title: The effect of bilaterality, pathological features and surgical outcome in nonhereditary renal cell carcinoma.
abstract: OBJECTIVE
  We evaluated the differences in cancer specific, distant metastasis-free and local recurrence-free survival in patients with sporadic subtype concordant bilateral synchronous renal cell carcinoma and those with unilateral renal cell carcinoma, controlling for the covariates of subtype, stage, tumor size, grade and necrosis. We also analyzed early surgical complications and long-term renal function in patients who underwent staged surgery and those who underwent a single operation for bilateral synchronous renal cell carcinoma.
  
  
  METHODS
  We retrospectively evaluated 44 patients with sporadic subtype concordant bilateral synchronous renal cell carcinoma treated at our institution between 1970 and 1998. There were 32 patients with bilateral synchronous clear cell renal cell carcinoma and 12 with bilateral synchronous papillary renal cell carcinoma. These patients were compared with 1,714 with sporadic unilateral clear cell renal cell carcinoma and 322 with sporadic unilateral papillary renal cell carcinoma treated with partial or radical nephrectomy during that period. Outcomes were estimated using the Kaplan-Meier method and Cox proportional hazard models were used to test associations with outcome.
  
  
  RESULTS
  Clinicopathological features were similar for patients with bilateral synchronous and unilateral renal cell carcinoma except for the incidence of multifocality, which was 28% and 33% for bilateral synchronous clear cell and papillary renal cell carcinoma compared with 2% and 7% for unilateral clear cell and papillary renal cell carcinoma, respectively. Cancer specific survival and distant metastasis-free survival in patients with bilateral synchronous disease was similar to that in those with unilateral disease when controlling for subtype, stage, tumor size, grade and tumor necrosis. However, patients with bilateral synchronous clear cell renal cell carcinoma were more likely to experience local recurrence even after controlling for these covariates. The majority of patients (84%) with bilateral synchronous disease underwent bilateral surgery at a single operation. The incidence of early surgical complications was low, in that only 2 patients had urinary extravasation, 3 had acute renal failure and 1 was ultimately rendered anephric and required hemodialysis.
  
  
  CONCLUSIONS
  The incidence of multifocality was greater in patients with bilateral synchronous renal cell carcinoma than in those with unilateral renal cell carcinoma. There were no statistically significant differences in cancer specific and distant metastasis-free survival in patients with bilateral synchronous renal cell carcinoma and unilateral renal cell carcinoma of the same histological subtype. These results suggest that subtype concordant bilateral renal cell carcinoma is a result of multiple de novo primary events rather than primary renal cell carcinoma with contralateral renal metastasis. A surgical approach is appropriate for bilateral synchronous renal cell carcinoma and most cases can be approached at a single surgical procedure with acceptable morbidity.
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Blute
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Itano
authors.forename: John C
authors.initials: JC
authors.lastname: Cheville
authors.forename: Amy L
authors.initials: AL
authors.lastname: Weaver
authors.forename: Christine M
authors.initials: CM
authors.lastname: Lohse
authors.forename: Horst
authors.initials: H
authors.lastname: Zincke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D009336:Necrosis; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D009392:Nephrectomy; D015996:Survival Rate; D016896:Treatment Outcome