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

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.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.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.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.