Utilization and quality outcomes of cT1a, cT1b and cT2a partial nephrectomy: analysis of the national cancer database

To describe the utilization and compare quality outcomes of partial nephrectomy (PN) for cT1a, cT1b and cT2a renal masses using a large national database.

We conducted a retrospective analysis of patients from the US National Cancer Database who underwent PN for cT1a/cT1b/T2a renal cell carcinoma between 2004 and 2013. We examined the use of PN over time and assessed quality indicators [positive surgical margin (PSM) and 30-day postoperative readmission rates]. Multivariable analysis was conducted to determine predictors for outcome comparisons.

A total of 43 749 patients underwent PN for cT1a, cT1b and cT2a renal masses (cT1a, n = 34 796; cT1b, n = 8 040; cT2a, n = 913). The proportion of patients undergoing PN increased from 30.8% in 2004 to 56.7% in 2013 (P < 0.001), and this trend was apparent for all clinical stages. The PSM rate was 6.8%. Predictive factors for increased risk of PSMs included cT1a stage (P = 0.03), age [odds ratio (OR) 1.01; P < 0.001] and later year of diagnosis (OR: 1.05; P < 0.001). The 30-day readmission rate was 4.2%. Predictive factors for increased risk of readmission included cT1b (P < 0.001), high Charlson comorbidity score (OR: 1.32; P = 0.001) and lack of private insurance (OR: 1.21-1.97; P < 0.05); later year of diagnosis was associated with decreased odds of readmission (OR: 0.96; P < 0.001). Subset analysis of the 2010-2013 cohort showed increases in the proportion of minimally invasive PN for cT1a (52.8-69.6%; P < 0.001), cT1b (39.9-59.6%; P < 0.001) and cT2a tumours (33.3-47.3%; P = 0.01). The PSM rate was also increased, at 7.3%. Predictive factors for PSMs included increasing age (OR: 1.01; P < 0.001), minimally invasive surgical approach (OR: 1.52; P < 0.001), and conversion to open surgery (OR: 1.52; P = 0.01), but not clinical stage (P = 0.75-0.99). The 30-day readmission rate was 4.0%. Predictive factors for readmission included lack of private insurance (P < 0.001) and conversion to open surgery (OR: 1.63; P < 0.001).

The use of PN has increased significantly over time for all clinical stage groups. PSM rates increased, while 30-day readmission rates decreased. The PSM rate increase was driven by increasing use of minimally invasive approaches, and not by higher clinical stage. The 30-day readmission rate was driven by patient comorbidities and socio-economic factors. Rising PSM rates represent a quality-of-care concern.