Background: Cabo is approved for the treatment for mRCC. We investigated the association of sites of mets and clinical outcomes (CO) in mRCC pts treated with cabo. Methods: We performed a retrospective analysis of 65 mRCC pts treated with cabo at Winship Cancer Institute from 2016 to 2018. Overall survival (OS) and progression-free survival (PFS) were measured from first dose of cabo to date of death and clinical or radiographic progression, respectively. Objective response was defined as a complete response (CR) or partial response (PR). Sites of mets were obtained from radiology and clinic notes and included bone, lymph node, brain, lung, and liver. Univariate analysis (UVA) and multivariate analysis (MVA) was performed using Cox proportional hazard or logistic regression model. Results: The median age was 63 years and most (68%) were males. The majority of pts (79%) had ccRCC and 48% received at least 2 prior systemic treatments. The distribution of mets were: bone (42%), lymph node (69%), brain (6%), lung (83%), and liver (40%). The UVA and MVA of association between sites of mets and CO are presented in Table. Pts with bone mets had significantly longer OS in UVA and trended towards longer OS and PFS in MVA compared to pts without bone mets. Conclusions: Bone mets may be a prognostic factor for improved CO in mRCC pts treated with cabo. Larger studies are needed to validate the results of this study. UVA and MVA† of bone metastases and CO.

†Multivariable model controlled for gender, race, IMDC risk group, number of distant metastases, age, and ccRCC *Objective response: probability of PR+CR were modeled. **Odds ratio ***statistical significance at alpha < 0.05.