e16080 Background: Renal cell carcinoma (RCC) is characterized by a propensity for extension into the renal vein and inferior vena cava (IVC), and affected patients have a poor prognosis. BAP1 mutation, which occurs in about 15% of patients with clear cell RCC (ccRCC), also predicts a poor prognosis. The aim of this study was to elucidate the association between BAP1 expression and clinicopathologic outcomes in patients with ccRCC with an IVC tumor thrombus. Methods: Thirty-nine patients with ccRCC with an IVC tumor thrombus who underwent radical nephrectomy and tumor thrombectomy at our institution from 1999 to 2010 were retrospectively evaluated. Immunohistochemical analyses were performed for the expression of BAP1, and the associations between the expression of BAP1 and clinical outcomes were assessed. Survival analyses were performed using the Kaplan–Meier method and log-rank test. Multivariate analyses of the associations between overall survival (OS) and clinical variables were performed using a Cox proportional hazard model. For all analyses, P < 0.05 was considered statistically significant. Results: The median follow-up time was 58.8 months (range, 2–130 months). The median age was 66 years (range, 37–80 years). Four patients (10.3%) had lung metastasis at the initial diagnosis. The primary tumor was right-sided in 27 (69.2%) patients and left-sided in 12 (30.8%). The IVC tumor thrombus extended above and below the diaphragm in 11 (28.2%) and 28 (71.8%) patients, respectively. The KPS score was > 80 in 23 patients (59.0%). BAP1 expression was positive in 26 (67.0%) cases and negative in 13 (33.0%). BAP1-negative tumors were associated with a significantly shorter OS than BAP1-positive tumors (median OS, 42.0 vs. 81.5 months, respectively; P = 0.019). The median disease-free survival in BAP1-negative and -positive tumors was 10.0 and 19.0 months, respectively (P = 0.019). Multivariate analysis showed that only a BAP1-negative status was significantly associated with shorter OS (P = 0.026). Conclusions: A BAP1-negative tumor status was significantly associated with a poor prognosis in patients with ccRCC with an IVC tumor thrombus who underwent radical nephrectomy and tumor thrombectomy.
Multidisciplinary surgical treatment of clear-cell renal carcinoma with inferior vena cava tumor thrombus level III and IV: our experience during the past decade
