title: Diabetes mellitus with obesity is a predictor of recurrence in patients with non-metastatic renal cell carcinoma.
abstract: OBJECTIVE
  To investigate the associations of diabetes mellitus with recurrence and prognosis after surgery for non-metastatic renal cell carcinoma and the effect modification of obesity on the above relationships.
  
  
  METHODS
  We retrospectively evaluated 543 patients with non-metastatic renal cell carcinoma (pT1-4N0M0) who underwent radical or partial nephrectomy. The association of diabetes mellitus with recurrence was analyzed using the Kaplan-Meier method and the Cox regression model. We also examined whether the above relationships were modified by obesity using subgroup analysis and tests of interaction. For subgroup analysis, the body mass index was categorized as non-obese (<25 kg/m(2)) and obese (≥25 kg/m(2)).
  
  
  RESULTS
  Eighty-two patients (15.1%) had a history of diabetes mellitus. During the mean follow-up of 66.7 months, 68 patients (12.5%) developed recurrence. Although the body mass index was not associated with recurrence, diabetes mellitus was an independent predictor of recurrence in multivariate analysis (hazard ratio 2.43, P = 0.003), along with tumor diameter, grade and pathological T stage. In further subgroup analysis, the same relationship between diabetes mellitus and recurrence was clearly shown in the obese group (hazard ratio 4.07, P = 0.010), but not in the non-obese group (hazard ratio 1.95, P = 0.125). At the same time, obesity modified the effect of diabetes mellitus on recurrence with a trend (P-interaction = 0.086). In the obese group, 5-year recurrence-free survival rates were 75.3 and 91.9% for diabetes mellitus and non-diabetes mellitus patients, respectively (P < 0.001). Restricting analyses to patients with clear cell type histology did not materially change these results.
  
  
  CONCLUSIONS
  Diabetes mellitus is a predictor of recurrence following surgery for non-metastatic renal cell carcinoma, especially in obese patients.
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukushima
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Masuda
authors.forename: Minato
authors.initials: M
authors.lastname: Yokoyama
authors.forename: Manabu
authors.initials: M
authors.lastname: Tatokoro
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yoshida
authors.forename: Junichiro
authors.initials: J
authors.lastname: Ishioka
authors.forename: Yoh
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: Noboru
authors.initials: N
authors.lastname: Numao
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Koga
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Saito
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fujii
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kihara
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000150:complications / Q000453:epidemiology* / Q000601:surgery; D048909:Diabetes Complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000150:complications / Q000453:epidemiology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000209:etiology; D009367:Neoplasm Staging; D009392:Nephrectomy / Q000379:methods; D009765:Obesity / Q000150:complications*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors
keywords: diabetes mellitus; obesity; recurrence; renal cell carcinoma