Assessing treatment patterns and outcomes among patients (pts) with metastatic renal cell carcinoma (mRCC): A British Columbia (BC) population-based analysis.

e16544 Background: Current first-line treatments for mRCC include immune check point inhibitors (IO) and tyrosine kinase inhibitors (TKIs). There is limited data on attrition rate between lines of therapy and clinical outcomes in relation to the institutional volume and/or hospital setting. Objective: To analyze treatment patterns, attrition rate and clinical outcomes in mRCC pts following first-line therapy in high vs. lower volume or community setting within BC. BC Cancer currently operates six regional cancer centres providing care for pts across BC. Methods: BC Cancer’s centralized pharmacy data were screened to identify 547 mRCC pts treated with first-line IO combinations or TKIs from May 2019 to December 2024. Patient charts were reviewed for baseline characteristics, relevant treatment data, reasons for treatment choices, and outcomes. Treatments received in each line of therapy and attrition rate were tabulated using frequencies and percentages. Results: In the first 327 pts, median age was 65, with 79.2% male. 86 percent of pts received first-line IO combinations (193 IO-IO, 103 IO+TKI). 60 pts have not yet progressed on first line therapy. 76% of pts treated at the highest volume centre received second-line therapy, compared with 55% of pts treated at other regional centres and 48% of pts treated in the community. After first line IO-IO, 28% of pts treated in the highest volume centre had third-line therapy versus 25% of pts treated at other regional centres and only 6% in the community. Following first-line IO-TKI, 23% of pts from the highest volume centre had third-line therapy versus only 14% at the other regional centres and in the community. Due to the lack of funding for third-line therapy after IO/TKI start in BC, assessment of attrition rate to third-line therapy has to be interpreted with caution. The most common therapy in subsequent lines included TKI monotherapy. Conclusions: In mRCC pts treated with first-line IO combinations and TKIs, the most prevalent subsequent regimens are TKI-based therapies. The attrition rate with each additional line of therapy remains substantial. Lower attrition rates were observed among pts treated in high-volume specialized settings. These findings reflect the increasing complexity of RCC management and emphasizes the need to manage these pts in or in cooperation with specialized, high-volume centers within a multidisciplinary setting.