Management of small solitary unilateral renal cell carcinomas: impact of central versus peripheral tumor location.

PURPOSE: Recent studies have suggested that nephron sparing surgery and radical nephrectomy provide equally effective therapy for patients with small (less than 4 cm.), solitary, unilateral renal cell carcinoma and a normal contralateral kidney. We evaluate whether central versus peripheral tumor location in the involved kidney is a significant factor affecting treatment outcome in these patients.
MATERIALS AND METHODS: Patients with a single, small (less than 4 cm.), localized, unilateral, sporadic renal cell carcinoma were identified from our institutional registry. From 1972 to 1995, 145 patients fulfilling these criteria were treated with either nephron sparing surgery (86) or radical nephrectomy (59). Mean postoperative followup was 51.4 months. Tumor characteristics and outcome measures were analyzed in 35 patients with central versus 110 with peripheral renal cell carcinomas according to the type of treatment.
RESULTS: We detected 27 central (77%) and 75 peripheral renal cell carcinomas (68%) incidentally. Nephron sparing surgery was used to treat 19 central (54%) and 67 peripheral (61%) carcinomas. Pathological tumor stage was T1 to 2 in 33 central (94%) and 91 peripheral (82%) cases. Grade 1 to 2 renal cell carcinoma was present in 28 central (80%) and 85 peripheral (77%) tumors. Postoperatively, when comparing patients with central versus peripheral renal cell carcinomas there was no difference in 5-year cancer specific survival (100 versus 97%), tumor recurrence (5.7 versus 4.5%) or renal function (mean serum creatinine 1.43 mg./dl. in both groups). These parameters were also equivalent in patients treated with nephron sparing surgery versus radical nephrectomy overall and within the central versus peripheral renal cell carcinoma subgroups. Nephron sparing surgery was technically more complicated in central renal cell carcinomas with a longer renal ischemia time (55 versus 34 minutes, p <0.05) and more frequent entry of the collecting system (74 versus 47%, p <0.05) compared to peripheral carcinomas. Two patients (2.3%, 1 central, 1 peripheral) had local tumor recurrence after nephron sparing surgery.
CONCLUSIONS: There were no significant biological differences between centrally versus peripherally located small solitary unilateral renal cell carcinomas. Nephron sparing surgery is technically more demanding in patients with central tumors. However, treatment with nephron sparing surgery or radical nephrectomy is equally effective regardless of tumor location.