Which factors predict conversion from partial to radical nephrectomy?

Unplanned conversion from partial to radical nephrectomy is low and has decreased from 2000 to 2015, reports a recent study.

Preoperative factors including hilar, posterior, and middle locations show a significant association with conversions after controlling for tumour size. This finding offers guidance for operative planning and patient counseling, according to the researchers.

In this analysis, the researchers matched patients who underwent converted (cases) and completed (controls) partial nephrectomy from 2000 to 2015. They reviewed perioperative imaging and calculated RENAL (for radius, exophytic/endophytic properties, anterior/posterior descriptor, and location relative to the polar line) nephrometry scores.

Reasons for conversions were obtained from operative reports, and preoperative risk factors for conversion were evaluated through multivariable conditional logistic regression analyses.

A total of 168 cases (6.1 percent of all partial nephrectomies) were matched 1:1 to controls based on tumour size, year of surgery, and surgery approach.

Rates of conversion fell from 13 percent in 2000–2003 to 4 percent in 2012–2015. The most cited reason for conversion was oncologic considerations (56 percent), which included concern for upstaging and positive margins.

Multivariable analyses revealed the following characteristics associated with a higher likelihood of conversion: male sex (odds ratio [OR], 2.34; p=0.03), Charlson score (OR per 1-unit increase, 1.28; p=0.03), posterior and middle (on anteroposterior axis) location (anterior: OR, 2.83; p=0.02 and OR, 6.38; p<0.001, respectively), and hilar location (peripheral/central: OR, 5.61; p<0.001).