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

Abstract

Purpose:Conversions from partial to radical nephrectomy are uncommon and reports on this topic are rare. In this study we present a detailed analysis of conversions from partial to radical nephrectomy in a single-institutional contemporary experience and provide an analysis of preoperative risk factors.Materials and Methods:Patients who underwent converted (cases) and completed (controls) partial nephrectomy from 2000 to 2015 were matched 1:1 for analysis. Perioperative imaging was reviewed and RENAL (for radius, exophytic/endophytic properties, anterior/posterior descriptor, and location relative to the polar line) nephrometry scores were calculated. Reasons for conversions were abstracted from operative reports. Multivariable conditional logistic regression analyses were used to assess preoperative risk factors for conversion.Results:A total of 168 cases (6.1% of all partial nephrectomies) were identified and matched on tumor size, year of surgery, and surgical approach to 168 controls. Conversion rates decreased from 13% in 2000-2003 to 4% in 2012-2015. Oncologic considerations, such as concern for upstaging and positive margins, were the most cited (56%) reasons for conversion. On multivariable analyses, male sex (odds ratio 2.34; P = .03), Charlson score (odds ratio per 1-unit increase: 1.28; P = .03), posterior and middle (on anteroposterior axis) location (reference: anterior, odds ratio 2.83, P = .02 and odds ratio 6.38, P < .001, respectively) and hilar location (reference: peripheral/central, odds ratio 5.61; P < .001) were associated with increased odds of conversion.Conclusions:Rates of conversion from partial to radical nephrectomy in our experience were low and decreased over time. Preoperative characteristics such as hilar, posterior, and middle locations were significantly associated with conversions after controlling for tumor size, and offer guidance for operative planning and patient counseling.

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.…”

Editorial Comment

“…Reasons to convert a robotic partial nephrectomy (RPN) to a radical nephrectomy (RN) include concern for compromising oncologic outcomes, anatomic complexity, hemorrhage, and challenges with required renorrhaphy. 1 We continue to seek clarity behind these reasons in order approach RPN as safely as possible.…”

This Month in Adult Urology

“…Tsivian et al (page 960) from Rochester, Minnesota, from a single-center prospectively collected data set, present the largest case-control study evaluating patient and tumor factors that might help predict the need for conversion from partial to radical nephrectomy. 3 Given past conflicting reports, this is a significant unmet need, as having a better understanding of the variables that might influence chance of conversion are important to provide patients more accurate expectations of potential outcomes. Although the requirement for conversion decreased over time, on multivariable analyses male sex, comorbidities, and posterior and middle (on anteroposterior axis) as well as hilar location were associated with conversion, even after adjusting for tumor size.…”