The diagnosis and treatment of the small renal cortical neoplasm has continued to go a remarkable and robust evolution over the past several decades. Retrospectively evaluating changes in our management strategies over time, it seems clear that we as a Urologic community have based our diagnosis and treatment of this entity in a reactive manner with the perpetuation of traditional management strategies that, in the contemporary era, may no longer be highly relevant.

Decades ago, the renal mass was often diagnosed with the classic triad, and small renal tumors were highly unusual. Indeed, speaking with my own father, an urologist who practiced for 4 decades, his experience with the small renal mass was quite limited as axial imagining was not widely available.

The introduction of axial imaging technologies and their wide spread applications resulted in an explosion in the diagnosis is small renal cortical neoplasms. Interestingly, despite our significant increase in diagnosis of these smaller lesions, the number of larger and more aggressive lesions has not diminished what so ever. Similarly we have had a stable and increasing mortality despite significant number of treatments for these small renal lesions. Again, this highlights both the need for new thinking strategies around the small incidentally discovered renal cortical neoplasm as well as the significant overtreatment that our current thinking processes have engendered.

One of the most remarkable changes in the management of small renal tumors of the past several decades has been the introductions of focal therapy. Focal therapy refers to the use of needles or other minimal invasive technologies to focally ablate the tumor without extirpation. Certainly, the introduction of ablation has resulted in growing pains with urologists slowly, overtime, learning the proper use of these technologies with regards to patient selection. Judiciously utilized and with proper patient selection, ablative technologies have been shown to have excellent long term tumor specific survival with improved patient tolerance and less diminishment in renal function compared to extirpative strategies. With time, we will continue to refine our understanding of the proper space for ablative technologies. However, at the current time, it is clear that they will remain a very important part of our overall armamentarium of the management of the small renal mass.

The current article was a small step in the evolution of ablation for the small renal cortical neoplasm. Our team and others initially started doing these ablative procedures under laparoscopic control. This was the most common access strategy, and it was certianly less invasive then open or laparoscopic / robotic-assisted partial nephrectomy. It has rapidly become clear that the percutaneous approach is a much less invasive strategy. I can distinctly recall the great pleasure of seeing my first percutaneous ablative patients feeling well immediately after their procedure and being discharged home on the same day. The elimination of general anesthesia is a significant evolutionary step in the minimally invasive direction. In fact, we find it hard to categorize laparoscopic and robotic procedures as “minimally invasive” in light of the remarkable results associated with percutaneous access under local anesthesia with sedation. At UC Irvine and other centers, the move away from general anesthesia during percutaneous ablation was done without supporting data. As such, we retrospectively evaluated our experience doing percutaneous ablation of renal masses with either general anesthesia or local anesthesia with conscious sedation. We were privileged to collaborate with the excellent team at Long Island Jewish lead by Dr. Louis Kavoussi in this regard. Our respective study certainly has its limitations. Most of the patients which were treated with general anesthesia were early in our experienced as evidenced by the longer follow in this patient group. Additionally, as a retrospect of study, the data must be considered suboptimal. However, the natural evolution to percutaneous ablation under local anesthesia with conscious sedation does seem well justified which was the clinical impression of both the team at the University of California, Irvine and Long Island Jewish where these procedures were performed. The data showed that despite having very similar patient populations with similar ASA scores, renal function, and overall health, the patients who were treated with conscious sedation responded much more favorably with shorter operative times, and shorter hospital stays. Despite improved recovery metrics we were pleased that there was no difference in immediate failure rates or reoccurrence rates between the general anesthesia and the local anesthesia with conscious sedation groups. There was also no difference between these groups with regards to intraoperative and postoperative treatment related complications.

The current manuscript was a small step forward in our understanding of ablation and its role in the treatment for small renal mass certainly we have a long way to go and current research efforts are being focused on the use of less ionizing radiation. The current study was performed under CT guidance and our technique has been modified to do initial targeting with ultrasound. Additionally, we are not incorporating MRI guided ablations into our armamentarium. MRI guided percutaneous ablation is still relatively immature and is a bit of a challenge to use successfully, but in the future it has tremendous potential as the targeting can be done in real time with active use of the MRI system throughout much of the procedure and MRI thermography may result in extraordinary precision that could improve contemporary results.

In summary, we are slowly making progress towards better management of the small renal mass. It has been exciting over the past several decades to see advances in both ablative and extirpative approaches, and current efforts will certainly bare fruits with improved diagnostic treatments incorporating preoperative biopsy and improved ablative and extirpative treatment strategies.

Written by:
Jaime Landman, MD
Department of Urology, University of California, Irvine, USA.

PubMed Abstract
PMID: 25440762

Poster: Comparison of Outcomes in Patients under Going Percutaneous Renal Cryoablation with Sedation versus General Anesthesia

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