Pattern of presentation of brain metastases (BM) in metastatic renal cell cancer (mRCC) patients (pts) treated with targeted therapies (TT): Implications for screening practice.

Abstract

Background: BM develop in 7-15% of patients with mRCC. The utility of screening for BM in mRCC is unknown and clinical practice varies. Identification of the timing of presentation of BM may optimise screening strategies for early BM detection. Method(s): Pts with mRCC from 5 Australian institutions treated with anti- VEGF or mTOR inhibitor targeted therapy (TT) and a diagnosis (dx) of BM were evaluated. The timing of dx of BM, clinicopathologic features, systemic and central nervous system (CNS) treatment were assessed. Prevalence data of BM in pts with mRCC treated with TT was evaluable from 2 institutions. A survey of Australian genito-urinary oncologists was conducted to evaluate current CNS screening practice. Result(s): From 2005 to 2014, 51 pts with mRCC had received TT prior/ subsequently to dx of BM (BM-TT). Median age was 57 yrs, 80% had clear cell histology and 82% had symptoms at dx of BM. 27% were dx with mRCC, observed, then dx with BM prior to TT, while 25% were dx with BM at initial dx of mRCC. After initiation of TT, 47% (24/51) developed BM. This occurred at a median of 19.9 months following mRCC dx and 11.2 months after commencing TT. BM were dx during 1st line TT in 71% (17/24). For the BM-TT group, median survival from diagnosis of stage IV disease (mRCC-OS) was 27.6 months (95% Confidence Interval (CI) 18.2 to 42.6) and from dx BM (BM-OS) was 8.6 months (95% CI 5.3 to 15.6) respectively. In two of the five institutions a total of 201 patients with mRCC were treated with TT and the prevalence of BM was 33/201 (17%). mRCC-OS for the pts without BM who were treated with TT was similar to the BM-TT group at 28.8 months (95% CI 21.4 to 45.5; p = 0.53). When surveyed, 18/40 practicing oncologists (45%) responded, with only 5 (28%) routinely using CNS surveillance. Conclusion(s): 47% of mRCC-BM pts present after commencing TT, with the majority diagnosed during first line TT. Interestingly, mRCC pts with BM treated with TT had similar OS to those without BM. CNS surveillance imaging is not routinely performed in clinical practice in Australia and may not impact OS.