Bilateral renal cancers: oncological and functional outcomes.

Purpose: The authors assessed the characteristics of bilateral renal cancers.
Methods: From January 1995 to January 2015, 65 patients underwent surgery for bilateral renal cancers. Thirty-four of the patients had 36 synchronous tumors, while the remaining 29 had metachronous tumors. The mean age of the patients was 60 ± 11 years. There were 22 females and 43 males. In all cases, bilateral partial nephrectomies or unilateral nephrectomy and contralateral nephron-sparing surgery were performed.
Results: The mean sizes of the synchronous tumors were 5.0 ± 2.7 and 4.7 ± 3.0 cm at the first and the second operations, respectively. The average diameters of the metachronous carcinomas were 6.6 ± 3.0 and 3.1 ± 1.6 cm at the initial and the second surgeries, respectively. Histologic concordance was 91.1 % in the synchronous and 96.5 % in the metachronous tumors. The mean postoperative creatinine levels increased by 116 %, while the GFR decreased by 44.8 % in synchronous tumors at the second operation. The mean postoperative creatinine levels increased by 42 %, while the GFR decreased by 30.4 % in metachronous carcinomas at the second operation. The mean follow-up time was 4.8 ± 3.7 years. During this period, distant metastases occurred in two patients with synchronous tumors and in six cases with metachronous tumors. Local recurrences were detected in one case of synchronous tumor and in four patients with metachronous carcinomas. The 5-year overall and tumor-specific survivals were 53 and 80 %, respectively.
Conclusions: In patients with bilateral renal carcinomas, the histologic concordance was 93.6 %. The bilateral partial nephrectomies or unilateral nephrectomy and contralateral resection provided acceptable oncological and functional outcomes.