title: Metachronous bilateral renal cell carcinoma with an interval of more than 10 years.
abstract: OBJECTIVE
  Renal cell carcinoma (RCC) is notorious for late recurrence. However, little is known about late recurrence in the contralateral kidney, that is, metachronous bilateral RCC after a long interval. Unlike other recurrent sites, cancer in the contralateral kidney may be a metastatic or a new and independent lesion. The clinical characteristics of such cases formed the basis of this study.
  
  
  METHODS
  Thirteen well-described cases in the English and Japanese literature were reviewed. Each clinical parameter, such as age, sex, size and number of the tumor(s), and interval, was divided into two groups and compared using the log rank test.
  
  
  RESULTS
  The clinical characteristics of these cases were similar to those of sporadic RCC cases, and no specific clinical or pathological features in these cases were found. As to the prognosis, among clinical parameters, cases with multiple second tumors had a favorable outcome compared with cases with a single second tumor.
  
  
  CONCLUSIONS
  Multiple second tumors may be suggestive of metastasis from the first tumor. The favorable outcome in this group reflects the gentle biological nature of these slow-growing tumors that had taken a long time to become clinically obvious. Because of the limited number of cases in this study, further investigation will be needed.
authors.affiliation: Department of Urology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. kume@kuc.biglobe.ne.jp
authors.forename: Haruki
authors.initials: H
authors.lastname: Kume
authors.forename: Shinji
authors.initials: S
authors.lastname: Teramoto
authors.forename: Tadaichi
authors.initials: T
authors.lastname: Kitamura
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D018570:Risk Assessment; D016019:Survival Analysis; D013997:Time Factors