824PDIFFERENCES BETWEEN PATIENTS (PTS) WITH METASTATIC RENAL CELL CARCINOMA (MRCC) WHO DEVELOP BRAIN METASTASES (BM) VERSUS THOSE WHO DO NOT

Abstract Aim: Brain imaging is not performed as routine follow-up in mRCC, and BM are commonly discovered mainly in pts reporting symptoms. The identification of differences between pts who develop BM vs those who do not, may allow us to define a subgroup more at risk. Methods: mRCC pts enrolled in clinical trials from 01/05 to 11/13 at Gustave Roussy with brain scan evaluation without neurological symptoms or for the onset of symptoms were evaluated. We compared the clinical and pathological characteristics, including location and number of metastatic sites in pts who develop BM during the course of the disease (BM+) and those who did not (BM-). Results: 234 pts were included with a median follow-up of 11 years (95%CI;10-12). Median age was 56 years, 74% pts were male, 89% with clear-cell histology, 9% with sarcomatoid features, 67% with intermediate Heng risk group. N = 44 pts developed BM either at diagnosis of mRCC (n = 8) or during the follow-up. There was no difference in prognostic groups between BM+ and BM-. The median number of metastatic sites at the time of first line treatment was 3 vs 2 (p < 0.001). Incidence of lung and adrenal gland metastases at baseline was higher in BM+ group (84 and 67%) vs BM- (67 and 13%) (p = 0.02 and 0.04). Interestingly, PFS to first line as well as OS from the start of first line were not different between BM+ (9.5 and 23 months) and BM- pts (9.3 and 31 months respectively). Conclusions: Classical prognostic factors as well as efficacy of first-line therapy do not seem to be different in pts who will develop BM. In this preliminary analysis, pts with lung and/or adrenal gland metastases have a higher risk of developing BM. In addition, the number of metastatic sites is higher in BM+ pts. Although this finding may have several biases, it warrants to be validated in larger and different cohorts of mRCC pts. Disclosure: B. Escudier: Honoraire: Novartis, Pfizer, GSK, Bayer. All other authors have declared no conflicts of interest.