Predictive factors for recurrence after partial nephrectomy for clinical T1 renal cell carcinoma: a retrospective study of 1227 cases from a single institution.

Identifying the predictive factors for tumor recurrence after partial nephrectomy (PN) is useful to determine patients who require careful observation after surgery. Therefore, we investigated recurrence after partial nephrectomy (PN) in patients with clinical T1 renal cell carcinoma (RCC) and analyzed predictive factors for recurrence-free survival (RFS). This study included 1227 patients who underwent PN for clinical T1 RCC and retrospectively investigated patients' characteristics and tumor factors that are associated with tumor recurrence. The median patient age was 59 years, and the median tumor size was 30 mm. Although 970 (74%) and 319 (26%) patients had clinical T1a and T1b RCCs, respectively, 20 patients (1.6%) were upstaged to pathological T3a. A positive surgical margin was found in 19 (1.5%) patients. The distribution of surgical approaches was open surgery in 428 (35%) patients and minimally invasive surgery in 799 (65%) patients. With a median follow-up of 35 months (Interquartile range 19-55 months), 39 (3.2%) patients, including ten with local recurrence, five with recurrence in the ipsilateral kidney, and 28 with other organs or lymph-nude, developed recurrence. The 3-year RFS was 99%, and the median recurrence time from PN was 19 months (interquartile range: 11-37 months). Multivariate analysis identified high grade tumor and upstaging to pT3a as significant predictors for worse RFS. Patients with high grade tumors and tumors upstaged to pT3 had a high risk of worse RFS, which suggested that careful monitoring is required for such patients after PN, even if a good prognosis is achieved in patients with clinical T1 RCC.