Objectives: To assess the clinical characteristics, pathology, and long-term follow-up of patients with bilateral nonfamilial renal tumors (BNFRTs).
Methods: Patients with BNFRTs and unilateral tumors were identified from a prospective surgery database. The Mann-Whitney U test, Cox proportional hazards regression analysis, and the log-rank test were used to compare groups.
Results: From a database of 1082 patients with nonmetastatic renal tumors, 46 were identified with BNFRTs (4.25%). Thirty-three had synchronous tumors and 13 had asynchronous tumors. The median patient age of BNFRT patients was 61 years. Of the 92 renal tumors in these 46 patients, 42% were managed with radical nephrectomy (RN) and 58% with partial nephrectomy (PN); 7 underwent bilateral PN. The tumors were conventional clear cell carcinoma in 66% (n = 61), papillary carcinoma in 14% (n = 13), and the remaining 20% were of varied histologic origin. A 76.2% concordance was noted between the histologic subtypes of the two renal tumors in each patient. Median follow-up was 74 months. Thirty-three patients (72%) were disease-free and 7 patients had recurrence (2 local, 5 metastatic). Compared with patients having unilateral disease, BNFRT patients had an equivalent disease-free survival (DFS) (bilateral: 3-year DFS 90%, 5-year DFS 83%; unilateral: 3-year DFS 92%, 5-year DFS 82% [P = 0.449]). No difference in DFS was observed between synchronous and asynchronous tumors.
Conclusions: BNFRTs were present in 4.25% of patients with sporadic renal tumors. Conventional clear cell histology was the most common histologic subtype; concordance among tumors was found to be 76%. DFS rates comparable to those of unilateral tumors can be obtained by using combinations of PN and RN.