Urologist-level variation in the management of T1a renal cell carcinoma: A population-based cohort study

Objectives: Lack of strict indications in current guidelines have led to significant variation in management patterns of small renal masses. The impact of the urologist on the management approach for patients with small renal masses has not been explored previously. Materials and Methods: Using the linked Surveillance, Epidemiology, and End Results-Medicare database, patients aged ≥66 years diagnosed with small renal masses from January 1, 2004 to December 31, 2013 were identified and assigned to primary urologists. Mixed-effects logistic models were used to evaluate factors associated with different management approaches, estimate urologist-level probabilities of each approach, assess management variation, and determine urologist impact on choice of approach. Results: A total of 12,402 patients with 2,794 corresponding primary urologists were included in the study. At the individual urologist level, the estimated case-adjusted probability of different approaches varied markedly: nonsurgical management (mean, 12.8%; range, 4.9%–36.1%); thermal ablation (mean, 10.8%; range, 2.4%–66.3%); partial nephrectomy (mean, 30.1%; range, 10.1%–66.6%); and radical nephrectomy (mean, 40.4%; range, 17.7%–71.6%). Compared to patient and tumor characteristics, the primary urologist was a more influential measured factor, accounting for 13.6% (vs. 12.9%), 33.8% (vs. 2.1%), 15.1% (vs. 8.4%), and 13.5% (vs. 4.0%) of the variation in management choice for nonsurgical management, thermal ablation, partial nephrectomy, and radical nephrectomy, respectively. Conclusions: Significant variation exists in the management of small renal masses and appears to be driven primarily by urologist preference and practice patterns. Our findings emphasize the need for unified guidance regarding management of these masses to reduce unwarranted variation in care.