title: Predictors and mechanisms of oncological failure following nephron-sparing surgery for renal cancer.
abstract: BACKGROUND
  One of the major concerns in performing nephron-sparing surgery (NSS) for renal cell carcinoma (RCC) is the risk of tumor recurrence.
  
  
  OBJECTIVE
  To assess the rate, predictors and mechanisms of oncological failure in patients after NSS for renal cancer.
  
  
  METHODS
  Between 1993 and 2008 NSS was performed in 229 patients via flank incision. Only patients without metastases at diagnosis and minimal 12 months follow-up were included in the outcome analysis.
  
  
  RESULTS
  During a mean follow-up of 45 +/- 34 months (range 6-168 months) tumor recurrence was observed in 13 patients (5.6%). Mean follow-up time for detection of oncological failure was 51 months (range 6-132 months). All patients with oncological failure were males, with a mean age of 61 years (median 58, range 51-74 years). The average size of the enucleated lesion was 5 cm (range 4-7 cm). Intraoperative frozen sections as well as postoperative final pathological examination of the surgical margins were negative in all recurrent cases. Mechanisms of recurrence were distant metastases (n=4), surgical scar implantation (n=2), perirenal fat recurrence (n=2), local renal recurrence at the surgical site (n=1), and new renal lesions (n=4). Predictors of oncological failure included warm ischemia time (P = 0.058), tumor size (P = 0.001), tumor location (central versus peripheral) (P = 0.015), and multifocality (P = 0.001).
  
  
  CONCLUSIONS
  Distant dissemination, seeding during surgery, residual disease and new growth are the mechanisms responsible for cancer relapse. Large central lesions, long warm ischemia time and multifocality were significant predictors of oncological failure.
authors: Department of Urology, Bnai Zion Medical Center, affiliated with Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors: Sarel
authors: S
authors: Halachmi
authors: Boaz
authors: B
authors: Moskovitz
authors: Roi
authors: R
authors: Farfara
authors: Ofer
authors: O
authors: Nativ