title: Evolving practice patterns for the management of small renal masses in the USA.
abstract: What's known on the subject? and What does the study add? Treatment options for small renal masses include radical nephrectomy (RN), partial nephrectomy (PN), ablation, and surveillance. PN provides equivalent oncological as RN for small tumours, but long-term outcomes for ablation and surveillance are poorly defined. Due to changing techniques and technology, treatment patterns for small renal masses are rapidly developing. Prior studies had analysed utilisation trends for PN and RN to 2006, revealing a relative rise in the rate of PN. However, overall treatment trends including surveillance and ablation had not been studied using a population-based cohort. It has become increasingly clear that RN is associated with greater renal and cardiovascular deterioration than nephron-sparing treatments. Thus, it is important to understand current population-based practice patterns for the treatment of small renal masses to assess whether practitioners are adhering to ever-changing principles in this field. The present study provides up-to-date treatment trends in the USA using a large population-based cohort.
  
  
  OBJECTIVE
  To describe the changing practice patterns in the management of small renal masses, including the use of surveillance and ablative techniques.
  
  
  METHODS
  All patients in the Surveillance, Epidemiology and End Results (SEER) registry treated for renal masses of ≤7 cm in diameter, from 1998 to 2008, were included for analysis. Annual trends in the use of surveillance, ablation, partial nephrectomy (PN), and radical nephrectomy (RN) were calculated. Multinomial logistic regression was used to determine the association of demographic and clinical characteristics with treatment method.
  
  
  RESULTS
  In all, 48 148 patients from 17 registry sites with a mean age of 63.4 years were included for analysis. Between 1998 and 2008, for masses of <2 cm and 2.1-4 cm, there was a dramatic increase in the proportion of patients undergoing PN (31% vs 50%, 16% vs 33%, respectively) and ablation (1% vs 11%, 2% vs 9%, respectively). In multivariable analysis, later year of diagnosis, male gender, being married, clinically localised disease, and smaller tumours were associated with increased use of PN vs RN. Later year of diagnosis, male gender, being unmarried, smaller tumour, and the presence of bilateral masses were associated with increased use of ablation and surveillance vs RN.
  
  
  CONCLUSIONS
  PN is now used in half of all patients with the smallest renal masses, and its use continues to increase over time. Ablation and surveillance are less common overall, but there is increased usage over time in select populations.
authors.affiliation: Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94143, USA. yangg2@urology.ucsf.edu
authors.forename: Glen
authors.initials: G
authors.lastname: Yang
authors.forename: Jacqueline D
authors.initials: JD
authors.lastname: Villalta
authors.forename: Maxwell V
authors.initials: MV
authors.lastname: Meng
authors.forename: Jared M
authors.initials: JM
authors.lastname: Whitson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000379:methods; D018426:SEER Program; D057832:Watchful Waiting