Factors Affecting Robotic Partial Nephrectomy Conversion to Radical Nephrectomy: A Retrospective Multi-Institutional Analysis in the Michigan Urologic Surgery Improvement Collaborative (MUSIC)

Abstract

Objective: To identify factors related to the conversion of robot-assisted partial nephrectomy (RPN) to robot-assisted radical nephrectomy (RRN) based on data collected by a statewide database in Michigan. Methods: Using the Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) database we identified 574 patients for whom RPN was planned. Patient and tumor characteristics were obtained including body mass index (BMI), Charlson comorbidity index (CCI), RENAL nephrometry score, tumor size, and pathologic staging. Treating centers were subdivided by annualized case volume and academic status. Bivariate and multivariate analyses were performed to assess the impact of these factors on the risk of conversion to RRN from RPN. Results: The conversion rate of RPN to RN was 5.75% (33/574). The difference in RENAL nephrometry score, tumor stage, and size reached statistical significance on bivariate analysis (p<0.001). The tumor stage also reached statistical significance on multivariate analysis [odds ratio (OR); 95%CI (8.97; 3.93-20.48) p<0.001]. The conversion rate was lower among high-volume versus low-volume practices; however, statistical significance was not reached [5.2% (27/520) vs.11% (6/54); p=0.11]. Conclusions: Patient factors such as tumor size and renal nephrometry score are likely related to the conversion of RPN to RRN decisions. The data shows that Michigan urologists appear to appropriately assess intra-operative findings and convert to RRN in cases of more advanced kidney tumors. Lower volume centers appear to trend towards a higher conversion rate. Continued quality improvement tracking analysis may further clarify this relationship.

Conversion to Radical Nephrectomy From Robotic Partial Nephrectomy Is Most Commonly Due to Anatomic and Oncologic Complexity

“…The 4.2% rate of conversion to RN reported in our study is comparable to other rates reported in literature, which have ranged from 0.14% to 14%. [11][12][13][14][15][16] Identifying patients who are at a high risk of conversion to RN may help inform preoperative counseling. Our study identified that patients with larger and high-complexity tumors were more likely to undergo conversion to RN.…”

“…score, hilar tumors/renal sinus invasion, laparoscopic PN, intraoperative bleeding, positive surgical margins, and advanced pathological tumor stage. 11,12,14,15 Assessment of tumor complexity is a necessary component to identify tumors at high risk for conversion and other complications. 19,20 Dahlkamp et al demonstrated the value of R.E.N.A.L.…”

“…Prior reports indicate rates of conversion of RPN to RN between 0.14% and 14%, with all sources but 1 at < 6%. [11][12][13][14][15][16] These published rates are often from highvolume and/or academic centers. Implicit within this literature is that these conversions are generally performed after a complication has occurred for patient safety, rather than as a decision intentionally made in order to obtain optimal cancer control.…”

Unplanned Conversion From Partial to Radical Nephrectomy: An Analysis of Incidence, Etiology, and Risk Factors

“…Overall, conversions to RN appear to be more common in open surgical approaches with reported incidences of 2.3% to 13.5% compared to 1.2% to 5.9% among cases managed with MI approaches. 8,10,11,13,[17][18][19][20] Nevertheless, conversion comparisons between open and MI PN have yielded conflicting results. In an evaluation of 177 consecutive patients undergoing planned PN, Long et al found the odds of conversion to RN to be 3 times more likely in robotic approaches.…”

“…Data describing the incidence of, reasons for, and patient and tumor characteristics associated with increased risk of conversions from PN to RN are sparse and often conflicting. [8][9][10][11][12][13] As the adoption of nephron-sparing surgery for localized kidney masses continues to grow and the limits of such approaches are increasingly tested, a better understanding of conversion risk is needed. 14,15 Identifying which patients are at increased risk of conversion to RN is important for identifying the limitations of this management option, guiding operative planning, and improving patient counseling.…”