Management of High Complexity Renal Masses in Partial Nephrectomy: A Multicenter Analysis

Almost three decades ago the first laparoscopic nephrectomy was performed. It was a controversial approach at the time, but over time the technique improved and we even started doing laparoscopic partial nephrectomies. However, partial nephrectomy is a technically challenging procedure and laparoscopy was a convenient option for simpler tumors. More complex tumors still required open partial nephrectomy. In fact, the majority of partial nephrectomies were performed as open surgery. Open partial nephrectomy is a successful surgery, however, it requires a large incision that is quite painful for the patient. Therefore, efforts needed to be made to improve the less invasive laparoscopic approach.

In the mid-2000s robot-assisted laparoscopic surgery entered our practice. Robot assistance allowed more precision and fine movements and made procedures like partial nephrectomy easier and reproducible. Like any new approach, it was performed on patients with smaller tumors at the beginning. However, over time urologists started to push the envelope and perform partial nephrectomy in patients with difficult tumors. There are multiple factors that affect the difficulty of the surgery. Tumor size is an obvious factor. However, tumor location, depth, vicinity to the kidney’s artery and vein factor in the decision to perform partial nephrectomy. Scoring systems have been developed to objectify the tumor’s difficulty. One such scoring is the RENAL Nephrometry score, first described by Dr. Kutikov and his colleagues from Fox Chase Cancer Center.

Anatomical complexity affects the decision to perform minimally invasive surgery. American Urological Association Guidelines suggests that the decision to perform robotic or open partial nephrectomy (PN) should be based on the surgeon's skill and expertise. Since the adoption of the robot, the utilization of minimally invasive PN has increased nationwide, including intermediate and high complexity renal masses. In this study, we sought to determine the safety and efficacy of performing robotic PN (RPN) in patients with high nephrometry score tumors. In this study, we analyzed the data of 144 patients with complex tumors, who underwent partial nephrectomy. These patients underwent surgery by experienced robotic surgeons from 6 centers in the US. Our main goal was to assess trifecta achievement, which is defined by warm ischemia time (WIT) less than 25 minutes, no perioperative complications, and negative surgical margins. We also assessed the relationship between baseline clinical and tumor characteristics data to trifecta achievement and perioperative complications.

When we look at the tumor characteristics, median clinical tumor size was 4.95 cm, with 74 (51.75%) being completely endophytic and 58 (41.73%) located on the hilum. Despite these difficult characteristics, median ischemia time was 20 mins. Median estimated blood loss was 150 ml and only one patient received a blood transfusion (0.69%). No patient had a conversion to open surgery. The median length of hospital stay was 1 day.

Twelve patients (8.33%) had intraoperative complications. Postoperative, perioperative and major complication rates were 10.42%, 17.3%, and 2.34% respectively. None of the baseline clinical factors were predictive of the complication rate. Despite the functional benefits of PN, 36 patients (37.89%) developed postoperative acute kidney injury and 28 (20.90%) developed new-onset CKD at a median follow-up of 6 months. Eight patients (5.56%) had a positive surgical margin. Follow-up recurrence data were available for 110 patients, and 8 (7.27%) had recurrence. Overall, the trifecta was achieved in 89 (61.81%) patients. There was no significant difference in baseline, clinical and tumor characteristics between those that achieved trifecta and in those where trifecta was not. Pathologic tumor stage was the only factor significantly associated with trifecta achievement (p=0.025).

Our study should be analyzed knowing that this is the data of very high volume surgeons, which makes our results less generalizable. Our follow up period was not sufficient enough to perform a strong oncological or functional outcome analysis. However, our data was sufficient to demonstrate the perioperative outcome. On the other hand, our analysis was performed on an extensive, granular database of multi-institutional design, which is a significant strength of our results. In conclusion, PN should be performed whenever it is possible. Although it remains a challenging procedure, with experience and appropriate case selection, the trifecta outcome can be achieved in a significant number of patients with high RENAL score lesions.

Written by: Ketan Badani, MD, Professor of Urology, Icahn School of Medicine at Mount Sinai, Vice Chairman of Urology and Robotic Operations, Director of Robotic Surgery, Director of the Comprehensive Kidney Cancer Program, Mount Sinai Health System, New York, New York and Alp Tuna Beksac, MD, Urologic Oncology Fellow, Icahn School of Medicine at Mount Sinai, New York, New York

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