Open partial nephrectomy for entirely intraparenchymal tumors: a matched case-control study of oncologic outcome and complication rate

PURPOSE: To compare the oncologic and clinical outcomes for open partial nephrectomy (OPN) performed in patients with entirely intraparenchymal tumors versus case-matched controls, with exophytic lesions. MATERIAL AND METHODS: Patients having undergone OPN between 2007 and 2012 were investigated. Exclusion criteria included patients with a benign tumor, advanced malignancy, malignancies other than renal cell carcinoma, end-stage renal failure, or 3 or more co-existing chronic diseases. Individuals with tumors that were invisible at the renal surface were identified, and then matched with 2 controls chosen for tumor size, pathology, age, follow-up period, and presence of a solitary kidney. Oncological status, perioperative, and postoperative data were collected and compared between groups. RESULTS: 17 individuals with entirely endophytic RCC tumors and available oncologic status were identified. For five patients, only one suitable control could be identified, bringing the control group number to 29. All tumors were clear cell carcinomas staged at pT1a. Median tumor size was 25mm for endophytic lesions, and 27mm for exophytic masses (P=0.32). The operative period was extended by 20 minutes for intrarenal tumors (P=0.03), with one case of a positive surgical margin in each group (P=0.7). There were no significant differences in perioperative or postoperative complications. Median follow-up was 47 and 43 months for patients with endophytic and exophytic tumors respectively. Disease recurrence was recorded in one patient after endophytic tumor resection, and in four controls (P=0.4). CONCLUSIONS: OPN shows equivalent safety and efficacy for both intrarenal RCC tumors and exophytic tumors of the same size and type.