V08-02: Office-Based, Ultrasound-Guided Renal Mass Biopsy: Technique and Results
Imaging advances have led to an increase in the incidental detection of small renal masses (SRM) (i.e. ≤4 cm) and, perforce, of renal cell carcinoma (RCC). Notably, 20% of SRM are benign, and some indolent malignant tumors can be safely managed with active surveillance; yet, pre-excision biopsy is practiced by a minority of urologists. Renal mass biopsy (RMB) could alter the management of SRM by reducing the number of benign masses excised. Historically, RMB required patient sedation, CT-guidance, and was a radiologist-performed, hospital-based procedure. Advances in ultrasound (US) technology now enable the urologist to perform office-based, US-guided RMB. This video presentation details our office-based, US-guided RMB technique in an 80-year-old male with a renal mass and provides further details on our experience with this approach in over 50 patients.
A few hours prior to the scheduled biopsy, the patient applies anesthetic cream (lidocaine 2.5% / prilocaine 2.5%) to the skin overlying the previously outlined biopsy entry point. The patient positions himself/herself in the prone position. Once the target lesion and renal anatomy are identified on US, 1% lidocaine is injected into the skin and along the entire biopsy needle track up to a few mm off the surface of the tumor. A standard 18G biopsy gun is used to insert a biopsy needle under direct US-guided vision using a facilitated US targeting system; 4-6 cores are obtained. After the procedure, the patient's vital signs are monitored; one hour after the biopsy, a Doppler US is performed in the office to assess for complications. The patient is evaluated for pain (scale 0-10) before and after the biopsy, and a follow-up appointment is made in order to discuss the biopsy results.
Our prospectively maintained RMB database (N=52) revealed a diagnostic rate of 73% and a concordance with final pathology in 100% (16/16) for primary histology, 93% (14/15) for histologic subtype, and 90% (9/10) for low (I-II) vs. high (III-IV) Fuhrman grade. RMB revealed benign pathology in 21% (11/52) of patients. No patient with a benign lesion underwent surgery. Of note, 39% (20/52) of our patients have opted for active surveillance. There were no complications. Patients reported a median pain score of 1/10 (range 0-5) and 0/10 (range 0-5.5) immediately after RMB and at one hour after RMB, respectively. Fewer than 10% (4/52) of patients required narcotics for pain.
Office-based RMB can safely be performed by a urologist skilled in renal ultrasonography. RMB guides patient management and markedly reduces the rate of surgery for benign renal masses.