title: Does left side renal cell carcinoma (RCC) with renal vein/vena cava thrombus predict worse prognosis than equivalent right side RCC tumor thrombus?
abstract: OBJECTIVE
  To determine whether renal cell carcinoma (RCC) thrombi that reach the vena cava from the left kidney are associated with a greater risk of RCC death than equivalent thrombi from the right kidney.
  
  
  METHODS
  Two hundred and fifty-nine patients treated with radical nephrectomy (1970-2006) for unilateral, sporadic RCC with level 1-4 RCC tumor thrombus were identified. Clinicopathologic features between patients with right-sided (N = 183) and left-sided (N = 76) thrombus were compared utilizing Wilcoxon rank sum and Fisher's exact tests. Associations with RCC-specific death using hazard ratios (HR) and 95 % confidence intervals (CIs) from Cox proportional hazards models were evaluated.
  
  
  RESULTS
  Left-sided RCC patients with thrombus are less likely to be clear cell subtype (85 % vs. 93 %; p = 0.013) and more likely to have nodal involvement (28 % vs. 16 %; p = 0.018) compared to right side RCC patients with thrombus. Overall, there is little evidence that the risk of RCC death is higher for left versus right-sided RCC thrombus (HR = 1.11; 95 % CI 0.81-1.53; p = 0.52). However, among those patients with a thrombus that has reached the vena cava (level III/IV), we observe evidence after multivariate adjustment that the risk of RCC death is higher for left versus right side patients (HR = 2.02; 95 % CI 0.91-4.47; p = 0.08).
  
  
  CONCLUSIONS
  Left side RCC with tumor thrombus is not associated with worse prognosis than right-sided tumors (all tumor thrombi levels). Our data suggest that among RCC patients with advanced tumor thrombi (level III/IV), a left side thrombus may be associated with worse prognosis compared to a right side thrombus.
authors.affiliation: Department of Urology, Mayo Medical School and Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL 32224, USA. thiel.david@mayo.edu
authors.forename: David D
authors.initials: DD
authors.lastname: Thiel
authors.forename: Christine M
authors.initials: CM
authors.lastname: Lohse
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Arnold
authors.forename: John C
authors.initials: JC
authors.lastname: Cheville
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Parker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000150:complications* / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000150:complications* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012082:Renal Veins; D012189:Retrospective Studies; D013997:Time Factors; D014684:Venae Cavae; D020246:Venous Thrombosis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*