definitive diagnosis. 18 patients with a benign biopsy (15% of all patients, 26% of biopsy group) were spared an unnecessary surgery. No patient suffered major morbidity as a result of biopsy hence biopsy is low risk and provides valuable information.