title: Population-based assessment of cancer-specific mortality after local tumour ablation or observation for kidney cancer: a competing risks analysis.
abstract: OBJECTIVE
  To examine, using competing risks regression, differences in cancer-specific mortality (CSM) that might distinguish between local tumour ablation (LTA) and observation (OBS) for patients with kidney cancer.
  
  
  METHODS
  The study focused on 1 860 patients with cT1a kidney cancer treated with either LTA or OBS between 2000 and 2009 in the Surveillance Epidemiology and End Results-Medicare database. Propensity-score matching was used. The study outcome was CSM. Multivariable competing risks regression analyses, adjusting for other-cause mortality as well as patient (including comorbidities) and tumour characteristics, were fitted.
  
  
  RESULTS
  Overall, fewer patients underwent LTA than OBS (30 vs 70%; n = 553 vs n = 1 307). Compared with patients in the OBS group, those in the LTA group were younger (median age 77 vs 78 years; P < 0.001), more likely to be white (84 vs 78%; P = 0.005), more frequently married (59 vs 52%; P = 0.02) and more frequently of high socio-economic status (54 vs 45%; P = 0.001). After propensity-score matching, 553 patients who underwent LTA and 553 who underwent OBS remained for subsequent analyses. The mean standardized differences of patient characteristics between the two groups were <10%, indicating a high degree of similarity. After LTA or OBS, the 5-year CSM estimates from Poisson regression-derived smoothed plots were 3.5 and 9.1%, respectively. In multivariable competing risks regression analyses, LTA use was found to have a protective effect on CSM (hazard ratio 0.47 [95% confidence interval 0.25-0.89]; P = 0.02).
  
  
  CONCLUSIONS
  After adjustment for comorbidity and tumour characteristics in elderly patients with kidney cancer, LTA was associated with a clinically and statistically significant protective effect on CSM, compared with OBS. This advantage of LTA deserves consideration when obtaining informed consent.
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada. alelarcher@gmail.com.|Division of Oncology, Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy. alelarcher@gmail.com.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Larcher
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.|Department of Urology, University of Montreal Health Center, Montreal, QC, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Trudeau
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.
authors.forename: Maxine
authors.initials: M
authors.lastname: Sun
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.|Martini-Clinic, Prostate Cancer Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Boehm
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.|Department of Urology, University of Montreal Health Center, Montreal, QC, Canada.
authors.forename: Malek
authors.initials: M
authors.lastname: Meskawi
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.|Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Division of Oncology, Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy.|Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Nicola
authors.initials: N
authors.lastname: Fossati
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.|Division of Oncology, Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Dell'Oglio
authors.affiliation: Division of Oncology, Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Capitanio
authors.affiliation: Division of Oncology, Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
authors.affiliation: Department of Urology, Medical University of Vienna, Vienna, Austria.
authors.forename: Shahrokh F
authors.initials: SF
authors.lastname: Shariat
authors.affiliation: Division of Oncology, Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, QC, Canada.|Department of Urology, University of Montreal Health Center, Montreal, QC, Canada.
authors.forename: Pierre I
authors.initials: PI
authors.lastname: Karakiewicz
mesh_terms: D055011:Ablation Techniques; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000401:mortality* / Q000628:therapy*; D008297:Male; D009392:Nephrectomy / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D057832:Watchful Waiting
keywords: elderly patients; kidney cancer; local tumour ablation; non-surgical management; observation; oncological outcomes