Abstract Background: Oncologists are often asked to provide information about expected survival times for patients with metastatic breast cancer (MBC). We have previously demonstrated that using estimates of best-case, typical and worst-case scenarios for survival to explain life expectancy conveys more meaning and hope than simply providing single point estimates of the median overall survival (OS). Our aim was to assess whether using simple multiples of the median could accurately assess scenarios for survival for patients with estrogen receptor (ER) positive, MBC starting endocrine therapy (ET) using simple multiples of the median. Methods: We systematically searched for randomised trials of ET for ER positive MBC. We then recorded the following percentiles (representative scenarios) from the OS curve of each trial using UN-SCAN-IT® graph digitising software: 90th (worst-case), 75th (lower-typical), 50th (median) 25th (upper-typical), and 10th (best-case). We assessed the accuracy of estimating these percentiles for each OS curve by multiplying the median OS by four simple multiples: 0.25 (to estimate the 90th percentile), 0.5 (75th), 2 (25th) and 3 (10th). Estimates were deemed accurate if within 0.75 -1.33 times the actual value. Results: We identified 24 trials with 10,068 patients. The median OS (interquartile range [IQR]) was: 61.3 months (53.4-64.8) for first-line ET with cyclin-dependant kinase 4/6 inhibitors (CDK4/6i) (4 treatment groups); 42.6 months (40.9-50.4) for first-line ET alone (23 treatment groups) and 29.2 months (24.8-33.4) for subsequent line ET (21 treatment groups). The median OS (IQR) for each scenario for first-line ET with CDK4/6i was: worst-case 17.4 months (13.8-20.7); lower-typical 32.5 months (29.3-34.9); upper-typical and best-case percentiles were not available. Simple multiples of the median OS accurately estimated the 90th percentile in 79%; 75th percentile in 93%; and 25th percentile in 76% of curves. The 10th percentile was only available for four OS curves and could not be accurately assessed. Conclusion: Using simple multiples of the median OS to estimate and explain survival times to patients with MBC starting ET, is accurate and meaningful. Longer follow-up of trials is required to help clinician’s estimate the best-case scenario for these patients. Citation Format: Andrew O. Parsonson, Sunit Sarkar, Lauren Brown, Belinda Kiely, Anuradha Vasista. Going beyond the median: Estimating survival times for patients with hormone receptor positive, metastatic breast cancer commencing endocrine therapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-01-10.