Multiple Tumor Excisions in Ipsilateral Kidney Increase Complications After Partial Nephrectomy.

INTRODUCTION: The surgical morbidity of ipsilateral synchronous multifocality (ISM) is poorly characterized. We assessed the impact of ISM on complications after robotic partial nephrectomy (RPN).

PATIENTS AND METHODS: We abstracted data on RPN cases performed between 2006 and 2015 at our institution. Multifocal disease was characterized by >1 renal mass on preoperative imaging or >1 mass excision during RPN. The primary outcome was the rate of overall postoperative complications. The association between multifocality and complications was evaluated using univariate and multivariable analyses.

RESULTS: Of 1121 cases, 59 (5.3%) had >1 ipsilateral renal mass and 50 (4.5%) required >1 excision. The overall complication rate was 20.3% (230/1121). The radiographic number of ipsilateral renal masses was not significantly associated with complications (20.2% for 1 mass vs. 25.4% for >1 mass, p = 0.338). However, the actual number of ipsilateral mass excisions performed during RPN was significantly associated with complications (20.2% for ≤2 excisions vs. 42.9% for >2 excisions, p = 0.037). Major complications were higher (14.3% vs. 5.3%) for >2 versus ≤2 excision(s), but this difference was not significant (p = 0.174). The most common complications associated with multiple excisions were transfusion, urine leak, arrhythmia, venous thromboembolism, and ileus. On multivariable analysis, number of excisions independently predicted complications (OR 3.1, 95% CI 1.03-9.33, p = 0.041). Other independent predictors of complications included age, race, Charlson score, body mass index, RENAL score, and surgeon experience.

CONCLUSIONS: ISM requiring ≥2 excisions is associated with increased morbidity after RPN. Pending external validation, this information may facilitate clinical decision-making and preoperative patient counseling.