Objective: To gain information regarding long-term follow-up in patients with synchronous bilateral solid renal neoplasms in whom renal-preserving surgery is imperative. Patients and Methods: We examined, our surgical experience and the survival outcome, as evaluated by Kaplan-Meier and log-rank analysis, of 94 patients (64 men and 30 women) who presented to the Mayo Clinic in Rochester, Minn, from 1973 to 1998 with bilateral synchronous solid renal neoplasms in the absence of von Hippel-Lindau disease. Follow-up of these patients ranged from 1 to 25 years, with a mean of 5.86 years and a median of 4.18 years. Tumors were staged according to the TNM classification. Pathologic staging and grading were usually performed on the kidney with the most extensive cancer. The Cox proportional hazards model was used to assess the relationship of grade (1-4), tumor size, and enucleation as opposed to extended (1 cm) partial nephrectomy on overall, cancer-specific, local recurrence-free, and metastasis-free survival. Results: Seventy-one patients (76%) had bilateral synchronous renal cell carcinoma, and 14 patients (15%) had a unilateral renal cell carcinoma with a contralateral benign solid neoplasm. Nine patients (10%) had bilateral benign solid lesions. Sixty-six patients (70%) underwent a single procedure, whereas 28 (30 %) underwent staged surgical procedures. Fifty-one patients (54%) are alive, and 43 (46%) have died. Twenty patients (21%) died of metastatic disease, and 5 (5%) had a local recurrence. Cancer-specific survival of the 85 patients with at least 1 renal cell carcinoma still under observation was 81% (±4.9% SE) and 59% (±8.1% SE) at 5 and 10 years, respectively, and survival to local recurrence was 96% (±2.6% SE) at 5 years and 93% (±3.7% SE) at 10 years with 14 patients still under observation. Grade 3 was a statistically significant factor for metastasis (P<.001). A significant difference in metastasis-free survival and cancer-specific survival was noted dependent on pathologic T stage (P<.001 and P=.02, respectively), with patients with local pT3 disease having a higher rate of metastasis and cancer-specific death. Multivariate analysis revealed that tumor grade was associated with metastasis-free survival (P=.002) and tumor size with cancer-specific survival (P=.04). There was no statistical significance on survival outcome end points according to procedure performed, ie, enucleation vs extended partial nephrectomy. Conclusion: Long-term results of renal-preserving procedures for a series of patients with bilateral solid renal neoplasms indicate that grade, stage, and tumor size are significant predictors of outcome. Mean follow-up of over 5 years supports nephron-sparing techniques in selected patients because local recurrence was infrequent compared with distant metastasis.
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